新生代阿尔金断层中、东段右行走滑特征

RIGHT LATERAL CHARACTERISTICS OF THE MIDDLE EASTERN SEGMENT OF ALTUN FAULT IN CENOZOIC ERA

从柴达木、准噶尔、塔里木３个地块近４个古地磁样品中得出的古纬度数据表明，新生代阿尔金断层中、东段的右行走滑特征明显。白垩纪以来，新疆板块相对柴达木地块向北移动了０．６°－５．４°。据此将断裂两侧各地块复原到白垩纪末的位置，天山－北山地体与祁连山地体相联，柴达木地体成为塔里木地体的东延部分。

Palaeo-Latitude data obtained frora nearly one thousand paleomagnetic specimens sampled from the Qaidam, Djungar and Tarim berranes show that the right lateral characteristics of the middle-eastern segment of the Altun fault is clear.Since the late Mesozoic Era Xingjian plate (consisting of the Tarim massif and the Djiungar massif) has moved northward about 50-90km(0.5°-0.9°) with respect to the Qaidam massif.In the Cenozoic Era the latitudes of the Qaidam massif and the Djungar massif have changed many times, though in different scales (Table 2), and the Djungar massif located at the north-west side off the Altun fault has moved northward 0.6°-5.4° with respect to the Qaidam basin which is located at the south ea.t side of the fault (table 3). Since the Miocene Era the Tarim massif has moved northward about 1.1 relative to the Qaidam massif.In view of the right lateral characteristics along the Altun Fault and on the basis of the data ill latitude change (figure 2) the Tarim basin in the northwest side of the middle-eastern segment of the fault can be repositioned, to its location late Cretaceous. The Cenozoic crops in the Qaidam basin would be as their eastward continuation in the Tarim basin. In the meantime the Tianshan-Beishan Mis. and the Qilianshan Mis. would link together. This reconstruction of geographical positions is in occordance with the similarity of the geologic histories between the two basins during the Mesozoic and Cenozoic Eras and between the Tianshan-Beishan Mis. and Qilianshan Mis. during the Paleozoic Era.