Relevant bibliographies by topics / Geochemical alteration

Academic literature on the topic 'Geochemical alteration'

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Published: 10 December 2022
Last updated: 28 January 2023

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Journal articles on the topic "Geochemical alteration"

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El-Desoky, Hatem M., Andongma W. Tende, Ahmed M. Abdel-Rahman, Antoaneta Ene, Hamdy A. Awad, Wael Fahmy, Hamada El-Awny, and Hesham M. H. Zakaly. "Hydrothermal Alteration Mapping Using Landsat 8 and ASTER Data and Geochemical Characteristics of Precambrian Rocks in the Egyptian Shield: A Case Study from Abu Ghalaga, Southeastern Desert, Egypt." Remote Sensing 14, no. 14 (July 18, 2022): 3456. http://dx.doi.org/10.3390/rs14143456.

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This study evaluates the geological attributes of rocks within the Abu Ghalaga area using spatial, geochemical, and petrographic approaches. ASTER and Landsat imagery processed using band ratio and principal component analysis were used to map hydrothermal alterations, while a regional tectonic evaluation was based on automated extraction of lineaments from a digital elevation model. Geochemical and petrographic analyses were then employed for discrete scale evaluation of alteration patterns of rocks across the study location. Based on satellite image processing, alteration patterns across the study area are widespread, while evidence from lineament analysis suggests a dominant NW–SE tectonic trend accompanied by a less dominant ENE–WSW direction. The different rock units exposed in the studied district are arranged chronologically from oldest to youngest as arc metavolcanic group (basalt and rhyolite), arc metagabbro–diorite, gneissose granite (granodiorite and tonalite), and dykes (aplite and felsite). Various types of igneous and metamorphic rocks have propylitic, phyllic, and argillic zones. Geochemical data indicate that the studied rocks are classified into granite, granodiorite, gabbroic diorite, and gabbro. Geochemically, the rocks have a sub-alkaline magma type. The granodiorite–tonalite is derived from the calc–alkaline magma nature, while gabbro and diorite samples exhibit tholeiitic to calc–alkaline affinity. The tectonic setting of the studied rocks trends toward volcanic arc granite (VAG). Based on petrographic, geochemical, and remote analyses, sericitization, chloritization, epidotization, kaolinitization, carbonatization, and silicification are the main alteration types present in the study area. As a result of lineaments analysis, the existing fractures and structural planes form valid flow paths for mineral-bearing hydrothermal solutions.
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Planavsky, Noah J., Leslie J. Robbins, Balz S. Kamber, and Ronny Schoenberg. "Weathering, alteration and reconstructing Earth's oxygenation." Interface Focus 10, no. 4 (June 12, 2020): 20190140. http://dx.doi.org/10.1098/rsfs.2019.0140.

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Deciphering the role—if any—that free oxygen levels played in controlling the timing and tempo of the radiation of complex life is one of the most fundamental questions in Earth and life sciences. Accurately reconstructing Earth's redox history is an essential part of tackling this question. Over the past few decades, there has been a proliferation of research employing geochemical redox proxies in an effort to tell the story of Earth's oxygenation. However, many of these studies, even those considering the same geochemical proxy systems, have led to conflicting interpretations of the timing and intensity of oxygenation events. There are two potential explanations for conflicting redox reconstructions: (i) that free oxygen levels were incredibly dynamic in both time and space or (ii) that collectively, as a community—including the authors of this article—we have frequently studied rocks affected by secondary weathering and alteration (particularly secondary oxidation) while neglecting to address the impact of this alteration on the generated data. There are now multiple case studies that have documented previously overlooked secondary alteration, resolving some of the conflicting constrains regarding redox evolution. Here, an analysis of a large shale geochemistry database reveals significant differences in cerium (Ce) anomalies, a common palaeoredox proxy, between outcrop and drill core samples. This inconsistency provides support for the idea that geochemical data from altered samples are frequently published in the peer-reviewed literature. As individuals and a geochemical community, most of us have been slow to appreciate how pervasive the problem is but there are examples of other communities that have faced and met the challenges raised by such quality control crises. Further evidence of the high potential for alteration of deep-time geochemical samples, and recognition of the manner in which this may lead to spurious results and palaeoenvironmental interpretations, indicate that sample archiving, in publicly accessible collections needs to become a prerequisite for publication of new palaeoredox data. Finally, the geochemical community need to think about ways to implement additional quality control measures to increase the fidelity of palaeoredox proxy work.
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Taylor, R. E., P. E. Hare, and T. D. White. "Geochemical criteria for thermal alteration of bone." Journal of Archaeological Science 22, no. 1 (January 1995): 115–19. http://dx.doi.org/10.1016/s0305-4403(95)80169-3.

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Bilić, Šime, and Vesnica Garašić. "PETROLOGICAL CHARACTERISTICS OF CLASTIC SEDIMENTARY ROCKS FROM THE ST. BARBARA ORE MINE IN RUDE NEAR SAMOBOR." Rudarsko-geološko-naftni zbornik 36, no. 1 (2021): 121–35. http://dx.doi.org/10.17794/rgn.2021.1.10.

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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.
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Mazzullo, S. J. "Geochemical and neomorphic alteration of dolomite: A review." Carbonates and Evaporites 7, no. 1 (March 1992): 21–37. http://dx.doi.org/10.1007/bf03175390.

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Lumpkin, Gregory R., and Rodney C. Ewing. "Geochemical alteration of pyrochlore group minerals; pyrochlore subgroup." American Mineralogist 80, no. 7-8 (August 1, 1995): 732–43. http://dx.doi.org/10.2138/am-1995-7-810.

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Lumpkin, Gregory R., and Rodney C. Ewing. "Geochemical alteration of pyrochlore group minerals; betafite subgroup." American Mineralogist 81, no. 9-10 (October 1, 1996): 1237–48. http://dx.doi.org/10.2138/am-1996-9-1022.

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Timkin, Timofey, Mahnaz Abedini, Mansour Ziaii, and Mohammad Reza Ghasemi. "Geochemical and Hydrothermal Alteration Patterns of the Abrisham-Rud Porphyry Copper District, Semnan Province, Iran." Minerals 12, no. 1 (January 16, 2022): 103. http://dx.doi.org/10.3390/min12010103.

