Sea-land oxygen isotopic relationships from planktonic foraminifera and speleothems in the Eastern Mediterranean region and their implication for paleorainfall during interglacial intervals
Sea-land oxygen isotopic relationships from planktonic foraminifera and speleothems in the Eastern Mediterranean region and their implication for paleorainfall during interglacial intervals
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DOI：
10.1016/s0016-7037(02)01031-1
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发表时间：
2003-09-01
影响因子：
5
通讯作者：
Hawkesworth, CJ
中科院分区：
文献类型：
--
作者：
Bar-Matthews, M;Ayalon, A;Hawkesworth, CJ
洞穴洞穴的氧和碳稳定同位素组成为了解大陆气候变化提供了有力的方法。在这里，我们研究该同位素记录的区域性问题及其与东地中海（EM）地区海洋同位素记录的联系。该研究提出了一项新的、准确年代为 250 kyr 的 delta(18)O 和 VC 记录，该记录是从以色列北部 Peqiin 洞穴的洞穴中确定的。其与以色列中部 Soreq 洞穴洞穴的连续 185 kyr 同位素记录的比较揭示了惊人的相似之处。因此，两个洞穴记录都反映了由温度和降雨量变化带来的强烈的区域气候信号。最后 250 至 185 kyr 时期（间冰期海洋同位素阶段 7）的 Peqiin 剖面中的低 delta(18)O 最小值与腐泥 9 至 7 的时间相匹配，表明 EM 地区在这些时间有高降雨量。过去 250 kyr 的 Soreq 和 Peqiin 8180 综合记录与已发布的 EM 海的 Globigerinoides ruber (G. ruber) 海洋三角洲 (18)O 记录完美匹配，同位素组成差异 Delta(G.ruber-speleothems) 保持相对稳定在 -5.6 +/- 0.7%，从而首次在陆地和海洋同位素之间建立了牢固的、可利用的联系记录。间冰期腐泥事件期间低δ(18)O 洞穴值和高洞穴水位与低G. ruber δ(18)O 值的对应关系表明，这些时期的特点是EM 陆地和海洋区域降雨量增加。通过使用从烯酮数据得出的海面温度作为 Soreq 洞穴陆地温度的代理，我们计算了古降雨 delta(18)O 值及其数量。最大降雨量和最低温度条件发生在腐泥事件开始时，随后降雨量减少和温度升高，导致 和 条件。过去 7000 年的记录显示了干旱加剧的趋势，与北非和中东的气候和考古数据非常吻合。版权所有 (C) 2003 爱思唯尔有限公司
The oxygen and carbon stable isotope compositions of cave speleothems provide a powerful method for understanding continental climate change. Here, we examine the question of the regionality of this isotopic record and its linkage with the marine isotopic record in the Eastern Mediterranean (EM) region. The study presents a new, accurately dated 250-kyr delta(18)O and VC record determined from speleothems of the Peqiin Cave, Northern Israel. Its comparison with the continuous 185-kyr isotopic record of the Soreq Cave speleothems from Central Israel reveals striking similarities. Thus, a strong regional climatic signal, brought about by variations in temperature and rainfall amount, is reflected in both cave records. Low delta(18)O minima in the Peqiin profile for the last 250- to 185-kyr period (interglacial marine isotopic stage 7) match the timing of sapropels 9 to 7 and are indicative of high rainfall in the EM region at these times. The combined Soreq and Peqiin 8180 record for the last 250 kyr excellently matches the published Globigerinoides ruber (G. ruber) marine delta(18)O record for the EM Sea, with the isotopic compositional difference Delta(G.ruber-speleothems) remaining relatively constant at -5.6 +/- 0.7%, thus establishing for the first time a robust, exploitable link between the land and the marine isotopic records. The correspondence of low delta(18)O speleothem values and high cave water stands with low G. ruber delta(18)O values during interglacial sapropel events indicates that these periods were characterized by enhanced rainfall in the EM land and sea regions. By use of sea surface temperatures derived from alkenone data as a proxy for land temperatures at the Soreq Cave, we calculate the paleorainfall delta(18)O values and its amounts. Maximum rainfall and lowest temperature conditions occurred at the beginning of the sapropel events and were followed by decrease in rainfall and increase in temperatures, leading to and conditions. The record for the last 7000 yr shows a trend toward increasing aridity and agrees well with climatic and archeological data from North Africa and the Middle East. Copyright (C) 2003 Elsevier Ltd.