LOESS STRATIGRAPHY IN CENTRAL CHINA
LOESS STRATIGRAPHY IN CENTRAL CHINA
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DOI：
10.1016/0031-0182(89)90143-0
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发表时间：
1989-08-15
影响因子：
3
通讯作者：
AN, ZS
中科院分区：
文献类型：
--
作者：
KUKLA, G;AN, ZS
中国中部的黄土序列提供了过去250万年气候变化的详细记录。在此期间，中国至少发生了44次从冰期到间冰期的重大转变。持续4万多年的黄土长期沉积发生了11次，其中只有4次发生在Brunhes Chron.2.4和0.5 Ma之间的气候振荡频率比过去50万年增加。向凉爽和干燥气候的主要转变发生在大约2.4 Ma，1.2 Ma和0.5 Ma，而不太明显的转变是在1.65 Ma，0.8 Ma和0.2 Ma。最近四次地磁反转中的三次都记录在一个冰川存款中，其岩石地层位置已详细阐明。黄土和土壤的低场磁化率反映了超细磁铁矿的浓度，它与成土作用的程度有关，并可作为气候的代用指标。在过去的120万年里，磁铁矿的积累速度相当稳定，可以作为时间的衡量标准。本文对西峰和洛川两个相距160km的地区的磁化率记录进行了对比，并将其用于黄土高原非正式岩石地层单位的划分。
Loess sequences in central China provide a detailed record of climate changes during the last 2.5 million years. At least 44 major shifts from glacial to interglacial conditions occurred during this time in China. Prolonged loess deposition lasting more than 40 millennia occurred eleven times with only four of these intervals in Brunhes Chron. The climate oscillations took place with increased frequency between 2.4 and 0.5 Ma compared to the last half million years. Major shifts toward cooler and drier climates occurred at about 2.4 Ma, 1.2 Ma, and 0.5 Ma, while less pronounced shifts are dated to 1.65 Ma, 0.8 Ma and 0.2 Ma. Three of the last four reversals of the earth's magnetic field whose lithostratigraphic position has been detail, are recorded in a glacial deposit.The low field magnetic susceptibility of loess and soils which reflects the concentration of ultrafine magnetite is related to the degree of pedogenesis and serves as a proxy measure of climate. The accumulation rate of the magnetite was fairly constant throughout the last 1.2 million years and can serve as a measure of time. Susceptibility records from localities near Xifeng and Luochuan, located 160 km apart are compared and used to define informal lithostratigraphic units in the Loess Plateau of China.