Seasonality of Holocene hydroclimate in the Eastern Mediterranean reconstructed using the oxygen isotope composition of carbonates and diatoms from Lake Nar, central Turkey

Dean, Jonathan R.; Jones, Matthew D.; Leng, Melanie J.; Sloane, Hilary J.; Eastwood, Warren J.; Roberts, C. Neil; Dean, Jonathan; Eastwood, Warren; Jones, Matthew; Leng, Melanie; Metcalfe, Sarah E.; Roberts, Neil; Sloane, Hilary

Abstract

A positive shift in the oxygen isotope composition (δ¹⁸O) of lake carbonates in the Eastern Mediterranean from the early to late Holocene is usually interpreted as a change to drier (reduced precipitation and evaporation (P/E)) conditions. However, it has also been suggested that changes in the seasonality of precipitation could explain these trends. Here, Holocene records of δ¹⁸O from both carbonates and diatom silica, from Lake Nar in central Turkey, provide insights into palaeoseasonality. We show how Δδ18Olakewater (the difference between spring and summer reconstructed δ¹⁸Olakewater) was minimal in the early Holocene and for most of the last millennium, but was greater at other times. For example, between ~4100 and 1600 yr BP, we suggest that increased Δδ¹⁸Olakewater could have been the result of relatively more spring/summer evaporation, amplified by a decline in lake level. In terms of change in annual mean δ¹⁸O, isotope mass balance modelling shows that this can be influenced by changes in seasonal P/E as well as inter-annual P/E, but lake level falls inferred from other proxies confirm that there was a mid-Holocene transition to drier climatic conditions in central Turkey.

Citation

Dean, J. R., Jones, M. D., Leng, M. J., Sloane, H. J., Eastwood, W. J., Roberts, C. N., Dean, J., Eastwood, W., Jones, M., Leng, M., Metcalfe, S. E., Roberts, N., & Sloane, H. (2018). Seasonality of Holocene hydroclimate in the Eastern Mediterranean reconstructed using the oxygen isotope composition of carbonates and diatoms from Lake Nar, central Turkey. Holocene, 28(2), 267-276. https://doi.org/10.1177/0959683617721326

• Journal Article Type: Article
• Acceptance Date: Jun 19, 2017
• Online Publication Date: Aug 1, 2017
• Publication Date: Feb 1, 2018
• Deposit Date: Aug 3, 2017
• Publicly Available Date: Aug 3, 2017
• Journal: The Holocene
• Print ISSN: 0959-6836
• Publisher: SAGE Publications
• Peer Reviewed: Peer Reviewed
• Volume: 28
• Issue: 2
• Pages: 267-276
• DOI: https://doi.org/10.1177/0959683617721326
• Keywords: Eastern Mediterranean, Lake sediment
• Public URL: https://hull-repository.worktribe.com/output/453886
• Publisher URL: http://journals.sagepub.com/doi/10.1177/0959683617721326
• Additional Information: This is the accepted manuscript of an article published in The Holocene, 2017.
• Contract Date: Aug 3, 2017