An optimized chronology for a stalagmite using seasonal trace element cycles from Shihua Cave, Beijing, North China.
An optimized chronology for a stalagmite using seasonal trace element cycles from Shihua Cave, Beijing, North China.
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利用华北北京石花洞季节性微量元素循环优化石笋年代学
DOI：
10.1038/s41598-018-22839-z
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发表时间：
2018-03-14
影响因子：
4.6
通讯作者：
Nagra G
中科院分区：
文献类型：
--
作者：
Ban F;Baker A;Marjo CE;Duan W;Li X;Han J;Coleborn K;Akter R;Tan M;Nagra G
石笋在从季节到轨道时间尺度的古气候重建中起着重要作用，因为230年代定年可以提供精确的绝对年龄。此外，季节性微量元素和光学层可以提供精确的年龄。分析了北京石花洞石笋（XMG）中多种微量元素的季节变化，并与纹层计数结果进行了比较。结果表明：(1)在常规透射显微镜下，XMG最上层的抛光部分存在明显的双光层，而在样品的其余部分没有观察到薄片；(2)P/Ca、Sr/Ca、Ba/Ca、U/Ca和Mg/Ca的变化在整个样品中呈现季节性循环。五种微量元素主成分分析（PCA）中的PC1代表了年周期。经PC1峰计数，该石笋沉积时间超过150±1年。这一结果与年层数和U-Th测年结果吻合较好。PC1的微量元素旋回可以提高石笋定年的准确性，特别是在没有明显纹层的情况下，是识别干湿对比强烈的季风气候区季节变化的有力方法。
Stalagmites play an important role in paleoclimatic reconstructions from seasonal to orbital time scales as230Th-dating can provide an accurate absolute age. Additionally, seasonal trace element and optical layers can provide a precise age. We analyzed the seasonal variability of multiple trace elements on a stalagmite (XMG) in Shihua Cave, Beijing and compared them with results from laminae counting. The results show that (1) the polished section of the topmost part of XMG has obvious bi-optical layers under a conventional transmission microscope, however, laminae are not observed using this method in the rest of the sample, and (2) The variations of P/Ca, Sr/Ca, Ba/Ca, U/Ca and Mg/Ca show seasonal cycles throughout the sample. The PC1 in the Principal Component Analysis (PCA) of five trace elements represents the annual cycle. This stalagmite was deposited over 150 ± 1 years through PC1 peak counting. This result corresponds well with the annual layers and U-Th dating. Trace element cyclicity of PC1 can increase the accuracy of stalagmite dating, especially in the absence of obvious laminae and are a powerful method to identify seasonal changes in a strongly contrasting wet-dry monsoon climate region.
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影响因子：
2
作者：
Frisia, S;Borsato, A;McDermott, F
通讯作者：
McDermott, F
影响因子：
64.8
作者：
BAKER, A;SMART, PL;RICHARDS, DA
通讯作者：
RICHARDS, DA
影响因子：
2.2
作者：
Hou, JZ;Tan, M;Liu, TS
通讯作者：
Liu, TS
影响因子：
5
作者：
Orland, Ian J.;Bar-Matthews, Miryam;Valley, John W.
通讯作者：
Valley, John W.
影响因子：
5.3
作者：
Finch, AA;Shaw, PA;Holmgren, K
通讯作者：
Holmgren, K