浅谈新疆罗布泊地区第四纪下限

DISCUSSION OF THE LOWER LIMIT OF QUATERNARY IN LOP NUR, XINJIANG

罗布泊地区东部AK1孔地层根据岩石地层单元和古地磁、孢粉、氧化铁、易溶盐、14 C等测定结果 ,划分为全新统 (Q4 )、上更新统 (Q3 )、中更新统 (Q2 )、下更新统 (Q1)和上新统 (N2 )。在孔深 416 .90m处 ,岩石、构造、古地磁、气候、地球化学等标志均非常明显 ,结合现在新疆第四纪划分方案 ,我们认为宜将此界线作为罗布泊地区第四系下界。其位于凯纳事件稍下 ,年龄约 30

The stratigraphy of Hole AK1 in the East of Lop Nur is divided into five parts: Q 4,Q 3,Q 2,Q 1 and N 2. This division is upon the strength of the lithostratigraphy unit and the analgsis of paleomagnetism, sporo-pollen, Fe 3+ , solubesalt, 14 C ete. There is a dividing line at the deep of 416.90m. It has very apparent differences on the characteristice of lithostratigraphy, structure, paleomagnetism, geological clmate, geochemistry etc. Integrating the project of Quaternary stratigraphic division in Xinjiang, that dividing line is the lower limit of Quaternary system in Lop Nur. It is before Keana Event and its age is about 2 050 Ka.