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In this study, the zonality method has been used to separate geochemical anomalies and to calculate erosional levels in the regional scale for porphyry-Cu deposit, Abrisham-Rud (Semnan province, East of Iran). In geochemical maps of multiplicative haloes, the co-existence of both the supra-ore elements and sub-ore elements local maxima implied blind mineralization in the northwest of the study area. Moreover, considering the calculated zonality indices and two previously presented geochemical models, E and NW of the study have been introduced as ZDM and BM, respectively. For comparison, the geological layer has been created by combining rock units, faults, and alterations utilizing the K-nearest neighbor (KNN) algorithm. The rock units and faults have been identified from the geological map; moreover, alterations have been detected by using remote sensing and ASTER images. In the geological layer map related to E of the study area, many parts have been detected as high potential areas; in addition, both geochemical and geological layer maps only confirmed each other at the south of this area and suggested this part as high potential mineralization. Therefore, high potential areas in the geological layer map could be related to the mineralization or not. Due to the incapability of the geological layer in identifying erosional levels, mineralogy investigation could be used to recognize this level; however, because of the high cost, mineralogy is not recommended for application on a regional scale. The findings demonstrated that the zonality method has successfully distinguished geochemical anomalies including BM and ZDM without dependent on alteration and was able to predict erosional levels. Therefore, this method is more powerful than the geological layer.
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Omotunde, V. B. "Mineralogy and Geochemistry of Hydrothermally altered Talcose rocks from Ila Orangun-Oyan areas, part of Southwestern Nigeria." Indian Journal of Science and Technology 13, no. 40 (October 31, 2020): 4244–61. http://dx.doi.org/10.17485/ijst/v13i40.1686.

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Background/Objectives: Talcose rocks within Precambrian Basement Complex serve as relics of Archean greenstones. alterations associated with polycyclic-orogenies that affected this complex is studied to understand mineralogical and geochemical alterations. Methods: Five fresh samples of talcose rocks were collected during field mapping. These samples were cut into thin sections to reveal modal mineralogy, altered minerals and degree of alteration of such minerals. Mineral phase identification of the talcose rocks was conducted using X-ray Broker D8 ADVANCE diffractometer while whole rock analysis was carried out using Inductively Coupled Plasma Mass Spectrometry. Findings: Lithological relationship revealed from field evidence showed that the talc bodies occurred in close association with micaceous schist. The mineral assemblage of talc, tremolite, actinolite, chlorite and calcite suggest low grade greenschist metamorphic facies from possible hydrothermal alteration. Geochemical results revealed the following range of concentrations; SiO2 42.19-59.03%; Al2O3 1.1 - 11.8%; Fe2O3 7.64-9.56%; MgO 24.47-26.639%; Ni 594-1207ppm; Co 43.2-113.9ppm; Sn 6-41ppm; V 32-75ppm and Zr 1.3-58.7ppm, and these are typical of talcose rocks. Petrogenetic studies suggest a komatiitic origin with a peridotitic komatiite precursor for the talc-chlorite-tremolite schist. Enrichment in LREE, depletion in HREE and a negative Eu anomaly suggest alteration of the parent magma for the talcose rock and plagioclase fractionation. The trends observed for the LILE, HFSE and REE suggest possible contamination or mixing of crustal and mantle materials during the formation of the protolith. Ni and Co concentrations are higher than average crustal values with implication for ultrabasic to basic magma composition for the komatiitic progenitor and also suggestive of possible mineralisation. Conclusion: Mineralogical examination has revealed a talc-chlorite-tremolite composition for the talcose rocks with peridotitic komatiite precursory while geochemical composition supported ultrabasic magmatism similar to those with the Ilesha schist belt.
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Marignac, Christian, Michel Cuney, Michel Cathelineau, Andreï Lecomte, Eleonora Carocci, and Filipe Pinto. "The Panasqueira Rare Metal Granite Suites and Their Involvement in the Genesis of the World-Class Panasqueira W–Sn–Cu Vein Deposit: A Petrographic, Mineralogical, and Geochemical Study." Minerals 10, no. 6 (June 23, 2020): 562. http://dx.doi.org/10.3390/min10060562.

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Elucidation of time-space relationships between a given wolframite deposit and the associated granites, the nature of the latter, and their alterations, is a prerequisite to establishing a genetic model. In the case of the world-class Panasqueira deposit, the problem is complicated because the associated granites are concealed and until now poorly known. The study of samples from a recent drill hole and a new gallery allowed a new approach of the Panasqueira granite system. Detailed petrographic, mineralogical, and geochemical studies were conducted, involving bulk major and trace analyses, BSE and CL imaging, EPMA, and SEM-EDS analyses of minerals. The apical part of the Pansqueira pluton consisted of a layered sequence of separate granite pulses, strongly affected by polyphase alteration. The use of pertinent geochemical diagrams (major and trace elements) facilitated the discrimination of magmatic and alteration trends. The studied samples were representative of a magmatic suite of the high-phosphorus peraluminous rare-metal granite type. The less fractionated members were porphyritic protolithionite granites (G1), the more evolved member was an albite-Li-muscovite rare metal granite (G4). Granites showed three types of alteration processes. Early muscovitisation (Ms0) affected the protolithionite in G1. Intense silicification affected the upper G4 cupola. Late muscovitisation (Fe–Li–Ms1) was pervasive in all facies, more intense in the G4 cupola, where quartz replacement yielded quartz-muscovite (pseudo-greisen) and muscovite only (episyenite) rocks. These alterations were prone to yield rare metals to the coeval quartz-wolframite veins.
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Dissertations / Theses on the topic "Geochemical alteration"

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Rich, Shane Daniel. "Geochemical mapping of porphyry deposits and associated alteration through transported overburden." Thesis, University of British Columbia, 2016. http://hdl.handle.net/2429/58704.

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Discoveries of porphyry copper deposits (PCDs) in British Columbia have declined over the past 20 years. Undiscovered PCDs are predicted to occur in the Intermontane Belt, an assemblage of volcanic arc terranes considered important for hosting large porphyry deposits. The Deerhorn Cu-Au porphyry, located within this belt, is covered with up to 60 m of undisturbed moraine. Detailed regolith mapping based on a new classification scheme for BC, combined with aqua regia and deionised water assays, sequential leaching, physicochemical measurements and hydrocarbon analysis, was undertaken to determine the response in the till to buried mineralisation. Geochemical relationships dependent on the regolith type were identified and are particularly evident in organic rich areas. To minimise background noise, data analysis was constrained to the dominent regolith unit: the undisturbed moraine (DrM), resulting in enhanced anomaly identification. Regolith mapping in advance of a soil survey can therefore allow targeted efficient sampling. Normalisation to organic carbon (Corg) to counteract the influence of organic matter on trace element variability resulted in anomalous response for elements As, Cs, Cu, Mo, Tl, U and W by conventional aqua regia on a 180-micron fraction B-upper-horizon soil. The response for six of these elements is peripheral to mineralisation in the surface environment. Multi-element evaluation is superior for mineralisation detection than individual element evaluation. Light hydrocarbon results indicate a surface response with a distinct depletion over mineralisation. Sequential leaching on selected anomalous Cu samples indicates that an aqua regia extraction was the optimal first choice for anomalous Cu detection. Copper-Fe-oxide-bearing grains interpreted as oxidised sulphides were recovered from an anomalous Cu-bearing sample and confirm a contribution of glacial clastic transport. Visual screening for clastic fragments allows a reprioritisation of anomalous response. Copper isotope results do not support Cu-ion migration from the buried mineralisation, but instead support a clastic contribution. Anomaly formation is interpreted as a combination of clastic transport, ionic migration of H⁺, vegetation uptake and surface redistribution.
Science, Faculty of
Earth, Ocean and Atmospheric Sciences, Department of
Graduate
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Dickie, Jennifer M. "Mineralogical and Geochemical Indicators of Subaerial Weathering in the Pozzolane Rosse Ignimbrite (Alban Hills Volcanic District, Italy)." Digital Archive @ GSU, 2010. http://digitalarchive.gsu.edu/geosciences_theses/23.

