Oxygen isotopic composition of fruit carbonate in Lithospermeae and its potential for paleoclimate research in the Mediterranean

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• 作者：Konstantin Pustovoytov ; Simone Riehl ; Hartmut H. Hilger ; Erich Schumacher
• 关键词：Boraginaceae ; Lithospermeae ; biogenic carbonate ; δ ; ¹⁸O ; δ ; ¹³C ; ¹⁴C ; Mediterranean ; paleoclimate
• 刊名：Global and Planetary Change
• 出版年：2010
• 出版时间：April 2010
• 年：2010
• 卷：71
• 期：3-4
• 页码：258-268
• 全文大小：681 K

文摘

Calcareous pericarps of the tribe Lithospermeae (fam. Boraginaceae) are a common component of archaeobotanical macroremain assemblages in the Mediterranean region. In this study, the relationship between oxygen isotopic composition of fruit biogenic carbonate and climatic conditions was examined. δ¹⁸O and δ¹³C values of biogenic carbonate were measured in modern Lithospermeae fruits from seven Eurasian sites (Berlin, Kirchentellinsfurt, Göttingen, Athens, Ankara, Tbilisi, and Almaty) and in fossil fruits from three archaeological sites in the eastern Mediterranean (Troy, Kumtepe, and Hirbet ez-Zeraqon). Additionally, three ¹⁴C measurements were performed on ancient fruit carbonate from Hirbet ez-Zeraqon. The δ¹⁸O and δ¹³C values varied from − 9 to 5‰ PDB and between − 35 and − 7‰ PDB respectively. In modern fruits, δ¹⁸O of biogenic carbonate was correlated to local summer precipitation amounts (inversely proportional) and summer air temperatures (proportional). In fossil fruits, the δ¹⁸O values of carbonate from Troy and Kumtepe were significantly lower than that from Hirbet ez-Zeraqon (ca. − 5 vs. 2‰ PDB respectively). The vertical distribution of stable isotopic values and ¹⁴C dates in cultural layers of Hirbet ez-Zeraqon indicate that fruit biogenic carbonate can persist in sediment without appreciable diagenetic alteration. These findings suggest that biogenic carbonate of Lithospermeae fruits can be useful as a paleoclimate proxy at least in the Mediterranean.