Artículos de revistas sobre el tema "Fluides – Provenance"
Siga este enlace para ver otros tipos de publicaciones sobre el tema: Fluides – Provenance.
Crea una cita precisa en los estilos APA, MLA, Chicago, Harvard y otros
Consulte los 50 mejores artículos de revistas para su investigación sobre el tema "Fluides – Provenance".
Junto a cada fuente en la lista de referencias hay un botón "Agregar a la bibliografía". Pulsa este botón, y generaremos automáticamente la referencia bibliográfica para la obra elegida en el estilo de cita que necesites: APA, MLA, Harvard, Vancouver, Chicago, etc.
También puede descargar el texto completo de la publicación académica en formato pdf y leer en línea su resumen siempre que esté disponible en los metadatos.
Explore artículos de revistas sobre una amplia variedad de disciplinas y organice su bibliografía correctamente.
1
Calandra, Sara, Emma Cantisani, Silvia Vettori, Marilena Ricci, Beatrice Agostini y Carlo Alberto Garzonio. "The San Giovanni Baptistery in Florence (Italy): Assessment of the State of Conservation of Surfaces and Characterization of Stone Materials". Applied Sciences 12, n.º 8 (16 de abril de 2022): 4050. http://dx.doi.org/10.3390/app12084050.
Texto completoResumen
During the last restoration campaign of the Baptistery of San Giovanni in Florence (Italy), the assessment of the state of conservation of external surfaces was performed, with a multi-analytical approach, in order to support the conservation and restoration treatments. Black crusts, red staining, sulphation, and organic patinas were identified. Moreover, a complete characterization of marble cladding, bricks, and mortars was carried out. A geochemical and minero-petrographic approach was used in order to classify and assess the provenance of marbles, and define raw materials and technologies of the production for bricks and mortars. Provenances from Italy (Carrara and Lasa marbles) and from Greece (Hymettus and Pentelicum marbles) were identified and attributed to different construction phases, restoration interventions, and re-use of ancient materials. For mortars, the obtained data suggested the use of local materials and traditional technologies for the production. Overall, two different minero-petrographic typologies were identified for the analyzed bricks.
2
Tang, Deyou, Rong Zhao, Yuebang Lin, Tangqing Zhang y Pingjian Zhang. "Modeling the Data Provenance of Relational Databases Supporting Full-Featured SQL and Procedural Languages". Applied Sciences 13, n.º 1 (21 de diciembre de 2022): 64. http://dx.doi.org/10.3390/app13010064.
Texto completoResumen
Data provenance is information about where data come from (provenance data) and how they transform (provenance transformation). Data provenance is widely used to evaluate data quality, trace errors, audit data, and understand references among data. Current studies on data provenance in relational database management systems (RDBMS) still have limitations in supporting full-featured SQL or procedural languages. With these challenges in mind, we present a formal definition of provenance data and provenance transformation for relational data. Then, we propose a solution to support data provenance in relational databases, including provenance graphs and provenance routes. Our method not only solves the complicated problem of modeling provenance in DBMS but also is capable of extending procedural languages in SQL. We also present ProvPg, a PostgreSQL-based prototype database system supporting data provenance in multiple granularities. ProvPg implements extraction, calculation, query, and visualization of provenance. We perform TPC-H tests for ProvPg and PostgreSQL, respectively. Experimental results show that ProvPg addresses the vision of supporting data provenance with little extra computation overhead for the execution engine, which indicates that our model is applicable to lineage tracing applications.
3
Boose, Jörg, Andreas Schmidt Mumm y Uwe Giese. "Petrographic, cathodoluminescence and fluid inclusion studies as provenance indicators of Early Palaeozoic sediments of Rügen, Germany". Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen 222, n.º 1-2 (26 de septiembre de 2001): 193–214. http://dx.doi.org/10.1127/njgpa/222/2001/193.
Texto completo
4
Ye, Qian y Minyan Lu. "s2p: Provenance Research for Stream Processing System". Applied Sciences 11, n.º 12 (15 de junio de 2021): 5523. http://dx.doi.org/10.3390/app11125523.
Texto completoResumen
The main purpose of our provenance research for DSP (distributed stream processing) systems is to analyze abnormal results. Provenance for these systems is not nontrivial because of the ephemerality of stream data and instant data processing mode in modern DSP systems. Challenges include but are not limited to an optimization solution for avoiding excessive runtime overhead, reducing provenance-related data storage, and providing it in an easy-to-use fashion. Without any prior knowledge about which kinds of data may finally lead to the abnormal, we have to track all transformations in detail, which potentially causes hard system burden. This paper proposes s2p (Stream Process Provenance), which mainly consists of online provenance and offline provenance, to provide fine- and coarse-grained provenance in different precision. We base our design of s2p on the fact that, for a mature online DSP system, the abnormal results are rare, and the results that require a detailed analysis are even rarer. We also consider state transition in our provenance explanation. We implement s2p on Apache Flink named as s2p-flink and conduct three experiments to evaluate its scalability, efficiency, and overhead from end-to-end cost, throughput, and space overhead. Our evaluation shows that s2p-flink incurs a 13% to 32% cost overhead, 11% to 24% decline in throughput, and few additional space costs in the online provenance phase. Experiments also demonstrates the s2p-flink can scale well. A case study is presented to demonstrate the feasibility of the whole s2p solution.
5
Xu, Tao, Ling Feng, Wen Yin, Jinpeng Wei, Yarong Wang y Xianli Zou. "Element Geochemical Characteristics and Provenance Conditions of the 1st Member of Jurassic Zhongjiangou Formation in Wudun Sag, Dunhuang Basin". Applied Sciences 12, n.º 9 (20 de abril de 2022): 4110. http://dx.doi.org/10.3390/app12094110.
Texto completoResumen
In order to clarify the provenance of the 1st member of the Zhongjiangou formation in Wudun sag, Dunhuang basin, the structural attributes, weathering and sedimentary characteristics of the provenance area were analyzed by means of element geochemistry, so as to determine the differences of sediment sources in different well areas. The results show that the higher the Al2O3 and K2O contents, the higher the enrichment of large ion lithophile elements and high field strength elements, while the iron and magnesium elements are relatively deficient, and there are characteristics of medium degree differentiation of light and heavy rare earth elements in Well XC1 and Well D2. The lower the Al2O3 content and the higher the SiO2 content, a loss of large ion lithophile elements and high field strength elements are observed, while the ferrophilic magnesium elements show serious loss, as shown in the characteristics of the high degree of differentiation of light and heavy rare earth elements in Well D1. In the UCC-normalized element spidergrams, the trend of Well XC1 and Well D2 is similar, which is different from that of well D1, indicating that the sediments of Well XC1 and Well D2 come from the same provenance area, while the sediment of Well D1 comes from a different provenance area. The provenance area of Well XC1 and Well D2 shows strong tectonic activity and strong weathering, while the provenance area of well D1 exhibits relatively weak tectonic activity and weathering. Combined with previous research results, Wudun sag is mainly characterized by a faulted lacustrine basin controlled by the southern boundary fault in the Jurassic layer. Therefore, the sediments of Well XC1 and Well D2 mainly come from the southern Sanweishan uplift provenance area, with strong tectonic activity; the sediments of Well D1 mainly come from the northern Beishan provenance area, with relatively weak tectonic activity.
6
Kan, Wenguang, Zailin Yang, Liangliang Yu y Menghan Sun. "Provenance and Tectonic Setting of Formation of Quaternary Sedimentary Successions from the Songhua River, Northeast China". Applied Sciences 12, n.º 15 (22 de julio de 2022): 7356. http://dx.doi.org/10.3390/app12157356.
Texto completoResumen
Drilling has been conducted to investigate the petrogeochemistry of the Late Pleistocene Guxiangtun Formation and Holocene Wenquanhe Formation in Northeast China. Both Guxiangtun and Wenquanhe Formations are fluvial facies, which are composed mainly of quartz and feldspar, with minor mica and clay minerals. To understand the provenance and tectonic setting of these sediments, geochemical analyses of fifteen selected samples from the drill core have been carried out. Compared to the composition of the upper continental crust (UCC), the sediments exhibit higher SiO2, similar TiO2 and K2O, and lower Fe2O3, MgO, MnO, CaO, and Na2O contents. The bivariant plot of Th/Sc versus Zr/Sc ratios indicates the contribution from recycled sedimentary provenance for our studied sediments; furthermore, the low to medium degree of weathering of these sediments is commonly indicated by the chemical index of alteration (CIA) of 52. The discriminant function diagram using major elements shows a mixed provenance of the sediments, including quartzose sedimentary and felsic igneous rocks. According to the Fe2O3+MgO vs. K2O/Na2O plot and Th–Sc–Zr/10 diagram, the sediments under the investigation fall mostly within the active continent margin field.
7
Ao, Cong, Xue-Ming Teng, Xue-Bin Wei, Tao Lei, Duo Wang y Jun Yang. "Geochemistry of Mudstones/Silty Mudstones from the Qigequan Formation and Shizigou Formation in Yuejin-II Area, Southwestern Area of the Qaidam Basin: Implications for Sedimentary Environment and Sandstone-Type Uranium Mineralization". Minerals 12, n.º 5 (23 de mayo de 2022): 658. http://dx.doi.org/10.3390/min12050658.
Texto completoResumen
The Qaidam Basin has been the focus of sandstone-type uranium prospecting since the 1950s. In recent years, relying on the uranium geological survey project supported by the China Geological Survey, and the cooperation with the Qinhai oil company, drilling work at the Yuejin-II area in this basin has achieved breakthroughs on industrial-level sandstone-type uranium exploration. In this study, we present major, trace and REE geochemical analysis of the Qigequan Formation and the Shizigou Formation mudstones/silty mudstones collected from an industrial uranium ore drillholes in the Yuejin-II area. The Shizigou and Qigequan Formations exhibit signatures of non-intense alteration, low rock maturity and proximal provenance. The overall arid paleoclimatic conditions controlled the sedimentation of large volume of uranium rich materials. The period of relative humidity prompted the sedimentation of reduced agents. Aided by the neotectonic-induced slopes and tectonic windows, oxygenated fluids migrated along permeable layers and extracted the hexavalent uranium, transported in the form of uranyl ion (UO22+). When the oxygen–uranium-rich fluids finally infiltrated into the reductive sand body, the hexavalent uranium was reduced to tetravalent uranium and deposited in the form of uranium compounds. Large-scale and centrally distributed reductive sand bodies provided favorable ore storage space for the sandstone-type uranium mineralization in the Yuejin-II area.
