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Holocene climate change in the eastern Mediterranean region: a comparison of stable isotope and pollen data from Lake Gölhisar, southwest Turkey
Author(s) -
Eastwood Warren J.,
Leng Melanie J.,
Roberts Neil,
Davis Basil
Publication year - 2007
Publication title -
journal of quaternary science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.142
H-Index - 94
eISSN - 1099-1417
pISSN - 0267-8179
DOI - 10.1002/jqs.1062
Subject(s) - holocene , geology , authigenic , isotopes of oxygen , pollen , physical geography , stable isotope ratio , climate change , mediterranean climate , arid , paleoclimatology , oceanography , sediment , paleontology , geochemistry , ecology , archaeology , geography , physics , quantum mechanics , biology
Stable isotope and pollen data from Gölhisar Gölü, a small intramontane lake located in southwest Turkey, provide complementary records of Holocene climate change. Modern oxygen and hydrogen isotope water data are used as a means of comparing present‐day isotope composition of the lake water to the past oxygen isotope composition of the lake water as calculated from 18 O/ 16 O ratios in calcite precipitated in the summer months. Despite the lake system being chemically dilute, the modern isotope data clearly establish that the lake water is evaporated in relation to its spring input, suggesting that the palaeo data can be interpreted primarily in terms of changing precipitation/evaporation ratios. δ 18 O and δ 13 C values from authigenic calcite through the Holocene show predominantly negative values indicating climatic conditions wetter than today. Particularly notable are low (depleted) isotope values during the earliest Holocene (ca. 10 600–8800 cal. yr. BP), a period for which pollen data imply drier conditions than at present. This divergence between pollen‐inferred and stable isotope palaeoclimate data is found in other east Mediterranean lake sediment records, and suggests that vegetation may have taken several millennia to reach climatic equilibrium at the start of the Holocene. Isotopic fluctuations during the early‐to‐mid Holocene (8800–5100 cal. yr. BP) suggest oscillations between aridity and humidity. Higher δ 18 O and δ 13 C values for the second half of the Holocene indicate generally drier conditions than during the period before ca.5100 cal. yr BP although there is some evidence for increased humidity coinciding with pollen evidence for increasing human impact and intensification of agriculture, notably during the so‐called Beyşehir Occupation Phase (Classical and early Byzantine periods). The modern trend towards aridity started about 1300 yr ago. Copyright © 2006 John Wiley & Sons, Ltd.