Clay mineral diagenesis in Cretaceous clastic reservoirs from West African passive margins (the South Gabon Basin) and its impact on regional geology and basin evolution history
The Gabon coastal region located along the western African margin hosts several sedimentary basins that developed prior, during and after the opening of the South Atlantic Ocean. A range of diagenetic processes controlled the distribution of clay paragenesis shown to be of high importance for the un...
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ftunivgeneve:oai:unige.ch:aou:unige:88289 2023-10-01T03:59:28+02:00 Clay mineral diagenesis in Cretaceous clastic reservoirs from West African passive margins (the South Gabon Basin) and its impact on regional geology and basin evolution history Zanoni, Giovanni Segvic, Branimir Moscariello, Andrea 2016 https://archive-ouverte.unige.ch/unige:88289 eng eng info:eu-repo/semantics/altIdentifier/doi/10.1016/j.clay.2016.09.032 https://archive-ouverte.unige.ch/unige:88289 unige:88289 info:eu-repo/semantics/restrictedAccess ISSN: 0169-1317 Applied clay science, vol. 134 (2016) p. 186-209 info:eu-repo/classification/ddc/550 Mixed-layer clay minerals Diagenesis Berthierine-chlorite Gabon Basin Sandstone South Atlantic Passive margins info:eu-repo/semantics/article Text Article scientifique info:eu-repo/semantics/submittedVersion 2016 ftunivgeneve https://doi.org/10.1016/j.clay.2016.09.032 2023-09-07T07:34:01Z The Gabon coastal region located along the western African margin hosts several sedimentary basins that developed prior, during and after the opening of the South Atlantic Ocean. A range of diagenetic processes controlled the distribution of clay paragenesis shown to be of high importance for the understanding of the basin's burial history and geotectonic development. Materials acquired for this study stem from the siliciclastic fluviolacustrine-deltaic, petroleum bearing, Early Cretaceous Dentale and Gamba formations cored by two respective wells at depths of ~1500 m. Sampled materials were analysed by X-ray diffraction, automated electron microscopy, and inductively coupled plasma mass spectrometry in order to reconstruct eogenetic and mesogenetic variations directing the formation of clay assemblages in the basin. The clay contents in both cores consist of authigenic mixed-layer minerals like illite-smectite, chlorite-smectite and berthierine-chlorite, and some minor detrital illite/mica and chlorite. I-Sm and C-Sm phase chemistry implied that the original dioctahedral (montmorillonite to beidellite) and trioctahedral (saponite) smectite precursors formed out of acid volcanic feedstock during eogenesis. Different magmatic fractionation degrees, from rhyodacite to trachyandesite, reflected in the uniform REE curves of volcanic glass conform to an active geotectonic development of the Cretaceous margins of Africa. Mesogenesis led to the decrease of smectite and formation of mixed-layered phases; I-Sm composition showed maximal burial depths of sediments to be ~1000 m and ~500 m deeper than today for Gamba and Dentale sediments, respectively. Besides, temperature, a major role in the formation of mixed layer minerals had the porosity of sediments and geochemistry of smectitic precursors. Thus, Fe-Mg smectite showed higher thermal stability and lower rates of transformations in non-expanding clays during burial compared to Al-rich smectite. Different burial histories of sediments from the two cores can be ... Article in Journal/Newspaper South Atlantic Ocean Université de Genève: Archive ouverte UNIGE Applied Clay Science 134 186 209 |
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Université de Genève: Archive ouverte UNIGE |
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ftunivgeneve |
language |
English |
topic |
info:eu-repo/classification/ddc/550 Mixed-layer clay minerals Diagenesis Berthierine-chlorite Gabon Basin Sandstone South Atlantic Passive margins |
spellingShingle |
info:eu-repo/classification/ddc/550 Mixed-layer clay minerals Diagenesis Berthierine-chlorite Gabon Basin Sandstone South Atlantic Passive margins Zanoni, Giovanni Segvic, Branimir Moscariello, Andrea Clay mineral diagenesis in Cretaceous clastic reservoirs from West African passive margins (the South Gabon Basin) and its impact on regional geology and basin evolution history |