8
Men, Yekai, Ende Wang, Jianfei Fu, Sanshi Jia, Xinwei You y Qiangwen He. "Geology and geochemistry of the Yuanjiacun banded iron formation in Shanxi Province, China: constraints on the genesis". Geological Magazine 156, n.º 11 (15 de abril de 2019): 1839–62. http://dx.doi.org/10.1017/s0016756819000219.
Texto completoResumen
AbstractThe Yuanjiacun banded iron formation (BIF) is hosted in lower Proterozoic metamorphic strata, and its structures are dominated by bands or streaks. Based on their differences in mineral compositions, the iron ores can be subdivided into haematite quartzite, magnetite quartzite, stilpnomelane magnetite quartzite and stilpnomelane haematite quartzite. The geochemical characteristics of the surrounding rocks show that the protoliths consisted of argillaceous and arenaceous sedimentary rocks. The predominant provenance was a high-maturity felsic sedimentary terrane. The absence of syn-depositional igneous rocks and the tectonic setting discrimination diagrams indicate that the Yuanjiacun BIF formed in a passive continental margin setting. Negligible terrigenous materials were involved in the precipitation of the Yuanjiacun BIF. The precipitation of the Yuanjiacun BIF was predominantly controlled by the mixing of seawater and hydrothermal fluids. Its metallogenic material originated from the leaching of mafic oceanic crust by hydrothermal fluids. The observed Ce anomaly deficiency and heavy Fe isotope enrichment indicate that the Yuanjiacun BIF formed in an anoxic marine environment. In a redox-stratified palaeo-ocean, the Yuanjiacun BIF formed in reducing seawater below the oxidation–reduction transition zone. The Si and O isotope compositions of quartz suggest that the formation of the Yuanjiacun BIF was closely related to submarine hydrothermal activity. The Si and Fe erupted from the seafloor and precipitated by supersaturation and biological oxidation under anoxic conditions, respectively.
9
Yan, Zhaobin, Hongjie Ji, Guolin Guo, Fei Xia, Wenwen Zhang, Saisai Song y Shaofang Liu. "Geochemical Characteristics of Trace Elements and REEs and their Geological Significance for Uranium Mineralization within the Qianjiadian Sandstone-Hosted Uranium Deposit, Songliao Basin". Geofluids 2023 (20 de abril de 2023): 1–16. http://dx.doi.org/10.1155/2023/6297033.
Texto completoResumen
The Qianjiadian uranium deposit is a typical interstratified oxidized zone sandstone-hosted uranium deposit hosted in the Upper Cretaceous Yaojia Formation of the southern Songliao Basin. Despite its significance, little research has been conducted on the relationship between trace elements, REEs, and uranium mineralization in this deposit. This study presents new geochemical data from sandstones in the oxidation, transition, and reduction zones. The sandstones in the transition zone are highly enriched in U and moderately enriched in Mo, Cd, and V compared to those in the oxidation and reduction zones. They are also weakly enriched in Co, Ni, and Zn. The oxidation and transition zone sandstones have higher ∑LREE and ∑HREE contents than those in the reduction zone. However, the oxidation zone sandstones are characterized by LREE enrichment and flat HRRE distribution, while the transition zone sandstones show HRRE enrichment and flat LREE distribution. These trace element and REE differentiation characteristics within each subzone are closely related to the geological process of interstratified oxygenation. Oxygenated uranium-bearing fluids from southwestern provenance areas carried multiple trace elements and REEs and infiltrated along the oxidation sandstones to reach the Yaojia Formation’s transition zone. During this process, a certain amount of Mo, V, Cd, and LREE from the oxygenated ore-forming fluids was precipitated by Fe-Mn hydroxide adsorption or calcite and siderite cementation. Meanwhile, about 20.33% of preexisting U in the oxidation zone sandstones was continuously extracted and entered into the oxygenated ore-forming fluids. In the transition zone, where dissolved oxygen was exhausted and hydrocarbons were continuously injected, U, Mo, Cd, V, Co, Ni, Zn, and REEs were unloaded and precipitated as uranium minerals, sulfide minerals, or carbonate minerals. The enrichment of Mo, Cd, V, and HREEs in the sandstones can serve as new prospecting indicators for the Qianjiadian uranium deposit.
10
Li, Jing, Peng Wu, Guanghua Yang, Lei Pan, Xinguo Zhuang, Xavier Querol, Natalia Moreno, Baoqing Li y Yunfei Shangguan. "Enrichment of Li–Ga–Zr–Hf and Se–Mo–Cr–V–As–Pb Assemblages in the No. 11 Superhigh Organic Sulfur Coal from the Sangshuping Coal Mine, Weibei Coalfield, Shaanxi, North China". Energies 13, n.º 24 (17 de diciembre de 2020): 6660. http://dx.doi.org/10.3390/en13246660.
Texto completoResumen
Superhigh organic sulfur(SHOS) coals have currently attracted great attention due to their typical depositional environments and formation history as well as their great negative impact on the ecosystem. This study investigated the geochemistry of the No. 11coalof the Late Carboniferous Taiyuan Formation from the Sangshuping coalmine, Hancheng miningarea, Weibei coalfield, Shaanxi, North China. The No. 11 coal is a high-sulfur coal with a large proportion of organic sulfur content (3.7 to 5.5%, avg. 4.4%) and belongs to typical SHOS coal. The high sulfur content in the Sangshuping coal mine has been mainly caused by the combined influences of seawater and hydrothermal fluids. The SHOS in No. 11 coal was formed in the Fe-poor and S-rich high-marine influenced occlusive environment. During the late coalification stage, a high proportion of pyritic sulfur was formed due to sufficient Fe supply from the Fe–S-rich epigenetic hydrothermal fluids. The No. 11 SHOS coal is enriched in Li–Ga–Zr–Hf and Se–Mo–Cr–V–As–Pb element assemblages. The sediment provenance of the Sangshuping coal mine is predominantly felsic–intermediate rocks from both the Yinshan and Qinling Oldland. However, the elevated concentrations of critical elements (Li, Ga, Zr, and Hf) in the No. 11 coal are primarily inherited from the Yinshan Oldland. The enrichment of the Se–Mo–Cr–V–As–Pb assemblage in No. 11 coal can be ascribed to the influence of both seawater and epigenetic hydrothermal activity.
11
Douville, Éric, Jean-Luc Charlou, Jean-Pierre Donval, Dorothée Hureau y Pierre Appriou. "Le comportement de l'arsenic (As) et de l'antimoine (Sb) dans les fluides provenant de différents systèmes hydrothermaux océaniques". Comptes Rendus de l'Académie des Sciences - Series IIA - Earth and Planetary Science 328, n.º 2 (enero de 1999): 97–104. http://dx.doi.org/10.1016/s1251-8050(99)80004-4.
Texto completo
12
Denge, Elelwani y Christopher Baiyegunhi. "Geochemical and Petrographical Characteristics of the Madzaringwe Formation Coal, Mudrocks and Sandstones in the Vele Colliery, Limpopo Province, South Africa: Implications for Tectonic Setting, Provenance and Paleoweathering". Applied Sciences 11, n.º 6 (19 de marzo de 2021): 2782. http://dx.doi.org/10.3390/app11062782.
Texto completoResumen
The sedimentary rocks of the Madzaringwe Formation in the Tuli Basin have been investigated using geochemical and petrographic methods to reveal their source area composition, tectonic setting, provenance and paleoweathering conditions. The petrographic studies show that the rocks consist mostly of clay minerals and quartz. The major elements geochemistry indicates that the rocks of the Madzaringwe Formation have the same source area. Based on the discriminant function plots, it can be inferred that the rocks are of quartzose sedimentary provenance, suggesting that they were derived from a cratonic interior or recycled orogen. The binary plots of TiO2 versus Zr and La/Sr against Th/Co shows that the rocks were derived from silicic or felsic igneous rocks. The tectonic setting discrimination diagrams of SiO2 against Log (K2O/Na2O), Th–Sc–Zr/10, and TiO2 versus (Fe2O3 + MgO) support passive-active continental margin settings of the provenance. The A–CN–K (Al2O3–CaO + Na2O–K2O) ternary diagram and binary plot of the index of compositional variability (ICV) against chemical index of alteration (CIA) shows that the rocks have been subjected to moderate to intensive weathering. Geochemical and petrographic characteristics of the rocks point to uplifted basement source areas predominantly composed of sedimentary rocks and/or granite-gneiss rocks. These source areas might have been from adjacent areas near the Tuli coalfield which include the Limpopo Belt (igneous and sedimentary rocks), and basement uplifted rocks of the Beit-Bridge Complex, consisting of the granite, granite-gneisses and schists.
13
Mohammedi, D. y S. Mohammedi. "Ochratoxine A dans les aliments, les fluides et les tissus de volaille en Algérie". Revue d’élevage et de médecine vétérinaire des pays tropicaux 67, n.º 1 (1 de julio de 2014): 35. http://dx.doi.org/10.19182/remvt.10157.
Texto completoResumen
L’ochratoxine A (OTA), mycotoxine produite par de nombreuses espèces d’Aspergillus et par Penicillium verrucosum, est néphrotoxique, hépato- toxique, immunotoxique et carcinogène chez les animaux et chez l’homme. La consommation d’aliments contaminés par l’OTA affecte la santé et la productivité des animaux et peut entraîner la présence d’OTA dans les produits animaux destinés à la consommation humaine. La prévalence de l’OTA dans les produits avicoles en Algérie a été déterminée à partir d’aliments, de sang et d’organes prélevés sur des volailles. La méthode d’analyse a été basée sur le coefficient de partage de l’OTA dans l’eau et les solvants organiques par ajustement du pH. La chromatographie en phase liquide à haute performance (HPLC) et la spectrofluorimétrie ont été utilisées pour la détection et la quantification. L’OTA a été présente dans une grande partie de l’aliment de volailles (poulets, poules pondeuses et dindes) à la concentration de 0,02 à 63 µg/kg. Les concentrations sériques ont été de 0,57 à 1,22 ng/ml. Bien que quelques prélèvements de sérums aient été négatifs, les organes (foie, testicules, reins) provenant des mêmes animaux contenaient de l’OTA. Les reins (concentrations de 0,02 à 9,73 ng/ml) et les testicules (concentrations de 0,12 à 2,11 ng/ ml) ont semblé être les tissus les plus contaminés. Cette étude montre qu’il serait important de proposer une recherche systématique de l’OTA sur les reins de volailles et, selon les résultats, interdire la consommation de leurs organes.
