A new speleothem record of the penultimate deglacial: Insights into spatial variability and centennial-scale instabilities of East Asian monsoon
A new speleothem record of the penultimate deglacial: Insights into spatial variability and centennial-scale instabilities of East Asian monsoon
复制标题
倒数第二次冰消期的一个新洞穴沉积记录：对东亚季风空间变化和百年尺度不稳定性的认识
DOI：
10.1016/j.quascirev.2019.02.023
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发表时间：
2019-04
影响因子：
4
通讯作者：
G. Xue;Yanjun Cai;Le Ma;Xing Cheng;Hai Cheng;R. Edwards;Dong Li;L. Tan
中科院分区：
文献类型：
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作者：
G. Xue;Yanjun Cai;Le Ma;Xing Cheng;Hai Cheng;R. Edwards;Dong Li;L. Tan
本文用高分辨氧同位素(δ18O)记录了中国东北部上小峰洞230Th年代石笋的倒数第二次冰期-间冰期转变。我们的δ18O记录显示了两个突出的特点。首先，SD1的δ18O记录记录了δ18O在128.5-128.1 ka BP之间的短暂增加。虽然这一事件已经在几个海洋记录中被确认，但我们的放射性成因年代记录精确地限制了气候恶化的时间和持续时间，这表明这种类似YD的事件很可能是冰河时代终止期间气候变化的内在特征。此外，冰川-间冰期变化的δ18O震级(∼0.7‰)明显小于内陆和相对高海拔洞穴(东阁、三堡和阳口洞穴)的δ18O记录(1.4-2.4‰)，但与低海拔和浅海渤海和黄海附近的葫芦洞相当(Kelly等人，2006年；程等人，2006；Wang等人，2008；程等人，2009；Li et al.，2014)。假设洞穴δ18O记录主要反映降水同位素组成的变化，中国各洞穴间冰期δ18O的差异可能与大气环流的变化、洞穴间海拔高度的变化以及海平面变化引起的区域陆海覆盖的大范围变化有关。后者导致渤海和黄海分别在冰期和间冰期消失和扩张，并可能影响降水的数量和同位素组成。综上所述，我们的研究强调了倒数第二次冰川-间冰期周期东亚季风变化的水气候印记在空间上是不均匀的，百年尺度的季风水气候不稳定可能是去冰期气候转变的内在特征。
We present a highly resolved oxygen isotope (δ18O) record of the penultimate glacial-interglacial transition from a230Th-dated stalagmite (SD1) from the Shangxiaofeng Cave in north-eastern China. Our δ18O record reveals two prominent features. First, the SD1 δ18O record documents a brief increase of δ18O between 128.5 and 128.1 ka BP. Though this event has been identified in several marine records, our radiogenic dated record precisely constraints the timing and duration of the climate deterioration suggesting that this YD-like event is likely an intrinsic feature of climate change during the ice age terminations. Additionally, the δ18O magnitude of the glacial-interglacial change (∼0.7‰) is significantly smaller compared to the δ18O records from inland and relatively high elevation caves (Dongge, Sanbao and Yangkou caves) (1.4–2.4‰) but comparable to the Hulu Cave at low elevation and proximal to the shallow Bohai and Yellow seas (Kelly et al., 2006; Cheng et al., 2006; Wang et al., 2008; Cheng et al., 2009; Li et al., 2014). Assuming that the cave δ18O records mainly reflect precipitation isotope composition changes, the glacial-interglacial speleothem δ18O difference between the various Chinese caves could be related to changes in atmospheric circulations, changing effect of altitude between the various caves and climate mean states, and large-scale changes in regional land-sea coverage due to sea level changes. The latter leads to disappearance and expansion of Bohai and Yellow seas during glacial and interglacial episodes, respectively, and likely affect the amount and isotope composition of precipitation. Taken together, our study highlights that hydroclimate imprints of the East Asian Monsoon changes during the penultimate glacial-interglacial cycle were spatially heterogeneous and centennial-scale monsoonal hydroclimate instabilities are likely inherent features of deglacial climate transition.