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The Pozzolane Rosse ignimbrite [PR] (457±4 ka) in the Alban Hills Volcanic District, Rome, Italy was exposed ~ 40 ka prior to a subsequent volcanic event which coverd it entirely. XRF, XRD, and clay separation results from PR samples from INGV and CA1 boreholes and Castel di Leva quarry show evidence of paleopedogenesis. All locations display loss of base cations, loss of K is consistent with XRD datat showing dissolution or alteration of leucite to analcime. Accumulation of Al and high L.O.I. support XRD evidence of 1:1 clay species at upper depth. Data suggest alteration extent can be determined by geochemistry. Hydrothermal alteration is assessed from geochemistry showing significant leaching of major and trace elements, primary mineralogy loss and iron sulfide and sulfate mineral development. Deep samples of PR may show groundwater influenced alteration with the presence of expandable 2:1 clays, zeolites, and possible mixing with the underlying Vallerano Lava.
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Nguyen, Thi Minh Ngoc. "Recent geochemical and mineralogical alteration processes in tropical coastal sediments of Vietnam." [S.l.] : [s.n.], 2006. http://deposit.ddb.de/cgi-bin/dokserv?idn=984452133.

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Czaja, Andrew David. "Characterization of the geochemical alteration of permineralized fossil plants based on macromolecular structure and composition." Diss., Restricted to subscribing institutions, 2006. http://proquest.umi.com/pqdweb?did=1280144881&sid=1&Fmt=2&clientId=1564&RQT=309&VName=PQD.

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Hamisi, Jonathan. "Defining The Geochemical Footprint For Gold Mineralisation Around Birthday Reef.Reefton Goldfield, New Zealand." Thesis, Stockholms universitet, Institutionen för geologiska vetenskaper, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-132115.

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Abstract Orogenic gold deposits from the Reefton goldfield in New Zealand hosted in Ordovician metasediments of the Greenland group have produce 67 tons of gold before 1951. The Blackwater mine in Waiuta account for about 1/3 of the gold production at Reefton prior 1951. The ore system at Blackwater consist of NE trending steeply dipping gold-bearing quartz veins (Birthday reef) occurring in faulted, sheared and folded alternating sequence of sandstone-mudstone metamorphosed to low greenschist facies and hydrothermally altered proximal to distal from the quartz vein. Host rock and ore forming fluids interaction resulted in a systematic change in the mineralogy and geochemistry of the wallrock developing a distinctive footprint of the ore system. The mineral assemblage subsequent to hydrothermal alteration is formed by quartz veining, chlorite, carbonates (minor calcite-dolomite-ankerite-siderite), albite, K-Mica and composite quartz-carbonate veining, carbonates spotting, pyrite, arsenopyrite, chalcopyrite, cobaltite, galena and in a lesser extent ullmannite, gersdorffite, pentlandite, millerite and sphalerite. Mass balance calculation based on geochemical data obtained by ultra-low detection analysis with a detection limit in part per trillion of Au, As and Sb provide new insight in the geochemical footprint of the ore system at Blackwater. A clear zone of roughly 40 meters (20 meters above and below the birthday reef) is enriched in Au, As and Sb up to respectively 6806%, 605% and 891% compared to the un-mineralised protolith. Furthermore, mass changes in K2O and Na2O indicate a consistent decrease in Na and increase in K in the vicinity of the Birthday reef reflecting the replacement of albite by K-mica. This is corroborated by pattern of alkali alteration index Na/Al for albite and 3K/Al for K-Mica showing similar trend. Carbonation and de/-hydration index also exhibits peaks in samples adjacent to the Birthday reef, though carbonation index is also influenced by carbonates content in the protolith or late carbonation that may not related to gold mineralisation. Using the indicators above-mentioned it is possible to define the mineralogical and geochemical “footprint” for the ore system in the host rock allowing to use this footprint as a tool for mineral exploration for orogenic gold deposits similar to Blackwater. Given that the geochemical footprint of orogenic gold deposit such as Blackwater is significantly wider than the economically viable part of the deposit defining the footprint of the ore system offers the potential for vectoring from sub-economic mineralisation towards higher-grade ore that is economically viable.
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Teagle, Damon Andrew Herbert. "A study of hydrothermal alteration of the Troodos ophiolite, Cyprus : petrological, geochemical and strontium isotopic constraints." Thesis, University of Cambridge, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.282928.

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Schmidt, Susanne Th. "Alteration under conditions of burial metamorphism in the North Shore Volcanic Group, Minnesota : mineralogical and geochemical zonation /." Heidelberg : Ruprecht-Karls-Universität, 1990. http://catalogue.bnf.fr/ark:/12148/cb374301378.

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Presswood, Severin. "Geochemical and Petrographic Alteration of Rapidly Heated Coals from the Herrin (No. 6) Coal Seam, Illinois Basin." OpenSIUC, 2015. https://opensiuc.lib.siu.edu/theses/1733.

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A petrographic, geochemical, and molecular assessment was performed on a series of Illinois Basin coal samples that were collected at various distances from a Permian-age igneous dike. Standard coal characterization techniques such as vitrinite reflectance, proximate, and ultimate analyses provide valuable insights to maturation pathways experienced by rapidly heated coals. These techniques were coupled with reflectance micro-FTIR and KBr-FTIR analysis to provide a deeper understanding of the molecular changes that occur in the coal structure during relatively short-lived, intensive heating events. With increasing proximity to the contact with the dike, coals and coals macerals exhibit increased maturation on both petrographic and molecular scales. KBr-FTIR spectra were collected to distinguish bulk trends expressed in coals with increasing maturity, whereas reflectance micro-FTIR spectra were collected to analyze characteristics of vitrinite macerals in-situ. With increasing proximity to the intrusion, coals have higher mean random vitrinite reflectance values (Rr) within the dike alteration zone. Liptinite macerals are not distinguishable at reflectances equal to or higher than 1.36%, and coking textures are developed within 2 m of the intrusion. Geochemical data indicate an overall loss of H, O, and N and an increase in C approaching the dike. Carbonate minerals contribute significantly to geochemical data, specifically volatile matter (VM), C content, and O content. Even after carbonate removal with HCl, coals have higher VM contents at high rank than expected compared to normal coalification trends. When plotted on a van Krevelen diagram or Seyler chart, intruded coals follow different coalification trends than coals matured through normal burial metamorphism. FTIR analysis shows increased aromaticity with rank, with the ratio of the aromatic CHx band at 3100-3000 cm-1 versus the aliphatic CHx band at 3000-2800 cm-1 (AR1), and the ratio of the aromatic out-of-plane deformation band at 900-700 cm-1 versus the aliphatic CHx band (AR2) becoming larger with increasing Rr. Within the 3000-2800 cm-1 bandwidth, there is an increase in the area under the asymmetric CH3 peak at ~2960 cm-1 relative to the asymmetric CH2 peak at ~2920 cm-1 with increased rank. The overall intensity of the aromatic out-of-plane deformation modes at 900-700 cm-1 increase relative to aliphatic CHx bandwidth response at high rank as well. This trend is much more traceable in micro-FTIR spectra, which avoids the influence of mineral matter bands in the 900-700 cm-1 range. Within the 900-700 cm-1 band, the overall intensity of the ~750 cm-1 peak relative to the ~870 cm-1 peak increases with rank, likely reflecting a lower degree of substitution (DOS) of alkyl groups on aromatic ring sites in high rank coals. This trend likely also represents the building of large aromatic clusters at high rank. General FTIR spectral trends for whole-coals and individual vitrinite macerals are similar. Semi-quantitative measurements become less reliable at high coal ranks, mostly due to very small aliphatic bandwidth areas. FTIR analysis of coals and coal macerals provides insight to the molecular changes that occur in coals during rapid heating. Research of this nature can offer deeper insights into coalbed methane development in response to localized heating (Gurba and Weber, 2001).
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Estholm, Madelen. "Mineralogical and Geochemical characterization of the Fe-Cu-Occurrence and associated Hanging wall and Footwall Alteration halo of the Viscaria D-Zone, Kiruna District, Northern Sweden." Thesis, Luleå tekniska universitet, Geovetenskap och miljöteknik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-73217.