14
Bracciali, Laura. "Coupled Zircon-Rutile U-Pb Chronology: LA ICP-MS Dating, Geological Significance and Applications to Sediment Provenance in the Eastern Himalayan-Indo-Burman Region". Geosciences 9, n.º 11 (5 de noviembre de 2019): 467. http://dx.doi.org/10.3390/geosciences9110467.
Texto completoResumen
U-Pb dating by LA ICP-MS is one of the most popular and successful isotopic techniques available to the Earth Sciences to constrain timing and rates of geological processes thanks to its high spatial resolution, good precision (absolute U/Pb age resolution of ca. 2%, 2s), rapidity and relative affordability. The significant and continuous improvement of instrumentation and approaches has opened new fields of applications by extending the range of minerals that can be dated by this method. Following the development and distribution to the community of good quality reference materials in the last decade, rutile U-Pb thermochronology (with a precision only slightly worse than zircon) has become a commonly used method to track cooling of deep-seated rocks. Its sensitivity to mid- to low-crustal temperatures (~450 °C to 650 °C) is ideal to constrain exhumation in active and ancient orogens as well as thermal evolution of slow-cooled terranes. Recrystallization and secondary growth during metamorphism and the presence of grain boundary fluids can also affect the U-Pb isotopic system in rutile. A growing body of research focusing on U-Pb dating of rutile by LA ICP-MS is greatly improving our understanding of the behavior of this mineral with regards to retention of radiogenic Pb. This is key to fully exploit its potential as a tracker of geological processes. The latest developments in this field are reviewed in this contribution. The combined application of U-Pb zircon and rutile chronology in provenance studies, particularly when complemented by lower-T thermochronometry data, allows the isotopic characterization of the sources across a wide range of temperatures. The benefits of applying detrital zircon-rutile U-Pb chronology as a coupled provenance proxy are presented here, with a focus on the Eastern Himalayan-Indo-Burman region, where a growing number of successful studies employs such an approach to help constrain river drainage and basin evolution and to infer feedback relationships between erosion, tectonics and climate.
15
Jo, Young Hoon y Chan Hee Lee. "Ultrasonic Properties of a Stone Architectural Heritage and Weathering Evaluations Based on Provenance Site". Applied Sciences 12, n.º 3 (30 de enero de 2022): 1498. http://dx.doi.org/10.3390/app12031498.
Texto completoResumen
In this study, we performed customized ultrasonic measurements of the stone block foundation of the Sungnyemun Gate, which is representative of the stone architectural heritage in the Republic of Korea. Furthermore, the weathering evaluation standards, which are extensively used in stone heritage, were improved considering the type of rock and its provenance site. In particular, the absolute weathering grade used the ultrasonic velocity (P-wave) of a universal hard rock, whereas the relative weathering grade used the differences between the ultrasonic velocities of the materials in the stone block foundation of the Sungnyemun Gate (weathered stone) and the fresh rocks in the provenance. Among these, the absolute weathering grade was observed to be constant regardless of the type of rock; however, the relative weathering grade varied depending on the type dof rock. Because the average ultrasonic velocity of the original blocks of the stone block foundation of the Sungnyemun Gate was 2665 m/s, it was estimated that their ultrasonic velocity reduced by approximately 2.1 m/s per year as compared to that observed in case of fresh rocks (average 3932 m/s) in the provenance site. Furthermore, the weathering evaluation exhibited that there were approximately two stages of difference between the original blocks and the new blocks. As compared to the relative weathering grade, the absolute weathering grade was observed to underestimate the overall ultrasonic velocity of the stone block foundation of the Sungnyemun Gate. This study presents a customized method for performing ultrasonic measurements and for evaluating weathering. It is assumed that the results of this study will be extensively used in diagnosing and monitoring the stone architectural heritage.
16
Koo, Hyo-Jin, Young-Keun Jin y Hyen-Goo Cho. "Change in Sediment Provenance on the Inner Slope of the Chukchi Rise and Their Paleoenvironmental Implications". Applied Sciences 11, n.º 14 (14 de julio de 2021): 6491. http://dx.doi.org/10.3390/app11146491.
Texto completoResumen
The Arctic Ocean is one of the world’s most remarkable regions with respect to global climate change. The core ARA09C-St03 was analyzed for mineral composition and Nd isotope to determine the sediment provenance and reconstruct the paleoenvironment in the inner slope of the Chukchi Rise. Core ARA09C-St03 represents overall cycles of brown and gray color with three distinct dark brown layers and two pinkish-white layers and is divided into eight sedimentary units based on the lithological feature. The core has a continuous record of the late marine isotope stage (MIS) 5 to the Holocene and in particular provides a particularly high-resolution record from the Last Glacial Maximum (LGM). Sediment is derived mainly from the adjacent East Siberian Sea and the North American region, and changes in sediment provenance are controlled by climate-dependent particle size. During the glacial/stadial periods, sediments in Units 3, 5, and 8 were supplied by the East Siberian Sea via meltwater-derived suspension. The major ice-rafted debris (IRD) events in Units 2, 4, and 7, characterized by abundant dolomite and K/C ratio, were sourced from North America. The North America-derived materials reflect the initiation and disintegration of the Laurentide Ice Sheet and icebergs transported them across the open Arctic Ocean. The differences in provenance within these periods may be related to the scale of the Laurentide Ice Sheet. Interglacial sediments, including those from Units 1 and 6, are of mixed origin from Eurasia and the Canadian Archipelago and may have been transported by oceanic current and seasonal sea ice. These periods are likely associated with the negative Arctic Oscillation (AO) intensifying the Beaufort Gyre.
17
Kerrich, Robert y John Ludden. "The role of fluids during formation and evolution of the southern Superior Province lithosphere: an overview". Canadian Journal of Earth Sciences 37, n.º 2-3 (2 de abril de 2000): 135–64. http://dx.doi.org/10.1139/e99-098.
Texto completoResumen
Models for fluid flow and hydrothermal alteration for the Abitibi greenstone belt are reviewed in the light of Lithoprobe results in the region. In the Abitibi greenstone belt, eruption of volcanic sequences over 2750-2700 Ma was accompanied by pervasive low-temperature hydrothermal alteration at high water/rock ratios, giving systematic 18O-enrichment. Archean ambient ocean water bottom temperatures were likely ca. 30°C, and δ18O ~0 ± 1. Chert-iron formations precipitated from low temperature hydrothermal discharge. Base metal massive sulphide deposits formed at or near the seafloor from focussed discharge of high-temperature (~300-400°C) fluids in convective cells sited above subvolcanic intrusions. The ore fluids were evolved seawater that had undergone compositional and isotopic evolution by high-temperature, low water/rock exchange with the volcanic pile to NaCl (3-7 wt.%) or CaCl2-NaCl (up to 30 wt.%) brines of δ18O = 0-8. These volcanic associated hydrothermal deposits are associated with greenstone belt asemblages in the northern Abitibi subprovince that were emplaced as a series of thrust slices over the Opatica plutonic belt. In the southern Abitibi subprovince the hydrothermal deposits were associated with a series of rift basins (Noranda, Val d'Or, etc.), formed on top of accreted oceanic assemblages comprising primitive arcs and plateaus, or in protoarcs, and associated with oblique convergence. Contemporaneous erosion of emergent arcs and the older cratonic provenance terrane of the Pontiac subprovince by orographic rainfall, and submarine weathering, fed first-cycle vol cano genic sediments to depositional basins in the Abitibi, but siliciclastic sediments of mixed old 3 Ga continent and 2.7 Ga arc provenance in the Pontiac subprovince. Abitibi subprovince turbidites were more weathered and 18O-enriched than Pontiac subprovince equivalents. Subduction-accretion assembly of the Opatica-Abitibi and Pontiac terranes involved allochthonous thrusting of the Abitibi subprovince over the Pontiac subprovince. There were several pulses of granitoid magmatism during accretionary assembly over 2695 to 2674 Ma. Syn- to late-tectonic tonalites were generated by melting of hot young hydrous ocean crust in a shallow-dipping intraoceanic subduction zone. The intrusions exsolved small quantities of magmatic fluids that formed Cu-Zn showings. Late-tectonic shoshonites formed at [Formula: see text]80 km in subarc mantle wedge by slab dehydration-wedge melting. This late-stage of arc development involved transfer of significant quantities of gas-rich alkaline magmas 80+ km through the lithosphere along the accretionary terrane bounding structures, and produced small phosphorus and barite deposits. Synmagmatic metamorphism was of the high-temperature low-pressure type, and occurred in several pulses; water/rock ratios were generally low distal from structures. Tens of thousands of cubic kilometres of fluids generated by dehydration reactions at the base of the subduction-accretion complex, during thermal relaxation following collision and the main granitoid pulses, advected up terrane boundary structures and locally generated lode gold deposits. At the highest structural levels these fluids mixed with Archean meteoric water where δ18O < 0. A second metamorphism (M2) occurred over 2645 to 2611 Ma leading to melting of Pontiac sediments and formation of S-type granites. Deposits of Mo, Th, and P were precipitated from magmatic fluids of δ18O 8-9. M2 variably reset radiogenic and stable isotope systems in nonrobust minerals of vol canogenic massive sulphide and lode gold deposits. Hypersaline CaCl2 formation brines evolved in Paleoproterozoic glaciogenic sediments; these penetrated into the Archean basement where they redistributed gold and are pervasively present as low-temperature secondary brine inclusions. The Matachewan (2.5 Ga) and Hearst dyke swarms drove higher temperature advection of the brines, and Ag-Co-Ni sulpharsenide deposits formed by thermal evolution of the brines driven by the Nipissing diabase dyke swarm at ~2219 Ma. Local resetting of 40Ar/39Ar spectra between 2550 and 2200 Ma was the product of tectonic pumping of fluids along reactivated Archean structures, possibly due to coupling of the 200 km thick mantle lithosphere to Archean crust. Seismic evidence for late overprinting of the lower crust and growth of 2450 Ma zircon rims in lower crustal assemblages were associated with this event. There was also fluid activity at 1950 to 1850 Ma due to the Hudsonian orogen induced Kapuskasing event. Hypersaline CaCl2-rich brines formed in the Paleozoic sedimentary cover (~500 Ma), penetrated deep (>5 km) into the Archean basement, and comprise vast reservoirs of hypersaline brines deep in the Shield. The brines precipitated prehnite-laumontite veins that record hundreds of increments of dilation. Subglacial 18O-depleted fluids penetrated to shallow ([Formula: see text]1 km) depths in the Quaternary; they form mixing lines with the hypersaline end member. Extremely D-depleted (-400 to -100) CH4 and H discharge in mining districts of the Shield. The depleted H may form by radiolysis of H2O and (or) by a Fischer-Tropsch type process. The hypersaline brine end-member was shifted to the left of the meteoric water line by exchange with D-depleted H.
