Littérature scientifique sur le sujet « U-ore deposit »
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Articles de revues sur le sujet "U-ore deposit"
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Bushuev, Yackov Yur’evich, et Vasilii Ivanovich Leontev. « The Geochemical Features of Epithermal Gold-Telluride (Au-Te) Ores of the Podgolechnoe Deposit (Central Aldan Ore District, Yakutia) ». Key Engineering Materials 743 (juillet 2017) : 422–25. http://dx.doi.org/10.4028/www.scientific.net/kem.743.422.
Texte intégralRésumé :
The Central Aldan ore district is a geologically unique area, representing the conjunction zone of the ancient structures of the Archean–Proterozoic crystalline shield, overlain by the Vendian–Cambrian sedimentary cover. The latter was formed in the Mesozoic by intensive alkaline magmatism. Within the Central Aldan ore district, most of primary gold-ore deposits are confined to the sedimentary cover. Until recently it was considered that only ancient complexes in the crystalline basement contain commercial Au-U mineralization. As a result of the geological exploration works over the period of 2003–2006, the Podgolechnoe deposit was discovered. Gold mineralization in this deposit occurs both in rocks of sedimentary cover and crystalline basement. Ore bodies in rocks of the crystalline basement (A-type alkaline deposits) contain epithermal gold-telluride (Au-Te) mineralization, which is new for Central Aldan ore district. This work presents results of the study of geochemical composition of the Podgolechnoe deposit ores and their comparison with typical epithermal gold-ore deposits. In total, 15 samples were studied. The homogeneity of the sample collection, the correlation between Au and other elements, the enrichment coefficients of elements-admixtures, and the REE distribution were analyzed. It was established that gold ores of the Podgolechnoe deposit are geochemically heterogeneous, but, in general, they correspond to the geochemical spectrum characteristic of the gold ores of A-type epithermal deposits. In contrast to Au-U deposits, common in the studied area, ores of the Podgolechnoe deposit show no correlation between gold and uranium.
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Su, Zhi-Kun, Xin-Fu Zhao, Xiao-Chun Li, Mei-Fu Zhou, Allen K. Kennedy, Jian-Wei Zi, Carl Spandler et Yue-Heng Yang. « UNRAVELING MINERALIZATION AND MULTISTAGE HYDROTHERMAL OVERPRINTING HISTORIES BY INTEGRATED IN SITU U-Pb AND Sm-Nd ISOTOPES IN A PALEOPROTEROZOIC BRECCIA-HOSTED IOCG DEPOSIT, SW CHINA ». Economic Geology 116, no 7 (1 novembre 2021) : 1687–710. http://dx.doi.org/10.5382/econgeo.4840.
Texte intégralRésumé :
Abstract Precambrian iron oxide copper-gold (IOCG) deposits are generally encountered with multistage hydrothermal overprints and hence have complex isotopic records. Precise dating of ore-forming and overprinting events and assessment of time-resolved metal sources are fundamental for understanding ore genesis. Here, we quantify the evolution history by integrating in situ U-Pb dating of texturally constrained allanite and Sm-Nd isotope data of ores and major rare earth element (REE) minerals in the breccia-hosted Lanniping Fe-Cu deposit in Kangdian region, southwestern China. The economically mineralized breccia in Lanniping Fe-Cu deposit is characterized by pervasive and texturally destructive replacement of polymictic clasts, including host metasedimentary packages, the intruded dolerite, and pre-ore halokinetic breccia. Ore minerals in cements are mainly composed of magnetite, chalcopyrite, bornite, and variable amounts of REE-rich minerals (e.g., apatite and allanite/epidote). Two types of allanite were identified in ores. Type I prismatic allanite texturally intergrown with magnetite has a SHRIMP U-Pb age of 1728 ± 20 Ma (1σ), which matches a zircon U-Pb age of 1713 ± 14 Ma (2σ) for the dolerite clasts and provides the direct age constraint on the Fe-Cu mineralization event. Type II anhedral allanite shows complex zoning and is spatially associated with, but texturally later than, magnetite, apatite, and chalcopyrite. This type of allanite yields significantly younger SHRIMP dates of 1015 ± 33 (1σ) and 800 ± 16 Ma (1σ) for cores and rims, respectively, which correspond to discrete regional magmatic events and hence record hydrothermal overprint/remobilization events of ore minerals in the deposit. Integrated Sm-Nd isotope compositions of type I allanite, apatite, and whole ores generally align along the reference Sm-Nd isochron of 1728 Ma, further confirming the primary ore formation at ~1.7 Ga. Corresponding εNd(1728 Ma) values ranging from –2.8 to 0.3 are significantly higher than those of the host metasedimentary rocks (–9.5 to –6.2) but comparable to those of contemporaneous igneous intrusions (–0.3 to 5.3) in the region, demonstrating that REE components of the primary ores were dominantly sourced from rocks of mantle-derived affinity. Both cores and rims of the younger type II allanite grains have Nd isotope compositions consistent with the unique time-evolved line of the ~1.7 Ga ores, implying that REEs incorporated into type II allanite were ultimately sourced from the primary ores in this deposit. The combined texture, chemical, U-Pb, and Sm-Nd isotope data thus demonstrate that REE remobilization was localized during post-ore hydrothermal overprint with negligible external inputs of REEs to the primary ores in the Lanniping deposit. In this contribution, we not only date primary ore formation but also recognize several younger allanite generations that record internal metal redistributions in response to post-ore tectonothermal events. Our study highlights the potential of ore-associated REE minerals such as allanite for resolving the age of multiple stages of hydrothermal events in complex ore deposits by ion probe, provided that careful examination of textural and paragenetic relationship of ores is conducted. Our finding of these younger allanite generations also exemplifies the significance of evaluation on time-resolved metal input for better characterizing the evolution history of the IOCG deposits.
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Gongalsky, B. « Deposits of the Udokan-Chineysky ore-magmatic system of Eastern Siberia ». IOP Conference Series : Earth and Environmental Science 962, no 1 (1 janvier 2022) : 012051. http://dx.doi.org/10.1088/1755-1315/962/1/012051.
Texte intégralRésumé :
Abstract The aggregate of ore deposits localized in the Udokan-Chineysky ore district is unique and is the result of multi–stage, polygenetic formation. The deposits of copper and other metals formed at various depths occur within a limited area. The oxide and sulfide ore are spatially associated in the sedimentary rocks pertaining to the Paleoproterozoic Udokan Supergroup and the intrusive mafic–ultramafic rocks of the Chineysky Complex. The granite rocks of the Kodar Complex and gabbro rocks of the Chineysky Complex also date back to Paleoproterozoic. The same age has been established for metasomatic Nb–Ta–Zr–REE–Y and U mineralization in the albitized terrigenous rocks of the Udokan Supergroup (Katugin deposit and Chitkanda prospect) and U–Pd prospects hosted in terrigenous rocks. The U–REE mineralization superposed on the titanomagnetite deposits in the Chineysky pluton has not analogues in the world’s practice. The occurrences of uranium mineralization have been noted in form of pitchblende and U–Th rims around chalcopyrite grains at the Unkur copper deposit hosted in sedimentary rocks. The enrichment in U and Pb has been documented in crosscutting quartz veinlets with bornite mineralization at the Udokan deposit.
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Qiu, Lin-Fei, Yu Wu, Qiong Wang, Lin-Feng Wu, Zhong-Bo He, Song Peng et Yun-Fei Fan. « Metallogenic Mechanism of Typical Carbonate-Hosted Uranium Deposits in Guizhou (China) ». Minerals 12, no 5 (6 mai 2022) : 585. http://dx.doi.org/10.3390/min12050585.
Texte intégralRésumé :
Research on topics such as geological–tectonic evolution, metallogenic models of deposits (gold, mercury, lead, zinc, etc.), and ore-forming fluids’ evolution has been conducted in Guizhou. However, few studies have been conducted on uranium (U) deposits (especially carbonate-hosted U deposits). Moreover, the relationship between hydrocarbon fluids and U-mineralization has not been addressed at all. Typical carbonate-hosted U deposits (including some ore spots) in Guizhou Province have been investigated through close field work, petrography, mineralogical, micro-spectroscopy, organic geochemical and C isotope studies. The central part of the U-ore body is often black (the black alternation zone) at the outcrop, and its sides are gray and gray-brown (the gray alternation zone); the color gradually becomes lighter (black to gray) from the center of the ore body out to the sides. Petrographic observations, microscopic laser Raman spectroscopy, and infrared spectroscopic and scanning electron microscope analyses have indicated that U-minerals (pitchblende and coffinite), pyrite and “black” organic matter (OM) are closely co-dependent, with the OM having the typical characteristics of bitumen. Large light oil fluid inclusions were found in gray alternation rocks (besides the U-ore body) with strong light blue fluorescence properties, indicating that hydrocarbon fluids and U-minerals may came from the same U-bearing hydrocarbon fluids. The values of the 13C isotope value, a biomarker of OM and trace elements, REEs in U-ores, were found to be similar here to those in the local paleo-petroleum reservoir, indicating that the bitumen may originate from the deeply intruding paleo-petroleum reservoir. The precipitation of U is related to the cracking differentiation of hydrocarbon fluids. As result, the carbonate-hosted U-mineralization in Guizhou is neither of a sedimentary diagenesis type, nor of a sedimentary diagenesis superimposed leaching hydrothermal transformation type, as have been described by previous scholars. To be exact, the U deposit is controlled by fault and hydrocarbon fluids, and so it can be defined as a structural hydrocarbon–carbonate-type U deposit. A new U-mineralization model was proposed in this study. Here, U, molybdenum, and other metals were mainly found in the black rocks in the lower stratum (presumably Niutitang Formation), having migrated together with hydrocarbon fluids in the form of tiny mineral inclusions. The hydrocarbon fluids (containing some brine) caused cracking and differentiation upon entering the fracture zone, at which point the ore-forming materials (U, pyrite, and other metals) were released and precipitated.
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Golubev, V. N., N. N. Tarasov, I. V. Chernyshev, A. V. Chugaev, G. V. Ochirova et B. T. Kochkin. « Post-Ore Processes of Uranium Migration in the Sandstone-Hosted Type Deposits : 234U/238U, 238U/235U and U–Pb Systematics of Ores of the Namaru Deposit, Vitim District, Northern Transbaikalia ». Geology of Ore Deposits 63, no 4 (juillet 2021) : 287–99. http://dx.doi.org/10.1134/s1075701521040024.
Texte intégralRésumé :
Abstract To assess the nature of the post-ore behaviour of uranium in the Namaru deposit (Khiagda ore field), U–Pb isotope systems and the isotopic composition of uranium (234U/238U and 238U/235U) were studied. The studied samples represent different ore zones of the deposit and were collected along cross-sections both vertically and horizontally. Wide variations in the isotopic composition of uranium and U–Pb isotopic age have been established. Deviations of the 234U/238U ratio from equilibrium values, which for some samples exceed 50%, along with significant variations in the isotopic age, indicate that permafrost layer, which covered the catchment areas of paleovalleys with meteoric oxygen-containing waters ca. 2.5 Ma ago, did not lead to preserving uranium ores at the deposit. Uranium migration took place during the Quaternary period. The effective combining the U–Pb dating and 234U/238U data in assessing the post-ore redistribution of uranium made it possible to recognize: removal of uranium from some zones of the ore body and its accompanying redeposition in others. Wide variations in the 238U/235U (137.484–137.851) ratios throughout the entire studied cross-sections can be explained by the different locations of samples relatively to the ore deposition front and change in redox conditions as this front advanced. Depletion of the light isotope 235U in the lower zone of the ore body may be associated with the influence of ascending carbonic waters established in the regional basement. The effect of such waters on uranium-bearing rocks causes predominant leaching of light 235U.
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Jiang, Hongjun, Chunsi Yang, Dequan Wang, Hui Zheng, Jie Li et Huayong Chen. « Multiple-Stage Mineralization in the Huayangchuan U−REE−Mo−Cu−Fe Ore Belt of the Qinling Orogen, Central China : Geological and Re−Os Geochronological Constraints ». Journal of Earth Science 33, no 1 (février 2022) : 193–204. http://dx.doi.org/10.1007/s12583-021-1557-1.