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Northern Norrbotten County is one of the three major ore producing districts in Sweden. Based on the predominance of epigenetic Cu-Au and Fe-oxide mineralization this region is regarded as a typical IOCG province. The massive to layered Viscaria Cu-deposit is proposed to be a VMS deposit of Besshi-type and is unique in deposit type of the region. The volcaniclastic rocks of the Viscaria Formation hosting the Viscaria deposit belong to the rift related Kiruna Greenstone Group. The Viscaria deposit consists of three stratiform-stratabound mineralized zones: A-, B- and D-zone. Sulphide mineralization of the D-zone differs in structural features, host rock, mineralization style and Fe-oxide dominance over Cu-sulphides compared to the main Cu-ore in the A-zone. These differences between A- and D-zone mineralization styles raise the subject that the D-zone could be of a different origin.   The Kiruna area is mainly covered by glacial-till, which contributes to limited bedrock exposure. This becomes a challenge when exploring for new deposits and highlights the importance of good geological knowledge obtained from existing deposits to carry through successful exploration programs. The objective of this study is to characterize the Fe-Cu-occurrence and the associated alteration halo of the Viscaria D-zone. Alteration halos can reach several kilometres away from the main ore zone and provides mineralogical and chemical signatures that extend the target area significantly in exploration for new deposits. Detailed core logging, optical microscopic studies, lithogeochemistry and electron microprobe analyses was utilized to contribute to a better genetic understanding of the D-zone and the associated hanging wall and footwall alteration features. The study shows that the main ore minerals of the D-zone consist of magnetite and chalcopyrite, and minor pyrite and hematite. The major alteration minerals associated with mineralization are calcite, actinolite/tremolite, epidote, chlorite and also biotite and scapolite in the hanging wall. The most prominent potential ore vector is calcite veins and biotite, as the abundance increase towards the D-zone. D-zone are further characterised by low REE concentrations, similarly to the calcic-dolomite host. The study also shows that the alteration halo of the D-zone is different in the hanging wall compared to the footwall, which is confirmed by the lithogeochemistry and mineral chemistry. The footwall is characterized by spilitization and chlorite alteration. The lithogeochemistry of the D-zone and the hanging wall reveals element mobility of Mg, Ba, Fe, Na, K, Cu and Zn. Mineral chemistry of epidote, amphibole and chlorite shows chemical changes in Fe/Al- and Mg/Fe-ratios. According to the result of this thesis and earlier studies, the D-zone mineralization is suggested to be part of the VMS system forming the stratigraphically above laying A-zone of the Viscaria Cu-deposit.
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Stock, Elizabeth Denise. "The mineralogical, geochemical and isotope characteristics of alteration, mineralization and metamorphism of the Red Lake Gold Mines, Ontario." Thesis, University of British Columbia, 2012. http://hdl.handle.net/2429/43305.

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Archean lode-gold deposits are a significant source of gold. However, exploration of this deposit type is hindered by their poorly understood genetic models and geochemical features. This project investigated the geochemical expression surrounding the Archean lode-gold Red Lake Gold Mines (RLGM) in the Superior Province, Canada. Mineral chemistry, whole rock and isotope geochemistry were used to establish how hydrothermal and metamorphic events influenced ore genesis. The RLGM is a basalt-hosted lode-gold deposit that formed from multiple superposed hydrothermal and metamorphic events. This study defined three significant superposed events which were important for gold mineralization. The first event was a widespread hybridized seafloor-magmatic event which caused reduction with FeO, MnO, K2O, SO3, SiO2, Rb, As and Cu enrichment. Seawater interaction created abundant micas-clays-chlorite-carbonate-FeMn oxides. Localized acidic magmatic fluids, in syn-volcanic faults, caused advanced argillic alteration. Subsequent peak-regional metamorphism created a widespread (>7km) occurrence of metamorphosed altered basalts. The micas-clays-chlorite-carbonate-FeMn oxides were metamorphosed to form Fe-biotite-Ti-magnetite±carbonate and Fe-chlorite-Fe-amphibole-FeMn-garnet-epidote/clinozoisite-magnetite-calcite-biotite assemblages. The metamorphosed argillic alteration created a quartz-muscovite-andalusite assemblage. Overprinting the widespread metamorphosed altered basalt was the significantly narrower (<1km), and structurally-controlled main vein and mineralization event. Abundant ankerite-calcite±quartz veins with replacement sulfide assemblages of pyrrhotite-pyrite-arsenopyrite-magnetite-gold-quartz-Mg-brown biotite were formed. The replacement ore-forming fluid enriched the basalt in CaO, MgO, SiO2, K2O, Ag, Au, Ni, Cu, Sb and Zn. Sulfides were created by sulfidation reactions between the host rock and ore-forming fluid. Redox differences during sulfidation reactions between the reduced wall rock and relatively oxidized fluid were identified as the main influence on gold precipitation. Carbon isotopes from the ankerite-calcite±quartz veins ranged from -4 to +4‰ δ13C which is consistent with a metamorphic origin by devolatilization reactions of pre-existing marine carbonates. Sulfur isotope from mineralized samples ranged from δ34SH2S 0–9‰. These are consistent with a magmatic source as well as metamorphic desulfidation of pre-existing sulfides (-7 to +6‰ 34S). The stable isotopes are most consisted with an evolved ore-forming fluid derived from a magmatic intrusion emplaced during regional-metamorphism. Therefore, gold mineralization at the RLGM was formed during ongoing, but post-peak regional metamorphism from an evolved magmatic source emplaced during a regional-contact metamorphic event.
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Books on the topic "Geochemical alteration"

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Fedikow, Mark Albert Fredrick. Rock geochemical alteration studies at the MacLellan Au-Ag deposit, Lynn Lake, Manitoba. Winnipeg: Manitoba Energy and Mines, Geological Services, 1992.

