Palaeoclimatic interpretation of high-resolution oxygen isotope profiles derived from annually laminated speleothems from Southern Oman
Palaeoclimatic interpretation of high-resolution oxygen isotope profiles derived from annually laminated speleothems from Southern Oman
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DOI：
10.1016/j.quascirev.2003.06.019
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发表时间：
2004-04-01
影响因子：
4
通讯作者：
Matter, A
中科院分区：
文献类型：
--
作者：
Fleitmann, D;Burns, SJ;Matter, A
阿曼南部一个浅洞穴中同时沉积的三个石笋的高分辨率稳定同位素剖面提供了过去780年印度洋季风降雨变异性的年度可分辨记录。铀系列年龄测定和年生长带计数可以实现极好的年龄校准。虽然现代洞穴并不是在完全的同位素平衡中生长，但氧同位素比率(δ(18)O)是季风降雨量的替代指标。增量(18)O与年带厚度之间的统计相关性支持了这一点，而增量(18)O与年带厚度呈负相关。此外，重叠的三角洲(18)O剖面在模式和范围上非常相似，表明样品特有的噪声并没有模糊气候信号。来自石笋S3的最长氧同位素剖面清楚地表明，大约在公元1320年，阿曼南部从普遍较潮湿的中世纪暖期过渡到较干燥的小冰期。自1960年代以来季风降雨量的减少在北非和印度的气象记录中也很明显，这表明我们基于洞穴的降雨量记录不仅反映了当地季风降雨量的变化。(C)2004爱思唯尔有限公司。保留所有权利。
High-resolution stable isotope profiles of three contemporaneously deposited stalagmites from a shallow cave in Southern Oman provide an annually resolved record of Indian Ocean monsoon rainfall variability for the past 780 years. Uranium-series age dating and counts of annual growth bands enable an excellent age calibration. Although modern speleothems do not grow in perfect isotopic equilibrium, oxygen isotope ratios (delta(18)O) are a proxy for the amount of monsoon rainfall. This is supported by the statistically significant correlation between delta(18)O and the thickness of annual bands, whereas delta(18)O is inversely correlated with annual band thickness. Additionally, overlapping delta(18)O profiles are very similar in pattern and range, indicating that sample specific noise did not blur the climatic signal. The longest oxygen isotope profile, derived from stalagmite S3, clearly shows the transition at similar to 1320 AD from a generally wetter Medieval Warm Period to a drier Little Ice Age that lasted from approximately AD 1320-1660 in Southern Oman. The decrease in monsoon rainfall since the 1960s is also obvious in meteorological records from Northern Africa and India, indicating that our speleothem-based rainfall records do not only reflect local monsoon rainfall variability. (C) 2004 Elsevier Ltd. All rights reserved.