What are the drivers of Caspian Sea level variation during the late Quaternary?

What are the drivers of Caspian Sea level variation during the late Quaternary?

Koriche, Sifan A. (University of Reading; Baylor University; JiT| Jimma University; The University of Texas at Austin)
Singarayer, Joy S. (University of Reading)
Cloke, Hannah L. (University of Reading; Uppsala University; CNDS)
Valdes, Paul J. (University of Bristol)
Wesselingh, Frank P. (Naturalis Biodiversity Center)
Kroonenberg, S.B. (TU Delft Applied Geology)
Wickert, Andrew D. (University of Minnesota; Helmholtz Centre Potsdam - GFZ German Research Centre for Geosciences)
Yanina, Tamara A. (Chemistry Faculty of M. V. Lomonosov Moscow State University)

2022

Quaternary Caspian Sea level variations depended on geophysical processes (affecting the opening and closing of gateways and basin size/shape) and hydro-climatological processes (affecting water balance). Disentangling the drivers of past Caspian Sea level variation, as well as the mechanisms by which they impacted the Caspian Sea level variation, is much debated. In this study we examine the relative impacts of hydroclimatic change, ice-sheet accumulation and melt, and isostatic adjustment on Caspian Sea level change. We performed model analysis of ice-sheet and hydroclimate impacts on Caspian Sea level and compared these with newly collated published palaeo-Caspian sea level data for the last glacial cycle. We used palaeoclimate model simulations from a global coupled ocean-atmosphere-vegetation climate model, HadCM3, and ice-sheet data from the ICE-6G_C glacial isostatic adjustment model. Our results show that ice-sheet meltwater during the last glacial cycle played a vital role in Caspian Sea level variations, which is in agreement with hypotheses based on palaeo-Caspian Sea level information. The effect was directly linked to the reorganization and expansion of the Caspian Sea palaeo-drainage system resulting from topographic change. The combined contributions from meltwater and runoff from the expanded basin area were primary factors in the Caspian Sea transgression during the deglaciation period between 20 and 15 kyr BP. Their impact on the evolution of Caspian Sea level lasted until around 13 kyr BP. Millennial scale events (Heinrich events and the Younger Dryas) negatively impacted the surface water budget of the Caspian Sea but their influence on Caspian Sea level variation was short-lived and was outweighed by the massive combined meltwater and runoff contribution over the expanded basin.

Caspian sea level
Climate change
Fennoscandian ice sheet
Meltwater
Palaeo-drainage

http://resolver.tudelft.nl/uuid:36dfeb28-fb2c-4b9e-adde-3a54962b40ad

https://doi.org/10.1016/j.quascirev.2022.107457

0277-3791

Quaternary Science Reviews, 283

Institutional Repository

journal article

© 2022 Sifan A. Koriche, Joy S. Singarayer, Hannah L. Cloke, Paul J. Valdes, Frank P. Wesselingh, S.B. Kroonenberg, Andrew D. Wickert, Tamara A. Yanina