topic_facet |
info:eu-repo/classification/ddc/550 Mixed-layer clay minerals Diagenesis Berthierine-chlorite Gabon Basin Sandstone South Atlantic Passive margins |
description |
The Gabon coastal region located along the western African margin hosts several sedimentary basins that developed prior, during and after the opening of the South Atlantic Ocean. A range of diagenetic processes controlled the distribution of clay paragenesis shown to be of high importance for the understanding of the basin's burial history and geotectonic development. Materials acquired for this study stem from the siliciclastic fluviolacustrine-deltaic, petroleum bearing, Early Cretaceous Dentale and Gamba formations cored by two respective wells at depths of ~1500 m. Sampled materials were analysed by X-ray diffraction, automated electron microscopy, and inductively coupled plasma mass spectrometry in order to reconstruct eogenetic and mesogenetic variations directing the formation of clay assemblages in the basin. The clay contents in both cores consist of authigenic mixed-layer minerals like illite-smectite, chlorite-smectite and berthierine-chlorite, and some minor detrital illite/mica and chlorite. I-Sm and C-Sm phase chemistry implied that the original dioctahedral (montmorillonite to beidellite) and trioctahedral (saponite) smectite precursors formed out of acid volcanic feedstock during eogenesis. Different magmatic fractionation degrees, from rhyodacite to trachyandesite, reflected in the uniform REE curves of volcanic glass conform to an active geotectonic development of the Cretaceous margins of Africa. Mesogenesis led to the decrease of smectite and formation of mixed-layered phases; I-Sm composition showed maximal burial depths of sediments to be ~1000 m and ~500 m deeper than today for Gamba and Dentale sediments, respectively. Besides, temperature, a major role in the formation of mixed layer minerals had the porosity of sediments and geochemistry of smectitic precursors. Thus, Fe-Mg smectite showed higher thermal stability and lower rates of transformations in non-expanding clays during burial compared to Al-rich smectite. Different burial histories of sediments from the two cores can be ... |
format |
Article in Journal/Newspaper |
author |
Zanoni, Giovanni Segvic, Branimir Moscariello, Andrea |
author_facet |
Zanoni, Giovanni Segvic, Branimir Moscariello, Andrea |
author_sort |
Zanoni, Giovanni |
title |
Clay mineral diagenesis in Cretaceous clastic reservoirs from West African passive margins (the South Gabon Basin) and its impact on regional geology and basin evolution history |
title_short |
Clay mineral diagenesis in Cretaceous clastic reservoirs from West African passive margins (the South Gabon Basin) and its impact on regional geology and basin evolution history |
title_full |
Clay mineral diagenesis in Cretaceous clastic reservoirs from West African passive margins (the South Gabon Basin) and its impact on regional geology and basin evolution history |
title_fullStr |
Clay mineral diagenesis in Cretaceous clastic reservoirs from West African passive margins (the South Gabon Basin) and its impact on regional geology and basin evolution history |
title_full_unstemmed |
Clay mineral diagenesis in Cretaceous clastic reservoirs from West African passive margins (the South Gabon Basin) and its impact on regional geology and basin evolution history |
title_sort |
clay mineral diagenesis in cretaceous clastic reservoirs from west african passive margins (the south gabon basin) and its impact on regional geology and basin evolution history |
publishDate |
2016 |
url |
https://archive-ouverte.unige.ch/unige:88289 |
genre |
South Atlantic Ocean |
genre_facet |
South Atlantic Ocean |
op_source |
ISSN: 0169-1317 Applied clay science, vol. 134 (2016) p. 186-209 |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.1016/j.clay.2016.09.032 https://archive-ouverte.unige.ch/unige:88289 unige:88289 |
op_rights |
info:eu-repo/semantics/restrictedAccess |
op_doi |
https://doi.org/10.1016/j.clay.2016.09.032 |
container_title |
Applied Clay Science |
container_volume |
134 |
container_start_page |
186 |
op_container_end_page |
209 |
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1778533553717379072 |