Texte intégralRésumé :
AbstractThe Huayangchuan ore belt is located in the western segment of Xiaoqinling Orogen in the southern margin of the North China Craton (NCC), and hosts voluminous magmatism and significant U−REE−Mo−Cu−Fe polymetallic mineralization. However, geochronological framework of the various mineralization phases in this region is poorly understood. Here, we present new Re−Os isochron ages on magnetite from the Caotan Fe deposit (2 675 ± 410 Ma, MSWD = 0.55), and on pyrite from the Jialu REE deposit (2 127 ± 280 Ma, MSWD = 1.9) and Yuejiawa Cu deposit (418 ± 23 Ma, MSWD = 11.5), and Re−Os weighted average model age on pyrite from the Taoyuan Mo−U deposit (235 ± 14 Ma, MSWD = 0.17). These ages, combined with regional geology and mineralization ages from other deposits, suggest that mineralization in the Huayangchuan ore belt lasted from the Neoarchean to the Late Mesozoic. The mineralization corresponds to regional tectono-magmatic events, including the Neoar-chean alkali magmatism (REE mineralization), Paleoproterozoic plagioclase-amphibolite emplacement (Fe mineralization), Paleoproterozoic pegmatite magmatism (U mineralization), Paleozoic Shangdan oceanic slab subduction-related arc magmatism (Cu mineralization), Early Mesozoic Paleo-Tethys Ocean subduction-related arc magmatism (Mo−U mineralization), and Late Mesozoic Paleo-Pacific oceanic plate subduction direction change-related Mo(-Pb) mineralization. We proposed that the Huayang-chuan ore belt has undergone prolonged metallogenic evolution, and the magmatism and associated mineralization were controlled by regional geodynamic events.
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Li, Li, Hai-Li Li, Guo-Guang Wang et Jian-Dong Sun. « Geochronology of the Baishi W-Cu Deposit in Jiangxi Province and Its Geological Significance ». Minerals 12, no 11 (30 octobre 2022) : 1387. http://dx.doi.org/10.3390/min12111387.
Texte intégralRésumé :
The Baishi W-Cu deposit is located in the Nanling metallogenic belt, which is famous for its numerous W deposits and reserves. The formation age of this deposit remains unclear. In order to further infer the formation age of the deposit, this study conducted detailed LA-ICP-MS U-Pb isotopic analyses of zircon and monazite selected from ore-related Baishi granite. The LA-ICP-MS zircon U-Pb weighted average ages of Baishi granite were determined to be 223 ± 2 Ma and 226 ± 1 Ma, and the LA-ICP-MS U-Pb weighted average ages of monazite were determined to be 224 ± 2 Ma and 223 ± 1 Ma. The BSE image of monazite was homogeneous, and the pattern of rare earth elements had an obvious negative Eu anomaly, indicating that monazite was of magmatic origin. Combining the ages of zircon and monazite, this study inferred that Baishi granite and the Baishi W-Cu deposit formed in the Triassic. The determination of the ore-forming event of the Baishi W-Cu deposit provides new data regarding the important Indosinian (Triassic) mineralization events in the Nanling metallogenic belt and suggests that geologists should strengthen the prospecting work of Indosinian tungsten deposits in the Nanling area. In terms of tectonic setting, it was inferred that the Triassic Baishi W-Cu deposit was formed in the extensional environment after intracontinental orogeny.
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Wang, Yongjian, Honghai Fan, Yaqing Pang et Wei Xiao. « Geochemical Characteristics of Chlorite in Xiangshan Uranium Ore Field, South China and Its Exploration Implication ». Minerals 12, no 6 (30 mai 2022) : 693. http://dx.doi.org/10.3390/min12060693.
Texte intégralRésumé :
Chlorite is one of the most important hydrothermal minerals in many hydrothermal uranium deposits worldwide and is commonly closely associated with the uranium mineralization. Trace elements in chlorite have been extensively applied to fingerprinting the hydrothermal fluid evolution and indicating the concealed ore bodies in porphyry Cu (-Au) deposits and skarn-related Pb-Zn deposits. However, this approach was rarely attempted on hydrothermal uranium deposits to date. Xiangshan uranium ore field, located in the southeast part of Gan-Hang Metallogenic (or Volcanic) Belt (GHMB), is the largest volcanic-related ore field in the whole country. In this study, the focus was placed on the petrographic characteristics and trace elements in hydrothermal chlorite from two typical deposits (Zoujiashan and Yunji) at Xiangshan. Four types of chlorites were identified, i.e., Chl1-Y and Chl2 from Yunji deposit, and Chl1-Z and Chl3 from Zoujiashan deposit. The pre-ore Chl1-Y and Chl1-Z are formed through replacing the original magmatic biotite. Chl2 and Chl3 occur as veinlets or disseminated, and are closely associated with early-ore U mineralization and main-ore U mineralization, respectively. All the four types of chlorites are typically trioctahedral chlorite. Vein-type/disseminated Chl2 and Chl3 in ore veins were precipitated directly from the hydrothermal fluids through dissolution-migration-precipitation mechanism, whereas the replacement-type chlorite was formed by the dissolution–crystallization mechanism. Empirical geothermometry indicates that the chlorite from Yunji and Zoujiashan were crystallized at 179~277 °C, indicating a mesothermal-epithermal precipitation environment. EPMA and LA-ICP-MS results show that the replacement-type chlorite has relatively consistent compositions at Yunji and Zoujiashan. Both Chl2 and Chl3 are enriched in U, Th but depleted in Mn and Ti. Compared with the Chl2 related to early-ore U mineralization, Chl3 that formed at main-ore stage has higher concentrations of Fe, U, Th, REEs, Mn and Ti, as well as higer Fe/(Fe + Mg) ratios. Such compositional differences between Chl2 and Chl3 are mainly attributed to the formation temperatures and fluid compositions/natures. Combined with petrology and chemical compositions of different types of chlorite, we propose that the presence of vein-type/disseminated chlorite with high U and Fe/(Fe + Mg) ratio but relatively low Mn, Ti and Pb contents can be regarded as an effective vector toward the most economic (high U grade) mineralized zone, whereas the occurrence of Chl2 is likely to indicate the subeconomic U mineralization and less potential exploration for uranium at depth.
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Fan, Gao-Hua, Jian-Wei Li, Xiao-Dong Deng, Wen-Sheng Gao et Si-Yuan Li. « Age and Origin of the Dongping Au-Te Deposit in the North China Craton Revisited : Evidence from Paragenesis, Geochemistry, and In Situ U-Pb Geochronology of Garnet ». Economic Geology 116, no 4 (1 juin 2021) : 963–85. http://dx.doi.org/10.5382/econgeo.4810.
Texte intégralRésumé :
Abstract Dongping is the largest Au-Te vein deposit (~120 t Au) in the North China craton, but its age, origin, and setting remain unsolved. Here, we integrate paragenesis, geochemistry, and in situ U-Pb geochronology of garnet to constrain the timing and possible origin of the Dongping Au-Te deposit. Gold mineralization at Dongping is hosted in the Shuiquangou alkaline complex (ca. 401–390 Ma) and dominated by quartz-sulfide veins with minor ores in adjacent alteration envelopes. Andradite to grossular garnets are recognized in pre-, syn-, and post-ore quartz veins as well as mineralized alteration envelopes and are closely associated with a variety of ore and gangue minerals, mainly including K-feldspar, quartz, specularite, magnetite, pyrite, tellurides, epidote, and calcite. The paragenetic, textural, fluid inclusion, and compositional data suggest that garnets precipitated directly from a low-salinity fluid at 302° to 383°C and 90 to 330 bar. Garnets from various veins and alteration envelopes have similar U contents ranging from 0.80 to 13.89 mg/kg and yield reproducible U-Pb dates of 142 ± 5 to 139 ± 6 Ma (1σ) by laser ablation-inductively coupled plasmamass spectrometry. The dating results suggest that gold mineralization at Dongping occurred in the Early Cretaceous and thus preclude a genetic link between Au-Te mineralization and the ore-hosting alkaline intrusion as commonly suggested. When combined with independent geologic, geochemical, and geochronological studies, the new garnet U-Pb dates allow us to classify the Dongping Au-Te deposit as an oxidized intrusion-related gold deposit, with the causative magma likely derived from melting of an ancient enriched lithospheric mantle source due to destruction of the subcontinental lithospheric keel beneath the North China craton—a catastrophic event induced by the westward subduction of the Paleo-Pacific plate. This study highlights garnet U-Pb dating as a potential robust geochronometer for gold vein deposits elsewhere.
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Courtney-Davies, Liam, Cristiana L. Ciobanu, Simon R. Tapster, Nigel J. Cook, Kathy Ehrig, James L. Crowley, Max R. Verdugo-Ihl, Benjamin P. Wade et Daniel J. Condon. « OPENING THE MAGMATIC-HYDROTHERMAL WINDOW : HIGH-PRECISION U-Pb GEOCHRONOLOGY OF THE MESOPROTEROZOIC OLYMPIC DAM Cu-U-Au-Ag DEPOSIT, SOUTH AUSTRALIA ». Economic Geology 115, no 8 (27 août 2020) : 1855–70. http://dx.doi.org/10.5382/econgeo.4772.
Texte intégralRésumé :
Abstract Establishing timescales for iron oxide copper-gold (IOCG) deposit formation and the temporal relationships between ores and the magmatic rocks from which hydrothermal, metal-rich fluids are sourced is often dependent on low-precision data, particularly for deposits that formed during the Proterozoic. Unlike accessory minerals routinely used to track hydrothermal mineralization, iron oxides are dominant components of IOCG systems and are therefore pivotal to understanding deposit evolution. The presence of ubiquitous, magmatic-hydrothermal U-(Pb)-W-Sn-Mo–bearing zoned hematite resolves a range of geochronological issues concerning formation of the ~1.6 Ga Olympic Dam IOCG deposit, South Australia, at up to ~0.05% precision (207Pb/206Pb weighted mean; 2σ) using isotope dilution-thermal ionization mass spectrometry (ID-TIMS). Coupled with chemical abrasion-ID-TIMS zircon dates from host granite and volcanic rocks within and enclosing the ore-body, a confident magmatic-hydrothermal chronology is defined. The youngest zircon date from the granite intrusion hosting Olympic Dam indicates magmatism was occurring up until 1593.28 ± 0.26 Ma. The orebody was principally formed during a major mineralizing event following granite uplift and during cupola collapse, whereby the hematite with the oldest age is recorded in the outer shell of the deposit at 1591.27 ± 0.89 Ma, ~2 m.y. later than the youngest documented magmatic zircon. Hematite dates captured throughout major lithologies, different ore zones, and the ~2-km vertical extent of the deposit support ~2 m.y. of hydrothermal activity. New age constraints on the spatial-temporal evolution of the formation of Olympic Dam are considered with respect to a mantle to crustal continuum model. Cyclical tapping of magma reservoirs to maintain crystal mushes for extended time periods and incremental building of batholiths on the million-year scale prior to main mineralization pulses can explain the ~2-m.y. temporal window temporal window inferred from the data. Despite the challenge of reconciling such an extended window with contemporary models for porphyry deposits (≤1 m.y.), formation of Proterozoic ore deposits has been addressed at high-precision and supports the case that giant IOCG deposits may form over millions of years.
Thèses sur le sujet "U-ore deposit"
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LOCCHI, SOFIA. « The Post-Variscan evolution of the central Southern Alps : insights from synchronous fault activity, hydrothermalism and magmatism in the Orobic and Collio Basins ». Doctoral thesis, Università degli Studi di Milano-Bicocca, 2023. https://hdl.handle.net/10281/404097.
Texte intégralRésumé :
Durante il Permiano Inferiore, l’evoluzione post-Varisica dell’attuale regione Alpina è stata caratterizzata da una importante estensione crostale combinata con intensa attività magmatica, che ha favorito lo sviluppo di bacini estensionali intra-continentali con deposizione di sedimenti vulcanoclastici (e.g. Bacino Orobico). Nel settore centrale delle Alpi Meridionali, l’apertura di questi bacini era controllata da complessi sistemi di faglia, attivi contemporaneamente con l’intrusione di plutoni e l’attività vulcanica in superficie.
Il seguente progetto di dottorato si focalizza sullo studio di queste caratteristiche, con l’intento di approfondire i processi geologici attivi durante il Permiano. Diverse faglie di età Permiana sono state indagate nel Bacino Orobico, con particolare enfasi sul riconoscimento dei loro tratti originali, poiché esse sono eccezionalmente sfuggite alla deformazione Alpina. Nel passato, l’architettura dei bacini Permiani era stata descritta con strutture a horst-graben, formatesi in risposta ad una tettonica transtensiva controllata da una zona di taglio che ha portato alla trasformazione da Pangea B a Pangea A. Tuttavia, studi più recenti hanno indicato un diverso setting di faglie che hanno controllato l’apertura dei bacini Permiani: si tratta di una combinazione di faglie normali a basso e alto angolo.