18
Bilić, Šime y Vesnica Garašić. "PETROLOGICAL CHARACTERISTICS OF CLASTIC SEDIMENTARY ROCKS FROM THE ST. BARBARA ORE MINE IN RUDE NEAR SAMOBOR". Rudarsko-geološko-naftni zbornik 36, n.º 1 (2021): 121–35. http://dx.doi.org/10.17794/rgn.2021.1.10.
Texto completoResumen
In the scope of this research, the petrographic and geochemical analyses of clastic sedimentary rocks from the St. Barbara, copper and iron ore mine in Rude near Samobor, have been made, aiming to classify and determine the provenance and environment of formation of clastic sedimentary rocks, as well as the influence of hydrothermal fluids on their properties. Eight samples were collected in total from different locations in the mine. Six of those samples have been studied in detail. The results showed structural and geochemical variability and uneven hydrothermal alteration intensity in the samples. Based on petrographic analyses, three rocks are classified as sublithoarenite, quartz arenite and quartz greywacke. Three of the samples are classified as ore breccia, ore sandstone, and ore silt-sandstone due to the pronounced hydrothermal alterations and ore mineralisation. Comprehensively, petrographic and geochemical analyses indicate that the source rocks of the investigated clastic sedimentary rocks were felsic (La/Sc = 0.9-6.2; Th/Sc = 1.3-2.4), most probably sedimentary, possibly resedimented rocks. The extent of source rock weathering was very high (Chemical Index of Alteration CIA = 52.1 - 81.3 %) and the geotectonic position of the sedimentary basin was very likely to be at the passive continental margin.
19
Prochaska, Walter. "Trading Marble for Steel: Early Roman Import of Carrara Marble into the Alps—The Example of the Magdalensberg Trading Post in Noricum". Minerals 13, n.º 8 (2 de agosto de 2023): 1036. http://dx.doi.org/10.3390/min13081036.
Texto completoResumen
The annexation of the Noricum Kingdom by the Roman Empire in 16 BC brought an increase in the trading relations between the empire and its northern neighbours. A first hub for these relations was the emporium on the Magdalensberg in Noricum Mediterraneum (today southern Carinthia/Austria). During the last decades, archaeological investigations of this settlement in a remote mountainous area revealed, inter alia, different kinds of marble decoration and architecture. Provenance analyses using a combination of different methods, including isotope analysis, trace element analysis and the analysis of inclusion fluids, show that the marbles used on the Magdalensberg are of different origins. Widely used were medium- to coarse-grained Alpine marbles from Roman quarries of the region of Gummern. Prominently used for plates, tiles, profiles, etc. were several types of fine-grained marbles of different origins. One group definitely originated from the quarries of Carrara (Carrara white and Carrara Bardiglio), testifying to the trading relations with northern Italy after the integration of Noricum into the Roman Empire. A database for the Carrara Bardiglio marble is presented and discussed. For the use of these data by further investigators, the numerical data are given as online material.
20
Li, Jing, Xinguo Zhuang, Xavier Querol, Natalia Moreno, Guanghua Yang, Lei Pan, Baoqing Li, Yunfei Shangguan, Zhejun Pan y Bo Liu. "Enrichment of Nb-Ta-Zr-W-Li in the Late Carboniferous Coals from the Weibei Coalfield, Shaanxi, North China". Energies 13, n.º 18 (15 de septiembre de 2020): 4818. http://dx.doi.org/10.3390/en13184818.
Texto completoResumen
Mineralogical and geochemical characteristics of coals provide crucial information on their potential clean, efficient, and integrated utilization. In this paper, the mineralogical and geochemical behaviors of the No. 5 coals of the Taiyuan Formation in the Weibei Coalfield, North China, were investigated, and their geological controlling factors were subsequently discussed. The minerals in the Weibei coals mainly consist of kaolinite (8.3%), calcite (5.0%), and pyrite (3.1%), with minor proportions of tobelite (2.9%), dolomite (1.7%), quartz (1.8%), and traces of siderite (0.4%) and gypsum (0.6%). Several critical elements, including Nb (19.8 mg/kg), Ta (3.6 mg/kg), Zr (71.0 mg/kg) and Li (32.3 mg/kg), occur at concentrations higher than those averages for world hard coals, making the Weibei coals potential sources of these critical elements. Several factors, terrigenous material, seawater invasion, and hydrothermal fluids are responsible for these mineralogical and geochemical characteristics. The L-type rare earth elements and yttrium (REE-Y) enrichment in the roofs and partings, Al2O3-TiO2 and Zr/TiO2-Nb/Y plots, and negative Eu and weak negative Ce anomalies in the Weibei coals indicate a felsic-intermediate dominated sediment provenance primarily derived from the Qilian-Qinling Oldland on the South. Marine bioclastic limestone, negative Ce and positive Y anomalies in coals imply the influence of seawater on the Weibei coals. Last but not least, the cleat-infilling and/or fracture-infilling calcite, pyrite, barite, and tobelite as well as the positive Eu and Gd anomalies, H-type, and M-type REE-Y enrichment patterns suggest the influence of hydrothermal fluids, which lead to re-distribution of some critical elements from roof and parting to the underlying coal seam.
21
Tian, Mi, Xueqiu Wang, Yu Qiao, Dongsheng Liu, Qinghua Chi, Hanliang Liu, Wei Wang y Baoyun Zhang. "Temporal Variations of Sediment Provenance in a Karst Watershed, China". Applied Sciences 13, n.º 2 (5 de enero de 2023): 771. http://dx.doi.org/10.3390/app13020771.
Texto completoResumen
The environmental quality of the sediments in karst areas is a common concern, and it is of great significance to analyze the sources of the sediments. This study investigates the sources and its temporal variations of catchment sediments in a typical small karst watershed area. Toxic metal concentrations in the catchment area were monitored via three geochemical baseline projects in China. The sediment identification fingerprint tool (SIFT) was used to establish a geochemical model for tracing the main source contributions and its temporal variations of catchment sediments over the past 28 years (1992–2019). The catchment sediments in the small karst catchment area were mainly sourced from the background lithologies, among which limestone contributed the most, followed by dolomite, sand-shale, and mudstone; however, the anthropogenic lead–zinc tailings contributed the least. The contributions and temporal variations of each source were closely related to the lithology, topography, and landform, as well as the change in land-use and vegetation cover and the degree of rocky desertification. Moreover, the implementation of vegetation restoration and control of rocky desertification decreased the contributions of the upstream geological bodies, and the toxic metal content of the catchment sediment decreased accordingly. This study is of great significance for environmental governance in karst areas.
22
Chaumont, Diane, André G. Roy y François Courchesne. "Traçage minéralogique de l’origine des sédiments aux confluents de cours d’eau". Géographie physique et Quaternaire 48, n.º 2 (30 de noviembre de 2007): 195–205. http://dx.doi.org/10.7202/032996ar.
Texto completoResumen
RÉSUMÉTraçage minéralogique de l'origine des sédiments aux confluents de cours d'eau. La dynamique sédimentaire des confluents de cours d'eau peut s'étudier par l'intermédiaire de traceurs marquant l'origine des particules. La connaissance de la source sédimentaire est essentielle pour comprendre les processus de mélange des sédiments du lit et établir des relations causales entre les sources de contamination et la dynamique des sites contaminés liés à l'arrivée d'un tributaire. On a examiné les particules du lit d'un confluent naturel sablonneux où la minéralogie des sédiments composant les bassins-versants est différenciée. En raison de leurs forme et densité, les feldspaths K s'avèrent des traceurs efficaces et indiquent qu'à la jonction étudiée le mélange des apports sédimentaires est presque complété à une distance de mélange de 2,1 (distance à partir de l'apex/largeur du confluent). Par contre, les micas et le pourcentage de minéraux lourds, sensibles au tri hydraulique, ne révèlent pas la provenance des particules. La méthode a aussi été employée pour déterminer le patron de dispersion des particules à un confluent du Saint-Laurent. Ici la minéralogie des particules diffère peu entre les bassins-versants. Toutefois, les variations spatiales du pourcentage de minéraux lourds sont directement liées à la morphologie du lit caractérisée par un banc d'accumulation se terminant par un abrupt à l'entrée du tributaire. Les faibles teneurs en minéraux lourds sur la pente de l'abrupt démontrent que le fluide est peu compétent à l'abri de la construction sédimentaire. Par contre, à son pied et à son sommet, le fluide effectue un tri hydraulique efficace, ce qui entraîne une concentration des particules lourdes. Ces variations des teneurs en minéraux lourds sont indicatrices du tri hydraulique plutôt que de la source sédimentaire.
23
Ouzounis, Athanasios G. y George A. Papakostas. "Machine Learning in Discriminating Active Volcanoes of the Hellenic Volcanic Arc". Applied Sciences 11, n.º 18 (8 de septiembre de 2021): 8318. http://dx.doi.org/10.3390/app11188318.
Texto completoResumen
Identifying the provenance of volcanic rocks can be essential for improving geological maps in the field of geology and providing a tool for the geochemical fingerprinting of ancient artifacts like millstones and anchors in the field of geoarchaeology. This study examines a new approach to this problem by using machine learning algorithms (MLAs). In order to discriminate the four active volcanic regions of the Hellenic Volcanic Arc (HVA) in Southern Greece, MLAs were trained with geochemical data of major elements, acquired from the GEOROC database, of the volcanic rocks of the Hellenic Volcanic Arc (HVA). Ten MLAs were trained with six variations of the same dataset of volcanic rock samples originating from the HVA. The experiments revealed that the Extreme Gradient Boost model achieved the best performance, reaching 93.07% accuracy. The model developed in the framework of this research was used to implement a cloud-based application which is publicly accessible at This application can be used to predict the provenance of a volcanic rock sample, within the area of the HVA, based on its geochemical composition, easily obtained by using the X-ray fluorescence (XRF) technique.
24
Zaccarini, Federica, Giorgio Garuti, George L. Luvizotto, Yuri de Melo Portella y Athokpam K. Singh. "Testing Trace-Element Distribution and the Zr-Based Thermometry of Accessory Rutile from Chromitite". Minerals 11, n.º 7 (22 de junio de 2021): 661. http://dx.doi.org/10.3390/min11070661.
