Yilong lake level record documents coherent regional-scale changes in Holocene water balance in Yunnan, southwestern China
Yilong lake level record documents coherent regional-scale changes in Holocene water balance in Yunnan, southwestern China
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DOI：
10.1016/j.palaeo.2022.111148
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发表时间：
2022-09
期刊：
影响因子：
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通讯作者：
A. Hillman;Angelena N. Campisi;M. Abbott;D. Bain;Melissa P. Griffore;R. Tisherman;Zijie Yuan;Duo Wu
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文献类型：
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作者：
A. Hillman;Angelena N. Campisi;M. Abbott;D. Bain;Melissa P. Griffore;R. Tisherman;Zijie Yuan;Duo Wu
尽管印度夏季季风（ISM）变化的全新世尺度趋势已经确定，但百年和数十年尺度变化的表现和驱动因素仍然存在争议。此外，代理在多大程度上反映了突然的气候变化而不是代理特定的阈值尚不清楚。为了解决这些问题，我们总结了中国云南异龙湖 9200 年的记录，使用多种指标，包括自生方解石的氧和碳同位素以及钛/铝比，分别表征湖泊水文平衡和流域侵蚀。我们将这些结果与云南高原附近另外两个经过充分研究的湖泊进行了比较。在这三个湖泊中，ISM 的全新世规模减弱是明显的，但其间出现了突然的变化，表明在 7900、5500 和 4500 卡路里年BP 处降水量减少和/或蒸发量增加。我们认为，印度洋偶极子持续多个世纪向正平均状态的转变可以解释这些事件，而厄尔尼诺南方涛动的影响可能会有所减弱。距今 1500 年以后，由于人类操纵水文平衡，仪陇氧同位素的负值转变为较小的值，这与流域侵蚀导致的红粘土层沉积一致。尽管仪陇水文平衡的人为管理强度远小于其他区域湖泊，但这些结果与云南其他湖泊相似。这些结果强调了人为对湖泊影响的多样性，即使是相距仅几公里的湖泊，并证明了淡水资源利用的时空差异。
Although Holocene-scale trends in Indian Summer Monsoon (ISM) variability have been well-established, manifestations and drivers of centennial- and multi-decadal-scale variability are still debated. Additionally, the extent to which proxies reflect abrupt climatic changes rather than proxy-specific thresholds is unclear. To address these questions, we summarize a 9200-year record from Yilong Lake in Yunnan China using multiple proxies including oxygen and carbon isotopes of authigenic calcite as well as Ti/Al ratio to characterize lake hydrologic balance and catchment erosion, respectively. We compare these results to two other well-studied nearby lakes on the Yunnan Plateau. At all three lakes, the Holocene-scale waning of the ISM is evident, but punctuated by abrupt shifts indicative of lower precipitation and/or greater evaporation at 7900, 5500, and 4500 cal yr B.P. We suggest that a shift to a positive mean-state of the Indian Ocean Dipole lasting multiple centuries can account for these events, with possible moderating influence from El Niño Southern Oscillation. After 1500 cal yr B.P., Yilong oxygen isotopes shift to less negative values as a result of human manipulation of hydrologic balance, coincident with the deposition of a red clay layer from catchment erosion. These results are similar to other Yunnan lakes although the intensity of anthropogenic management of Yilong's hydrologic balance is substantially smaller than at the other regional lakes. These results underscore the diversity of anthropogenic impacts to lakes, even ones that are only a few kilometers apart, and demonstrate spatiotemporal differences in freshwater resource use.