Le faglie normali a basso angolo identificate lungo il Bacino Orobico rappresentano il miglior luogo in cui osservare l’interazione tra attività tettonica e magmatismo, poiché i loro nuclei di faglia sono caratterizzati da cataclasiti sigillate da livelli di tormaliniti. Queste ultime testimoniano la circolazione di fluidi arricchiti in boro e incanalati lungo importanti zone di faglia correlate all’apertura del Bacino Orobico. Simili brecce a tormalina affiorano anche in Val Trompia (BS): molti autori hanno suggerito che le tormaliniti delle Alpi Orobie, quelle della Val Trompia unitamente alla mineralizzazione di uranio del distretto di Novazza-Val Vedello potrebbero essere geneticamente correlate. Esse potrebbero essere correlate ad un sistema idrotermale di alta temperatura su ampia scala, coevo con l’attività tettono-magmatica del Permiano Inferiore che è responsabile anche della messa in posto di svariati depositi di minerali metalliferi nelle Alpi Meridionali. Tuttavia, la genesi delle tormaliniti non è mai stata dettagliatamente caratterizzata e la loro connessione con i giacimenti di U finora non è mai stata investigata.
Le faglie tormalinizzate sono state riconosciute in molte località del settore centrale delle Alpi Meridionali quando ancora non era nota l’importanza delle faglie normali a basso angolo. In questa tesi di dottorato, vengono caratterizzate tutte le aree con i ritrovamenti di tormaliniti, ricercando la causa dell’idrotermalismo regionale nel contesto di estensione durante il Permiano Inferiore. Inoltre, per via del possibile link con i giacimenti di uranio, lo studio dei borosilicati viene proposto come strumento per meglio caratterizzare la genesi delle mineralizzazioni. Nuove osservazioni di terreno su tormaliniti sono combinate con lo studio della geochimica dei minerali e della roccia totale, insieme alla geocronologia, a studi microstrutturali e analisi isotopiche del B, con lo scopo finale di definire l’origine di questi fluidi arricchiti in boro. I risultati ottenuti da questa ricerca dimostrano che le tormaliniti e il magmatismo Permiano sono in stretta correlazione temporale e genetica. Inoltre, i dati geochimici sugli elementi in tracce forniscono maggiori indizi su una diretta connessione tra tormaliniti e la mineralizzazione a U dell’area di Novazza-Val Vedello. Tutti questi dati, per concludere, sono discussi nel contesto di interazione di processi tettonici, magmatici e di formazione di giacimenti che hanno interessato l’attuale settore centrale delle Alpi Meridionali durante il Permiano Inferiore.During the Early Permian, the post-Variscan evolution of the present-day Alpine region was characterized by crustal extension combined with strong magmatic activity at different crustal levels, which finally led to the development of intracontinental extensional basins filled with volcanoclastic sediments (e. g. the Orobic Basin, N Italy). In the central Southern Alps (cSA), the opening of these basins was controlled by complex fault system that were active at the same time of plutons intrusion and volcanic activity at the surface. Relationships among magmatism, tectonics and hydrothermal activity related to the formation of ore deposits in the Early Permian so far have been only briefly addressed. This Ph.D. research project focuses on the investigations of the above described features, trying to consider the geological processes active in the Early Permian in an integrated scenario. Several Early Permian faults of the Orobic Basin have been investigated with special emphasis on the recognition of their original features, as they have exceptionally escaped most of the Alpine deformation. In the past, the architecture of Permian basins was described as horst-and-graben structures, formed in response to wrench tectonics developed during the activity of a megashear zone that led to the Pangea B to Pangea A transformation after the collapse of the Variscan orogen. However, thanks recent studies, a different fault architecture has been suggested to had controlled the opening of the Permian basins: a combination of Low-Angle Normal faults and High-Angle Normal Faults. The identified LANFs of the Orobic Basin represent the best site to study the interplay among tectonics and magmatism, as they are characterized by cataclastic bands sealed with cm to dm thick layers of dark, aphanitic tourmalinites. These latter are proof of fluids circulation channelled along higher permeability fault zones related to opening of the Orobic Basin. Such tourmaline breccias also crop out in the Trompia Valley (BS): several authors suggested that tourmalinites from Orobic Alps, tourmalinites from Trompia Valley together with uranium mineralization of Novazza - Vedello Valley are genetically linked. They are seen as products of a large-scale high-temperature hydrothermal system coeval with the Early Permian plutonic-volcanic activity and tectonism, which was also responsible for the emplacement of various types of magmatic-hydrothermal ore deposits in the Southern Alps (Sn-W, U-Mo-Zn, Fe carbonates, sulphides, quartz). However, their genesis has never been fully characterized and the connection between tourmalinites and U ore bodies has also not been deeply investigated so far. The tourmalinized faults were first noted in various sites of the cSA during the 90’s, when the tectonic importance of LANFs was not yet recognized. In this thesis, all the occurrences of tourmalinites are characterized, looking for the cause of the regional hydrothermalism in the context of intracontinental extension during the Early Permian. Furthermore, due to the likely connection with U ore deposits, the borosilicate study is proposed as tool for better understanding the genesis of the mineralizations. New field based structural analysis are combined with mineral and whole-rock geochemistry, geochronology, microstructural studies and boron- isotopic analysis of tourmalinites from different sectors of the study area, in order to evaluate the origin of these fluids. Results coming out from this study demonstrate, together with B isotope ratios, a temporal and genetical relationship between tourmalinites and Early Permian magmatism in the cSA. Furthermore, the geochemical data on trace elements provide more clues on a direct connection between tourmalinites and the U-mineralization. All these results are finally discussed in the frame of the interplay between tectonic, magmatic and ore generation processes that interested the present day cSA area in the Early Permian
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Meunier, Jean-Dominique. « Mécanismes de concentration de l'uranium dans les sédiments : génèse des gisements de type tabulaire ». Nancy 1, 1989. http://www.theses.fr/1989NAN10346.
Texte intégralRésumé :
Les mécanismes de concentration de l'uranium dans les formations sédimentaires sont étudiés dans le but de modéliser les gisements de type tabulaire. De nouveaux traceurs de l'uranium sont proposés grâce à l'utilisation de la cathodoluminescence et des deséquilibres isotopiques dans la famille de l'#2#3#8U. Dans le gisement de coutras (Gironde, France), situé dans des sables lutetiens, l'uranium se concentre au cours de la diagénèse précoce, en formant des complexes d'uranyle avec la matière organique. Au cours d'une simulation expérimentale de la diagénèse thermique, ces complexes d'uranyle se détruisent, l'uranium est réduit par l'hydrogène de la matière organique et l'uraninite se forme. Dans les gisements du plateau du Colorado (Etats-Unis), situés dans des grés jurassiques, les dépôts urano-vanadifères se sont mis en place au cours de la diagénèse profonde (100#OC environ)
3
Huang, Q. « Petrology, geochemistry and geochronology of mafic lithologies at the Olympic Dam iron oxide Cu-U-Au-Ag deposit : implications for tectonic settings and ore-forming processes ». Thesis, 2016. https://eprints.utas.edu.au/23061/1/Huang_whole_thesis.pdf.
Texte intégralRésumé :
The Olympic Dam deposit, South Australia, is a supergiant iron oxide Cu-U-Au-
Ag deposit currently containing the world’s largest uranium, fifth largest copper, and
third largest gold resource (10,100 Mt at 0.78% Cu, 0.25 kg/t U₃O8, 0.30 g/t Au, 1 g/t
Ag, BHP Billiton 2015 Annual Report). The exploration model leading to the discovery
of the deposit in 1975 was source-oriented: altered mafic lithologies were considered
as the potential source of copper and early exploration focused on defining and
searching for these lithologies. Not surprisingly, drilling and underground mining at
Olympic Dam have revealed the occurrence of more than one generation of mafic
lithologies. Previous studies have considered these mafic lithologies to be closely
related to brecciation, hydrothermal circulation (by providing heat), and mineralization
at Olympic Dam. One suite of mafic rocks, inferred to belong to the ca. 1590 Ma Gawler
Range Volcanics (GRV), has been proposed to be a major source of Cu (~50% of the
contained Cu) found in the deposit.
However, at over forty years since discovery of the deposit, questions remain as
to which groups the various mafic lithologies at Olympic Dam belong to regionally, as
to what kinds of tectonic settings there were when the mafic lithologies were emplaced,
and as to how the emplacement and alteration of the mafic lithologies were related to
the ore-forming processes at Olympic Dam.
This study endeavours to provide answers to these issues. The presence of two
generations of mafic lithologies at Olympic Dam has been confirmed by primary
accessory apatite U-Pb dating. The first group is found to be correlated with the ca.
1590 Ma Gawler Range Volcanics and the Gawler silicic large igneous province (SLIP),
consisting of intensely altered olivine-phyric basalt, and other mafic dykes of various
textures (aphanitic, porphyritic, and doleritic). The second group comprises basaltic to
mainly doleritic dykes (named the Olympic Dam dolerite), proved to belong to the ca.
820 Ma Gairdner Dyke Swarm and the Gairdner large igneous province (LIP).
The ca. 1590 Ma olivine-phyric basalt at Olympic Dam typically contains a higher
abundance of former olivine phenocrysts (~20 vol.%) and is more intensely altered thanequivalent mafic GRV outside the deposit at Kokatha, Mount Gunson and Wirrda Well.
Therefore, this suite of basalt represents the most ultramafic component in the GRV
recognized thus far. Compositions of a large number of Cr-spinel inclusions within
olivine pseudomorphs and olivine-phyric basalt samples of mafic GRV (including
Olympic Dam samples) reveal different magma types and indicate derivation of mafic
GRV from a heterogeneous mantle source that may have been modified by subduction,
implying a setting proximally to a continental margin or in a back-arc. This inference
is also compatible with the previous proposal that the formation of the Gawler SLIP
was associated with the assembly of the Laurentian supercontinent. The ca. 820 Ma
Olympic Dam dolerite shows similar petrographic features and comparable
compositional variations to the regional Gairdner Dyke Swarm. The correlation of the
Olympic Dam dolerite with the Gairdner Dyke Swarm thus extends the spatial
distribution and the compositional spectrum of the latter. Geochemical comparisons
among LIP and mafic suites in South Australia (including the Gairdner Dyke Swarm),
South China and North America, associated with the break-up of the supercontinent
Rodinia are in support of the “missing-link” model in which South China was situated
on top of a mantle plume and South Australia (including Olympic Dam) was affected
by the plume-induced rift magmatism at ca. 820 Ma. In conclusion, from the
perspective of mafic magmatism, the evolution of the supergiant Olympic Dam deposit
turned out to be linked to two supercontinent cycles: the assembly of Laurentia at ca.
1590 Ma, and the break-up of Rodinia at ca. 820 Ma.
Investigations of the alteration of the two generations of mafic lithologies at
Olympic Dam have shown that they contain similar major secondary minerals (chlorite,
sericite, and carbonate). Both are characterized by a mineral assemblage of magnetiteapatite
± chlorite ± quartz that is strikingly similar to the inferred early reduced iron
oxide alteration present in the periphery and at depth of the Olympic Dam Breccia
Complex that is the immediate host to ore. Secondary spongy apatite in the ca. 1590
Ma olivine-phyric basalt yielded an age that is broadly coeval with the basalt’s
emplacement. Sericite-altered basalt produced a post-primary Rb-Sr isochron age of ca.
1180 Ma, likely to indicate the most recent significant sericite alteration of these rocks.
Extreme concentrations of some components (e.g. up to 26 wt.% CO₂, 50 wt.% of Fe₂O₃,
and 6,000ppm of Cr) and extraordinary near linear positive correlations between Cr andhigh field strength elements (e.g. Ti, Nb, and Zr) revealed in drill core assays of the
basalt indicate significant whole-rock mass and/or volume loss due to hydrothermal
alteration, in accordance with its previously proposed role as a major Cu source. Results
obtained on the secondary apatite and titanite in the ca. 820 Ma Olympic Dam dolerite
also confirmed hydrothermal activities associated with the emplacement of the younger
dolerite. Pb isotope compositions of the dolerite as well as chalcopyrite and galena
within the dolerite indicate derivation of radiogenic Pb from hydrothermal fluids
circulating through the Olympic Dam Breccia Complex, implying that the dolerite was
a part of the active hydrothermal system at Olympic Dam at ca. 820 Ma. Elevated Zn,
Pb and depleted Cu concentrations of the ca. 820 Ma Olympic Dam dolerite compared
to dolerite worldwide suggest that the dolerite can even be an additional Cu source to
the Olympic Dam deposit. Moreover, the younger and less altered dolerite provides a
better opportunity to envisage Cu depletion processes that may also be anticipated for
the older olivine-phyric basalt, where such processes are no longer recognizable due to
superimposition of multiple hydrothermal events on the basalt. At last and most
importantly, magmatic-hydrothermal activities (ca. 1590 Ma, 1180 Ma, 820 Ma)
recorded in both generations of mafic rocks can be correlated with ages (spanning from
ca. 1590 Ma to 570 Ma) obtained on the Olympic Dam Breccia Complex. This
advocates the existence of an all-encompassing, multi-stage, hydrothermal system at
the supergiant Olympic Dam deposit.
4
Wolff, Reinhard. « Fluorite (U-Th-Sm)/He thermochronology ». Thesis, 2015. http://hdl.handle.net/11858/00-1735-0000-0028-87A4-2.