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Williams, Patrick J. Alteration in the Cloncurry District: Roles of recognition and interpretation in exploration for Cu-Au and Pb-Zn-Ag deposits. Townsville, Qld., Australia: Economic Geology Research Unit, Geology Dept., James Cook University of North Queensland, 1993.

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Dunbar, Paul A. Geology and geochemical alteration of the carbonate shear zone at Hotstone Lake - Swayze Greenstone Belt, Greenlaw Township, Ontario. [s.l: s.n.], 1989.

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Calagari, Ali Asghar. Geochemical, stable isotope, noble gas and fluid inclusion studies of mineralization and alteration at Sunun porphyry copper deposit, East Azarbaidjan, Iran: Implications for genesis. Manchester: University of Manchester, 1997.

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Araujo, Sylvia Maria de. Geochemical and isotopic characteristics of alteration zones in highly metamorphosed volcanogenic massive sulfide deposits and their potential application to mineral exploration. 1996.

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Kalinin, A. A., Ye E. Savchenko, and V. Yu Prokofiev. Mineralogy and genesis of the Oleninskoe gold deposit (Kola Peninsula). FRC KSC RAS, 2021. http://dx.doi.org/10.37614/978.5.91137.446.4.

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Data on geology of the Oleninskoe deposit, and results of mineralogical and geochemical investigations of ores and altered rocks are presented. Mineralization is connected with granite porphyry sills, an end member of gabbrodiorite-diorite-granodiorite complex of minor intrusions. The main alteration processes are diopsidization and biotitization, formation of quartz-muscovite-albite, quartz-aresenopyrite-tourmaline, and quartz metasomatic rocks. More than 50 ore minerals (sulfides, sulfosalts, tellurides, and native metals) were identified in the ore, including 20 minerals of silver and gold. Mineral associations in the ore and sequence of mineral formation are defined. Five generations of gold-silver alloys are identified, its composition covers spectrum from native silver to high-grade gold. Mineralized fluids in the deposit are of high salinity (sodium and calcium chlorides), and rich in As, Sb, Pb, Cu, Zn, and Ag. The Oleninskoe deposit is classified as an epithermal metamorphosed gold deposit.The book is of interest for specialists in economic geology, mineralogy and geochemistry of ore deposits.
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Book chapters on the topic "Geochemical alteration"

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Pandarinath, Kailasa. "Impacts of Hydrothermal Alteration on Magnetic Susceptibility and Some Geochemical Properties of Volcanic Rocks from Geothermal Areas." In Geochemical Treasures and Petrogenetic Processes, 431–51. Singapore: Springer Nature Singapore, 2022. http://dx.doi.org/10.1007/978-981-19-4782-7_16.

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Rivera-Gómez, María Abdelaly, Kailasa Pandarinath, and Alfredo Quiroz-Ruiz. "GraHyAlt—A Computer Program for the Graphical Presentation of the Hydrothermal Alteration Induced Effects in Geochemical Parameters of Volcanic Rocks." In Geochemical Treasures and Petrogenetic Processes, 485–504. Singapore: Springer Nature Singapore, 2022. http://dx.doi.org/10.1007/978-981-19-4782-7_18.

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Olenin, Sergej, and Erkki Leppäkoski. "Non-native animals in the Baltic Sea: alteration of benthic habitats in coastal inlets and lagoons." In Biological, Physical and Geochemical Features of Enclosed and Semi-enclosed Marine Systems, 233–43. Dordrecht: Springer Netherlands, 1999. http://dx.doi.org/10.1007/978-94-017-0912-5_24.

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Khalili, Mahmoud, and Forough Malekmahmoudi. "Geochemical Variations During Alteration of an Andesite-Basalt to Bentonite, In Khur, East of Isfahan, Iran." In Proceedings of the 10th International Congress for Applied Mineralogy (ICAM), 361–68. Berlin, Heidelberg: Springer Berlin Heidelberg, 2012. http://dx.doi.org/10.1007/978-3-642-27682-8_43.

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Staudigel, Hubert, Terry Plank, Bill White, and Hans-Ulrich Schmincke. "Geochemical Fluxes During Seafloor Alteration of the Basaltic Upper Oceanic Crust: DSDP Sites 417 and 418." In Subduction Top to Bottom, 19–38. Washington, D. C.: American Geophysical Union, 2013. http://dx.doi.org/10.1029/gm096p0019.

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Neumayr, Peter, Klaus J. Petersen, Louis Gauthier, Joanna Hodge, Steffen G. Hagemann, John L. Walshe, Kylie Prendergast, et al. "Mapping of hydrothermal alteration and geochemical gradients as a tool for conceptual targeting: St Ives Gold Camp, Western Australia." In Mineral Deposit Research: Meeting the Global Challenge, 1479–82. Berlin, Heidelberg: Springer Berlin Heidelberg, 2005. http://dx.doi.org/10.1007/3-540-27946-6_376.

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Luis Manrique Carreño, John. "Geochemistry Applied to the Exploration of Mineral Deposits." In Geochemistry [Working Title]. IntechOpen, 2022. http://dx.doi.org/10.5772/intechopen.103941.

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Geochemistry can be applied to the exploration of mineral deposits, for which it is necessary to understand the fundamentals of geochemical prospecting, the geochemical dispersion of elements based on their chemical properties. This chapter presents the basics of geochemical prospecting including: element mobility depending on ionic potential, pH, and Eh, with examples of Cu mobility during supergenic alteration of a primary sulfide deposit, a brief overview of sampling/geochemical prospecting methods, as well as a case study of the geochemical prospecting study carried out in the vanadium (V), uranium (U), and zinc (Zn) sedimentary mineral deposit of Puyango, Ecuador, in which anomalous and subanomalous values were detected in rock samples of various pathfinder elements of V and U.
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Bethke, Craig M. "Hydrothermal Fluids." In Geochemical Reaction Modeling. Oxford University Press, 1996. http://dx.doi.org/10.1093/oso/9780195094756.003.0020.

