Abstract
The sedimentary record of the Caspian Basin is an exceptional archive for the palaeoenvironmental, palaeoclimatic and biodiversity changes of continental Eurasia. During the Pliocene-Pleistocene, the Caspian Basin was mostly isolated but experienced large lake level fluctuations and short episodes of connection with the open ocean as well as the Black Sea Basin. A series of turnover events shaped a faunal record that forms the backbone of the Caspian geological time scale. The precise ages of these events are still highly debated, mostly due to the lack of well-dated sections. Here, we provide an integrated magneto-biostratigraphic age model for two sections from the Kura Basin – Goychay and Hajigabul. Our results reveal several major intervals with elevated salinity, associated with mesohaline faunas, and propose the following age constraints: 1) The Productive Series-Akchagylian boundary is marked by a marine transgression from the open ocean that occurred around the Gauss-Matuyama reversal (∼2.7–2.6 Ma); 2) The Akchagylian-Apsheronian transition is characterized by a regression event and introduction of a new, “Pontocaspian” mollusc assemblage, dated within the Reunion subchron (∼2.13 Ma). The ostracod assemblages of the two sections do not show a major faunal turnover here; 3) The early Bakunian transgression occurs after the upper Apsheronian lowstand (0.85–0.83 Ma). We conclude that major transitions in the age-indicative mollusc groups sometimes occur at different time intervals (i.e. diachronic) and are highly depended on the local depositional environments. A high-resolution interdisciplinary approach on sections outside the Kura Basin is required to better understand the potential diachroneity of these turnover events in the entire Caspian Basin.
Original language | English |
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Article number | 105895 |
Number of pages | 26 |
Journal | Quaternary Science Reviews |
Volume | 222 |
DOIs | |
Publication status | Published - 15 Oct 2019 |
Funding
We thank Tom Hoyle, Vusala Aghayeva, Rashad Amrahov, Sevinj Shiraliyeva, Gülçin Aygün and the research staff of the Geological and Geographic Institutes of the National Academy of Sciences of Azerbaijan for assistance in the field. We thank Guzel Danukalova for help with the Akchagylian cardiid identifications. The suggestions of three reviewers including Imre Magyar, have been very helpful to improve our manuscript. The research is part of the PRIDE project (Pontocaspian RIse and DEmise), which is funded by the European Union's Horizon 2020 research and innovation program , under the Marie Sklodowska-Curie Action (grant agreement № 642973 ). This paper is dedicated to the establishment of peace in the Caucasian region. Appendix A
Keywords
- Akchagylian
- Apsheronian
- Bakunian
- Biostratigraphy
- Caspian Sea
- Early – Middle Pleistocene
- Kura Basin
- Magnetostratigraphy
- Mollusc fauna
- Ostracods