Texte intégralChapitres de livres sur le sujet "U-ore deposit"
1
Zentilli, Marcos, Milton C. Graves, Ryan Mathur, Jacob J. Hanley, Larry M. Heaman et Ricardo Boric. « Locating the “Missing Half” of the Giant Chuquicamata Porphyry Copper Deposit, Chile ». Dans Tectonomagmatic Influences on Metallogeny and Hydrothermal Ore Deposits : A Tribute to Jeremy P. Richards (Volume I), 69–85. Society of Economic Geologists, 2021. http://dx.doi.org/10.5382/sp.24.05.
Texte intégralRésumé :
Abstract The supergiant Chuquicamata porphyry Cu-Mo deposit in northern Chile is truncated on its west side by a N-S-trending regional fault (the West fault), juxtaposing its ore to a relatively barren granodiorite (Fortuna Igneous Complex). There has been much speculation about the fate of, and extensive exploration for, the “missing half” of the deposit. It has been proposed that the west side of the fault hides the ore at depth, or that it was uplifted and the ore eroded; however, regional geologic mapping suggests that the West fault had a postore left-lateral strike-slip displacement of ca. 35 km. Accordingly, exploration, so far unsuccessful, has been focused in an area 35 km south near the Loa River and the city of Calama. In 1989, the Mina Ministro Hales (MMH) deposit was unexpectedly discovered west of the fault, under thick gravels, only 7 km south of the main mine. A previous study at MMH had suggested that mineralization was as old as 39 Ma, hence its ores were correlated with deposits of that age near Calama. Our recent U-Pb and Re-Os dating indicates that MMH mineralization was formed between 35 and 31 Ma, thus concurrently with Chuqui. The geochemistry of host Triassic and Eocene porphyry intrusions, ore mineralogy, and common Pb isotope ratios of hypogene sulfides at MMH and Chuqui proper are indistinguishable. Fluid inclusion data for paragenetically early porphyry assemblages at MMH closely mimic Th-salinity data from earlier studies at Chuqui, showing little or no evidence of boiling but indicating widely fluctuating confining pressures, compatible with hydraulic fracturing and fault movement during and after mineralization at a minimum initial lithostatic constraint of 5- to 8-km depth. We propose that MMH is a sheared-off portion of Chuqui, wedged in a fault cymoid loop and spared the full 35-km displacement of the West fault.
2
Wilson, Alan J., Nick Lisowiec, Cameron Switzer, Anthony C. Harris, Robert A. Creaser et C. Mark Fanning. « Chapter 11 : The Telfer Gold-Copper Deposit, Paterson Province, Western Australia ». Dans Geology of the World’s Major Gold Deposits and Provinces, 227–49. Society of Economic Geologists, 2020. http://dx.doi.org/10.5382/sp.23.11.
Texte intégralRésumé :
Abstract The giant (>20 Moz) Telfer Au-Cu deposit is located in the Paterson Province of Western Australia and is hosted by complexly deformed marine Neoproterozoic metasedimentary siltstones and quartz arenites. The Telfer district also contains magnetite- and ilmenite-series granitoids dated between ca. 645 and 600 Ma and a world-class W skarn deposit associated with the reduced, ~604 Ma O’Callaghans granite. Based on monazite and xenotime U-Pb geochronology, Telfer is estimated to be older than O’Callaghans, forming between 645 and 620 Ma. Au-Cu mineralization at Telfer is hosted in multistage, bedding-parallel quartz-dolomite-pyrite-chalcopyrite reefs and related discordant veins and stockworks of similar composition that were emplaced into two NW-striking doubly plunging anticlines or domes. Mineralization is late orogenic in timing, with hot (≤460°C), saline (<50 wt % NaCl equiv) ore fluids channeled into preexisting domes along a series of shallow, ENE-verging thrust faults and associated fault-propagated fold corridors. A combination of fault-propagated fold corridors acting as fluid conduits below the apex of the Telfer domes and the rheology and chemical contrast between interbedded siltstone and quartz arenite units within the dome are considered key parameters in the formation of the Telfer deposit. Based on the presence of the reduced Au-Cu-W-Bi-Te-Sn-Co-As assemblage, saline and carbonic, high-temperature hydrothermal fluids in Telfer ore, and widespread ilmenite-series granites locally associated with W skarn mineralization, Telfer is considered to be a distal, intrusion-related gold deposit, the high copper content of which may be explained by the predominance of highly saline, magmatic fluids in gangue assemblages cogenetic with ore.
3
Poulsen, K. Howard, Rodney Barber et François Robert. « Chapter 4 : Hemlo Gold System, Superior Province, Canada ». Dans Geology of the World’s Major Gold Deposits and Provinces, 81–100. Society of Economic Geologists, 2020. http://dx.doi.org/10.5382/sp.23.04.
Texte intégralRésumé :
Abstract Hemlo combines several rare to unique features in the spectrum of Archean greenstone gold deposits. It is an isolated, approximately 800-metric ton (t) gold system in a region of otherwise limited known gold endowment. The geology of Hemlo is dominated by deformed and metamorphosed sedimentary, felsic volcanic, and volcaniclastic units, a premineral coherent felsic porphyry, and a swarm of mainly postmineral, intermediate, feldspar-phyric dikes. Ore is dominantly in the form of gold-bearing lenses of pyritic, feldspathic schist derived from deformation of both the clastic rocks and the felsic porphyry. The deposit and its host rocks were metamorphosed at moderate pressures to assemblages diagnostic of the mid-amphibolite facies, followed by progressive retrogression to those of the greenschist facies. The result is a wide range of silicate mineral species in ambiguous textural relationships. The gold system itself is known for ore and related alteration minerals with significant concentrations of Mo-As-Sb-Hg-Tl-V-Ba-K-Na. The inferences derived from lithologic mapping, structural chronology, U-Pb geochronology, and mineral paragenesis favors an interpretation of Hemlo as a deformed and metamorphosed gold system formed from oxidized hydrothermal fluids in an upper crustal setting. Uncertainty remains as to the exact nature and geometry of that ore-forming hydrothermal system, however, and the role subsequent metamorphism and deformation have played in the local remobilization of ore constituents into their present paragenetically late structural sites.
4
Viala, M., et K. Hattori. « Magmatism and Related Au-Cu Mineralization in the Hualgayoc Mining District, Northern Peru ». Dans Tectonomagmatic Influences on Metallogeny and Hydrothermal Ore Deposits : A Tribute to Jeremy P. Richards (Volume I), 137–58. Society of Economic Geologists, 2021. http://dx.doi.org/10.5382/sp.24.09.
Texte intégralRésumé :
Abstract The Hualgayoc district in the Cajamarca region of northern Peru experienced middle Miocene andesitic to rhyolitic magmatism and magmatic hydrothermal activity that produced Au and Cu mineralization, including the Cerro Corona porphyry Au-Cu, Tantahuatay high-sulfidation epithermal Au, and the AntaKori skarn Cu-Au-Ag deposits. We examined 32 samples from 22 units that encompass the entire igneous rock record in the district. Our new U-Pb dating of 454 zircon grains from these 22 igneous units yielded Concordia ages showing continuous magmatic activity in the district, from 14.8 to 9.7 Ma. Igneous activity in the eastern part of the district took place between 14.8 and 14.0 Ma, including the Cerro Corona intrusive complex that hosts a porphyry Au-Cu deposit. Magmatism in the western part of the district occurred between 13.7 and 11.5 Ma and included the Tantahuatay Volcanic Complex that hosts a high-sulfidation Au deposit. The different styles of mineralization and ages of igneous rocks in the eastern and western parts are accounted for by deeper erosion to the east. Bulk-rock compositions indicate that parental magmas originated from amphibole-rich juvenile lithospheric mantle or lower crust and evolved through amphibole fractional crystallization. Amphibole and zircon compositions indicate that parental magmas of all igneous units in the Hualgayoc district were water-rich, >3 wt % H2O, and oxidized above the fayalite-magnetite-quartz (FMQ) redox buffer. Our observations in the Hualgayoc district suggest that oxidized conditions and high-water contents are necessary to produce porphyry-type mineralization, but that other factors were also critical to form mineralization, such as a shallow depth of magma emplacement, with near-vertical shape of intrusions. These findings are likely applicable elsewhere.
5
Lee, Well-Shen, Daniel J. Kontak, Jeremy P. Richards, Tony Barresi et Robert A. Creaser. « Superimposed Porphyry Systems in the Dawson Range, Yukon ». Dans Tectonomagmatic Influences on Metallogeny and Hydrothermal Ore Deposits : A Tribute to Jeremy P. Richards (Volume I), 29–48. Society of Economic Geologists, 2021. http://dx.doi.org/10.5382/sp.24.03.
Texte intégralRésumé :
ABSTRACT Superimposed porphyry systems are a subset of telescoped porphyry deposits, whereby significantly younger ore zones overprint older, nongenetically related systems. Recognition of superimposed features in porphyry systems is important for determining and assessing their prospectivity. The Mount Nansen gold corridor in the southern Dawson Range gold belt of Yukon, Canada, contains porphyry prospects and epithermal deposits with enigmatic genetic models. Geologic, petrologic, temporal (U-Pb zircon, Re-Os molybdenite), and geochemical (whole-rock) studies are used to demonstrate the presence of superimposed porphyry systems in this district. The arc-related episodic magmatism of the Mount Nansen gold corridor has been classified into four intrusive suites: (1) Late Triassic Minto, (2) mid-Cretaceous Whitehorse, (3) Late Cretaceous Casino (eLKc; 80–72 Ma), and (4) Late Cretaceous Prospector Mountain (lLKp; 72–65 Ma). Geochemical fingerprinting of these suites indicates intermediate to evolved, calc-alkaline compositions with a common lower crust melt source. The eLKc and lLKp suites lack an Eu anomaly and show increasing amounts of light rare earth element (LREE) enrichment and heavy rare earth element (HREE) depletion over time. These features suggest that garnet was stable in the melt source and oxidized magmas were generated in these Late Cretaceous suites. The mildly alkaline lLKp and associated Carmacks Group shoshonitic basalts reflect localized extension in an overall compressive arc setting in the Mount Nansen gold corridor, hence a setting conducive for Au-rich porphyry and epithermal systems. The ca. 79 to 72 Ma Casino suite is commonly interpreted as the causative magmatic event for most well-endowed porphyry deposits (76 to 74 Ma in age) in the Dawson Range gold belt. However, our detailed study of the Klaza setting shows that at this locality, intermediate-sulfidation epithermal veins are a distal expression of a Prospector Mountain-age (ca. 71 Ma) porphyry system, which overprints two Casino-age porphyry systems (ca. 77 and 80 Ma). The Mount Nansen gold corridor thus hosts at least two spatially and temporally overprinting Late Cretaceous magmatic-hydrothermal systems in the Dawson Range gold belt. Importantly, recognition of this feature at other porphyry deposit settings in the Dawson Range gold belt (e.g., Freegold Mountain district) is critical as it provides the potential for metal (Cu-Au-Mo)-enriched hypogene ore shells.
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Xu, Bo, Zeng-qian Hou, William L. Griffin, Ye Zhou, Yu-Fei Zhang, Yong-Jun Lu, Elena Belousova, Ji-Feng Xu et Suzanne Y. O’Reilly. « Elevated Magmatic Chlorine and Sulfur Concentrations in the Eocene-Oligocene Machangqing Cu-Mo Porphyry Systems ». Dans Tectonomagmatic Influences on Metallogeny and Hydrothermal Ore Deposits : A Tribute to Jeremy P. Richards (Volume II), 257–76. Society of Economic Geologists, 2021. http://dx.doi.org/10.5382/sp.24.14.
Texte intégralRésumé :
Abstract The Machangqing porphyry Cu-Au deposit is located in the Sangjiang region, Jinshajiang-Ailaoshan metallogenic belt, southeastern Tibet. It has three main phases of felsic-mafic intrusions: barren granites, ore-forming porphyry intrusions, and mafic lamprophyres. U-Pb zircon dating shows that these intrusions were emplaced over a period of ~3 m.y., with lamprophyres at 36.50 ± 1.6 Ma (1σ), porphyry intrusion at 34.26 ± 0.22 Ma (1σ), and granite intruded at 34.00 ± 0.26 Ma (1σ). The in situ Rb-Sr analysis of phlogopite and amphibole, primary minerals in the lamprophyres, also gives a date of 36.5 ± 1.5 Ma (2σ), regarded as the emplacement age of the lamprophyre, earlier than the ore-forming porphyry intrusions. The magmatic phases have significantly different sulfur and chlorine contents. The SO3 contents of igneous apatite microphenocrysts from the mineralization-related porphyry intrusions are higher (0.24 ± 0.14 wt %, 1σ, n = 82) than those from the barren granites (0.08 ± 0.07 wt %, 1σ, n = 30). The chlorine contents in apatite grains from the porphyry intrusions (0.18 ± 0.16 wt %, 1σ) are also higher than those from granites (0.04 ± 0.02 wt % Cl, 1σ). The apatite in lamprophyres have higher sulfur (0.68 ± 0.19 wt %, 1σ, n = 40) and chlorine (0.48 ± 0.13 wt %, 1σ). The large difference of Cl and S in lamprophyres might suggest that elevated magmatic volatile contents derived from the mafic magma were important for ore formation in the Machangqing porphyry systems. The in situ Sr and O isotopes in apatite phenocrysts from the porphyry intrusions (87Sr/86Sr: 0.70593–0.70850; δ18O: 6.0–7.0) are similar to those in the lamprophyres (87Sr/86Sr: 0.70595–0.70964; δ18O: 5.4–6.9), consistent with similar origins for their volatile contents. These data may indicate that the deeper magma chamber was recharged by a relatively S-Cl-rich mafic magma similar to the lamprophyres, triggering the ore-forming magmatic event. This study also suggests that origin of apatite Sr and also volatile contents, combined with in situ Sr and O isotopes, could be useful for fingerprinting fertile intrusions associated with mineralization within drainage source areas or in outcrops.
