PALEOCLIMATIC CHANGES DEDUCED FROM C-13/C-12 AND C/N RATIOS OF KAREWA LAKE-SEDIMENTS, INDIA
PALEOCLIMATIC CHANGES DEDUCED FROM C-13/C-12 AND C/N RATIOS OF KAREWA LAKE-SEDIMENTS, INDIA
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DOI：
10.1038/323150a0
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发表时间：
1986-09-11
期刊：
影响因子：
64.8
通讯作者：
KUSUMGAR, S
中科院分区：
文献类型：
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作者：
KRISHNAMURTHY, RV;BHATTACHARYA, SK;KUSUMGAR, S
大多数基于同位素研究的长期古气候记录来自深海岩心;然而，为了获得区域气候变化的信息，必须研究大陆沉积物。主要的限制是缺乏保存完好的可定年的地质记录，除了洞穴构造。我们在这里报告的稳定碳同位素比值，13 C/12 C，和元素的碳，氮（C/N）比的有机部分的古地磁和放射性测定的更新世Karewa湖沉积物从克什米尔，印度。总之，这两个比率，这是相关的，提供了一个很好的标志物的有机物的来源在湖泊。Karewa沉积物表明，至少有三个主要的浅于正常水平的事件。这些浅水湖水位的变化，以及由此产生的寒冷、干燥的气候状况，在很大程度上可以用深海记录来校正。
Most long palaeoclimatic records based on isotope studies have come from deep-sea cores; however, in order to obtain information on regional climatic variations, it is essential to study continental deposits. The chief limitation has been the lack of well-preserved datable geological records, with the exception of cave formations. We report here values for the stable carbon isotope ratio,13C/12C, and the elemental carbon to nitrogen (C/N) ratio of the organic fraction of the palaeomagnetically and radiometrically dated Pleistocene Karewa lake sediments from Kashmir, India. Together, the two ratios, which are anticorrelated, provide an excellent marker of the source of organic matter in the lake. The Karewa sediments indicate at least three major episodes of shallower than normal levels. These episodes of shallow lake levels, and hence a cold, dry climatic regime, are broadly correctable with deep-sea records.