Magnetostratigraphy and Palaeolatitudes of Hole Kl in Lop Nur, Xinjiang
Wang Mili Huang Xinggen Liu Chenglin Pu QingyuLi Qinghai Zhao ZhenhongInstitute of Mineral Deposits, Chinese Academy of Geological Sciences, Beijing, 100037 No. 2 Hydrogeological Party, Changji, Xinjiang, 831000
From satellite images, it may be found that hole K1 is located on the northern margin of the Lop Nur "helix" structure, at 90. 5°E and 40. 3°N, with an elevation of 780 m above sea level. It is the only hole that has been studied systematically in the Lop Nur region at present. The mag-netostratigraphic study indicates that by choosing the hole depth of 61-62 m as the boundary, the interval above the depth belongs to the Brunhes normal polarity zone (Br) , the interval below the depth belongs to the Matuyama reversed polarity zone (Ma) , and the normal palrity migration at depths of 97 - 100 m on the hole bottom should belong to the Cobb Mountains polarity event. According to the Cande - Kent geomagnetic polarity time scale, the age of the strata on the hole bottom is 1. 20 Ma, assigned to the middle part of the early Pleistocene. The middle Pleistocene, late Pleistocene and Holocene strata are 50 m, about 10m and 5 m thick, respectively.Calculation of palaeomagnetic data shows that the palaeolatitude of hole Kl of Lop Nur is 34. 1°N. And, according to the calculation of palaeomagnetic data from the Kuche and Qaqa sections, their palaeolatitudes are 26. 7°N and 20. 0 °N respectively. In comparison with the present latitude, their positions have all migrated northwards. This feature is closely related to the com-pressional collision of the Indian and Eurasian plates and the sinistral strike-slip movement of the Altun fault- on the southern margin of the Tarim basin.
【CateGory Index】： P539.3