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Yurdakul, Emrecan, Ali İmer et Mustafa Cihan. « Timing and Nature of Mineralization and Associated Hydrothermal Alteration at the Öksüt High-Sulfidation Epithermal Au-Cu Deposit (Kayseri Province, Central Anatolia) ». Dans Tectonomagmatic Influences on Metallogeny and Hydrothermal Ore Deposits : A Tribute to Jeremy P. Richards (Volume I), 49–68. Society of Economic Geologists, 2021. http://dx.doi.org/10.5382/sp.24.04.
Texte intégralRésumé :
ABSTRACT Öksüt is a breccia-hosted high-sulfidation epithermal gold-copper deposit, situated within the Develidağ Volcanic Complex in south-central Anatolia. The volcanic complex, exposed on the northern edge of the Tauride range, is largely made up of late Miocene andesitic to dacitic porphyries, covered by a succession of Pliocene basalts and basaltic andesites. A series of N-S- to NNW-trending faults of the regional central Anatolian fault zone partly cut and border the volcanic complex to the east and west. Mineralization at Öksüt follows a predominant north-northwest trend that correlates well with the regional stress regime. The bulk of the mineralization occurs in two domains, the Keltepe and Güneytepe orebodies, where steeply dipping and pervasively supergene oxidized breccia zones exploited funnel-shaped diatreme conduits within pyroxene andesite porphyry. Emplacement of these phreatomagmatic breccias was largely controlled by vertical to subvertical faults with dominant normal-slip components. Mineralized breccias comprise a central zone of residual vuggy to massive silica alteration, laterally and vertically grading into zones of quartz-alunite and quartz-alunite-clay alteration. These silica-altered breccias contain relatively high gold grades, whereas significant mineralization was also encountered in quartz-alunite-clay alteration. In the oxide zone, gold occurs in native form, whereas in the hypogene zone it occurs both as native gold or within pyrite-enargite accompanied by marcasite, and rare chalcopyrite and tetrahedrite. To the west of Keltepe and in Güneytepe, at depth, the altered and mineralized breccias pass into barren zones of argillic and then into biotite-magnetite ± K-feldspar ± anhdyrite alteration, the latter typical of porphyry-type systems. Sporadic zones of calc-silicate alteration, represented by grossularite, diopside, and vesuvianite, are also present. Three 40Ar/39Ar ages obtained from alunite and illite range between 5.7 to 5.5 Ma and are concordant with previously reported U-Pb and 40Ar/39Ar ages (~6–5.5 Ma) from host pyroxene andesite porphyry. This suggests that high-sulfidation alteration and mineralization developed contemporaneously with postsubduction magmatism at the Develidağ Volcanic Complex, in relationship to regional E-W-directed extension that commenced at ~6 Ma. Our new ages also confirm Öksüt as the youngest epithermal gold deposit discovered to date in Anatolia, and possibly in the entire Western Tethyan metallogenic belt. The topographic prominence of the volcanic edifice combined with high permeability of the breccias favored deep supergene sulfide oxidation, thereby rendering Öksüt economically viable. Gold encapsulated in hypogene sulfides was liberated during the oxidation, whereas the copper was leached to produce a discontinuous chalcocite- and covellite-dominated enrichment zone, up to 50 m thick, at the base of oxidation.
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Moritz, Robert, Pierre Hemon, Alexey Ulianov, Richard Spikings, Massimo Chiaradia et Vagif Ramazanov. « Jurassic-Early Cretaceous Magmatic Arc Maturation and Ore Formation of the Central Tethyan Metallogenic Belt : Evidence from the Gedabek Mining District, Lesser Caucasus, Azerbaijan ». Dans Tectonomagmatic Influences on Metallogeny and Hydrothermal Ore Deposits : A Tribute to Jeremy P. Richards (Volume II), 181–203. Society of Economic Geologists, 2021. http://dx.doi.org/10.5382/sp.24.11.
Texte intégralRésumé :
Abstract The Jurassic to Early Cretaceous magmatic and metallogenic evolution of the Lesser Caucasus and Eastern Pontides segment of the Central Tethyan orogenic belt is still poorly understood. This study reports an investigation about the link between ore formation and magmatic evolution in the major Gedabek porphyry-epithermal mining district, which is located in the Somkheto-Karabagh belt, Azerbaijan. Long-lasting magmatic arc evolution of ~50 m.y., from the Middle Jurassic to the Early Cretaceous, is supported by new U-Pb zircon ages between 164.3 ± 0.7 and 125.1 ± 0.5 Ma. Middle Jurassic magmatic rocks have a dominantly tholeiitic to transitional and primitive island-arc composition, whereas Late Jurassic to Early Cretaceous magmatic rocks are calc-alkaline to shoshonitic and have mature island-arc compositions. Radiogenic isotopes document a higher mantle contribution during petrogenesis of the Late Jurassic-Early Cretaceous magmatic rocks. The combined data document progressive magmatic arc maturation and crustal thickening from the Middle Jurassic to the Early Cretaceous, accompanied by slab roll-back and asthenospheric upwelling. This evolution is shared by other areas of the Somkheto-Karabagh belt and its southern extension in the Kapan block, which also host porphyry-epithermal mining districts. Muscovite and K-feldspar from a porphyry Cu-related potassic alteration assemblage at the Gedabek deposit (overprinted by a younger intermediate- to high-sulfidation epithermal system) have yielded 40Ar/39Ar ages between 140.1 ± 1.0 and 136.3 ± 0.9 Ma. Together with a previous Re-Os molybdenite age, they document formation of the porphyry-epithermal systems at the end of the long magmatic arc maturation of the Gedabek district. Although ore-forming events were diachronous along the arc, the relative timing of magmatic evolution and ore formation at Gedabek is shared by the other Late Jurassic to Early Cretaceous mining districts of the Somkheto-Karabagh belt and the Kapan block. Our study demonstrates that long arc maturation and crustal thickening has taken place along the southern Eurasian margin from a Middle Jurassic nascent arc to an Early Cretaceous evolved arc. This evolution is in line with the essential prerequisites for the genesis of porphyry-epithermal systems in orogenic belts. It also provides evidence that Middle Jurassic to Early Cretaceous magmatic fertile systems and porphyry-epithermal centers have been preserved in this belt.
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Ross, Colin, Jeremy P. Richards et Ross Sherlock. « Geology, Alteration, and Geochronology of the Cerro Vetas Porphyry Gold-Copper Deposit, Middle Cauca Belt, Colombia ». Dans Tectonomagmatic Influences on Metallogeny and Hydrothermal Ore Deposits : A Tribute to Jeremy P. Richards (Volume II), 311–32. Society of Economic Geologists, 2021. http://dx.doi.org/10.5382/sp.24.17.
Texte intégralRésumé :
Abstract The Cerro Vetas porphyry deposit is part of the Titiribi district of the Middle Cauca porphyry-epithermal belt of western Colombia. The Cerro Vetas porphyry stock consists of a premineral diorite intruded by a late-mineral quartz monzonite, with intrusion and contact breccias. These units intrude pre-Cenozoic basement metabasalts and schists, Oligocene-Miocene Amagá Formation sedimentary rocks with intercalated andesite flows. Two phases of potassic alteration are recognized, a biotite-dominant phase in the diorite, and secondary K-feldspar in the quartz-monzonite intrusion. An overprinting and grade destructive, calcic-sodic alteration (actinolite + albite ± magnetite) affects both porphyries. Biotite alteration is overprinted by weak-moderate phyllic alteration in the upper 100 m in the deposit. Below 100 m, phyllic alteration assemblages are constrained to structural zones. Mineralization is dominated by a chalcopyrite-gold-pyrite assemblage associated with biotite that is hosted in a truncated stockwork in the apical portion of the deposit with metal ratios typical of a gold-rich copper-gold porphyry. The intrusions were dated, using U-Pb in zircon laser ablation inductively coupled plasma-mass spectroscopy, to between 7.65 to 7.24 Ma, consistent with other deposits in the Middle Cauca belt. Lithologic, alteration, and stratigraphic relationships at the deposit suggest that the Cerro Vetas porphyry was emplaced at shallow depths and that the upper portion of the deposit has been eroded.
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Sharman, Glenn R., Daniel F. Stockli, Peter Flaig, Robert G. Raynolds, Marieke Dechesne et Jacob A. Covault. « Tectonic influence on axial-transverse sediment routing in the Denver Basin ». Dans Tectonic Evolution of the Sevier-Laramide Hinterland, Thrust Belt, and Foreland, and Postorogenic Slab Rollback (180–20 Ma). Geological Society of America, 2022. http://dx.doi.org/10.1130/2021.2555(11).
Texte intégralRésumé :
ABSTRACT Detrital zircon U-Pb and (U-Th)/He ages from latest Cretaceous–Eocene strata of the Denver Basin provide novel insights into evolving sediment sourcing, recycling, and dispersal patterns during deposition in an intracontinental foreland basin. In total, 2464 U-Pb and 78 (U-Th)/He analyses of detrital zircons from 21 sandstone samples are presented from outcrop and drill core in the proximal and distal portions of the Denver Basin. Upper Cretaceous samples that predate uplift of the southern Front Range during the Laramide orogeny (Pierre Shale, Fox Hills Sandstone, and Laramie Formation) contain prominent Late Cretaceous (84–77 Ma), Jurassic (169–163 Ma), and Proterozoic (1.69–1.68 Ga) U-Pb ages, along with less abundant Paleozoic through Archean zircon grain ages. These grain ages are consistent with sources in the western U.S. Cordillera, including the Mesozoic Cordilleran magmatic arc and Yavapai-Mazatzal basement, with lesser contributions of Grenville and Appalachian zircon recycled from older sedimentary sequences. Mesozoic zircon (U-Th)/He ages confirm Cordilleran sources and/or recycling from the Sevier orogenic hinterland. Five of the 11 samples from syn-Laramide basin fill (latest Cretaceous–Paleocene D1 Sequence) and all five samples from the overlying Eocene D2 Sequence are dominated by 1.1–1.05 Ga zircon ages that are interpreted to reflect local derivation from the ca. 1.1 Ga Pikes Peak batholith. Corresponding late Mesoproterozoic to early Neoproterozoic zircon (U-Th)/He ages are consistent with local sourcing from the southern Front Range that underwent limited Mesozoic–Cenozoic unroofing. The other six samples from the D1 Sequence yielded detrital zircon U-Pb ages similar to pre-Laramide units, with major U-Pb age peaks at ca. 1.7 and 1.4 Ga but lacking the 1.1 Ga age peak found in the other syn-Laramide samples. One of these samples yielded abundant Mesozoic and Paleozoic (U-Th)/He ages, including prominent Early and Late Cretaceous peaks. We propose that fill of the Denver Basin represents the interplay between locally derived sediment delivered by transverse drainages that emanated from the southern Front Range and a previously unrecognized, possibly extraregional, axial-fluvial system. Transverse alluvial-fluvial fans, preserved in proximal basin fill, record progressive unroofing of southern Front Range basement during D1 and D2 Sequence deposition. Deposits of the upper and lower D1 Sequence across the basin were derived from these fans that emanated from the southern Front Range. However, the finer-grained, middle portion of the D1 Sequence that spans the Cretaceous-Paleogene boundary was deposited by both transverse (proximal basin fill) and axial (distal basin fill) fluvial systems that exhibit contrasting provenance signatures. Although both tectonic and climatic controls likely influenced the stratigraphic development of the Denver Basin, the migration of locally derived fans toward and then away from the thrust front suggests that uplift of the southern Front Range may have peaked at approximately the Cretaceous-Paleogene boundary.
