Sedimentary talc in Neoproterozoic carbonate successions
Mineralogical, petrographic and sedimentological observations document early diagenetic talc in carbonate-dominated successions deposited on two early Neoproterozoic (similar to 800-700 million years old) platform margins. In the Akademikerbreen Group, Svalbard, talc occurs as nodules that pre-date...
Published in: | Earth and Planetary Science Letters |
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Main Authors: | , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
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2011
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Online Access: | https://research-portal.st-andrews.ac.uk/en/publications/d8df453e-881a-4404-a892-e0c1966ecd84 https://doi.org/10.1016/j.epsl.2011.03.041 |
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ftunstandrewcris:oai:research-portal.st-andrews.ac.uk:publications/d8df453e-881a-4404-a892-e0c1966ecd84 2024-09-30T14:34:19+00:00 Sedimentary talc in Neoproterozoic carbonate successions Tosca, Nick Macdonald, Francis A. Strauss, Justin V. Johnston, David T. Knoll, Andrew H. 2011-06-01 https://research-portal.st-andrews.ac.uk/en/publications/d8df453e-881a-4404-a892-e0c1966ecd84 https://doi.org/10.1016/j.epsl.2011.03.041 eng eng https://research-portal.st-andrews.ac.uk/en/publications/d8df453e-881a-4404-a892-e0c1966ecd84 info:eu-repo/semantics/restrictedAccess Tosca , N , Macdonald , F A , Strauss , J V , Johnston , D T & Knoll , A H 2011 , ' Sedimentary talc in Neoproterozoic carbonate successions ' , Earth and Planetary Science Letters , vol. 306 , no. 1-2 , pp. 11-22 . https://doi.org/10.1016/j.epsl.2011.03.041 Proterozoic geobiology mineralogy geochemistry carbonate silica MAGNESIUM-SILICATE HYDRATE MACKENZIE MOUNTAINS AQUEOUS-SOLUTION EAST GREENLAND SVALBARD INSIGHTS CONGO GELS STRATIGRAPHY SPITSBERGEN article 2011 ftunstandrewcris https://doi.org/10.1016/j.epsl.2011.03.041 2024-09-04T23:45:35Z Mineralogical, petrographic and sedimentological observations document early diagenetic talc in carbonate-dominated successions deposited on two early Neoproterozoic (similar to 800-700 million years old) platform margins. In the Akademikerbreen Group, Svalbard, talc occurs as nodules that pre-date microspar cements that fill molar tooth structures and primary porosity in stromatolitic carbonates. In the upper Fifteenmile Group of the Ogilvie Mountains, NW Canada, the talc is present as nodules, coated grains, rip-up clasts and massive beds that are several meters thick. To gain insight into the chemistry required to form early diagenetic talc, we conducted precipitation experiments at 25 degrees C with low-SO4 synthetic seawater solutions at varying pH, Mg2+ and SiO2(aq). Our experiments reveal a sharp and reproducible pH boundary (at similar to 8.7) only above which does poorly crystalline Mg-silicate precipitate: increasing Mg2+ and/or SiO(2()aq) alone is insufficient to produce the material. The strong pH control can be explained by Mg-silica complexing activated by the deprotonation of silicic acid above similar to 8.6-8.7. FT-IR, TEM and XRD of the synthetic precipitates reveal a talc-like 2:1 trioctahedral structure with short-range stacking order. Hydrothermal experiments simulating burial diagenesis show that dehydration of the precipitate drives a transition to kerolite (hydrated talc) and eventually to talc. This formation pathway imparts extensive layer stacking disorder to the synthetic talc end-product that is identical to Neoproterozoic occurrences. Early diagenetic talc in Neoproterozoic carbonate platform successions appears to reflect a unique combination of low Al concentrations (and, by inference, low siliciclastic input), near modern marine salinity and Mg2+, elevated SiO2(aq), and pH > similar to 8.7. Because the talc occurs in close association with microbially influenced sediments, we suggest that soluble species requirements were most easily met through microbial influences on pore ... Article in Journal/Newspaper East Greenland Greenland Mackenzie mountains Ogilvie Mountains Svalbard Spitsbergen University of St Andrews: Research Portal Akademikerbreen ENVELOPE(18.391,18.391,78.718,78.718) Canada Greenland Ogilvie ENVELOPE(-139.746,-139.746,63.563,63.563) Ogilvie Mountains ENVELOPE(-138.254,-138.254,64.583,64.583) Rip ENVELOPE(-19.509,-19.509,65.690,65.690) Svalbard Earth and Planetary Science Letters 306 1-2 11 22 |
institution |
Open Polar |
collection |
University of St Andrews: Research Portal |
op_collection_id |
ftunstandrewcris |
language |
English |
topic |
Proterozoic geobiology mineralogy geochemistry carbonate silica MAGNESIUM-SILICATE HYDRATE MACKENZIE MOUNTAINS AQUEOUS-SOLUTION EAST GREENLAND SVALBARD INSIGHTS CONGO GELS STRATIGRAPHY SPITSBERGEN |
