EGU21-3390
https://doi.org/10.5194/egusphere-egu21-3390
EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Mongolian dryland paleoenvironment and paleoclimate issues : calibrations and applicability of GDGT and pollen reconstructions over the Late Holocene.

Lucas Dugerdil1,2, Sébastien Joannin2, Odile Peyron2, Isabelle Jouffroy-Bapicot3, Boris Vannière3, Boldgiv Bazartseren4, Julia Unkelbach5, Hermann Behling5, and Guillemette Ménot1
Lucas Dugerdil et al.
  • 1Univ. Lyon, ENS de Lyon, Université Lyon 1, CNRS, UMR 5276 LGL-TPE, F-69364, Lyon, France (lucas.dugerdil@ens-lyon.fr)
  • 2Université de Montpellier, CNRS, IRD, EPHE, UMR 5554 ISEM, Montpellier, France
  • 3Université Bourgogne Franche Comté, CNRS UMR 6249 Laboratoire Chrono- environnement, F-25030, Besançon, France
  • 4Ecology Group, Department of Biology, School of Arts and Sciences, National University of Mongolia, Ulaanbaatar 14201, Mongolia
  • 5Department of Palynology and Climate Dynamics, Albrecht-von-Haller-Institute for Plant Sciences, University of Goettingen, Germany

Our understanding of climate changes throughout the Holocene is hampered by representativeness in sedimentary archives. Potential production and preservation biases of the markers are identified by comparing these proxies with modern environments. It is important to conduct robust calibrations on each biome. These calibrations use large database dominated by forest samples. The Mongolian plateau is especially characterized by low annual precipitation and continental annual air temperature. The characterization of the climate system of this area is crucial for the understanding of Holocene Monsoon Oscillations. This study focuses on the calibration of proxy-climate relationships for pollen and glycerol dialkyl glycerol tetraethers (GDGTs) by comparing large published Eurasian calibrations with a set of 49 new surface samples (moss polster, soil and mud from temporary dry pond). These calibrations are then cross-validated by an independent dataset of top-core samples and applied to two Late Holocene paleosequences in the Altai mountains and the Qaidam basin. We show that: (1) preserved pollen assemblages are clearly imprinted on the extremities of the ecosystem range but mitigated and unclear on the ecotones; (2) for both proxies, inferred relationships depend on the geographical range covered by the calibration database as well as on the nature of samples; (3) even if local calibrations suffer from reduced amplitude of climatic parameter due to local homogeneity, they better reflect actual climate than the global ones by reducing the limits for saturation impact, (4) a bias in climatic reconstructions is induced by the over-parameterization of the models and (5) paleoclimate values reconstructed here are consistent with Mongolia-China Late Holocene climate trends, and validate the application of local calibrations for both pollen and GDGTs. We encourage the application of this surface calibration method to reconstruct paleoclimate and especially consolidate our understanding of the Holocene climate and environment variations in Arid Central Asia.

How to cite: Dugerdil, L., Joannin, S., Peyron, O., Jouffroy-Bapicot, I., Vannière, B., Bazartseren, B., Unkelbach, J., Behling, H., and Ménot, G.: Mongolian dryland paleoenvironment and paleoclimate issues : calibrations and applicability of GDGT and pollen reconstructions over the Late Holocene., EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-3390, https://doi.org/10.5194/egusphere-egu21-3390, 2021.

Displays

Display file