Actes de conférences sur le sujet "U-ore deposit"
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Jiang, Hua, et Wenchang Li. « Zircon U-Pb and Molybdenite Re-Os Dating of Gangjiang Porphyry Cu-Mo Deposit in Nimu Ore Belt, Southern Tibet, China and Its Geological Significance ». Dans 2016 2nd International Conference on Architectural, Civil and Hydraulics Engineering (ICACHE 2016). Paris, France : Atlantis Press, 2016. http://dx.doi.org/10.2991/icache-16.2016.46.
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Yamagishi, Isao, Masaki Ozawa, Hitoshi Mimura, Shohei Kanamura et Koji Mizuguchi. « Advanced ORIENT Cycle : Progress on Fission Product Separation and Utilization ». Dans ASME 2010 13th International Conference on Environmental Remediation and Radioactive Waste Management. ASMEDC, 2010. http://dx.doi.org/10.1115/icem2010-40053.
Texte intégralRésumé :
Fission reaction of U-235 and/or plutonium generates more than 40 elements and 400 nuclides in the spent fuel. Among them, 31 elements are categorized as rare metals. In a conventional fuel cycle U and Pu are reused but others are vitrified for disposal. Adv.-ORIENT (Advanced Optimization by Recycling Instructive Elements) Cycle strategy was drawn up for the minimization of radio-toxicity and volume of radioactive waste as well as the utilization of valuable elements/nuclides in the waste. The present paper describes the progress on Fission Products (FP) separation in this Cycle. Highly functional inorganic adsorbent (AMP-SG, silica gel loaded with ammonium molybdophosphate) and organic microcapsule (CE-ALG, alginate gel polymer enclosed with crown ether D18C6) were developed for separation of heat-generating Cs and Sr nuclides, respectively. The AMP-SG adsorbed more than 99% of Cs selectively from a simulated High-level Liquid Waste (HLLW). The ALG microcapsule adsorbed 0.0249 mmol/g of Sr and exhibited the order of its selectivity; Ba > Sr > Pd >> Ru > Rb > Ag. The electrodeposition is advantageous for both recovery and utilization of PGMs (Ru, Rh, Pd) and Tc because PGMs are recovered as metal on Pt electrode. Among PGMs, Pd was easily deposited on the Pt electrode. In the presence of Pd or Rh the reduction of Ru and Tc was accelerated more in hydrochloric acid media than in nitric acid. In the simulated HLLW, the redox reaction of Fe(III)/Fe(II) disturbed deposition of elements except for Pd. The deposits on Pt electrode showed higher catalytic reactivity on electrolytic hydrogen production than the original Pt electrode. The reactivity of deposits prepared from the simulated HLLW was higher than that from solution containing only PGM.
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Priewisch, A., L. J. Crossey et K. E. Karlstrom. « U-series ages and morphology of a Quaternary large-volume travertine deposit at Mesa del Oro, NM : Implications for paleohydrology, paleoclimate, and neotectonic proceses ». Dans 64th Annual Fall Field Conference. New Mexico Geological Society, 2013. http://dx.doi.org/10.56577/ffc-64.229.
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Punanova, Svetlana. « ORE CONCENTRATIONS OF METALS IN NAPHTHIDES OF HYPERGENESIS ZONE : ASSESSMENT AND ENVIRONMENTAL ASPECT ». Dans GEOLINKS International Conference. SAIMA Consult Ltd, 2020. http://dx.doi.org/10.32008/geolinks2020/b1/v2/17.
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The study examines the formation of secondary-altered crude oils associated with the processes of modern or ancient hypergenesis. As a result of geological processes during intense upward movement of the earth's crust, oil undergoes physical weathering, inorganic oxidation, washing out with water, biodegradation and sulfurization, and turn into heavy oils and hard bitumen. In zones of hypergenesis, the loss of light fractions occurs and the absolute concentration of trace elements (TE) associated with resinous-asphaltene components, such as V, Ni, Co, Mo, Cr, Cu, etc. sharply increases. In addition, oils absorb elements of variable valence (V, Fe, U) from low-salinity stratal waters. As a result of experimental studies on the interaction of oils with low mineralization waters, which are characteristic of hypergenesis zones, leaching of some elements (e.g., Zn) from oils and absorption of others from contacting waters (for example, concentrations of newly-formed organometallic compounds V and Fe increased by 1.3-12 times) were found. The author utilized the method of neutron-activation analysis to study the content of TE in oils and natural bitumens of the Volga-Ural, Timan-Pechora, Kazakhstan, Tajikistan, and etc. Ore-level concentration values were found, for example: 180-1162 ppm for V and up to 100 ppm for Ni in the oils of the Melekess depression in Tatarstan, and 940 ppm for V and 130 ppm for Ni in the oils of Kazakhstan deposits. Classification of oils by the content of “biogenic” elements V, Ni, Fe and by physical and chemical properties revealed significant differences of hypergene-altered oils in the general cycle of genesis of naphthides. Deposits of secondarily-altered oils are found in a wide stratigraphic range in oil and gas basins of various geostructural types in traps of the combined morphology – lithologically and tectonically shielded. During the development of oil deposits that contain high concentrations of TE, it is necessary to take into account ecological aspects. The environmental aspect is due to the fact that many metals contained in oils – V, Ni, Cd, As, Hg, U, etc. belong to highly toxic compound chemicals.
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Herescu, Alexandru, et Jeffrey S. Allen. « Implications of Contact Line Dynamics on Taylor Bubble Flow Morphology ». Dans ASME 2010 8th International Conference on Nanochannels, Microchannels, and Minichannels collocated with 3rd Joint US-European Fluids Engineering Summer Meeting. ASMEDC, 2010. http://dx.doi.org/10.1115/fedsm-icnmm2010-30911.
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Film deposition experiments are performed in circular glass capillaries of 500 μm diameter. Two surface wettabilities are considered, contact angle of 30° for water on glass and of 105° when a hydrophobic coating is applied. It was observed that the liquid film deposited as the meniscus translates with a velocity U presents a ridge that also moves in the direction of the flow. The ridge is bounded by a contact line moving at a velocity UCL as well as a front of velocity UF, and it translates over the deposited stagnant film. The behavior of the ridge presents striking dissimilarities when the wettability is changed. Both UCL and UF are approximately twice as large for the non-wetting case at the same capillary number Ca. The Taylor bubbles forming due to the growth of the ridge are also differentiated by wettability, being much shorter in the non-wetting case. The dynamics of the contact line is studied experimentally and a criterion is proposed to explain the occurrence of a shock at the advancing front of the ridge. The hydraulic jump cannot be explained by the Froude condition of shock formation in shallow waters, or by an inertial dewetting of the deposited film. For a dynamic contact angle of θd = 6° and according to the proposed criterion, a hydraulic jump forms at the front of the ridge when a critical velocity is reached.
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Chowdhury, Manabesh, Arun Babu Nalamara, VR Sunder, Pankaj Kumar, Pinakadhar Mohapatra et Savitri Roy. « Utilization of Spectral Gamma Ray Logs to Ascertain Stratigraphic Surfaces in Carbonate Reservoir and Integration with Seismic Interpretation : An Integrated Case Study from Eocene-Oligocene Carbonate Reservoirs, D31 Cluster, Mumbai Offshore Basin, India ». Dans SPE/IATMI Asia Pacific Oil & Gas Conference and Exhibition. SPE, 2021. http://dx.doi.org/10.2118/205709-ms.
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Abstract D31 cluster is located in the prolific Mumbai Offshore Basin, Western part of India. B-192Afield is part of this cluster, where Bassein (Middle Eocene),Mukta and Panvel (Early Oligocene)Formations are the main reservoirs. The reservoirs are complex in terms of reservoir heterogeneity. They were deposited in a shallow marine carbonate platform.Sea level fluctuations andchange in depositional environment impacted the porosity development. The main objective of this study was to integrate spectral gamma ray signatures with seismic interpretation for demarcating significant stratigraphic surfaces and differentiating depositional environments for robust reservoir characterization. Regionally, Bassein Formation (Middle Eocene) is characterized by thick foraminiferal and algal wackestone, packstone and occasional grainstone facies.The Mukta Formation (Early Oligocene),which unconformably overlies the Bassein Formation, is characterized by presence of fossiliferous limestone with shale intercalations. In the present study, data from four exploration wells data have been analyzed, where spectral gamma ray log patterns in carbonate reservoirs appear to have a distinctive relationship to depositional facies and stratigraphic surfaces in the Bassein and Mukta Formations. Different cross plots have also been utilized for analyzing the depositional conditions (i.e. oxic or anoxic).Later, the spectral log interpretations have been integrated with seismic interpretation. This study is part of a larger effort for reservoir characterization, as a basis for seismic interpretation and integrated reservoir modelling. The spectral gamma ray signatures demarcated significant stratigraphic surfaces. In BasseinFormation, three different units have been marked as Upper, Middle and Lower Bassein. The major lithological boundary between the Bassein and Mukta Formation is also well demarcated with spectral GR signature. The carbonate strata of Bassein & Mukta Formation have also been subdivided with U-Th-K abundance.The "Low Th-Low U" units indicative of pure carbonate and deposition in oxidizing environment whereas "Low Th-High U"is indicative ofreducing environment, which gave a relative sea level fluctuation in the area.The major stratigraphic boundaries identified from these spectral GR logs has been incorporated in the seismicinterpretation and used for regional seismic mapping.As porosity development is governed by thesea level fluctuations,this study also gave an indication of the possibility of porous zonein the reservoir section. These results can be useful as a basis for applying spectral GR signature as a tool for stratigraphic interpretation in un-cored heterogenous carbonate sections. Along with the petrophysical interpretation, integration of core analysis, biostratigraphy and seismic attribute are critical for detailed carbonate reservoir characterization incorporating depositional environment.This approach can be applied to support commercial development of the complex carbonate reservoirs.
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Krasznai, John P. « OXIPROBE : A Non Destructive Tool for Determining Steam Generator Oxide Characteristics ». Dans ASME 2009 12th International Conference on Environmental Remediation and Radioactive Waste Management. ASMEDC, 2009. http://dx.doi.org/10.1115/icem2009-16250.
Texte intégralRésumé :
CANDU Stations are designed with significant amounts of carbon steel piping in the primary circuit. Although the primary coolant chemistry is such that carbon steel corrosion is minimized, nevertheless magnetite transport from the carbon steel surfaces to the steam generators is a significant issue leading to potential reduction in heat transfer efficiency in the steam generator. There are other contributors to the reduction of heat transfer efficiency such as divider plate leakage whereby some of the coolant short circuits the steam generator tubes and secondary side steam generator tube fouling. CANDU station operators have utilized a number of mitigating measures such as primary and secondary side mechanical and chemical tube cleaning, and divider plate refurbishment to counter these problems but these are all expensive and dose intensive, It is therefore very important to establish the relative contribution of each source to the overall heat transfer degradation problem so the most effective results are obtained. Tube removal and laboratory assessment of the oxide loading is possible and has been utilized but at best it provides an incomplete picture since typically only short lengths of tubes are removed — most often from the hot leg and the tube removal process adversely impacts the primary side oxide integrity. Kinectrics Inc. has developed, qualified and deployed Oxiprobe, a highly mobile non destructive technology able to remove and quantify the deposited oxide loading on the primary surfaces of steam generator tubes. The technology is deployed during shutdown and provides valuable, direct information on: • Primary oxide distribution within the steam generator; • Oxide loading (thickness of oxide) on the primary surfaces of steam generator tubes; • Oxide composition and radiochemical characterization. The End Effector probe can reach either side of the straight section of the steam generator U tube but as currently designed it is unable to be deployed in the U-tube region. The current technology is able to visit 4 tubes simultaneously. The technology is Code classified as a Class 6 fitting by the Canadian Nuclear Safety Commission and registered by the Ontario Technical Standards and Safety Authority as a pressure boundary retaining system. Although the application of the technology to date has been applied to steam generator tubes, in principle it can be applied to any heat exchanger tube, vertical or horizontal. This paper will describe the system, the qualification program for its deployment as well as some actual field results. The applicability of the technology for PWR steam generators is also addressed.
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Tiwari, Alok, Dhananjay Gughe, Radhika Dureja et Satinder Kaur. « Synchronous primary malignancy of ovary and cervix with different histopathology : A rare case report ». Dans 16th Annual International Conference RGCON. Thieme Medical and Scientific Publishers Private Ltd., 2016. http://dx.doi.org/10.1055/s-0039-1685388.