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Hydrothermal fluids, hot groundwaters that circulate within the Earth’s crust, play central roles in many geological processes, including the genesis of a broad variety of ore deposits, the chemical alteration of rocks and sediments, and the origin of hot springs and geothermal fields. Many studies have been devoted to modeling how hydrothermal fluids react chemically as they encounter wall rocks, cool, boil, and mix with other fluids. Such modeling proliferated in part because hydrothermal fluids are highly reactive and because the reaction products are commonly well preserved, readily studied, and likely to be of economic interest. Further impetus was provided by the development of reliable modeling software in the 1970s, a period of concern over the availability of strategic and critical minerals and of heightened interest in economic geology and the exploitation of geothermal energy. As a result, many of the earliest and most imaginative applications of geochemical modeling, beginning with Helgeson’s (1970) simulation of ore deposition in hydrothermal veins and the alteration of nearby country rock, have addressed the reaction of hydrothermal fluids. For example, Reed (1977) considered the origin of a precious metal district; Garven and Freeze (1984), Sverjensky (1984, 1987), and Anderson and Garven (1987) studied the role of sedimentary brines in forming Mississippi Valley-type and other ore deposits; Wolery (1978), Janecky and Seyfried (1984), Bowers et al. (1985), and Janecky and Shanks (1988) simulated hydrothermal interactions along the midocean ridges; and Drummond and Ohmoto (1985) and Spycher and Reed (1988) modeled how fluid boiling is related to ore deposition. In this chapter, we develop geochemical models of two hydrothermal processes: the formation of fluorite veins in the Albigeois ore district and the origin of “black smokers, ” a name given to hydrothermal vents found along the ocean floor at midocean ridges. As a first case study, we borrow from the modeling work of Rowan (1991), who considered the origin of fluorite (CaF2) veins in the Albigeois district of the southwest Massif Central, France. Production and reserves for the district as a whole total about 7 million metric tons, making it comparable to the more famous deposits of southern Illinois and western Kentucky, USA.
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Yang, H., F. D. Van der Meer, and J. Zhang. "Chapter 7 Aerospace detection of hydrocarbon-induced alteration." In Geochemical Remote Sensing of the Sub-surface, 233–45. Elsevier, 2000. http://dx.doi.org/10.1016/s0168-6275(00)80031-8.

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Simoneit, Bernd R. T., K. E. Peters, B. G. Rohrback, S. Brenner, and I. R. Kaplan. "Thermal alteration of Cretaceous black shale from the Eastern Atlantic. III: Laboratory simulations." In The Geochemical Society Special Publications, 321–40. Elsevier, 2004. http://dx.doi.org/10.1016/s1873-9881(04)80023-3.

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Conference papers on the topic "Geochemical alteration"

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Bordeaux Rego, Fabio, Shayan Tavassoli, Esmail Eltahan, and Kamy Sepehrnoori. "Geochemical Modeling of Petrophysical Alteration Effect on CO2 Injectivity in Carbonate Rocks." In SPE International Conference on Oilfield Chemistry. SPE, 2021. http://dx.doi.org/10.2118/204284-ms.

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Abstract Carbon dioxide injection into sedimentary formations has been widely used in enhanced oil recovery (EOR) and geological-storage projects. Several field cases have shown an increase in water injectivity during CO2 Water-Alternating-Gas (WAG) projects. Although there is consensus that the rock-fluid interaction is the main mechanism, modeling this process is still challenging. Our main goal is to validate a physically based model on experimental observations and use the validated model to predict CO2 injectivity alteration based on geochemical reactions in carbonate rocks. In this paper, we present a new method for CO2 reactive transport in porous media and its impact on injectivity. We hypothesize that if CO2 solubilizes in the connate water, then it induces a shift in chemical equilibrium that stimulates mineral dissolution. Consequently, porosity and permeability will increase, and cause alterations to well injectivity. We develop a predictive model to capture this phenomenon and validate the model against available data in the literature. We use UTCOMP-IPhreeqc, which is a fully coupled fluid-flow and geochemical simulator to account for rock/hydrocarbon/water interactions. In addition, we perform several experiments to test CO2/water slug sizes, mineralogy assembly, injected brine composition, and gravity segregation combined with the effect of heterogeneity. Coreflood simulations using chemical equilibrium and kinetics indicate mineral dissolution at reservoir conditions. The results suggest that the intensity of rock dissolution depends on formation mineralogy and brine composition as carbonate systems work as buffers. Additionally, we show that prolonged CO2 and brine injection induces petrophysical alteration close to the injection region. Our field-scale heterogeneous reservoir simulations show that permeability alteration calculated based on Carman-Kozeny correlation and wormhole formulation had the same results. Furthermore, we observed that water injectivity increased by almost 20% during subsequent cycles of CO2-WAG. This finding is also supported by the Pre-Salt carbonate field data available in the literature. In the case of continuous CO2 injection, the carbonate dissolution was considerably less severe in comparison with WAG cases, but injectivity increased due to unfavorable CO2 mobility. With the inclusion of gravity segregation, we report that the injectivity doubles in magnitude. The simulations show more extensive dissolution at the upper layers of the reservoir, suggesting that preferential paths are the main cause of this phenomenon. The ideas presented in this paper can be utilized to improve history-matching of production data and consequently reduce the uncertainty inherent to CO2-EOR and carbon sequestration projects.
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Reddy, R. Dileepkumar, Sridhar D. Iyer, S. Balakrishnan, and Rajneesh Bhutani. "Seawater Alteration of Central Indian Ocean Ridge Basalts: Geochemical and Isotopic Evidences." In Goldschmidt2020. Geochemical Society, 2020. http://dx.doi.org/10.46427/gold2020.2179.

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Moore, Johnathan, J. Alexandra Hakala, Amelia Vankeuren, Thai T. Phan, and Dustin Crandall. "EXPERIMENTS EVALUATING GEOCHEMICAL ALTERATION OF MATRIX MATERIALS ADJACENT TO SIMULATED HYDRAULIC FRACTURES." In Joint 52nd Northeastern Annual Section and 51st North-Central Annual GSA Section Meeting - 2017. Geological Society of America, 2017. http://dx.doi.org/10.1130/abs/2017ne-291075.

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Manzelati, Negin, Seyedeh Narges Sadati, and Ali Lotfibakhsh. "Alteration mapping for geochemical exploration in Niazgholi-Moshiran area,Using Aster data." In Goldschmidt2021. France: European Association of Geochemistry, 2021. http://dx.doi.org/10.7185/gold2021.4816.

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Hao, Xingjuan, Moataz Abu-Al-Saud, Subhash Ayirala, and Yogarajah Elakneswaran. "Evaluating the Effect of Carbonate Impurities on Wettability Alteration Using a Geochemical Model." In SPE Improved Oil Recovery Conference. SPE, 2022. http://dx.doi.org/10.2118/209424-ms.

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Abstract Wettability alteration considered as the principal mechanism has attracted more attention for low salinity waterflooding effect. It was significantly affected by electrokinetic interactions, which occurred at the interfaces of rock/brine and crude oil/brine. The mineral impurities of natural carbonate releasing ions have an important impact on the electrokinetics, which could lead to wettability shift subsequently. In this study, the effect of dolomite and anhydrite as the main impurities in natural carbonate, which caused wettability alteration, was evaluated using triple-layer surface complexation and thermodynamic equilibrium models coupled with extended Derjaguin-Landau-Verwey-Overbeek (DLVO) theory. The electrokinetics of crude oil and carbonate in brines were predicted by the triple-layer surface complexation model (TLM) based on zeta potential, while thermodynamic equilibrium model was mainly used for analyzing the carbonate impurities on wettability alteration. The equilibrium constants of reactions were determined by successfully fitting the calculated zeta potentials with measured ones for crude oil and carbonate in different solutions, which were validated for zeta potential prediction in smartwater. The disjoining pressure results show that there is a repulsion between crude oil and carbonate in Na2SO4 brine (Brine3) or smartwater (Brine4) equilibrating with calcite when comparing to that in MgCl2 (Brine1) and CaCl2 (Brine2), indicating the water-wet condition caused by the presence of sulphate ions. Moreover, the equilibrium of carbonate impurities with smartwater increases the repulsion between oil and carbonate. When the sulphate ion concentration in the adjusted smartwater exceeds a certain value, the effect of carbonate impurities on wettability alteration is not significant. Finally, the influence of smartwater pH on the interaction between oil and carbonate was evaluated with or without considering the equilibrium of carbonate impurities.
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Lerch, B., D. A. Karlsen, and D. Duggan. "Migration and Alteration Processes in Barents Sea Oils and Condensates - A Geochemical Appraoch." In 76th EAGE Conference and Exhibition 2014. Netherlands: EAGE Publications BV, 2014. http://dx.doi.org/10.3997/2214-4609.20141672.