Texto completoResumen
Trace element distribution and Zr-in-rutile temperature have been investigated in accessory rutile from stratiform (UG2, Merensky Reef, Jacurici), podiform (Loma Peguera), and metamorphic chromitites in cratonic shields (Cedrolina, Nuasahi). Rutile from chromitite has typical finger-print of Cr-V-Nb-W-Zr, whose relative abundance distinguishes magmatic from metamorphic chromitite. In magmatic deposits, rutile precipitates as an intercumulus phase, or forms by exsolution from chromite, between 870 °C and 540 °C. The Cr-V in rutile reflects the composition of chromite, both Nb and Zr are moderately enriched, and W is depleted, except for in Jacurici, where moderate W excess was a result of crustal contamination of the mafic magma. In metamorphic deposits, rutile forms by removal of Ti-Cr-V from chromite during metamorphism between 650 °C and 400 °C, consistent with greenschist-amphibolite facies, and displays variable Cr-Nb, low V-Zr, and anomalous enrichment in W caused by reaction with felsic fluids emanating from granitoid intrusions. All deposits, except Cedrolina, contain Rutile+PGM composite grains (<10 µm) locked in chromite, possibly representing relics of orthomagmatic assemblages. The high Cr-V content and the distinctive W-Nb-Zr signature that typifies accessory rutile in chromitite provide a new pathfinder to trace the provenance of detrital rutile in placer deposits.
25
Dong, Zhicheng, Lina Zhang y Bingfu Jin. "Detrital Mica Composition Quantitatively Indicates the Sediment Provenance along the Subei Coast to the Yangtze Estuary". Applied Sciences 12, n.º 24 (9 de diciembre de 2022): 12653. http://dx.doi.org/10.3390/app122412653.
Texto completoResumen
The influence of large rivers on the Subei littoral plain area requires more research than the results that have been available up to now. Thus, specific diagnostic indices of detrital mica are successfully applied for the first time to identify the detritus of the Yangtze River and the ancient Yellow River and to analyze their influence on the coast in the Subei littoral plain area. Based on field investigation and sample collection, detrital mica minerals within the 0.063–0.125 mm grain size fraction were selected and identified. Their content/ratio differentiations and possible origins were analyzed. Moreover, specific diagnostic indices were evaluated for detritus identification considering these two large rivers in addition to their provenance influences on the Subei littoral plain area. The results indicate that the detrital mica contents in the Yangtze River Estuary differed from those in the ancient Yellow River Estuary. The mass percentage in the former (average value of 32.2%) was much higher than that in the latter (average value of 13.1%). The former contained abundant weathered mica, with a particle percentage of approximately 50.6%, while the latter contained abundant biotite (with a particle percentage of approximately 40.9%). Differences, including but not limited to those above, could be attributed to basic geological, climatic and hydrodynamic conditions. In particular, the mica indices were clearly distinguished between these two river estuaries. These indices constitute specific diagnostic indices for differentiating river detritus and quantitative contribution analysis of detritus provenance in the Subei littoral plain area. Finally, the changes and quantitative contributions of four diagnostic indices demonstrated that in the Subei littoral plain area, northward from the Yangtze River Estuary to sample site SBY11 located in Yangkou town, Rudong County, detrital micas were mainly affected by the Yangtze River, and southward from the ancient Yellow River Estuary to sample site SBY12 located in Bengcha town, Rudong County, detrital micas were largely affected by the ancient Yellow River. The main mixing area should be located between these two towns. This study provides both a good example and an efficient approach to the application of detrital mica in detritus identification, mixed zone determination, sediment provenance analysis and transport tracing.
26
Madondo, Joseph, Carles Canet, Fernando Núñez-Useche y Eduardo González-Partida. "Geology and geochemistry of jasperoids from the ‘Montaña de Manganeso’ district, San Luis Potosí, north-central Mexico". Revista Mexicana de Ciencias Geológicas 38, n.º 3 (24 de noviembre de 2021): 193–209. http://dx.doi.org/10.22201/cgeo.20072902e.2021.3.1651.
Texto completoResumen
Large outcrops of jasperoids occur in the ‘Montaña de Manganeso’ mining district in north-central Mexico. They range from massive manganiferous jasperoids to highly brecciated, hematitic jasperoid. The jasperoids of ‘Montaña de Manganeso’ occur mainly as replacements of limestone, sandstone and shale, commonly nearby high-angle fault systems. The mineralogy of the jasperoids consist of quartz and its polymorphs (chalcedony, tridymite and cristobalite), Fe-Mn oxyhydroxides, calcite and minor barite. Many outcrops show evidence of several periods of brecciation and silicification. The geochemical signature of the jasperoids suggests that silicification was product of hydrothermal activity. The jasperoids display enrichment in elements of hydrothermal provenance such as Ba, Sr, As, Cr, Mo, Sb, Ni, Zn and Cu, whereas are strongly depleted in the elements indicative of clastic sources such as Ti, K, Th and Zr. Element ratios such as (Fe+Mn)/Ti, Al/(Al+Fe+Mn), Fe/Mn and U /Th, along with the Al-Fe-Mn and Fe-Mn-(Ni+Co+Cu)×10 ternary diagrams confirm a hydrothermal origin. Low ∑REE, an enrichment of LREE over HREE, negative Ce anomalies and positive Y anomalies (YPASS/HoPAAS) also support the hydrothermal processes. The geological evidence, in the form of a feeder zone and extensive hydrothermal alteration, show that the silica forming the rocks originated from ascending hot fluids.
27
Leckie, Dale A. y David Craw. "Westerly derived Early Cretaceous gold paleoplacers in the Western Canada foreland basin, southwestern Alberta: tectonic and economic implications". Canadian Journal of Earth Sciences 32, n.º 8 (1 de agosto de 1995): 1079–92. http://dx.doi.org/10.1139/e95-090.
Texto completoResumen
Albian-aged (Early Cretaceous) igneous pebble to cobble conglomerates fill multiple, northeast–southwest-oriented, subparallel channels in the upper Blairmore Group (upper Beaver Mines and Mill Creek formations) of the Rocky Mountain foreland basin, southwestern Alberta and southeastern British Columbia. Paleocurrent data show that the conglomerate was derived from the west. Clast petrography implies a provenance that includes granitoids, mafic volcanics, low-grade metamorphic rocks, and shallow-level (ca. 7 km depth) postmetamorphic quartz veins formed from meteoric fluids. The conglomerate was probably derived from the southern Omineca Belt of British Columbia prior to the rise of the Rocky Mountains. The conglomerate contains detrital gold grains up to 150 μm in diameter, and chemical analyses indicate widespread anomalous gold concentrations (up to 910 ppb Au) in conglomerate matrix. Gold content in these igneous-clast conglomerates excèdes that reported from the richest modern placers in Alberta. Less pronounced but persistent As anomalies (up to 260 ppm) occur also. Postdepositional alteration of conglomerate matrix chemically mobilized Au and As from their detrital source grains and redistributed these elements. Gold enrichment in the igneous-clast conglomerate contrasts strongly with background gold concentrations in the underlying conglomeratic Cadomin Formation. The gold concentrations in the igneous-clast conglomerate demonstrate that paleoplacers derived from the Canadian Cordillera have accumulated in the Western Canada foreland basin, a sedimentary succession previously dismissed as a host for detrital gold.
28
Brettell, Rhea, Janet Montgomery y Jane Evans. "Brewing and stewing: the effect of culturally mediated behaviour on the oxygen isotope composition of ingested fluids and the implications for human provenance studies". Journal of Analytical Atomic Spectrometry 27, n.º 5 (2012): 778. http://dx.doi.org/10.1039/c2ja10335d.
Texto completo
29
Gahramanov, G., M. Babayev, S. Shpyrko y Kh Mukhtarova. "SUBSIDENCE HISTORY AND HYDROCARBON MIGRATION MODELING IN SOUTH CASPIAN BASIN". Visnyk of Taras Shevchenko National University of Kyiv. Geology, n.º 1 (88) (2020): 82–91. http://dx.doi.org/10.17721/1728-2713.88.12.
Texto completoResumen
We study the mechanisms of migration and spacial distribution of hydrocarbon deposits along a regional 1000 km long SW - NE seismic cross section of the South Caspian Basin. A retrospective 2D geological simulation of basin subsidence and sediment filling history is performed taking into account accompanying processes of thermal and catagenetic transformations of organic matter, and subsequent migration and accumulation of hydrocarbons. The start of the basin opening with accumulation of considerable sedimentary mass can be dated as middle Mesozoic (Triassic or Jurassic), and hydrocarbon prone horizons can now be located at depths of 12 km. The hydrocarbon saturation of the Pliocene Productive Series is of epigenetic (allochtonous) nature, which is also confirmed in literature by geochemical data from mud volcanoes and by other facts. Geochemical age, depth of provenance and reworking degree of hydrocarbons point at generation sources in Mesozoic (gas) and Paleogene-Miocene formations (oil) with only subordinate participation of the lower "Productive Series" Pliocene suites. The dominant migration pattern of fluids is interformational (interstratal) intermittent injective subvertical flow along disjunctive planes, zones of increased fracturing and loose rocks, diapir intrusion contacts, eruptives of mud volcanoes, lithofacial unconformities and other structures, breaking the rocks continuity. This implies the possibility of commercial-scale accumulations of hydrocarbons at ultra high depths, if trap structures of sufficiently large sizes are available, comparable with already discovered giant oil and gas fields (Shah-Deniz, Azeri-Chirag-Gyuneshli etc).
30
Sutton, S. J. y J. B. Maynard. "Petrology, mineralogy, and geochemistry of sandstones of the lower Huronian Matinenda Formation: resemblance to underlying basement rocks". Canadian Journal of Earth Sciences 30, n.º 6 (1 de junio de 1993): 1209–23. http://dx.doi.org/10.1139/e93-103.
Texto completoResumen
Bulk chemistry, mineralogy, mineral chemistry, cathodoluminescence characteristics, and textural data are used to constrain provenance and the role of postdepositional alteration processes in sandstones of the lower Huronian Matinenda Formation. Samples studied are from the Elliot Lake – Blind River and Agnew Lake areas, which experienced subgreenschist and biotite-grade greenschist metamorphism, respectively. Both areas, but particularly the lower grade area, contain some K-rich samples, with much of the K in detrital-appearing K-feldspar. In places K-feldspar is partially replaced by potassic mica. Plagioclase (mostly albite) is rare in the Elliot Lake – Blind River samples, and only common along a few horizons in the Agnew Lake section. It is suggested that the predominance of K-feldspar over plagioclase and the high K/Na ratios indicate a K-rich source area and in particular a weathered granite source. Framework mineralogy is found to be similar to material reported from sub-Matinenda weathered granite. The abundance of fine-grained micaceous matrix within the Matinenda varies considerably among samples, and the composition of the mica varies, correlating strongly with bulk chemistry. Some matrix has clearly been generated by alteration of framework K-feldspar. Feldspar alteration may have liberated K that was carried to the underlying regolith where it was fixed by weathering-product clay minerals. Fluids involved in alteration do not appear to have pervasively affected the Matinenda in either the Elliot Lake – Blind River or the Agnew Lake area.
