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首页> 外文期刊>Journal of Geophysical Research. Biogeosciences >Climate instability during the penultimate glaciation: Evidence from two high-resolution loess records, China
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Climate instability during the penultimate glaciation: Evidence from two high-resolution loess records, China

机译：倒数第二次冰期期间的气候不稳定：来自两个高分辨率黄土记录的证据，中国

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摘要

The Xinzhuangyuan and Lijiayuan loess sections in the northwestern part of the Chinese Loess Plateau were studied down to paleosol unit S2, which probably formed during marine oxygen isotopic stage 7, approx 200,000 years B. P. The thickness of the loess-soil sequence above S2 is approx 63 m at Xinzhuangyuan and 43 m at Lijiayuan. A 2 cm sample spacing yields a mean depositional resolution of 50-80 years for the last and penultimate glacial loess units (L1 and L2) and approx 200 years for the last interglacial soil unit (S1), thus enabling us to reconstruct high-resolution climatic changes during the last two glacial-interglacial cycles. The grain size records of the two sections are regarded as a proxy for changes in the monsoon-desert system over northern China. Results show that frequent, large-amplitude climatic oscillations on millennial timescales occurred during the penultimate glaciation in a manner similar to that during the last glaciation, suggesting that suborbital-scale climatic variations may be a common feature of the climate system during glacial periods of the Pleistocene. The last interglacial soil (S1) is composed of three individual soils and tow thin intervening loess horizons in both of the sections. Short-term variations in grain size are not prominent within the soil complex, implying the absence of strong millennial-scale climatic oscillations during the last interglaciation in northern China.
机译：研究了黄土高原西北部的新庄苑和李家园黄土剖面，直至古土壤单元S2，这可能是在海洋氧同位素阶段7形成的，大约200,000年BP。S2以上的黄土-土壤层的厚度约为63米在新庄苑和李家园43 m。 2 cm的样本间距可得出最后和倒数第二个冰川黄土单元（L1和L2）的平均沉积分辨率为50-80年，而最后一个冰川间土壤单元（S1）的平均沉积分辨率为200年，因此使我们能够重建高分辨率最近两个冰期至冰期之间的气候变化。这两部分的粒度记录被认为是中国北方季风-沙漠系统变化的代表。结果表明，在倒数第二次冰期期间，千年时间尺度上频繁发生大幅度的气候振荡，类似于上一次冰期，这表明亚轨道规模的气候变化可能是冰期冰期气候系统的共同特征。更新世。最后的冰间土壤（S1）由三个单独的土壤组成，并且在这两个部分中拖曳着薄薄的中间黄土层。在土壤复合物中，颗粒大小的短期变化并不明显，这意味着在中国北方的最后一次冰期期间，没有千年强尺度的气候振荡。

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