Paleohydrological changes in southeastern China from 13.1 to 2.5 ka based on a multi-proxy peat record
Paleohydrological changes in southeastern China from 13.1 to 2.5 ka based on a multi-proxy peat record
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DOI：
10.1016/j.palaeo.2019.109282
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发表时间：
2019-11
期刊：
影响因子：
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通讯作者：
Xinxin Wang;Xianyu Huang
中科院分区：
文献类型：
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作者：
Xinxin Wang;Xianyu Huang
研究全新世中国东亚季风区的水文变化，对东亚夏季风（EASM）降水的机制和未来变率具有重要意义。因此，在水文记录较少的中国东南部地区，尤其需要具有精确年代的多代理记录。本研究利用水柱阳泥炭岩心的藿烷类通量、腐殖化程度、有机质总有机碳（TOC）浓度和总有机碳/总氮原子比（C/N），重建了13.1 ~ 2.5 ka的古水文变化。结果表明：13.1 ~ 11.6 ka为中度干旱期，11.6 ~ 8.6 ka为中度干旱期。在4.4 ~ 2.5 ka气候变干之前，8.6 ~ 4.4 ka出现了全新世最佳（此处称为有效水分最大值）。SZY在全新世期间的水文变化与中国东南地区的区域气候记录一致，并具有全新世中期的最佳期。这一全新世中国东南部整体干旱-湿-干旱格局与热带太平洋西-东海温梯度变化密切相关。我们初步认为，ENSO状态和西太平洋副热带高压位置与热带太平洋热态变化有关，是中国东南部全新世水文变化的主要原因。本研究为全新世以来中国东部地区水文变化的时空格局提供了新的证据。
Investigating the hydrological changes in the East Asian monsoon regions of China during the Holocene could provide important insights into the mechanism and future variability of the East Asian summer monsoon (EASM) rainfall. However, existing studies have revealed large inconsistencies in the spatiotemporal pattern of the hydrological changes in East China, probably due to different climatic sensitivities of various proxies, the uncertainties of sedimentary chronologies and unevenness of proxy record distributions. Thus, multi-proxy records with precise dating are needed, especially in southeastern China which is one of the key places to determine the spatiotemporal pattern with few hydrological records available. In this study, hopanoid flux, humification degree, the concentration of total organic carbon (TOC) and the atomic ratio between total organic carbon and total nitrogen (C/N) of organic matter were applied on Shuizhuyang (SZY) peat cores retrieved from southeastern China to reconstruct the paleohydrological changes spanning from 13.1 to 2.5 ka. Results of these proxies reveal a moderately dry period during 13.1–11.6 ka, followed by an interval of increasing aridity from 11.6 to 8.6 ka. The Holocene optimum (referred here as an effective moisture maximum) occurred at 8.6–4.4 ka before the climate became drier from 4.4 to 2.5 ka. The hydrological changes in SZY during the Holocene with a mid-Holocene Holocene optimum are consistent with the regional climate records in southeastern China. Such an overall arid-wet-arid pattern in Southeast China during the Holocene closely tracked the variations in the west-to-east sea surface temperature (SST) gradient in tropical Pacific. We preliminarily concluded the ENSO state and the western Pacific subtropical high (WPSH) position associated with variations in the thermal state of the tropical Pacific were primarily responsible for the hydrological changes in Southeast China during the Holocene. Our study added new evidence to the spatiotemporal pattern of hydrological changes in eastern China during the Holocene.