| 鄂西和尚洞石笋500年生长周期及其对区域水文变化的响应 |
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| 引用本文： | 张翠贞,朱宗敏,丁建宇,石太衡.鄂西和尚洞石笋500年生长周期及其对区域水文变化的响应[J].地质科技通报,2022,41(3):246-253. |
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| 作者姓名： | 张翠贞 朱宗敏 丁建宇 石太衡 |
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| 基金项目： | 国家自然科学基金项目KZ18W30141 |
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| 摘 要： | 洞穴石笋是目前高分辨率古气候研究的重要载体，拥有丰富的物理、化学及微生物类古气候重建指标。其中，与环境关系密切的石笋生长速率因具有数据采集简便、快捷、经济等优点而应用广泛，但由于影响因素复杂，其气候指示意义仍存在较大的不确定性。本研究利用前人高分辨率年代数据建立了鄂西和尚洞HS4石笋8.8 ka BP以来的生长速率序列，发现，该石笋在8.8~5.0 ka BP之间生长速率低于整根石笋的生长速率，其平均值仅为236 μm/a，而5.0 ka BP以来生长速率较之前增加1.5倍，平均达到334 μm/a。我们发现，从表象上，石笋生长速率在千年尺度上的变化趋势与指标重建的区域夏季风强度呈负相关关系，但与厄尔尼诺事件的发生频率呈正相关关系。频谱分析显示该石笋的生长速率变化呈500年周期特征，与太阳活动周期及其与厄尔尼诺与南方涛动(ENSO)活动共同影响下的区域强降水事件发生周期一致，且在部分时段两者呈同相位变化，即强降水频繁时期该石笋的生长速率更快。结合区域温度、水文特征、季风强度以及古El Ni?o事件发生频率记录，本研究认为HS4石笋的生长速率主要响应太阳活动及ENSO活动控制下当地有效降水量的变化，即降雨量大(小)则生长速率高(低)。
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| 关 键 词： | 石笋 生长速率 ENSO 长江中游 频谱分析 |
| 收稿时间： | 2021-07-12 |
500-year growth cycle of stalagmite and its response to regional hydrological changes in Heshang cave,western Hubei |
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| Abstract: | Stalagmitesare important high-resolution paleoclimate archives, and possess abundant physical, chemical and microbial paleoclimate proxies. Among of them, the growth rate (GR)of stalagmites quite popular because its easy access and non-destruction.However, the environmental implicationsof GR are still ambiguous due to the complex influence factors. Here we established the GR series span past 8.8 ka of HS4 stalagmite came from the Heshang Cave located in the middle reaches of Yangtze River. It was found that the GR of HS4 stalagmite showed two stages in the millennial timescale: the low and stable GR duration between 8.8 and 5.0 ka BP and the high and fluctuated GR duration since 5.0 ka BP. Above millennial variation is negative correlated with the intensity of regional summer monsoon and positive correlated with the frequency of El Nino and regional paleo-hydrological condition. The GR of HS4 stalagmite exhibited a significant 500-year cycle with confidence level more than 99%. The centennial periodic GR variation coincide well with the occurrence of regional heavy precipitation with the higher frequency of heavy precipitation correspond to the faster GR, and this correlation is especially significant in the Late Holocene. but which was forcing by considering the regional precipitation in millennial and centennial time scale were mainly affected direct or indirectly by the solar radiation and El Nino-Southern Oscillation (ENSO) activity, we conclude that the GR of HS4 stalagmite is mainly controlled by the regional effective precipitation forcing by the solar radiation and ENSO activity, showing the greater the rainfall the faster the growth rate. |
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