Loess-soil sequence at Toshan (Northern Iran): Insights into late Pleistocene climate change
Loess-soil sequence at Toshan (Northern Iran): Insights into late Pleistocene climate change
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DOI：
10.1016/j.quaint.2015.04.028
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发表时间：
2016-04
影响因子：
2.2
通讯作者：
Stefan Vlaminck;M. Kehl;T. Lauer;A. Shahriari;Jafar Sharifi;E. Eckmeier;E. Lehndorff;F. Khormali;M. Frechen
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文献类型：
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作者：
Stefan Vlaminck;M. Kehl;T. Lauer;A. Shahriari;Jafar Sharifi;E. Eckmeier;E. Lehndorff;F. Khormali;M. Frechen
伊朗的古气候知识仍然有限。然而，深入了解伊朗第四纪气候变化的时间和动力学可能为改善全球古气候记录提供有价值的信息。托山的黄土-土壤序列提供了伊朗晚更新世气候动态的第一个高分辨率记录，并补充了迄今为止已知的内卡、Now Deh和Agh Band剖面，以建立里海东北部的土壤地层记录。低地。我们的光谱和粒度分析相结合，提出（一）在托山序列的土壤地层方案，（二）描述和估计土壤发育的程度选定的地层单位，（三）推断古气候信息，并提供（四）与以前的黄土-古土壤记录的伊朗北部的土壤地层假设的基础上的相关性。托山剖面有一个强烈发育的红棕色泥质古土壤层（Bt）和8个中等至弱发育的棕色古土壤层（Bw/Bwk），缺乏粘土插图特征。这些化石土壤的残留物被质地良好的黄土和具有黄土和矿物底土（CB/CBk）特征的土层分开，为同生土壤形成提供了证据。古土壤，黄土和同生蚀变沉积物的地层序列，覆盖了最后一个世纪。130 ka，提供了证据，经常性的气候变化以及波动之间的优势土壤形成或灰尘积累的水分制度的变化。Bt和Bw/Bwk层位的形成与相对潮湿和温暖的条件有关，可能与间冰期和间冰期气候相对应。
The knowledge of palaeoclimate in Iran is still limited. However, insight into the timing and the dynamics of Quaternary climate change in Iran might offer valuable information to improve the global palaeoclimate record. The loess-soil sequence of Toshan provides the first high-resolution record of late Pleistocene climate dynamics in Iran and complements the hitherto known sections at Neka, Now Deh and Agh Band to establish a pedostratigraphic record of the north-eastern Caspian Lowland. Our spectroscopic and grain-size analysis are combined to propose (i) a pedostratigraphical scheme for the sequence at Toshan, (ii) describe and estimate the degree of soil development of selected stratigraphical units, (iii) infer palaeoclimatic information, and provide (iv) a correlation with previous loess-palaeosol records of N-Iran as based on pedostratigraphic assumptions. The section at Toshan hosts a strongly developed reddish-brown argillic palaeosol (Bt) as well as eight moderately to weakly developed brownish palaeosol horizons lacking clay illuviation features (Bw/Bwk). These remnants of fossil soils are separated by finely textured loess and horizons that host characteristics of both loess and mineral subsoils (CB/CBk), giving evidence for syngenetic soil formation. The stratigraphical succession of palaeosols, loess and syngenetically altered sediments, covering the last ca. 130 ka, gives evidence for recurrent climate changes as well as fluctuations between dominance of soil formation or dust accumulation in relation to changes in moisture regime. The formation of Bt and Bw/Bwk-horizons is related to relatively humid and warm conditions likely corresponding with interglacial and interstadial climate.