Hydroclimatic changes since the Last Glacial Maximum recorded in mountain peat deposit on the southwestern margin of the Sichuan Basin, China
Hydroclimatic changes since the Last Glacial Maximum recorded in mountain peat deposit on the southwestern margin of the Sichuan Basin, China
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DOI：
10.3389/fevo.2022.1050429
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发表时间：
2022-11
期刊：
影响因子：
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通讯作者：
Ming Huang;Y. Deng;Haijun Peng;Zhenming Wen;G. Shang;Houchun Guan;Chunmei Ma
中科院分区：
文献类型：
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作者：
Ming Huang;Y. Deng;Haijun Peng;Zhenming Wen;G. Shang;Houchun Guan;Chunmei Ma
了解末次冰盛期以来西南中国地区的水文气候变化，对于厘清亚洲季风的长期演化和预测亚洲季风区山地泥炭矿床的未来命运具有重要意义。本研究从中国西南干池湿地采集了长达530 cm的泥炭岩芯，并对其进行了总氮、总有机碳、有机质稳定碳同位素组成(δ13Corg)和几种常量元素浓度等地球化学指标的分析，以研究末次盛冰期以来的沉积和水文气候演化。研究发现，甘池湿地泥炭地层是从13.7ka Kyr BP开始逐渐发育的，这可能归因于Bölling-Allerød(B/A)时期的温暖气候。总有机碳、δ13Corg、K/Ti和Fe/Mn记录表明，自最后一次冰川消融以来，古气候发生了显著变化。观测到末次盛冰期后的第一个增暖期始于18.2cal KYR BP，这与西南地区中国的其他记录一致。重建结果表明，最后一次冰川消融期间，四川盆地西缘受东亚夏季风(EASM)影响最大，受印度夏季风(ISM)影响较小。全新世早期(11.2-7.5CALKYR BP)气候同时受ISM和EASM的影响，导致当地气候特征更加复杂。观测到的全新世大温期为7.5~3.5cal KYR BP，与西南中国其他记录中发现的时间一致。
Knowledge of the hydroclimatic changes in Southwest China since the Last Glacial Maximum (LGM) is crucial for disentangling the long-term evolution of the Asia Monsoon and predicting the future fate of the mountain peat deposit in the Asia Monsoon region. In this study, we obtained a 530-cm-long peat core from the Ganchi wetland in Southwest China and analyzed its geochemical indices, including total nitrogen (TN), total organic carbon (TOC), stable carbon isotope composition of organics (δ13Corg), and the concentration of several major elements, to investigate the sedimentary and hydroclimate evolution since the LGM. We found that the peat strata in the Ganchi wetland have developed gradually from 13.7 cal kyr BP, which is likely ascribed to the warm climate during the Bølling-Allerød (B/A) period. TOC, δ13Corg, K/Ti, and Fe/Mn records showed notable paleoclimate shifts since the last deglaciation. The first warming period after the LGM was observed starting at 18.2 cal kyr BP, which is consistent with other records from Southwest China. The reconstruction results show that the western margin of the Sichuan Basin during the last deglaciation was most affected by the East Asia summer monsoon (EASM), and less affected by the Indian summer monsoon (ISM). The climate of the early Holocene (11.2–7.5 cal kyr BP) was affected by both the ISM and EASM, resulting in more complex local climatic features. The Holocene Megathermal period observed from 7.5 to 3.5 cal kyr BP, is consistent with the timing detected in other records of Southwest China.