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Bordeaux Rego, Fabio, Mehran Mehrabi, Alireza Sanaei, and Kamy Sepehrnoori. "Improvements on Modelling Wettability Alteration by Engineered Water Injection: Geochemical Pore-Scale Approach." In SPE Improved Oil Recovery Conference. Society of Petroleum Engineers, 2020. http://dx.doi.org/10.2118/200361-ms.

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M. S. Elgendy, Ahmed, Simone Ricci, Elena I. Cojocariu, and Claudio Geloni. "A Streamlined Workflow From Experimental Analyses to Dynamic Geochemical Modelling." In SPE Europec featured at 82nd EAGE Conference and Exhibition. SPE, 2021. http://dx.doi.org/10.2118/205128-ms.

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Abstract Dynamic-geochemical model is a powerful instrument to evaluate the geochemical effects on CO2storage capacity, injectivity and long-term containment. The study objective is to apply an integrated multi-step workflow to a carbon capture and storage (CCS) candidate field (offshore), namely hereinafter H field. From experimental analyses, a comprehensive real data-tailored reactive transport model (RTM) has been built to capture the dynamics and the geochemical phenomena (e.g., water vaporization, CO2solubility, mineral alteration) occurring during and after the CO2injection in sedimentary formations. The proposed integrated workflow couples lab activities and numerical simulations and it is developed according to the following steps: Mineralogical-chemical characterization (XRD, XRF and SEM-EDX experimental techniques) of field core samples; Data elaboration and integration to define the conceptual geochemical model; Synthetic brine reconstruction by means of 0D geochemical models; Numerical geochemical modelling at different complexity levels. Field rocks chosen for CO2injection have been experimentally characterized, showing a high content of Fe in clayey, micaceous and carbonate mineralogical phases. New-defined, site-specific minerals have been characterized, starting from real XRD, XRF and SEM-EDX data and by calculation of their thermochemical parameters with a proprietary procedure. They are used to reconstruct synthetic formation water chemical composition (at equilibrium with both rock mineralogy and gas phase), subsequently used in RTM. CO2injection is simulated using 2D radial reactive transport model(s) built in a commercial compositional reservoir simulator. The simulations follow a step-increase in the complexity of the model by adding CO2solubility, water vaporization and geochemical reactions. Geochemical processes impact on CO2storage capacity and injectivity is quantitatively analyzed. The results show that neglecting the CO2solubility in formation water may underestimate the max CO2storage capacity in H field by around 1%, maintaining the same pressure build-up profile. Sensitivities on the impact of formation water salinity on the CO2solubility are presented. In a one thousand years’ time-scale, changes in reservoir porosity due to mineral alteration, triggered by CO2-brine-rock interactions, seem to be minimal in the near wellbore and far field. However, it has been seen that water vaporization with the associated halite precipitation inclusion in the simulation models is recommended, especially at high-level of formation brine salinity, for a reliable evaluation of CO2injectivity related risks. The proposed workflow provides a new perspective in geochemical application for CCS studies, which relies on novel labs techniques (analyses automation), data digitalization, unification and integration with a direct connection to the numerical models. The presented procedure can be followed to assess the geochemical short-and long-term risks in carbon storage projects.
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Adila, Ahmed, Emad W. Al-Shalabi, and Waleed AlAmeri. "Geochemical Modeling of Hybrid Surfactant and Engineered Water Injections in Carbonate Reservoirs under Harsh Conditions." In SPE International Conference on Oilfield Chemistry. SPE, 2021. http://dx.doi.org/10.2118/204351-ms.

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Abstract Engineered water injection (EWI) has gained popularity as an effective technique for enhancing oil recovery. Surfactant flooding is also a well-established and commercially-available technique in the petroleum industry. In this study, a numerical simulation model is developed and used to investigate the hybrid effect of surfactant-EWI in carbonates. This developed model was validated by history-matching a recently conducted surfactant coreflood in the secondary mode of injection. Oil recovery, pressure drop, and surfactant concentration data were utilized. The surfactant flooding model was then coupled with a geochemical model that captures different reactions during engineered water injection. The geochemical reactions considered include: aqueous, dissolution/precipitation, and ion- exchange reactions. Also, different simulation scenarios were considered including waterflooding, surfactant flooding, engineered water injection, and the hybrid surfactant-EWI technique. For the case of EWI, wettability alteration was considered as the main mechanism underlying incremental oil recovery. However, both wettability alteration and interfacial tension reduction mechanisms were considered for surfactant flooding depending on the type of surfactant used. The results showed that for the hybrid surfactant-EWI, wettability alteration is considered as the controlling mechanism where surfactant boosts oil recovery rate through increasing oil relative permeability while EWI reduces residual oil. Moreover, the simulation runs showed that the hybrid surfactant-EWI is a promising technique for enhancing oil recovery from carbonates under harsh conditions. The hybrid surfactant-EWI outperformed other injection techniques followed by EWI, then surfactant flooding, and least waterflooding. This work gives more insight into the application of hybrid surfactant-EWI on enhancing oil recovery from carbonates.
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Awolayo, Adedapo, Hemanta Sarma, Long Nghiem, and Gorucu Emre. "A Geochemical Model for Investigation of Wettability Alteration during Brine-Dependent Flooding in Carbonate Reservoirs." In Abu Dhabi International Petroleum Exhibition & Conference. Society of Petroleum Engineers, 2017. http://dx.doi.org/10.2118/188219-ms.

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Reports on the topic "Geochemical alteration"

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Buscheck, T., K. Knauss, N. Rosenberg, and B. Viani. Geochemical alteration of backfill FY98 status report. Office of Scientific and Technical Information (OSTI), September 1998. http://dx.doi.org/10.2172/3020.

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Kupsch, B. G., and O. Catuneanu. Alteration features and geochemical signatures of the Maybelle River uranium zone, Athabasca Basin, Alberta. Natural Resources Canada/ESS/Scientific and Technical Publishing Services, 2007. http://dx.doi.org/10.4095/223780.