31
Qasim, Muhammad, Owais Tayyab, Lin Ding, Javed Iqbal Tanoli, Zahid Imran Bhatti, Muhammad Umar, Hawas Khan, Junaid Ashraf y Ishtiaq Ahmad Khan Jadoon. "Exhumation of the Higher Himalaya: Insights from Detrital Zircon U–Pb Ages of the Oligocene–Miocene Chitarwatta Formation, Sulaiman Fold–Thrust Belt, Pakistan". Applied Sciences 13, n.º 6 (8 de marzo de 2023): 3418. http://dx.doi.org/10.3390/app13063418.
Texto completoResumen
This study reports the detrital zircon U–Pb ages of the post collisional Chitarwatta Formation, exposed along the western margin of the Indian plate at the Sulaiman fold–thrust belt (SFB), Pakistan. The Chitarwatta Formation overlies the shallow marine carbonate sequence of the Kirthar Formation and represents an Oligocene–Miocene transitional marine sequence. The sequence consists of sandstone, siltstone, and mudstone. The sandstone consists predominantly (79–82%) of quartz grains. The framework grains are sub-angular to sub-rounded and show recycled orogenic provenance. The detrital zircon U–Pb age data show the dominant population between 390 Ma and ~1100 Ma, which is ~70% of the total population. In addition to this, a significant percentage of the younger detrital ages exist between ~40 Ma and ~120 Ma. This younger age cluster indicates the northern sources, including the Kohistan–Ladakh arc (KLA) and Karakoram block (KB), whereas the provenance for the 390–1100 Ma detrital zircon is likely the Higher Himalaya (HH), with contribution from Tethyan Himalaya (TH). This post-collisional scenario suggests that the Chitarwatta Formation received detritus from the northern sources through a drainage system, named as the Indus drainage system. A comparison with the coeval units in the north (Murree Formation, Dagshai Formation, and Dumre Formation) suggests that the sediments may have been delivered through the same drainage system that shares similar detritus. Relying on the contribution of the HH detritus, we propose that the HH uplifted during the Oligocene–Miocene along the Main Central Thrust (MCT) and provided detritus to the foreland basin.
32
Birkle, Peter. "Recovery rates of fracturing fluids and provenance of produced water from hydraulic fracturing of Silurian Qusaiba hot shale, northern Saudi Arabia, with implications on fracture network". AAPG Bulletin 100, n.º 06 (junio de 2016): 917–41. http://dx.doi.org/10.1306/02101615120.
Texto completo
33
PROCHASKA, W. y S. M. GRILLO. "A NEW METHOD FOR THE DETERMINATION OF THE PROVENANCE OF WHITE MARBLES BY CHEMICAL ANALYSIS OF INCLUSION FLUIDS: THE MARBLES OF THE MAUSOLEUM OF BELEVI/TURKEY*". Archaeometry 52, n.º 1 (febrero de 2010): 59–82. http://dx.doi.org/10.1111/j.1475-4754.2009.00470.x.
Texto completo
34
Grist, A. M., P. H. Reynolds, M. Zentilli y C. Beaumont. "The Scotian Basin offshore Nova Scotia: thermal history and provenance of sandstones from apatite fission track and 40Ar/39Ar data". Canadian Journal of Earth Sciences 29, n.º 5 (1 de mayo de 1992): 909–24. http://dx.doi.org/10.1139/e92-077.
Texto completoResumen
Apatite fission track and 40Ar/39Ar age spectrum data from sandstone drill-core minerals taken from depths of 2–5 km in nine wells from the Scotian Basin are presented and interpreted in terms of the thermal history of the basin and the provenance of its sediments. The focus of the study is a comparison of the data from these thermochronometers with each other and with previously published vitrinite reflectance and aromatization–isomerization (A–I) reactions in biomarker compounds from the same or nearby wells.Apatite fission track ages are generally in agreement with expectations in that they trend to zero at a depth of ~4 km (corrected bottom-hole temperature ~120 °C). Shallower (lower present temperature) samples are partially annealed; the degree of partial annealing correlates closely with the degree of A–I reactions. Both thermal indicators are activated over the temperature range 60–120 °C.Samples from two wells, Mic Mac J-77 and Erie D-26, are anomalous. They are more annealed than present formation temperatures would predict, an anomaly that is also indicated by the A–I data. These samples are interpreted as having experienced higher than present temperatures subsequent to deposition, possibly resulting from the passage of hot fluids related to localized volcanism or the sudden venting of an overpressured reservoir.K-feldspars record minor (< 20%) argon loss as a result of burial heating in the basin only at the greatest depths of the sampled range (> 4.3 km). This result is in agreement with the thermal models of the Scotian Basin and extrapolation of the A–I and fission track data to greater depths. The inferred argon loss implies an activation energy of 40 ± 4 kcal/mol for the smallest diffusion domains.The argon age spectra for samples that have not lost argon during residence in the basin provide evidence on the provenance of the sediments. K-feldspars from the Early Cretaceous Missisauga Formation have spectra that are similar to those obtained from K-feldspars from the Grenville Province of the Canadian Shield, whereas muscovites from the same formation give Cambrian to Carboniferous argon ages (mean 387 Ma), an indication of contributions from other source rocks. Corresponding data from the Jurassic Mohican Formation are similar to those reported for plutons from the southern Nova Scotia mainland (ca. 250–350 Ma argon ages). By implication, the Mohican Formation, which is the earliest postrift deposit, was derived from local sources inferred to be adjacent flank uplifts, whereas the Missisauga Formation was derived in part either directly or indirectly from the Grenvillian-aged interior of eastern Canada.
35
Bissada, K. K., L. W. Elrod, C. R. Robison, L. M. Darnell, H. M. Szymczyk y J. L. Trostle. "Geochemical Inversion - A Modern Approach to Inferring Source-Rock Identity from Characteristics of Accumulated Oil and Gas". Energy Exploration & Exploitation 11, n.º 3-4 (julio de 1993): 295–328. http://dx.doi.org/10.1177/0144598793011003-405.
Texto completoResumen
In recent years, petroleum geochemists have been re-focusing their efforts on developing practical means for inferring, from hydrocarbon chemistry and geologic constraints, the “provenance” of hydrocarbon accumulations, seeps or stains. This capability, referred to here as “Geochemical Inversion”, can be invaluable to the explorationist in deriving clues as to the character, age, identity, maturity and location of an accumulation's source rocks and evaluating a petroleum system's hydrocarbon supply volumetrics. Geochemical inversion is most useful where pertinent source-rock information may be absent because exploratory drilling focused strictly on structural highs and failed to penetrate the deeply buried, effective basinal source facies. Advances in chemical analysis technology over the last decade have facilitated the development of powerful geochemical methods for unravelling of complex chemistries of crude oil and natural gas at the molecular and subatomic levels to extract specific information on the hydrocarbons' source. Inferences on such factors as organic matter make-up, depositional environment, lithology, age and maturity of the source can frequently be drawn. These inferences, together with a sound analysis of the geologic and architectural constraints on the system, can supply clues as to the identity and location of the probable source sequence. This paper describes the principles underlying geochemical “inversion” and provides applications in exploration and exploitation settings. In addition, this paper demonstrates inversion of geochemical characteristics of migrated hydrocarbon fluids to specific attributes of the source. The paper also illustrates the use of systematic variations in fluid chemistry within a geologic setting to infer source location, degree of hydrocarbon mixing and relative migration distance.
36
Fong-Silva, Waldyr, Carlos Severiche-Sierra, Remedios Pitre-Redondo, Luz Vargas-Ortiz y Eduardo Espinosa-Fuentes. "Association between self-regulation of learning, student attitude, provenance and age in engineering students". Contemporary Engineering Sciences 10 (2017): 665–72. http://dx.doi.org/10.12988/ces.2017.7765.
Texto completo
37
Hussain, Zahid, Chunhui Tao, Chun-Feng Li, Shili Liao, Masroor Alam, Muhammad Farhan, Huichao Zhang y Amjad Hussain. "Mineralogy, Fluid Inclusions, and Isotopic Study of the Kargah Cu-Pb Polymetallic Vein-Type Deposit, Kohistan Island Arc, Northern Pakistan: Implication for Ore Genesis". Minerals 11, n.º 11 (14 de noviembre de 2021): 1266. http://dx.doi.org/10.3390/min11111266.
Texto completoResumen
The Kargah Cu-Pb polymetallic deposit is a newly discovered ore deposit from the Gilgit-Baltistan region, located in the Kohistan Island Arc, northern Pakistan. However, this area is poorly researched on the ore genesis, and its origin and the evolution of its magmatic-hydrothermal system remain unclear. Three stages of mineralization were identified, including quartz-pyrite, quartz-sulfide, and carbonate representing early, middle, and late stages, respectively. The major ore minerals are pyrite, chalcopyrite, galena, and zincian tetrahedrite with minor native silver, and native gold mainly distributed in pyrite. Here, we present a systematic study on ore geology, hydrothermal alterations, trace element composition of pyrite, fluid inclusions, and isotopes (S and Pb) characteristics to gain insights into the nature of the ore-forming fluids, types of unknown deposits, and hydrothermal fluid evolution. The high Co/Ni ratio (1.3–16.4) and Co content (average 1201 ppm), the low Mo/Ni ratio (0.43–0.94) and Mo contents (average 108 ppm) of both Py-I and Py-II suggest a mafic source for the mineralization. The Au-Ni plots, Co-As-Ni correlation, and the δ34S values range from −2.8 to 6.4‰ (average of 3.4‰) indicating the affiliation of the mineralization with a mantle-derived magmatic-hydrothermal provenance. The Pb isotope data showing the narrow variations in 206Pb/204Pb, 207Pb/204Pb and 208Pb/204Pb values suggest a single lead source from crustal-derived materials. The microthermometry data suggest that the dominant mechanisms are fluid boiling and mixing for mineral precipitation at temperatures ranging between 155 and 555 °C, and represent an intrusion-related magmatic-hydrothermal environment for the Kargah Cu-Pb polymetallic deposit.
