Cool kaolins in Finland
We use D/H and 18O/16O ratios to explore the age of kaolins on the Fennoscandian Shield. Sub-Cretaceous kaolins in southern Scandinavia have isotopic compositions indicative of weathering under warm mean annual temperatures (MATs) of > 15 °C. Deep kaolins on the shield surface in Finland previous...
Published in: | Palaeogeography, Palaeoclimatology, Palaeoecology |
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2013
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ftunstandrewcris:oai:research-portal.st-andrews.ac.uk:publications/2c9cce61-4d81-4378-963b-4f49e4944bc2 2024-06-23T07:50:30+00:00 Cool kaolins in Finland Gilg, H. A. Hall, A. M. Ebert, K. Fallick, A. E. 2013-12-15 https://research-portal.st-andrews.ac.uk/en/researchoutput/cool-kaolins-in-finland(2c9cce61-4d81-4378-963b-4f49e4944bc2).html https://doi.org/10.1016/j.palaeo.2013.09.030 eng eng https://research-portal.st-andrews.ac.uk/en/researchoutput/cool-kaolins-in-finland(2c9cce61-4d81-4378-963b-4f49e4944bc2).html info:eu-repo/semantics/restrictedAccess Gilg , H A , Hall , A M , Ebert , K & Fallick , A E 2013 , ' Cool kaolins in Finland ' , Palaeogeography, Palaeoclimatology, Palaeoecology , vol. 392 , pp. 454-462 . https://doi.org/10.1016/j.palaeo.2013.09.030 article 2013 ftunstandrewcris https://doi.org/10.1016/j.palaeo.2013.09.030 2024-06-13T00:41:10Z We use D/H and 18O/16O ratios to explore the age of kaolins on the Fennoscandian Shield. Sub-Cretaceous kaolins in southern Scandinavia have isotopic compositions indicative of weathering under warm mean annual temperatures (MATs) of > 15 °C. Deep kaolins on the shield surface in Finland previously also have been regarded as products of humid tropical weathering of Mesoproterozoic to Eocene age. New oxygen and hydrogen isotope ratios indicate, however, weathering by cool groundwater under MATs of 13–15 °C. Isotope ratios are also not consistent with deep (> 1 km) burial by cover rocks, indicating that a very old age for the weathering is unlikely. Palaeotemperatures are below Cretaceous MATs, yet substantially above Plio-Pleistocene MATs. Comparisons with palaeotemperatures in N Europe and around the Arctic Ocean indicate that the Finnish kaolins developed on the shield surface in the Palaeogene or, alternatively, Miocene. Deep weathering was selectively developed in highly fractured shield rocks and took place in response to latest Cretaceous and Palaeogene uplift and after stripping of Palaeozoic cover rocks. The cool kaolins in Finland indicate that previous routine attributions of kaolinitic weathering products in the geological record to humid tropical environments should be closely scrutinised. Article in Journal/Newspaper Arctic Arctic Ocean Fennoscandian University of St Andrews: Research Portal Arctic Arctic Ocean Palaeogeography, Palaeoclimatology, Palaeoecology 392 454 462 |
institution |
Open Polar |
collection |
University of St Andrews: Research Portal |
op_collection_id |
ftunstandrewcris |
language |
English |
description |
We use D/H and 18O/16O ratios to explore the age of kaolins on the Fennoscandian Shield. Sub-Cretaceous kaolins in southern Scandinavia have isotopic compositions indicative of weathering under warm mean annual temperatures (MATs) of > 15 °C. Deep kaolins on the shield surface in Finland previously also have been regarded as products of humid tropical weathering of Mesoproterozoic to Eocene age. New oxygen and hydrogen isotope ratios indicate, however, weathering by cool groundwater under MATs of 13–15 °C. Isotope ratios are also not consistent with deep (> 1 km) burial by cover rocks, indicating that a very old age for the weathering is unlikely. Palaeotemperatures are below Cretaceous MATs, yet substantially above Plio-Pleistocene MATs. Comparisons with palaeotemperatures in N Europe and around the Arctic Ocean indicate that the Finnish kaolins developed on the shield surface in the Palaeogene or, alternatively, Miocene. Deep weathering was selectively developed in highly fractured shield rocks and took place in response to latest Cretaceous and Palaeogene uplift and after stripping of Palaeozoic cover rocks. The cool kaolins in Finland indicate that previous routine attributions of kaolinitic weathering products in the geological record to humid tropical environments should be closely scrutinised. |
format |
Article in Journal/Newspaper |
author |
Gilg, H. A. Hall, A. M. Ebert, K. Fallick, A. E. |
spellingShingle |
Gilg, H. A. Hall, A. M. Ebert, K. Fallick, A. E. Cool kaolins in Finland |
author_facet |
Gilg, H. A. Hall, A. M. Ebert, K. Fallick, A. E. |
author_sort |
Gilg, H. A. |
title |
Cool kaolins in Finland |
title_short |
Cool kaolins in Finland |
title_full |
Cool kaolins in Finland |
title_fullStr |
Cool kaolins in Finland |
title_full_unstemmed |
Cool kaolins in Finland |
title_sort |
cool kaolins in finland |
publishDate |
2013 |
url |
https://research-portal.st-andrews.ac.uk/en/researchoutput/cool-kaolins-in-finland(2c9cce61-4d81-4378-963b-4f49e4944bc2).html https://doi.org/10.1016/j.palaeo.2013.09.030 |
geographic |
Arctic Arctic Ocean |
geographic_facet |
Arctic Arctic Ocean |
genre |
Arctic Arctic Ocean Fennoscandian |
genre_facet |
Arctic Arctic Ocean Fennoscandian |
op_source |
Gilg , H A , Hall , A M , Ebert , K & Fallick , A E 2013 , ' Cool kaolins in Finland ' , Palaeogeography, Palaeoclimatology, Palaeoecology , vol. 392 , pp. 454-462 . https://doi.org/10.1016/j.palaeo.2013.09.030 |
op_relation |
https://research-portal.st-andrews.ac.uk/en/researchoutput/cool-kaolins-in-finland(2c9cce61-4d81-4378-963b-4f49e4944bc2).html |
op_rights |
info:eu-repo/semantics/restrictedAccess |
op_doi |
https://doi.org/10.1016/j.palaeo.2013.09.030 |
container_title |
Palaeogeography, Palaeoclimatology, Palaeoecology |
container_volume |
392 |
container_start_page |
454 |
op_container_end_page |
462 |
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