Millennial-timescale climate change over the last 800 kyrs evidenced by magnetic, colorimetric and ATR-FTIR data from the Suhia Kladenetz quarry loess-paleosol sequence (Pleven, Bulgaria) - Archive ouverte HAL Accéder directement au contenu
Communication Dans Un Congrès Année : 2022

Millennial-timescale climate change over the last 800 kyrs evidenced by magnetic, colorimetric and ATR-FTIR data from the Suhia Kladenetz quarry loess-paleosol sequence (Pleven, Bulgaria)

Christian Laag
France Lagroix
Yohan Guyodo

Résumé

Eastern European loess-paleosol sequences (LPS) are excellent archives of past climate change. Millennial-timescale climate change is successfully evidenced in loess of the last and penultimate glacial periods. However, study designs with similar or lower sampling resolution strategies and/or single proxy investigations do not favor their identification for earlier glacials, which are generally scarcer, thinner and characterized by lower sedimentation rates. The high-sampling resolution multi-proxy study presented here demonstrates the first evidence of millennial-timescale climate change for periods older than MIS6 archived in an Eastern European LPS. The Suhia Kladenetz 27 m long profile was sampled continuously at a 2 cm resolution for bulk sediment. Magnetic and colorimetric measurements are performed on all samples. ATR-FTIR data is acquired at the same resolution through loess units and at a 12 cm interval elsewhere, while grain size analyses are conducted continuously at a 12 cm interval. Rock magnetic data and microscopic observations, from our previous work, characterized a 20-cm-thick outcropping tephra in the MIS6 loess unit and identified several cryptotephras. Moreover, a correlative age model demonstrating that the LPS covers the last ~800 kyrs allowed to provide age estimates for the tephra and cryptotephras and thereafter to deduce their likely volcanic sources. The integrated age model in combination with high-resolution colorimetry-based estimates of goethite and hematite concentrations, and clay mineralogy highlight a cyclicity undoubtedly driven by climate change within interstadials/stadials as shown by correlations with the NGRIP δ18O ice core records for the last glacial/interglacial cycle.
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hal-04076238 , version 1 (20-04-2023)

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  • HAL Id : hal-04076238 , version 1

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Christian Laag, France Lagroix, Yohan Guyodo, Diana Jordanova, Neli Jordanova, et al.. Millennial-timescale climate change over the last 800 kyrs evidenced by magnetic, colorimetric and ATR-FTIR data from the Suhia Kladenetz quarry loess-paleosol sequence (Pleven, Bulgaria). GeoMinKöln 2022 – the Annual Conference of the Deutsche Mineralogische Gesellschaft (DMG – The German Mineralogical Society) and the Deutsche Geologische Gesellschaft – Geologische Vereinigung (DGGV – The German Geological Society), Sep 2022, Cologne, Germany. ⟨hal-04076238⟩
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