Wang Xin, Wei Haitao, Taheri Mehdi, Khormali Farhad, Danukalova Guzel, Chen Fahu
Key Laboratory of Western China's Environmental Systems (Ministry of Education), College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, China.
Department of Soil Science, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan 49138-15739, Iran.
Sci Rep. 2016 Feb 3;6:20560. doi: 10.1038/srep20560.
Arid central Asia (ACA) is one of the most arid regions in the mid-latitudes and one of the main potential dust sources for the northern hemisphere. The lack of in situ early Pleistocene loess/dust records from ACA hinders our comprehensive understanding of the spatio-temporal record of aeolian loess accumulation and long term climatic changes in Asia as a whole. Here, we report the results of sedimentological, chronological and climatic studies of early Pleistocene loess-palaeosol sequences (LPS) from the northeastern Iranian Golestan Province (NIGP) in the western part of ACA. Our results reveal that: 1) Accumulation of loess on the NIGP commenced at ~2.4-1.8 Ma, making it the oldest loess known so far in western ACA; 2) the climate during the early Pleistocene in the NIGP was semi-arid, but wetter, warmer, and less windy than during the late Pleistocene and present interglacial; 3) orbital-scale palaeoclimatic changes in ACA during the early Pleistoceneare in-phase with those of monsoonal Asia, a relationship which was probably related to the growth and decay of northern hemisphere ice sheets.
干旱的中亚地区是中纬度地区最干旱的区域之一，也是北半球主要的潜在沙尘源之一。由于缺乏来自干旱中亚地区的早更新世黄土/沙尘原地记录，阻碍了我们全面了解整个亚洲风尘黄土堆积的时空记录以及长期气候变化。在此，我们报告了对位于干旱中亚西部地区的伊朗东北部戈勒斯坦省（NIGP）早更新世黄土-古土壤序列（LPS）进行沉积学、年代学和气候学研究的结果。我们的研究结果表明：1）NIGP地区的黄土堆积始于约240万至180万年前，这使其成为目前已知的干旱中亚西部地区最古老的黄土；2）NIGP地区早更新世的气候为半干旱，但比晚更新世和当前的间冰期更湿润、温暖且风更小；3）干旱中亚地区早更新世的轨道尺度古气候变化与亚洲季风区的变化同步，这种关系可能与北半球冰盖的消长有关。
