Abstract
A 25 m long sediment core from hypersaline Urmia Lake (north-west Iran) was studied for the Late Quaternary depositional history and palaeoclimate variations using the abundance and compositional characteristics of Artemia faecal pellets. Sediment analysis is supported by scanning electron microscopy – energy dispersive X-ray spectroscopy, organic and inorganic carbon content measurements, and stable isotopes (δ13C and δ18O) from faecal pellet carbonates. The imprecise chronology of the core back to 50 kyr bp is supported by ten radiocarbon ages from faecal pellets and bulk sediments. The palaeoenvironmental record is subdivided into four periods: (i) During much of Marine Isotope Stage 3, a period of lake level lowering is characterized by a decreasing amount of faecal pellets, and an increasing amount of coated grains, sulphate minerals and reworked shell fragments. (ii) During late Marine Isotope Stage 3 and early Marine Isotope Stage 2 a lake level lowstand and a lake floor exposure is interpreted based on the relatively low abundance of pellets, which are multicoloured and appear together with volcanic lithics and rounded sulphate minerals. (iii) During late Marine Isotope Stage 2 the record is devoid of pellets but dominated by large sulphate crystals suggesting a prolonged low lake level. (iv) During Marine Isotope Stage 1 a relative lake level highstand is rapidly established with sediments that are highly abundant in fresh pellets. The modern lake level lowstand is represented by a salt crust. The δ13C and δ18O records measured from faecal pellet carbonates suggest a link with the precipitation versus evaporation balance in the lake over time. From bottom to top the linear trend towards more negative delta values illustrates the increasing amount of precipitation arriving at the lake from the Late Pleistocene to the Holocene. Two prominent isotope minima during the Late Pleistocene and one prominent minimum in the early Holocene mark relative high lake levels, which can also be linked to Lake Van in Turkey.
| Original language | English |
|---|---|
| Pages (from-to) | 887-911 |
| Number of pages | 25 |
| Journal | Sedimentology |
| Volume | 71 |
| Issue number | 3 |
| DOIs | |
| Publication status | Published - Apr 2024 |
Bibliographical note
Publisher Copyright:© 2023 The Authors. Sedimentology published by John Wiley & Sons Ltd on behalf of International Association of Sedimentologists.
Funding
The authors thank the Iran Water and Power Resources Development Company and Research Institute for Earth Sciences, Geological Survey of Iran, for providing the core. The laboratory support from AWI (Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research) is highly appreciated. We thank especially the colleagues Dorothee Wilhelms‐Dick and Ralf Tiedemann for helping with isotope data, and Yeong Bae Seong for his scientific support. Angélique Opitz and Justin Lindemann for helping with elemental data, Gültekin Topuz for helping with thin sections preparation. The Institute for Earth Sciences, Geological Survey of Iran, and the Hacettepe University Advanced Technologies Application and Research Center (HUNITEK) are thanked for SEM‐EDS measurements. ITU EMCOL laboratory is acknowledged for cutting core tubes, sub‐sampling, and sample sieving. Our thanks are due to Dursun Acar and Ceren Naz Yakupoğlu for their support in sample preparation. The authors would like to thank Rick Sarg (Associate Editor), Charles G. Oviatt and an anonymous reviewer for their detailed and constructive comments, significantly improving the quality of the manuscript. We thank Gabriela Mángano for the efficient editorial handling of the manuscript. This work was supported by the Istanbul Technical University (İTÜ)/BAP project (A. Başlangıç/TAB‐2021‐42619).
| Funders | Funder number |
|---|---|
| Istanbul Teknik Üniversitesi | |
| İTÜ | /TAB‐2021‐42619 |
Keywords
- Artemia faecal pellet
- Urmia Lake
- deposition history
- lake level fluctuation
- radiocarbon age
- stable oxygen and carbon isotopes