Texte intégralRésumé :
Concurrent different histopathological types of gynecologic tumors arise rarely. We present ovarian serous and cervical squamous cell carcinoma formed synchronously. A 51-year-old woman with a poor general condition was admitted with gradual distension of abdomen for 1 year with gradual loss of weight and appetite for the last three months and pain in the abdomen and irregular vaginal bleeding for the last two months. There was no family history of malignancy of genital tract, breast or colon. On examination she was cachexic, pale, dehydrated, tachypnoeic and had edema over feet. Per abdomen examination revealed solid, non-mobile palpable mass arising from pelvis. Per vaginal examination revealed large mass in pelvis and uterus can not be felt separately on per speculum examination there was small endocervical erosion, hypertrophied cervix. On per rectal examination bilateral parametria were free. Her tumor marker were evaluated and CA-125 was found to be raised (CA 125: 915.6 u/ml U/mL); rest tumor markers were normal. Cervical punch biopsy was suggestive of moderately differentiated carcinoma and pap smear was also suggestive of cervical cancer. MRI findings revealed a mass of altered signal intensity 2.5 × 1.5 × 2.2 cm with diffusion restriction and post contrast enhancement in the anterior lip of cervix and another large, lobulated predominantly solid mass, hypo intense on T1, intermediate on T2 with diffusion restriction and post contrast enhancement in the right adnexal region abutting the small bowel and sigmoid colon optimal debulking surgery with standard protocol was done. Histopathology report revealed squamous cell carcinoma of cervix, grade III and high grade serous cystadenocarcinoma of ovary. Tumour deposits from ovary were seen on right fallopian tube and right parametrium. Squamous cell carcinoma cervix involved ectocervix, endocervix and infiltrated near full thickness of cervical stroma, endomyometrium, vaginal cuff, paracervical tissue omentum and appendix were free of tumour. Twenty five right pelvic lymphnodes dissected were free of tumour, (00/25). One out of fifteen lymphnode dissected were involved with extra capsular extent, 01/15 and thirteen para aortic lymph node dissected were free of tumor. Immunohistochemistry markers: Ovarian mass-tumour cell expressed ck, vimentin, wt-1 with focal Ck positivity, no expression of ck20, p63, ck5/6 and CEA seen. Cervical tumour-tumour cells expressed ck, ck7, p63 and ck5/6 no expression of ck20, wt-1. Based on our case report we need to keep in mind that even if patient presents with symptoms pertaining to a single malignancy; still the rare possibility of synchronous malignancies should be looked for by doing proper investigations. In our case, patient had symptoms pertaining to ovarian malignancy; whereas cervical malignancy was diagnosed after investigating the patient. Histologic examination should be done properly as the prognosis depends on the malignancies being metastatic or synchronous one appropriate management should be offered in all such cases. Long term follow up of such patients should be maintained to determine the prognosis.
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Giri, Shveta, Swati Shah, Rupinder Sekhon et Sudhir Rawal. « Clinical outcomes of cytoreductive surgery and HIPEC in advanced and recurrent epithelial ovarian cancers with peritoneal carcinomatosis ». Dans 16th Annual International Conference RGCON. Thieme Medical and Scientific Publishers Private Ltd., 2016. http://dx.doi.org/10.1055/s-0039-1685311.
Texte intégralRésumé :
Introduction: The role of surgery for Peritoneal carcinomatosis (PC) has slowly evolved from palliation to potential curative intent. Attempting to remove all visible tumor deposits, “surgical cytoreduction” (CRS) was reported in 1930s for ovarian cancer and eventually became an accepted therapy with proven survival benefit. The new approach of combining CRS and Hyperthermic intraperitoneal chemotherapy (HIPEC) to treat peritoneal metastasis offer hope for long term survival in this group of patients. The risk and benefit of this approach continued to be debated. A prospective study was conducted to understand the perioperative outcomes of CRS & HIPEC. Aim: To evaluate the perioperative outcomes associated with CRS & HIPEC in Advanced and Recurrent Epithelial Ovarian Cancer with PC. Methods: Prospective analysis of patients undergoing CRS & HIPEC from November 2014 to July 2015 was done. Inclusion criteria included localized disease in peritoneal cavity, no distant metastasis and PS <2. Grade 3/4 complications from day of surgery until 30 days postoperatively were recorded. Results: We performed CRS & HIPEC in 20 patients from Nov 2014 to June 2015. HIPEC Plus regimens included Cisplatin (50 mg/m2) and Lipodox (15 mg/m2) intraperitoneally and Ifosphamide (1300 mg/m2) & Mesna (260 mg/m2) Infusion time was 90 minutes with a temperature range of 41-43 °C. Out of 20 patients 6 (30%) underwent primary debulking surgery and 14(70%) underwent secondary debulking surgery. PCI score ranged from 2-26 (mean 13.65). Mean operating time was 6.42 hrs and average blood loss was 1046 ml. Average hospital stay was 8 days and SICU stay was 4.9 days (range 3-14 days). Total 26 adverse events were observed of which grade 1 were 11 (42%), grade 2 were 8 (30%), grade were 3 (11.5%) and grade4 were 2 (8%). Most common complication was hematological (8) followed by respiratory (6), sepsis (4) renal (2), GI (2). 4 patients (5 events) developed grade3 or 4 complications in the form of septicaemia, pulmonary embolism, GI fistula of which 2 patients expited and remaining recovered although required prolonged hospitalization. Increased morbidity were observed in cases with symptomatic relapse, higher PCI score and CA 125 level higher than 250 U/ml. Most of the adverse events were grade 1 and 2 and were managed by observation only or GCSF support, transfusions and other minor interventions. The combined grade 3-4 morbidity was 20% (4out of 20) which consisted of neutropenia, infection and respiratory complications. One patient required relaparotomy and two patients expired attributed to pulmonary embolism and septicaemia respectively. Conclusion: Enthusiasm associated with improvement in survival is often dampened by increased perioperative mortality and morbidity figures and therefore CRS & HIPEC has not yet been considered standard of care by many centres. HIPEC after extensive cytoreductive surgery for ovarian cancer is a procedure whth acceptable morbidity that patients can tolerate. More follow up is needed to determinr the effect of HIPEC on survival. Till such time more data are obtained by way of larger randomised trials, this approach remains investigational.
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Giri, Shveta, Swati Shah, Rupinder Sekhon et Sudhir Rawal. « Clinical outcomes of cytoreductive surgery and HIPEC in advanced and recurrent epithelial ovarian cancers with peritoneal carcinomatosis ». Dans 16th Annual International Conference RGCON. Thieme Medical and Scientific Publishers Private Ltd., 2016. http://dx.doi.org/10.1055/s-0039-1685300.
Texte intégralRésumé :
Introduction: The role of surgery for peritoneal carcinomatosis (PC) has slowly evolved from palliation to potential curative intent. Attempting to remove all visible tumor deposits, “surgical cytoreduction” (CRS) was reported in 1930s for ovarian cancer and eventually became an accepted therapy with proven survival benefit. The new approach of combining CRS and hyperthermic intraperitoneal chemotherapy (HIPEC) to treat peritoneal metastasis offer hope for long term survival in this group of patients. The risk and benefit of this approach continued to be debated. A prospective study was conducted to understand the perioperative outcomes of CRS and HIPEC. Aim: To evaluate the perioperative outcomes associated with CRS and HIPEC in Advanced and Recurrent Epithelial Ovarian Cancer with PC. Method: Prospective analysis of patients undergoing CRS and HIPEC from November 2014 to July 2015 was done. Inclusion criteria included localized disease in peritoneal cavity, no distant metastasis and PS <2. Grade 3/4 complications from day of surgery until 30 days postoperatively were recorded. Results: We performed CRS and HIPEC in 20 patients from November 2014 to June 2015. HIPEC Plus regimens included Cisplatin (50 mg/m2) and Lipodox (15 mg/m2) intraperitoneally and Ifosphamide (1300 mg/m2) and Mesna (260 mg/m2). Infusion time was 90 minutes with a temperature range of 41-43°C. Out of 20 patients 6 (30%) underwent primary debulking surgery and 14 (70%) underwent secondary debulking surgery. PCI score ranged from 2-26 (mean 13.65). Mean operating time was 6.42 hrs and average blood loss was 1046 ml. Average hospital stay was 8 days and SICU stay was 4.9 days (range 3-14 days). Total 26 adverse events were observed of which grade 1 were 11 (42%), grade 2 were 8 (30%), grade were 3 (11.5%) and grade 4 were 2 (8%). Most common complication was hematological (8) followed by respiratory (6), sepsis (4) renal (2), GI (2). 4 patients (5 events) developed grade 3 or 4 complications in the form of septicaemia, pulmonary embolism, GI fistula of which 2 patients expited and remaining recovered although required prolonged hospitalization. Increased morbidity were observed in cases with symptomatic relapse, higher PCI score and CA 125 level higher than 250 U/ml. Most of the adverse events were grade 1 and 2 and were managed by observation only or GCSF support, transfusions and other minor interventions. The combined grade 3-4 morbidity was 20% (4 out of 20) which consisted of neutropenia, infection and respiratory complications. One patient required relaparotomy and two patients expired attributed to pulmonary embolism and septicaemia respectively. Conclusion: Enthusiasm associated with improvement in survival is often dampened by increased perioperative mortality and morbidity figures and therefore CRS and HIPEC has not yet been considered standard of care by many centres. HIPEC after extensive cytoreductive surgery for ovarian cancer is a procedure whth acceptable morbidity that patients can tolerate. More follow up is needed to determinr the effect of HIPEC on survival. Till such time more data are obtained by way of larger randomised trials, this approach remains investigational.
Rapports d'organisations sur le sujet "U-ore deposit"
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Corriveau, L., E. G. Potter, J. F. Montreuil, O. Blein, K. Ehrig et A. F. De Toni. Iron-oxide and alkali-calcic alteration ore systems and their polymetallic IOA, IOCG, skarn, albitite-hosted U±Au±Co, and affiliated deposits : a short course series. Part 2 : overview of deposit types, distribution, ages, settings, alteration facies, and ore deposit models. Natural Resources Canada/ESS/Scientific and Technical Publishing Services, 2018. http://dx.doi.org/10.4095/306560.
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Kontak, D. J., A. M. McDonald, R. Poulin, J. Petrus et M B McClenaghan. Scheelite as a possible ore-deposit discriminator based on luminescence, trace-element chemistry, delta-18O signature, fluid inclusions, and U-Pb geochronology. Natural Resources Canada/ESS/Scientific and Technical Publishing Services, 2017. http://dx.doi.org/10.4095/306315.
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Jackson, G. D. Bedrock geology, northwest part of Nuluujaak Mountain, Baffin Island, Nunavut, part of NTS 37-G/5. Natural Resources Canada/CMSS/Information Management, 2021. http://dx.doi.org/10.4095/314670.
Texte intégralRésumé :
The map area lies about 40 km northwest of Baffinland's iron mine. Dykes of unit mAnA3 within unit mAnA2 suggest that unit mAnA2 predates unit mAnA3. Unit nAMqf, basal Mary River Group unit, includes regolith material from units mAnA2 and mAnA3. Unit mAnAm may include some dykes of unit nAMb. The Mary River Group was deposited in a volcanic-arc environment, yielding zircon U-Pb ages mostly in the range of 2.88 to 2.72 Ga. Iron-formation (unit nAMi) is approximately 276 m thick locally, with oxide facies (unit nAMio) being most abundant. The quartzite triangle west of 'Iron lake' (unofficial name) may be a small horst. The main east-west-trending synclinal fold, including the area around 'Iron lake' and the no. 4 ore deposit, is upright, nearly isoclinal, and plunges mostly easterly at both ends with small scale anticlines and synclines in the middle. Magnetite constitutes about 75% of high-grade iron deposits in the north limb, whereas hematite predominates in south-limb deposits. K-Ar and Rb-Sr ages indicate middle Paleoproterozoic overprinting. Central Borden Fault Zone was active at ca. 1.27 Ga and during or after Ordovician time. Note: please be aware that the information contained in CGM 408 is based on legacy data from the 1960-1990s and that it has been superseded by regional-scale information contained in CGM 403.
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Corriveau, L., J. F. Montreuil, O. Blein, E. Potter, M. Ansari, J. Craven, R. Enkin et al. Metasomatic iron and alkali calcic (MIAC) system frameworks : a TGI-6 task force to help de-risk exploration for IOCG, IOA and affiliated primary critical metal deposits. Natural Resources Canada/CMSS/Information Management, 2021. http://dx.doi.org/10.4095/329093.