38
Gurjar, Kuldeep, Yang-Sae Moon y Tamer Abuhmed. "TruMuzic: A Deep Learning and Data Provenance-Based Approach to Evaluating the Authenticity of Music". Applied Sciences 13, n.º 16 (19 de agosto de 2023): 9425. http://dx.doi.org/10.3390/app13169425.
Texto completoResumen
The digitalization of music has led to increased availability of music globally, and this spread has further raised the possibility of plagiarism. Numerous methods have been proposed to analyze the similarity between two pieces of music. However, these traditional methods are either focused on good processing speed at the expense of accuracy or they are not able to properly identify the correct features and the related feature weights needed for achieving accurate comparison results. Therefore, to overcome these issues, we introduce a novel model for detecting plagiarism between two given pieces of music. The model does this with a focus on the accuracy of the similarity comparison. In this paper, we make the following three contributions. First, we propose the use of provenance data along with musical data to improve the accuracy of the model’s similarity comparison results. Second, we propose a deep learning-based method to classify the similarity level of a given pair of songs. Finally, using linear regression, we find the optimized weights of extracted features following the ground truth data provided by music experts. We used the main dataset, containing 3800 pieces of music, to evaluate the proposed method’s accuracy; we also developed several additional datasets with their own established ground truths. The experimental results show that our method, which we call ‘TruMuzic’, improves the overall accuracy of music similarity comparison by 10% compared to the other state-of-the-art methods from recent literature.
39
Iacoviello, F., G. Giorgetti, F. Nieto y I. T. Memmi. "Evolution with depth from detrital to authigenic smectites in sediments from AND-2A drill core (McMurdo Sound, Antarctica)". Clay Minerals 47, n.º 4 (diciembre de 2012): 481–98. http://dx.doi.org/10.1180/claymin.2012.047.4.07.
Texto completoResumen
AbstractWe have examined the nature and origin of smectites in glaciomarine sediments of the AND-2A drill core (McMurdo Sound, Antarctica) by means of X-ray diffraction (XRD) analyses on the clay fraction, field emission scanning electron microscopy (FESEM), scanning electron microscopy (SEM) observations and SEM-EDS microanalyses on smectite particles. Relying on the smectite variation throughout the drill core it was possible to split the sequence into three units. Smectites throughout the core are either detrital or authigenic. Detrital smectites are close to montmorillonite-beidellite in composition while newly-formed smectites frequently have higher Fe-Mg contents and intermediate compositions between the saponite and nontronite field, with lower amounts in the montmorillonite-beidellite field. In the upper sedimentary sections (Unit I, and Unit II, 36-440 mbsf, 0.7-16.5 Ma) smectites are interpreted to be predominantly detrital, whereas in the lower portion of the core (Unit III, 440-1123.20 mbsf, 16.5-20.2 Ma) authigenic smectites are the most common feature. The predominance of mica, the abundance of chlorite, and the nature of smectites in the upper units indicate physical weathering under cold and dry climate, and a dominant provenance for the clay minerals from the Transantarctic Mountains. Smectites in the lower unit are considered mostly authigenic and they are most likely to be the result of early diagenetic processes, being formed from the alteration of volcanic material (glass, pyroxenes and feldspars) and/or through precipitation from fluids of a possible hydrothermal origin. Our survey attests to the importance of discriminating between a detrital and authigenic nature of smectites as the occurrence of authigenic clay minerals in ancient sedimentary successions might lead to incorrect palaeoclimatic interpretations, since they can be affected by diagenetic processes, thus obliterating the climatic signal.
40
Longman, Mark W., Nik Svihlik, Joan Burleson y James W. Hagadorn. "Opal Cement in the Eocene Castle Rock Conglomerate, Central Colorado". Mountain Geologist 61, n.º 1 (1 de enero de 2024): 49–69. http://dx.doi.org/10.31582/rmag.mg.61.1.49.
Texto completoResumen
The Castle Rock Conglomerate is one of Colorado’s most iconic, youngest, and coarsest grained rock units. It is also one of the hardest sedimentary rocks in Colorado and forms prominent buttes in the southwestern Denver Basin. Yet the reasons for its induration and resistance to weathering have not previously been investigated. Sedimentologic observations paired with sedimentary petrology indicate that much of the unit is comprised of a planar-bedded to cross-bedded, mostly poorly sorted, angular to subrounded assemblage of quartz, K-feldspar, quartzite, and unusually large volcanic rock fragments along with some plagioclase and mica flakes. The largest volcanic rock fragments are up to ∼2 m in size and composed of the immediately subjacent Wall Mountain Tuff of late Eocene age. Sedimentary rock fragments and well-rounded quartz grains are rare. Together these features suggest a diverse and relatively proximal provenance for the unit. Pervasive opaline cement coats most grains, and locally exhibits pendant features typical of vadose precipitation. These opal cements formed prior to any grain compaction and indicate early silica precipitation at shallow burial depths. Where the primary pores were not completely cemented by the opal, most were later filled with length-fast chalcedony cement. We hypothesize that cementation of the conglomerate began soon after deposition as weathering of the Wall Mountain Tuff and weathering of clasts of the tuff within the conglomerate, yielded ground water super-saturated with silica. These fluids initially catalyzed precipitation of common opal (hydrous amorphous silica) and later fostered precipitation of length-fast chalcedony. Together, these cements created a silica-cemented “concrete” much more resistant to weathering than any carbonate-cemented sandstone, and much harder than man-made calcite-cemented concrete found in many sidewalks and roadways.
41
Giannossa, Lorena Carla, Tiziana Forleo y Annarosa Mangone. "The Distinctive Role of Chemical Composition in Archaeometry. The Case of Apulian Red Figure Pottery". Applied Sciences 11, n.º 7 (30 de marzo de 2021): 3073. http://dx.doi.org/10.3390/app11073073.
Texto completoResumen
Correlation of the scientific approach to the archaeological investigation and vice versa is considered, for at least the past 30 years, as the best strategy to answer questions in cultural heritage. Many archaeological queries have merged archaeological and scientific studies and have been carried out with a multidisciplinary approach that uses complementary analytical techniques. Here, we focused our efforts on outlining the strong relevance of elemental composition in chemistry and mineralogical investigations to answer important archaeological questions in the case of Apulian red figure pottery. This ceramic class is the most important quantitative handcraft production group of figured pottery in Magna Grecia and the most widespread and commercialized production from the third quarter of the fifth century to the end of the next century. The results obtained indicate that, by exploring chemical elements in the ceramic mixture, it is possible to extract information about provenance, manufacturing processes, originality and restoration techniques.
42
Coli, Massimo, Anna Livia Ciuffreda, Tessa Donigaglia y Marco Tanganelli. "The Building Stones of Prato’s Cathedral and Bell Tower, Italy". Applied Sciences 12, n.º 19 (9 de octubre de 2022): 10132. http://dx.doi.org/10.3390/app121910132.
Texto completoResumen
This study defines the assemblage, lithotypes and mechanical parameters of the building stones used for the external cladding of Prato’s Cathedral and Bell Tower (XIV century), now subject to extensive conservation work. By means of a drone flight, a full 3D model of the Cathedral and Bell-Tower complex was developed with photoplanes of the façades. On this basis, a GIS of the façades with all the stone elements embedded was developed. Historical data and organoleptic analysis enabled the identification of the types of the stones constituting the cladding. The results show that the building stones used for the cladding are all local historical stones, namely white Alberese and Palombini limestones, green Verde Prato peridotites, and grey Pietra Serena sandstone. The quarries of provenance of these stones were determined, along with their physical-mechanical properties and decay processes, in order to contribute to conservation works according to authenticity and integrity principles.
43
Mihălcică, Mircea, Mariana Domnica Stanciu, Silviu Marian Nastac, Florin Dinulică, Alina Maria Nauncef, Ioan Călin Roșca y Adriana Savin. "Signature Modes of Old and New Violins with Symmetric Anatomical Wood Structure". Applied Sciences 11, n.º 23 (29 de noviembre de 2021): 11297. http://dx.doi.org/10.3390/app112311297.
Texto completoResumen
The paper aims to investigate old and new violins from the perspective of the correlation between the anatomical structure of spruce and maple wood, and the dynamic response of violins. Thus, in the first stage, for each violin, the characteristics of the annual rings were measured on the entire width of the top plate, determining the degree of symmetry of the face with respect to the longitudinal axis of the violin body. Then, each violin was dynamically tested with the impact hammer, determining its own frequency spectrum, mainly the so-called “signature” mode and quality factors. The most important findings consist of identification of the first five modes for old violins, (known as provenance), current new violins, and violins whose origin is unknown, but which could correlate with anatomical, constructive and dynamic characteristics, in order to be able establish origins, and also the measurement of anatomical features of top and back plates in the violins’ construction.
44
Gómez-Marín, Ernesto, Valerio Senni, Luis Parrilla, Jose L. Tejero López, Encarnación Castillo y Davide Martintoni. "An Innovative Strategy Based on Secure Element for Cyber–Physical Authentication in Safety-Critical Manufacturing Supply Chain". Applied Sciences 13, n.º 18 (19 de septiembre de 2023): 10477. http://dx.doi.org/10.3390/app131810477.
Texto completoResumen
The accurate tracking of every production step and related outcome in a supply chain is a stringent requirement in safety-critical sectors such as civil aviation. In such a framework, trusted traceability and accountability can be reliably and securely managed by means of blockchain-based solutions. Unfortunately, blockchain cannot guarantee the provenance and accuracy of the stored information. To overcome such a limitation, this paper proposes a secure solution to strongly rely on the tracking information of the physical assets in the supply chain. The proposed solution exploits Hardware Security Modules (HSMs) to provide required cryptographic primitives through a Near-Field Communication (NFC) connection. In our approach, each transfer of the assets is authenticated, verified, and recorded in the blockchain through the HSM. Transaction entries are signed, thus providing a guarantee of ownership and authenticity. The proposed infrastructure has been subject of an exhaustive security analysis and proved resilient against counterfeiting attempts, stakeholder repudiations, and misleading information.
45
Baldermann, Andre, Oliver Wasser, Elshan Abdullayev, Stefano Bernasconi, Stefan Löhr, Klaus Wemmer, Werner E. Piller, Maxim Rudmin y Sylvain Richoz. "Palaeo-environmental evolution of Central Asia during the Cenozoic: new insights from the continental sedimentary archive of the Valley of Lakes (Mongolia)". Climate of the Past 17, n.º 5 (29 de septiembre de 2021): 1955–72. http://dx.doi.org/10.5194/cp-17-1955-2021.
