A major hydrobiological change in Dasht-e Arjan Wetland (SW Iran) during the late glacial-early Holocene transition revealed by subfossil chironomids

Aubert, Cyril; Djamali, Morteza; Jones, Matthew; Lahijani, Hamid; Marriner, Nick; Naderi-Beni, Abdolmajid; Sharifi, Arash; Ponel, Philippe; Gandouin, Emmanuel

Abstract

The late glacial-early Holocene transition is a key period in the Earth’s history. However, although this transition is well studied in Europe, it is not well constrained in the Middle East and palaeohydrological records with robust chronologies remain scarce from this region. Here we present an interesting hydrobiological record showing a major environmental change occurring in the Dasht-e Arjan Wetland (SW Iran, near to Persepolis) during the late glacial-early Holocene transition (ca. 11,650 years cal BP). We use subfossil chironomids (Insecta: Diptera) as a proxy for hydrological changes and to reconstruct lake-level fluctuations. The Arjan wetland was a deep lake during the Younger Dryas (YD) marked by a dominance of Chironomus plumosus/anthracinus-type, taxa adapted to anoxic conditions of deep waters. At the beginning of the Holocene a drastic decrease (more than 80% to less than 10%) of Chironomus plumosus/anthracinus-type, combined with diversification of littoral taxa such as Polypedilum nubeculosum-type, Dicrotendipes nervosus-type and Glyptotendipes pallens-type suggest a lake-level decrease and a more vegetalized aquatic environment. We compare and contrast the chironomid record of Arjan with a similar record from northwestern Iran. The palaeoclimatic significance of the record, at a local and regional scale, is subsequently discussed. The increase in northern hemisphere temperatures, inferred by geochemical data from NGRIP, at the beginning of the Holocene best explains the change from the YD highstand to early Holocene lowstand conditions in the Dasht-e Arjan wetland. However, a contribution of the melt-water inflow from small local glaciers in the catchment basin is not excluded.

Citation

Aubert, C., Djamali, M., Jones, M., Lahijani, H., Marriner, N., Naderi-Beni, A., …Gandouin, E. (2019). A major hydrobiological change in Dasht-e Arjan Wetland (SW Iran) during the late glacial-early Holocene transition revealed by subfossil chironomids. Canadian Journal of Earth Sciences, 56(8), 848-856. https://doi.org/10.1139/cjes-2018-0256

• Journal Article Type: Article
• Acceptance Date: Jan 20, 2019
• Online Publication Date: Jul 24, 2019
• Publication Date: 2019-08
• Deposit Date: Jan 21, 2019
• Publicly Available Date: Jan 22, 2019
• Journal: Canadian Journal of Earth Sciences
• Print ISSN: 0008-4077
• Electronic ISSN: 1480-3313
• Publisher: NRC Research Press
• Peer Reviewed: Peer Reviewed
• Volume: 56
• Issue: 8
• Pages: 848-856
• DOI: https://doi.org/10.1139/cjes-2018-0256
• Keywords: General Earth and Planetary Sciences
• Public URL: https://nottingham-repository.worktribe.com/output/1486100
• Publisher URL: https://www.nrcresearchpress.com/doi/10.1139/cjes-2018-0256#.XVZe6OhKhhE