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Cryogenic wedges and cryoturbations on the Ordos Plateau in North China since 50 ka BP and their paleoenvironmental implications
Permafrost and Periglacial Processes ( IF 5 ) Pub Date : 2020-08-26 , DOI: 10.1002/ppp.2084
Ruixia He 1, 2 , Huijun Jin 1, 2, 3 , Hugh M. French 4, 5 , Jef Vandenberghe 6, 7 , Xiaoying Li 1, 2 , Fang Li 1, 2 , Guanli Jiang 1, 2 , Ze Zhang 1, 2, 3 , Xuemei Chen 1, 2 , Raul D. Serban 1, 2 , Shaoling Wang 1, 2 , Dongxin Guo 1, 2
Affiliation  

During the last 50 ka, cryogenic wedges on the Ordos Plateau formed during three major periods: (i) early local Last Glaciation, ca. 50 ka BP; (iii) local Last Permafrost Maximum(local LPM), 25–19 ka BP; and (v) post-local LPM, 16–9 ka BP. Cryoturbations mainly formed in the following periods: (ii) pre-local LPM, 45–30 ka BP and (iv) ~ 20 ka BP. The coldest periods with well-developed permafrost (i and iii) were most conducive for forming cryogenic wedges. The following periods of warming climate and degrading permafrost favored the formation of cryoturbations. During the local LPM, sand wedges and polygons were well developed and widely distributed on the Ordos Plateau when mean annual air temperatures (MAATs) were approximately 12°C lower than that at present. At ~30 ka BP, MAAT was 6–7°C lower than that at present. Paleoclimate conditions on the Ordos Plateau were reconstructed since 50 ka BP as follows: cold (ca. 50 ka BP) → cool (45–30 ka BP) → very cold (25–19 ka BP) → cool (19–9 ka BP) → intermittent warming until the present day. The amount of precipitation fluctuated, but with a general trend of drying since 50 ka BP. Under the next generally warming climate (after 9 ka BP), permafrost gradually degraded and eventually disappeared from the Ordos Plateau.

中文翻译:

50 ka BP以来华北鄂尔多斯高原低温楔形和低温扰动及其古环境意义

在过去的 50 ka 中,鄂尔多斯高原上的低温楔形在三个主要时期形成:(i)早期局部末次冰期,约。50 KA BP;(iii) 当地最后永久冻土最大值(当地 LPM),25-19 ka BP;(v) 后局部 LPM,16-9 ka BP。低温扰动主要形成于以下时期:(ii) 前局部 LPM,45-30 ka BP 和 (iv) ~ 20 ka BP。多年冻土发育良好的最冷时期(i 和 iii)最有利于形成低温楔。随后的气候变暖和永久冻土退化时期有利于低温扰动的形成。局部LPM期间,鄂尔多斯高原年平均气温(MAATs)比目前低12℃左右,沙楔和多边形发育良好,分布广泛。在~30 ka BP,MAAT比目前低6-7°C。鄂尔多斯高原自50 ka BP以来的古气候条件重建如下:寒冷(约50 ka BP)→凉爽(45-30 ka BP)→极冷(25-19 ka BP)→凉爽(19-9 ka BP) ) → 间歇性升温直到今天。降水量有所波动,但自50 ka BP以来总体呈干燥趋势。在接下来的普遍变暖气候下(9 ka BP之后),多年冻土逐渐退化并最终从鄂尔多斯高原消失。
更新日期:2020-08-26
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