Biomarkers reveal two paramount Pliocene-Pleistocene connectivity events in the Caspian Sea Basin

Iuliana Vasiliev*, Marcel T.J. van der Meer, Marius Stoica, Wout Krijgsman, Gert Jan Reichart, Sergei Lazarev, Geanina A. Butiseacă, Eva M. Niedermeyer, Elmira Aliyeva, Christian G.C. van Baak, Andreas Mulch

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

Landlocked basins like the Caspian Sea are highly sensitive to changes in their hydrological budget, especially at times of disconnection from the global ocean. Here, we reconstruct the Pliocene to Pleistocene palaeohydrological and palaeoenvironmental changes occurring in the South Caspian Basin between ~3.6 and ~ 1.9 Ma, using compound-specific hydrogen isotope (δ2H) data on long chain n-alkanes and alkenones. Additionally, we established a record of mean annual air temperature (MAT) and the source of organic matter, based on the relative distribution of branched and isoprenoid glycerol dialkyl glycerol tetraethers (BIT). The ~55‰ variation in the δ2H measured on the terrestrial plant long chain n-alkanes indicates significant continental hydrological changes in the region surrounding the Caspian Sea over the investigated 1.7 Myr interval. The MAT and BIT data show that the so-called Akchagylian marine incursion at around 2.75 Ma, marked by influx of marine biota into the Caspian Basin, originated from a cold region of the open ocean, endorsing a hydrological connection with the Arctic domain. The onset of the regional Apsheronian stage at ~2.13 Ma, identified by the invasion of Tyrrhenocythere sp. ostracods, coincided with a change towards constant δ2Hn-alkane and is shortly followed by the occurrence of alkenones in the Caspian Basin. The relative distributions of alkenones and their δ2H values indicate that a connection with a saline basin, most likely the Black Sea, was established at the Akchagylian–Apsheronian transition.

Original languageEnglish
Article number110802
Pages (from-to)1-15
JournalPalaeogeography, Palaeoclimatology, Palaeoecology
Volume587
DOIs
Publication statusPublished - 1 Feb 2022

Bibliographical note

Funding Information:
I.V. thanks Linda van Roij (Utrecht University) and Ulrich Treffert (SBiK-F) for help in the organic geochemistry laboratories. This research was financially supported by the Netherlands Life and Earth Sciences Foundation (ALW) with support from the Netherlands Organization for Scientific Research (NWO) to W.K. and Senckenberg Gesellschaft für Naturforschung. We would like to thank the two anonymous reviewers for their suggestions that significantly improved the manuscript.

Funding Information:
I.V. thanks Linda van Roij (Utrecht University) and Ulrich Treffert (SBiK-F) for help in the organic geochemistry laboratories. This research was financially supported by the Netherlands Life and Earth Sciences Foundation (ALW) with support from the Netherlands Organization for Scientific Research (NWO) to W.K. and Senckenberg Gesellschaft f?r Naturforschung. We would like to thank the two anonymous reviewers for their suggestions that significantly improved the manuscript.

Publisher Copyright:
© 2021 Elsevier B.V.

Funding

I.V. thanks Linda van Roij (Utrecht University) and Ulrich Treffert (SBiK-F) for help in the organic geochemistry laboratories. This research was financially supported by the Netherlands Life and Earth Sciences Foundation (ALW) with support from the Netherlands Organization for Scientific Research (NWO) to W.K. and Senckenberg Gesellschaft für Naturforschung. We would like to thank the two anonymous reviewers for their suggestions that significantly improved the manuscript. I.V. thanks Linda van Roij (Utrecht University) and Ulrich Treffert (SBiK-F) for help in the organic geochemistry laboratories. This research was financially supported by the Netherlands Life and Earth Sciences Foundation (ALW) with support from the Netherlands Organization for Scientific Research (NWO) to W.K. and Senckenberg Gesellschaft f?r Naturforschung. We would like to thank the two anonymous reviewers for their suggestions that significantly improved the manuscript.

Keywords

  • Akchagylian marine incursion
  • Black Sea influx
  • Hydrogen isotopes
  • N-alkanes
  • Palaeohydrology
  • Pleistocene
  • South Caspian Basin

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