Textural characteristics, mode of transportation and depositional environment of the Stormberg Group in the Eastern Cape, South Africa: evidence from grain size and lithofacies analyses

The Stormberg Group comprises the Molteno, Elliot and Clarens formations and is one of four stratigraphical groups that make up the Karoo Supergroup in South Africa. The group is the highest unit in the Karoo Basin, representing the final phase of preserved sedimentation. The major problem with th...

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Main Authors: Chima, Priscilla, Baiyegunhi, Christopher
Format: Article
Language:English
Published: Sciendo and Adam Mickiewicz University 2022
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Online Access:https://doi.org/10.2478/logos-2022-0005
http://hdl.handle.net/11408/5067
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author Chima, Priscilla
Baiyegunhi, Christopher
author_facet Chima, Priscilla
Baiyegunhi, Christopher
author_sort Chima, Priscilla
collection DSpace
description The Stormberg Group comprises the Molteno, Elliot and Clarens formations and is one of four stratigraphical groups that make up the Karoo Supergroup in South Africa. The group is the highest unit in the Karoo Basin, representing the final phase of preserved sedimentation. The major problem with the Stromberg Group is that the mode of transport, hy- drodynamic energy conditions and depositional environment are still poorly understood. For the present paper, grain size and lithofacies studies on selected sandstones from the Molteno, Elliot and Clarens formations were performed so as to elucidate their textural characteristics, depositional processes, sedimentation mechanisms and hydrodynamic energy conditions and to discriminate different depositional environments. The statistical parameters of grain size distribution (mean grain size, standard deviation, skewness and kurtosis) show that the sandstones are predominantly unimodal, fine grained, moderately well sorted, mesokurtic and near symmetrical. The bivariate diagrams of the afore- mentioned statistical parameters demonstrate that river and aeolian dune had the greatest impact on the depositional environments. Likewise, the C-M pattern (Passega diagram) shows that the sandstones were mostly deposited through tractive current process. Furthermore, the C-M diagram reveals the prevalence of rolling, suspension and graded sus- pension modes of sediment transportation. Seventeen sedimentary lithofacies were identified and grouped into seven lithofacies associations. These lithofacies associations indicate braided channel, overbank and swamp deposits for the Molteno Formation, alluvial fan/floodplain and playa deposits for the Elliot Formation and aeolian deposits for the Clarens Formation.
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spelling ir-11408-50672022-08-04T09:24:30Z Textural characteristics, mode of transportation and depositional environment of the Stormberg Group in the Eastern Cape, South Africa: evidence from grain size and lithofacies analyses Chima, Priscilla Baiyegunhi, Christopher Grain size distribution textural parameters ithofacies classification hydrodynamic energy conditions Tri- assic Jurassic The Stormberg Group comprises the Molteno, Elliot and Clarens formations and is one of four stratigraphical groups that make up the Karoo Supergroup in South Africa. The group is the highest unit in the Karoo Basin, representing the final phase of preserved sedimentation. The major problem with the Stromberg Group is that the mode of transport, hy- drodynamic energy conditions and depositional environment are still poorly understood. For the present paper, grain size and lithofacies studies on selected sandstones from the Molteno, Elliot and Clarens formations were performed so as to elucidate their textural characteristics, depositional processes, sedimentation mechanisms and hydrodynamic energy conditions and to discriminate different depositional environments. The statistical parameters of grain size distribution (mean grain size, standard deviation, skewness and kurtosis) show that the sandstones are predominantly unimodal, fine grained, moderately well sorted, mesokurtic and near symmetrical. The bivariate diagrams of the afore- mentioned statistical parameters demonstrate that river and aeolian dune had the greatest impact on the depositional environments. Likewise, the C-M pattern (Passega diagram) shows that the sandstones were mostly deposited through tractive current process. Furthermore, the C-M diagram reveals the prevalence of rolling, suspension and graded sus- pension modes of sediment transportation. Seventeen sedimentary lithofacies were identified and grouped into seven lithofacies associations. These lithofacies associations indicate braided channel, overbank and swamp deposits for the Molteno Formation, alluvial fan/floodplain and playa deposits for the Elliot Formation and aeolian deposits for the Clarens Formation. 2022-08-04T09:24:30Z 2022-08-04T09:24:30Z 2022-05-14 Article Chima, Priscilla and Baiyegunhi, Christopher. "Textural characteristics, mode of transportation and depositional environment of the Stormberg Group in the Eastern Cape, South Africa: evidence from grain size and lithofacies analyses" Geologos, vol.28, no.1, 2022, pp.61-78. https://doi.org/10.2478/logos-2022-0005 2080-6574 https://doi.org/10.2478/logos-2022-0005 http://hdl.handle.net/11408/5067 en Geologos;Vol. 8, No. 1; Pages 61 – 78 open Sciendo and Adam Mickiewicz University
spellingShingle Grain size distribution
textural parameters
ithofacies classification
hydrodynamic energy conditions
Tri- assic
Jurassic
Chima, Priscilla
Baiyegunhi, Christopher
Textural characteristics, mode of transportation and depositional environment of the Stormberg Group in the Eastern Cape, South Africa: evidence from grain size and lithofacies analyses
title Textural characteristics, mode of transportation and depositional environment of the Stormberg Group in the Eastern Cape, South Africa: evidence from grain size and lithofacies analyses
title_full Textural characteristics, mode of transportation and depositional environment of the Stormberg Group in the Eastern Cape, South Africa: evidence from grain size and lithofacies analyses
title_fullStr Textural characteristics, mode of transportation and depositional environment of the Stormberg Group in the Eastern Cape, South Africa: evidence from grain size and lithofacies analyses
title_full_unstemmed Textural characteristics, mode of transportation and depositional environment of the Stormberg Group in the Eastern Cape, South Africa: evidence from grain size and lithofacies analyses
title_short Textural characteristics, mode of transportation and depositional environment of the Stormberg Group in the Eastern Cape, South Africa: evidence from grain size and lithofacies analyses
title_sort textural characteristics, mode of transportation and depositional environment of the stormberg group in the eastern cape, south africa: evidence from grain size and lithofacies analyses
topic Grain size distribution
textural parameters
ithofacies classification
hydrodynamic energy conditions
Tri- assic
Jurassic
url https://doi.org/10.2478/logos-2022-0005
http://hdl.handle.net/11408/5067
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