Isotope signature of sand calcites in the Paris Basin: a proxy for permafrost/groundwater paleoconditions
International audience Sand calcites occurring as rhombohedral crystals and spherolitic concretions in several Tertiary sandstone formations in the Paris basin have been dated to the cooling periods of the four last glacial stages, using 14C and U-Th methods. Sand calcites constitute a novel proxy t...
Published in: | Procedia Earth and Planetary Science |
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Main Authors: | , , |
Other Authors: | , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
HAL CCSD
2015
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Subjects: | |
Online Access: | https://minesparis-psl.hal.science/hal-01236662 https://minesparis-psl.hal.science/hal-01236662/document https://minesparis-psl.hal.science/hal-01236662/file/Thiry%26al_2015_sand_calcites_Paris_Basin_isotopes.pdf https://doi.org/10.1016/j.proeps.2015.07.005 |
Summary: | International audience Sand calcites occurring as rhombohedral crystals and spherolitic concretions in several Tertiary sandstone formations in the Paris basin have been dated to the cooling periods of the four last glacial stages, using 14C and U-Th methods. Sand calcites constitute a novel proxy to estimate paleo-groundwater levels and the extension of permafrost conditions. The δ13C and δ18O compositions of sand calcites are a function of precipitation depth in relation with the warming of surface water during infiltration. Sand calcites appear as precious markers for Pleistocene paleo-landscape reconstructions. |
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