Texto completoResumen
Abstract. The Valley of Lakes basin (Mongolia) contains a unique continental sedimentary archive, suitable for constraining the influence of tectonics and climate change on the aridification of Central Asia in the Cenozoic. We identify the sedimentary provenance, the (post)depositional environment and the palaeo-climate based on sedimentological, petrographical, mineralogical, and (isotope) geochemical signatures recorded in authigenic and detrital silicates as well as soil carbonates in a sedimentary succession spanning from ∼34 to 21 Ma. The depositional setting was characterized by an ephemeral braided river system draining prograding alluvial fans, with episodes of lake, playa or open-steppe sedimentation. Metamorphics from the northern adjacent Neoarchean to late Proterozoic hinterlands provided a continuous influx of silicate detritus to the basin, as indicated by K–Ar ages of detrital muscovite (∼798–728 Ma) and discrimination function analysis. The authigenic clay fraction is dominated by illite–smectite and “hairy” illite (K–Ar ages of ∼34–25 Ma), which formed during coupled petrogenesis and precipitation from hydrothermal fluids originating from major basalt flow events (∼32–29 and ∼29–25 Ma). Changes in hydroclimate are recorded in δ18O and δ13C profiles of soil carbonates and in silicate mineral weathering patterns, indicating that comparatively humid to semi-arid conditions prevailed in the late(st) Eocene, changing into arid conditions in the Oligocene and back to humid to semi-arid conditions in the early Miocene. Aridification steps are indicated at ∼34–33, ∼31, ∼28 and ∼23 Ma and coincide with some episodes of high-latitude ice-sheet expansion inferred from marine deep-sea sedimentary records. This suggests that long-term variations in the ocean–atmosphere circulation patterns due to pCO2 fall, reconfiguration of ocean gateways and ice-sheet expansion in Antarctica could have impacted the hydroclimate and weathering regime in the basin. We conclude that the aridification in Central Asia was triggered by reduced moisture influx by westerly winds driven by Cenozoic climate forcing and the exhumation of the Tian Shan and Altai Mountains and modulated by global climate events.
46
Ivančič, Kristina, Rok Brajkovič y Mirijam Vrabec. "Geochemical and Mineralogical Approaches in Unraveling Paleoweathering, Provenance, and Tectonic Setting of the Clastic Sedimentary Succession (Western Central Paratethys)". Applied Sciences 14, n.º 2 (8 de enero de 2024): 537. http://dx.doi.org/10.3390/app14020537.
Texto completoResumen
Pronounced tectonic and paleogeographic changes were detected in the Alpine–Pannonian region during the Miocene at the interface between the Alps, the Dinarides, and the Pannonian Basin. To understand the major tectonic, paleogeographic, and paleoclimatic changes during this period, geochemical and mineralogical investigations were carried out on the fine-grained clastic sedimentary rocks in the Tunjice Hills. The paleoweathering indicates a cold and/or arid to a warm and humid period. The paleoclimate and the regional climatic conditions correspond well with the Middle Miocene Climatic Optimum. The mineral composition shows an abundance of quartz and calcite. Quartz is associated with detrital origin from volcanic and metamorphic rocks of the Eastern and Southern Alps and with authigenic processes in sediments. Calcite is related to authigenic origin formed in shallow marine environments and to detrital provenance from the Southern Alps. Not all discriminant functions based on major oxides provided adequate results in determining the tectonic setting. The source rocks were subjected to oceanic island arc and collision. Moreover, sedimentation was influenced by both active and passive margin settings. The former is related to the Alpine collision, which continued from the Cenozoic onward, and the latter is connected to the processes associated with the formation of the Pannonian Basin System, which began in the late Early Miocene.
47
Tenorio-Fornés, Ámbar, Samer Hassan y Juan Pavón. "Peer-to-Peer System Design Trade-Offs: A Framework Exploring the Balance between Blockchain and IPFS". Applied Sciences 11, n.º 21 (26 de octubre de 2021): 10012. http://dx.doi.org/10.3390/app112110012.
Texto completoResumen
The current state of the web, which is dominated by centralized cloud services, raises several concerns regarding different aspects such as governance, privacy, surveillance, and security. A way to address these issues is to decentralize the platforms by adopting new distributed technologies, such as IPFS and Blockchain, which follow a full peer-to-peer model. This work proposes a set of guidelines to design decentralized systems, taking the different trade-offs these technologies face with regard to their consistency requirements into consideration. These guidelines are then illustrated with the design of a decentralized questions and answers system. This system serves to illustrate a framework to create decentralized services and applications that uses IPFS and Blockchain technologies and incorporates the discussion and guidelines of the paper, providing solutions for data access, data provenance, and data discovery. Thus, this work proposes a framework to assist in the design of new decentralized systems, proposing a set of guidelines to choose the appropriate technologies depending on the relevant requirements; e.g., considering if Blockchain technology may be required or IPFS might be sufficient.
48
Moon, Inkyeong, Lei Liu, Xiaoyong Yang, Yeon Jee Suh, Jaewoo Jung y Youngji Ha. "Chemical Signatures of Ge in Magnetite of Wugang BIF, China". Applied Sciences 13, n.º 14 (16 de julio de 2023): 8246. http://dx.doi.org/10.3390/app13148246.
Texto completoResumen
Magnetite is a representative ore mineral found in various deposits. The trace element composition of ore deposits is controlled by several physiochemical factors such as temperature, pressure, and oxygen or sulfur fugacity. The chemical behavior of Germanium (Ge) is distinct in different environments. Consequently, the composition patterns of Ge in magnetite can be used to infer the provenance conditions. This study focuses on the Ge composition in magnetite from the Wugang banded iron formation (BIF) to understand the compositional characteristics of BIF sources and reconstruct of origin of Wugang BIF. The magnetite of the Wugang BIF has a porous texture, indicating high dissolution-reprecipitation processes and easy fluid infiltration, owing to its increased effective permeability. The Ge in the magnetite of the Wugang BIF was incorporated into iron hydroxide from the hydrothermal fluid and seawater during precipitation. The formation period of the Wugang BIF was consistent with significant oxidation events that led to the oxidation of ferrous ions in the Precambrian Ocean. Certain processes promote the chemisorption and coprecipitation of Ge into iron hydroxides or oxides.
49
Oluyede, Kehinde, Ibrahim Garba, Umar Danbatta, Paul Ogunleye y Urs Klötzli. "Petrography and geochemistry of the granitoids and associated volcanic rocks of the northern part of Kushaka and Birnin Gwari schist belts, NW Nigeria: implications for provenance and geological setting". International Journal of Advanced Geosciences 9, n.º 2 (24 de julio de 2021): 42. http://dx.doi.org/10.14419/ijag.v9i2.31269.
Texto completoResumen
The granitoids and the associated volcanic rocks of the northern part of Kushaka and Birnin Gwari schist belts were emplaced in the ca. 3.5 – 1. 0 Ga remobilized basement complex terrain composed of metasedimentary and metaigneous rocks that later underwent medium- to high-grade metamorphism during the Pan-African thermo-tectonic event. They comprise dominantly of diorite, granodiorite, granite, granite gneiss and basalt, and are product of metasomatism and injections. The diorite and granodiorite occur as paleosome and the granite as leucosome with the development of high temperature minerals, locally attaining granulite facie metamorphism. Plagioclase, biotite, hornblende, pyroxene and olivine fractionation played an important role during their genesis through fractional crystallization of basaltic magma and partial melting of older dioritic-granodioritic source rock in the deep crust which were themselves ultimately derived through fusion of mantle materials contaminated by continental crust and enriched by fluids derived from oceanic crust in an arc setting. Geochemical characteristics have revealed different chemical trends in granitoids and basalts. The granitoids are calc-alkaline, ferroan and magnesian, metaluminous and peraluminous in character. They also exhibit I- and S-type signatures with enrichment in LILE, radioelements (Th and U), depletion in Nb, Sr, P and Ti, high LREE fractionation factors (La/Yb) (1.05 to 77.20), and pronounced negative Eu anomalies (Eu/Eu* = 0.34 to 1.10). Similar patterns of spidergrams show that the rocks are genetically related and were emplaced in a volcanic arc and syn-collisional setting. The basalt is tholeiitic, metaluminous and high in Fe and Mg with relative enrichment in LILE, HFSE, low and near flat LREE and HREE, low fractionation [(La/Yb)N = 1.4] with Eu/Eu* value of 1.10. It is evidently a back arc cum mid-ocean ridge (MORB) basalt. The consistent decrease in the content of MgO, Fe2O3 MnO, CaO, Sc, Cr and V of the basalt, diorites, granodiorites, and granites indicates continuous igneous crystallization process. It seems that extrusion of basaltic magmas from the sub-circular Kushaka Complex derived from subduction of oceanic crust resulted in complete change in the genesis of the magmas at the time, in this region. The granitoids and the basalt may have formed behind subducted Pan-African plate due to effects of compressional and tensional forces caused by oceanic plate roll-back which resulted to a zone of extension, parallel to the island arc. The granitoids present similar chemical characteristics to those in the other areas underlain by the basement complex and schist belts in the north and eastern parts of the Pan-African mobile belt, while basalts are similar to ophiolites and amphibolites in other schist belts of Nigeria forming a lateral continuation of the same mobile belt.
50
Li, Jie, Bimin Zhang, Qingjie Gong, Hanliang Liu y Ningqiang Liu. "Microscopic Morphology and Indicative Significance of Nanoscale Au Particles in Soils and Fault Muds: A Case Study of Jiaojia, Shandong Province". Applied Sciences 13, n.º 4 (7 de febrero de 2023): 2126. http://dx.doi.org/10.3390/app13042126.
Texto completoResumen
In recent decades, the human demand for mineral resources has increased dramatically, and the mining of shallow deposits has basically been completed. The prospecting direction has turned to concealed deposits. For this reason, various penetrating geochemical methods have been developed to find concealed minerals and a series of geochemical exploration techniques have been proposed. At the same time, the use of the geochemical gene as a new technique presented in recent years is feasible in discussing component classification and provenance tracing. In this study, we applied these methods for mineral exploration in the Jiaojia gold deposit in Shandong Province, China. The results show that a large number of ore-forming element particles can be observed in ores, fault muds, and soils; compared with Chinese soil, Au has higher enrichment coefficients; according to the LG03 lithogene, the ores belong to a neutral composition, and the fault muds and soils belong to an acidic composition. Based on the above results, it can be found that the ore-forming elements in the Jiaojia gold deposit have migrated. Although this migration cannot change the original lithology, it can provide theoretical support for the fine-grained soil-prospecting method.