Texte intégralRésumé :
Australia's and China's resources (e.g. Olympic Dam Cu-U-Au-Ag and Bayan Obo REE deposits) highlight how discovery and mining of iron oxide copper-gold (IOCG), iron oxide±apatite (IOA) and affiliated primary critical metal deposits in metasomatic iron and alkali-calcic (MIAC) mineral systems can secure a long-term supply of critical metals for Canada and its partners. In Canada, MIAC systems comprise a wide range of undeveloped primary critical metal deposits (e.g. NWT NICO Au-Co-Bi-Cu and Québec HREE-rich Josette deposits). Underexplored settings are parts of metallogenic belts that extend into Australia and the USA. Some settings, such as the Camsell River district explored by the Dene First Nations in the NWT, have infrastructures and 100s of km of historic drill cores. Yet vocabularies for mapping MIAC systems are scanty. Ability to identify metasomatic vectors to ore is fledging. Deposit models based on host rock types, structural controls or metal associations underpin the identification of MIAC-affinities, assessment of systems' full mineral potential and development of robust mineral exploration strategies. This workshop presentation reviews public geoscience research and tools developed by the Targeted Geoscience Initiative to establish the MIAC frameworks of prospective Canadian settings and global mining districts and help de-risk exploration for IOCG, IOA and affiliated primary critical metal deposits. The knowledge also supports fundamental research, environmental baseline assessment and societal decisions. It fulfills objectives of the Canadian Mineral and Metal Plan and the Critical Mineral Mapping Initiative among others. The GSC-led MIAC research team comprises members of the academic, private and public sectors from Canada, Australia, Europe, USA, China and Dene First Nations. The team's novel alteration mapping protocols, geological, mineralogical, geochemical and geophysical framework tools, and holistic mineral systems and petrophysics models mitigate and solve some of the exploration and geosciences challenges posed by the intricacies of MIAC systems. The group pioneers the use of discriminant alteration diagrams and barcodes, the assembly of a vocab for mapping and core logging, and the provision of field short courses, atlas, photo collections and system-scale field, geochemical, rock physical properties and geophysical datasets are in progress to synthesize shared signatures of Canadian settings and global MIAC mining districts. Research on a metamorphosed MIAC system and metamorphic phase equilibria modelling of alteration facies will provide a foundation for framework mapping and exploration of high-grade metamorphic terranes where surface and near surface resources are still to be discovered and mined as are those of non-metamorphosed MIAC systems.
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Rempel, K. U., A. E. Williams-Jones et K. Fuller. An experimental investigation of the solubility and speciation of uranium in hydrothermal ore fluids. Natural Resources Canada/CMSS/Information Management, 2021. http://dx.doi.org/10.4095/328995.
Texte intégralRésumé :
Experimental data on the solubility and speciation of uranium in hydrothermal solution is required to improve genetic models for the formation of ore deposits, yet very few data of this type have been published. Of particular interest is the oxidation state of the uranium in solution, as conventional wisdom suggests that U is dissolved in the oxidized U(VI) state and precipitated as reduced U(IV) minerals, yet recent experiments have shown ppm-level solubility for U(IV). This study investigated the mobility of reduced U(IV) and oxidized U(VI) in acidic (pH = 2), fluoride- bearing and alkaline (pH = 10), chloride-bearing solutions at 100-200°C and 1 to 15.8 bars (0.1-1.58 MPa). Preliminary data for the mobility of U(IV) in pH 2 fluids with 0.01 m F- show concentrations of 1.76 to 3.92 ppm U at 200°C, indicating that, contrary to common belief, the reduced U(IV) can be transported in solution. We have also conducted experiments on U(VI) solubility in pH 2 fluoride-bearing, and pH 10 chloride-bearing solutions. Uranium concentrations in the F- -bearing experiments ranged from 624 to 1570 ppm (avg. 825 ppm, n = 6) at 100°C, 670 to 1560 ppm (avg. 931 ppm, n = 4) at 150°C, and 3180 to 7550 ppm (avg. 5240, n = 9) at 200°C. In comparison, U concentrations in the Cl- -bearing runs range from 86.1 to 357 ppm (avg. 185 ppm, n = 15) at 200°C. Clearly, oxidized U(VI) is very readily mobilized in hydrothermal fluids. However, the measured concentrations of U(VI) are independent of those of F- or Cl-, suggesting the formation of U oxide or hydroxide species rather than U chlorides or fluorides. These experimental data will be verified and supplemented in future experiments, which will be used to derive the stoichiometry and thermodynamic constants for the dominant uranium species in hydrothermal solutions. The data from this study will then be integrated into a comprehensive genetic model for uranium ore-forming systems.
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Piercey, S. J., et J. L. Pilote. Nd-Hf isotope geochemistry and lithogeochemistry of the Rambler Rhyolite, Ming VMS deposit, Baie Verte Peninsula, Newfoundland : evidence for slab melting and implications for VMS localization. Natural Resources Canada/CMSS/Information Management, 2021. http://dx.doi.org/10.4095/328988.
Texte intégralRésumé :
New high precision lithogeochemistry and Nd and Hf isotopic data were collected on felsic rocks of the Rambler Rhyolite formation from the Ming volcanogenic massive sulphide (VMS) deposit, Baie Verte Peninsula, Newfoundland. The Rambler Rhyolite formation consists of intermediate to felsic volcanic and volcaniclastic rocks with U-shaped primitive mantle normalized trace element patterns with negative Nb anomalies, light rare earth element-enrichment (high La/Sm), and distinctively positive Zr and Hf anomalies relative to surrounding middle rare earth elements (high Zr-Hf/Sm). The Rambler Rhyolite samples have epsilon-Ndt = -2.5 to -1.1 and epsilon-Hft = +3.6 to +6.6; depleted mantle model ages are TDM(Nd) = 1.3-1.5 Ga and TDM(Hf) = 0.9-1.1Ga. The decoupling of the Nd and Hf isotopic data is reflected in epsilon-Hft isotopic data that lies above the mantle array in epsilon-Ndt -epsilon-Hft space with positive ?epsilon-Hft values (+2.3 to +6.2). These Hf-Nd isotopic attributes, and high Zr-Hf/Sm and U-shaped trace element patterns, are consistent with these rocks having formed as slab melts, consistent with previous studies. The association of these slab melt rocks with Au-bearing VMS mineralization, and their FI-FII trace element signatures that are similar to rhyolites in Au-rich VMS deposits in other belts (e.g., Abitibi), suggests that assuming that FI-FII felsic rocks are less prospective is invalid and highlights the importance of having an integrated, full understanding of the tectono-magmatic history of a given belt before assigning whether or not it is prospective for VMS mineralization.
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Corriveau, L. Iron-oxide and alkali-calcic alteration ore systems and their polymetallic IOA, IOCG, skarn, albitite-hosted U±Au±Co, and affiliated deposits : a short course series. Part 1 : introduction. Natural Resources Canada/ESS/Scientific and Technical Publishing Services, 2017. http://dx.doi.org/10.4095/300241.
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Harris, L. B., P. Adiban et E. Gloaguen. The role of enigmatic deep crustal and upper mantle structures on Au and magmatic Ni-Cu-PGE-Cr mineralization in the Superior Province. Natural Resources Canada/CMSS/Information Management, 2021. http://dx.doi.org/10.4095/328984.
Texte intégralRésumé :
Aeromagnetic and ground gravity data for the Canadian Superior Province, filtered to extract long wavelength components and converted to pseudo-gravity, highlight deep, N-S trending regional-scale, rectilinear faults and margins to discrete, competent mafic or felsic granulite blocks (i.e. at high angles to most regional mapped structures and sub-province boundaries) with little to no surface expression that are spatially associated with lode ('orogenic') Au and Ni-Cu-PGE-Cr occurrences. Statistical and machine learning analysis of the Red Lake-Stormy Lake region in the W Superior Province confirms visual inspection for a greater correlation between Au deposits and these deep N-S structures than with mapped surface to upper crustal, generally E-W trending, faults and shear zones. Porphyry Au, Ni, Mo and U-Th showings are also located above these deep transverse faults. Several well defined concentric circular to elliptical structures identified in the Oxford Stull and Island Lake domains along the S boundary of the N Superior proto-craton, intersected by N- to NNW striking extensional fractures and/or faults that transect the W Superior Province, again with little to no direct surface or upper crustal expression, are spatially associated with magmatic Ni-Cu-PGE-Cr and related mineralization and Au occurrences. The McFaulds Lake greenstone belt, aka. 'Ring of Fire', constitutes only a small, crescent-shaped belt within one of these concentric features above which 2736-2733 Ma mafic-ultramafic intrusions bodies were intruded. The Big Trout Lake igneous complex that hosts Cr-Pt-Pd-Rh mineralization west of the Ring of Fire lies within a smaller concentrically ringed feature at depth and, near the Ontario-Manitoba border, the Lingman Lake Au deposit, numerous Au occurrences and minor Ni showings, are similarly located on concentric structures. Preliminary magnetotelluric (MT) interpretations suggest that these concentric structures appear to also have an expression in the subcontinental lithospheric mantle (SCLM) and that lithospheric mantle resistivity features trend N-S as well as E-W. With diameters between ca. 90 km to 185 km, elliptical structures are similar in size and internal geometry to coronae on Venus which geomorphological, radar, and gravity interpretations suggest formed above mantle upwellings. Emplacement of mafic-ultramafic bodies hosting Ni-Cr-PGE mineralization along these ringlike structures at their intersection with coeval deep transverse, ca. N-S faults (viz. phi structures), along with their location along the margin to the N Superior proto-craton, are consistent with secondary mantle upwellings portrayed in numerical models of a mantle plume beneath a craton with a deep lithospheric keel within a regional N-S compressional regime. Early, regional ca. N-S faults in the W Superior were reactivated as dilatational antithetic (secondary Riedel/R') sinistral shears during dextral transpression and as extensional fractures and/or normal faults during N-S shortening. The Kapuskasing structural zone or uplift likely represents Proterozoic reactivation of a similar deep transverse structure. Preservation of discrete faults in the deep crust beneath zones of distributed Neoarchean dextral transcurrent to transpressional shear zones in the present-day upper crust suggests a 'millefeuille' lithospheric strength profile, with competent SCLM, mid- to deep, and upper crustal layers. Mechanically strong deep crustal felsic and mafic granulite layers are attributed to dehydration and melt extraction. Intra-crustal decoupling along a ductile décollement in the W Superior led to the preservation of early-formed deep structures that acted as conduits for magma transport into the overlying crust and focussed hydrothermal fluid flow during regional deformation. Increase in the thickness of semi-brittle layers in the lower crust during regional metamorphism would result in an increase in fracturing and faulting in the lower crust, facilitating hydrothermal and carbonic fluid flow in pathways linking SCLM to the upper crust, a factor explaining the late timing for most orogenic Au. Results provide an important new dataset for regional prospectively mapping, especially with machine learning, and exploration targeting for Au and Ni-Cr-Cu-PGE mineralization. Results also furnish evidence for parautochthonous development of the S Superior Province during plume-related rifting and cannot be explained by conventional subduction and arc-accretion models.
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Knight, R. D., et B. A. Kjarsgaard. Comparative pXRF and Lab ICP-ES/MS methods for mineral resource assessment, Northwest Territories. Natural Resources Canada/CMSS/Information Management, 2022. http://dx.doi.org/10.4095/331239.
Texte intégralRésumé :
The Geological Survey of Canada undertook a mineral resource assessment for a proposed national park in northern Canada (~ 33,500 km2) spanning the transition from boreal forest to barren lands tundra. Bedrock geology of this region is complex and includes the Archean Slave Craton, the Archean and Paleoproterozoic Rae domain of the Churchill Province, the Paleoproterozoic Thelon and Taltson magmatic-tectonic zones, and the Paleoproterozoic East Arm sedimentary basin. The area has variable mineral potential for lode gold, kimberlite-hosted diamonds, VMS, vein uranium and copper, SEDEX, as well as other deposit types. A comparison of analytical methods was carried out after processing the field collected samples to acquire both the &lt; 2 mm and for the &lt; 0.063 mm size fractions for 241 surficial sediment (till) samples, collected using a 10 x 10 km grid. Analytical methods comprised: 1) aqua regia followed by ICP-MS analysis, 2) 4-acid hot dissolution followed by ICP-ES/MS analysis, 3) lithium metaborate/tetraborate fusion methods followed by ICP-ES for major elements and ICP-MS for trace elements and, 4) portable XRF on dried, non-sieved sediment samples subjected to a granular segregation processing technique (to produce a clay-silt proxy) for seventeen elements (Ba, Ca, Cr, Cu, Fe, K, Mn, Ni, Pb, Rb, Sr, Th, Ti, U, V, Zn, and Zr) Results indicate that pXRF data do not replicate exactly the laboratory 4-acid and fusion data (in terms of precision and accuracy), but the relationship between the datasets is systematic as displayed in x-y scattergrams. Interpolated single element plots indicate that till samples with anomalies of high and low pXRF concentration levels are synonymous with high and low laboratory-based analytical concentration levels, respectively. The pXRF interpolations thus illustrate the regional geochemical trends, and most importantly, the significant geochemical anomalies in the surficial samples. These results indicate that pXRF spectrometry for a subset of elements is comparable to traditional laboratory methods. pXRF spectrometry also provides the benefit of rapid analysis and data acquisition that has a direct influence on real time sampling designs. This information facilitates efficient and cost-effective field projects (i.e. where used to identify regions of interest for high density sampling), and to prioritize samples to be analyzed using traditional geochemical methods. These tactics should increase the efficiency and success of a mineral exploration and/or environmental sampling programs.