spellingShingle |
Proterozoic geobiology mineralogy geochemistry carbonate silica MAGNESIUM-SILICATE HYDRATE MACKENZIE MOUNTAINS AQUEOUS-SOLUTION EAST GREENLAND SVALBARD INSIGHTS CONGO GELS STRATIGRAPHY SPITSBERGEN Tosca, Nick Macdonald, Francis A. Strauss, Justin V. Johnston, David T. Knoll, Andrew H. Sedimentary talc in Neoproterozoic carbonate successions |
topic_facet |
Proterozoic geobiology mineralogy geochemistry carbonate silica MAGNESIUM-SILICATE HYDRATE MACKENZIE MOUNTAINS AQUEOUS-SOLUTION EAST GREENLAND SVALBARD INSIGHTS CONGO GELS STRATIGRAPHY SPITSBERGEN |
description |
Mineralogical, petrographic and sedimentological observations document early diagenetic talc in carbonate-dominated successions deposited on two early Neoproterozoic (similar to 800-700 million years old) platform margins. In the Akademikerbreen Group, Svalbard, talc occurs as nodules that pre-date microspar cements that fill molar tooth structures and primary porosity in stromatolitic carbonates. In the upper Fifteenmile Group of the Ogilvie Mountains, NW Canada, the talc is present as nodules, coated grains, rip-up clasts and massive beds that are several meters thick. To gain insight into the chemistry required to form early diagenetic talc, we conducted precipitation experiments at 25 degrees C with low-SO4 synthetic seawater solutions at varying pH, Mg2+ and SiO2(aq). Our experiments reveal a sharp and reproducible pH boundary (at similar to 8.7) only above which does poorly crystalline Mg-silicate precipitate: increasing Mg2+ and/or SiO(2()aq) alone is insufficient to produce the material. The strong pH control can be explained by Mg-silica complexing activated by the deprotonation of silicic acid above similar to 8.6-8.7. FT-IR, TEM and XRD of the synthetic precipitates reveal a talc-like 2:1 trioctahedral structure with short-range stacking order. Hydrothermal experiments simulating burial diagenesis show that dehydration of the precipitate drives a transition to kerolite (hydrated talc) and eventually to talc. This formation pathway imparts extensive layer stacking disorder to the synthetic talc end-product that is identical to Neoproterozoic occurrences. Early diagenetic talc in Neoproterozoic carbonate platform successions appears to reflect a unique combination of low Al concentrations (and, by inference, low siliciclastic input), near modern marine salinity and Mg2+, elevated SiO2(aq), and pH > similar to 8.7. Because the talc occurs in close association with microbially influenced sediments, we suggest that soluble species requirements were most easily met through microbial influences on pore ... |
format |
Article in Journal/Newspaper |
author |
Tosca, Nick Macdonald, Francis A. Strauss, Justin V. Johnston, David T. Knoll, Andrew H. |
author_facet |
Tosca, Nick Macdonald, Francis A. Strauss, Justin V. Johnston, David T. Knoll, Andrew H. |
author_sort |
Tosca, Nick |
title |
Sedimentary talc in Neoproterozoic carbonate successions |
title_short |
Sedimentary talc in Neoproterozoic carbonate successions |
title_full |
Sedimentary talc in Neoproterozoic carbonate successions |
title_fullStr |
Sedimentary talc in Neoproterozoic carbonate successions |
title_full_unstemmed |
Sedimentary talc in Neoproterozoic carbonate successions |
title_sort |
sedimentary talc in neoproterozoic carbonate successions |
publishDate |
2011 |
url |
https://research-portal.st-andrews.ac.uk/en/publications/d8df453e-881a-4404-a892-e0c1966ecd84 https://doi.org/10.1016/j.epsl.2011.03.041 |
long_lat |
ENVELOPE(18.391,18.391,78.718,78.718) ENVELOPE(-139.746,-139.746,63.563,63.563) ENVELOPE(-138.254,-138.254,64.583,64.583) ENVELOPE(-19.509,-19.509,65.690,65.690) |
geographic |
Akademikerbreen Canada Greenland Ogilvie Ogilvie Mountains Rip Svalbard |
geographic_facet |
Akademikerbreen Canada Greenland Ogilvie Ogilvie Mountains Rip Svalbard |
genre |
East Greenland Greenland Mackenzie mountains Ogilvie Mountains Svalbard Spitsbergen |
genre_facet |
East Greenland Greenland Mackenzie mountains Ogilvie Mountains Svalbard Spitsbergen |
op_source |
Tosca , N , Macdonald , F A , Strauss , J V , Johnston , D T & Knoll , A H 2011 , ' Sedimentary talc in Neoproterozoic carbonate successions ' , Earth and Planetary Science Letters , vol. 306 , no. 1-2 , pp. 11-22 . https://doi.org/10.1016/j.epsl.2011.03.041 |
op_relation |
https://research-portal.st-andrews.ac.uk/en/publications/d8df453e-881a-4404-a892-e0c1966ecd84 |
op_rights |
info:eu-repo/semantics/restrictedAccess |
op_doi |
https://doi.org/10.1016/j.epsl.2011.03.041 |
container_title |
Earth and Planetary Science Letters |
container_volume |
306 |
container_issue |
1-2 |
container_start_page |
11 |
op_container_end_page |
22 |
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1811637971769622528 |