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Dann, J., K. Hattori, E. G. Potter, and C. Sorba. Alteration assemblages and geochemical signatures associated with the Phoenix unconformity-related uranium deposit, Athabasca Basin, Saskatchewan. Natural Resources Canada/ESS/Scientific and Technical Publishing Services, 2013. http://dx.doi.org/10.4095/292564.

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Gillis, K. M., and P. T. Robinson. Alteration of the Icrdg Cy - 1 and Cy - 1a Drill Cores, Troodos Ophiolite: Mineralogical and Geochemical Studies. Natural Resources Canada/ESS/Scientific and Technical Publishing Services, 1992. http://dx.doi.org/10.4095/133532.

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Olson, L. C., R. D. Knight, H L Crow, and H. A. J. Russell. Chemostratigraphic logging of the Lower Ordovician and Precambrian, Bells Corners borehole calibration facility, Ottawa, Ontario. Natural Resources Canada/CMSS/Information Management, 2022. http://dx.doi.org/10.4095/330519.

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Geochemical data were collected from a 120-meter-deep borehole (BC81-2) located at the Geological Survey of Canada's Bells Corners Borehole Calibration Facility in Ottawa, Ontario. This report documents geochemical data collected for the most frequently logged of the six boreholes located at the facility. The geochemical data were collected using a portable X-ray fluorescence (pXRF) spectrometer with a subset of samples collected for modern laboratory based fusion and multi-acid methods to calibrate the pXRF data for improved accuracy. Borehole geochemistry provides a characterization of Precambrian and overlying Ordovician rocks in the Ottawa area that augments the understanding of geophysical properties obtained from the calibration borehole. The combined geochemical and geophysical datasets further define rock characteristics, formational boundaries, as well as alteration zones. The results demonstrate the usefulness of pXRF derived geochemical data and chemostratigraphy of rock cores. The chemostratigraphic data augment data collected with spectral gamma logging tools and support an enhanced interpretation of geological contacts across transitional boundaries and the nature of the matrix mineralogy.
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McNab, W. Quarterly Status Report: Injection and Reservoir Hazard Management: The Role of Injection-Induced Mechanical Deformation and Geochemical Alteration at In Salah CO2 Storage Project. Office of Scientific and Technical Information (OSTI), January 2010. http://dx.doi.org/10.2172/1129998.

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Morris, J. P., W. W. McNab, S. K. Carroll, Y. Hao, W. Foxall, and J. L. Wagoner. Injection and Reservoir Hazard Management: The Role of Injection-Induced Mechanical Deformation and Geochemical Alteration at In Salah CO2 Storage Project: Status ReportQuarter end, June 2009. Office of Scientific and Technical Information (OSTI), July 2009. http://dx.doi.org/10.2172/964517.

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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.

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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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Matte, S., M. Constantin, and R. Stevenson. Mineralogical and geochemical characterisation of the Kipawa syenite complex, Quebec: implications for rare-earth element deposits. Natural Resources Canada/CMSS/Information Management, 2022. http://dx.doi.org/10.4095/329212.

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The Kipawa rare-earth element (REE) deposit is located in the Parautochton zone of the Grenville Province 55 km south of the boundary with the Superior Province. The deposit is part of the Kipawa syenite complex of peralkaline syenites, gneisses, and amphibolites that are intercalated with calc-silicate rocks and marbles overlain by a peralkaline gneissic granite. The REE deposit is principally composed of eudialyte, mosandrite and britholite, and less abundant minerals such as xenotime, monazite or euxenite. The Kipawa Complex outcrops as a series of thin, folded sheet imbricates located between regional metasediments, suggesting a regional tectonic control. Several hypotheses for the origin of the complex have been suggested: crustal contamination of mantle-derived magmas, crustal melting, fluid alteration, metamorphism, and hydrothermal activity. Our objective is to characterize the mineralogical, geochemical, and isotopic composition of the Kipawa complex in order to improve our understanding of the formation and the post-formation processes, and the age of the complex. The complex has been deformed and metamorphosed with evidence of melting-recrystallization textures among REE and Zr rich magmatic and post magmatic minerals. Major and trace element geochemistry obtained by ICP-MS suggest that syenites, granites and monzonite of the complex have within-plate A2 type anorogenic signatures, and our analyses indicate a strong crustal signature based on TIMS whole rock Nd isotopes. We have analyzed zircon grains by SEM, EPMA, ICP-MS and MC-ICP-MS coupled with laser ablation (Lu-Hf). Initial isotopic results also support a strong crustal signature. Taken together, these results suggest that alkaline magmas of the Kipawa complex/deposit could have formed by partial melting of the mantle followed by strong crustal contamination or by melting of metasomatized continental crust. These processes and origins strongly differ compare to most alkaline complexes in the world. Additional TIMS and LA-MC-ICP-MS analyses are planned to investigate whether all lithologies share the same strong crustal signature.
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Kingston, A. W., O. H. Ardakani, and R A Stern. Tracing the subsurface sulfur cycle using isotopic and elemental fingerprinting: from the micro to the macro scale. Natural Resources Canada/CMSS/Information Management, 2022. http://dx.doi.org/10.4095/329789.

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Hydrogen sulfide (H2S) is a toxic and corrosive gas that commonly occurs in deeply buried sedimentary systems. Understanding its distribution is paramount to creating safe and effective models of H2S occurrence aiding in the identification of high-risk areas. Characterizing subsurface sulfur sources and H2S formation pathways would enhance these models leading to more accurate predictions of potential high H2S regions. However, gaps remain in our understanding of the dominant formation processes and migration pathways of key ingredients for H2S production in the Lower Triassic Montney Formation of the Western Canada Sedimentary Basin (WCSB). Essential to this is assessing the reactants necessary for H2S production, potential pathways for fluid migration, diagenetic history, and changes in redox conditions through time. The Montney Formation has undergone several phases of diagenesis related to post-depositional alteration and multiple cycles of tectonic burial and uplift. Early chemical alteration includes dolomitization and, in some cases, microbial reduction of porewater sulfate to sulfide that occurred prior to significant burial (Davies et al., 1997; Vaisblat et al., 2021; Liseroudi et al., 2020, 2021). The most recent tectonic-related burial during the Laramide Orogeny resulted in burial depths in excess of 3-5 km (Ness, 2001; Ducros et al., 2017) leading to significant thermal and barometric alteration. Associated with this orogenic activity was the reactivation of underlying faults (O'Connell et al., 1990) and development of fractures especially near the deformation front. These fractures provide conduits for fluid migration into the Montney that combined with heat and pressure resulting in hydrocarbon generation, migration, and development of overpressure, notably in the western margin of the basin. In addition, high temperatures resulted in thermochemical sulfate reduction (TSR) leading to the formation of H2S and subsequently pyrite. We present an interpretation of the Montney subsurface sulfur cycle through the use of petrography, micro- and macro-scale geochemical analysis (isotopic and elemental) to illustrate the complexity of this system. This work relies heavily on previous studies within and outside our research group and incorporates new analytical techniques to expand the toolbox. We aim to guide future research directions and activities by addressing issues related to sampling and data quality issues, analytical approaches, and highlight knowledge gaps.
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