Varve counting reveals high resolution radiocarbon reservoir age variations in palaeolake Lisan
Varve counting reveals high resolution radiocarbon reservoir age variations in palaeolake Lisan
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Varve 计数揭示了 Lisan 古湖高分辨率放射性碳储层年龄变化
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发表时间：
2009
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影响因子：
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通讯作者：
M. Stein
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作者：
Sushma Prasad;J. Negendank;M. Stein
末次冰期里三湖沉积的层状湖相沉积物代表了原生文石和粉质碎屑的年度沉积物，反映了每年向该湖供应的含碳酸氢盐的淡水。构建了大约 ca 时间间隔的 varve 计数曲线。 17.4–22 口径ka BP 基于文石 U/Th 和从研究部分回收的有机碎片的大气放射性碳年龄。原生（蒸发）霰石中的放射性碳包含大气碳和旧碳（反映储层年龄）。通过将文石放射性碳测年与 varve 计数曲线进行比较来确定文石储层年龄，发现文石储层年龄在 1900 年至 600 年范围内，并呈持续下降趋势。这为在海洋同位素阶段（MIS）2上部进行水库年龄的高分辨率（年度）监测提供了可能性，其质量类似于树木年轮计数。我们的工作还表明，在确定湖泊环境中短期气候事件的年表时，“统一”的水库年龄校正是不合适的。版权所有 © 2009 约翰·威利父子有限公司
The laminated lacustrine sediments deposited in the last glacial Lake Lisan represent annual deposits of primary aragonite and silty detritus that reflect the annual supply of bicarbonate‐bearing freshwater to the lake. A varve‐counting curve was constructed for the time interval of ca. 17.4–22 cal. ka BP based on aragonite U/Th, and atmospheric radiocarbon ages of organic debris recovered from the studied section. Radiocarbon in the primary (evaporitic) aragonite comprises both atmospheric and old carbon (reflecting the reservoir age). The aragonite reservoir ages were determined by comparing the aragonite radiocarbon dates to the varve counting curve, and are found to lie in the range 1900–600 a and display a continuous decline. This opens the possibility for high (annual) resolution monitoring of the reservoir age, similar in quality to tree ring counting, during the upper part of Marine Isotope Stage (MIS) 2. Our work also demonstrates that a ‘uniform’ reservoir age correction is inappropriate when determining the chronology of short‐term climate events in lacustrine environments. Copyright © 2009 John Wiley & Sons, Ltd.