塔里木盆地东北缘晚新生代钻孔岩心磁性地层年代学及其构造意义

塔里木盆地的高分辨率沉积记录对于理解青藏高原隆升、亚洲内陆干旱化乃至全球气候变化至关重要.建立可靠的地层年代标尺对于研究塔里木盆地晚新生代沉积环境演化、构造运动及古气候变化具有重要意义.本文对塔里木盆地东北缘库尔勒地区的两个全取心钻孔ZK3（深500 m）、ZK5（深300 m）进行详细的磁性地层学研究，结果表明，ZK3孔中更新统底界为54.8 m，下更新统底界为167.0 m，上新统底界为432.0 m，钻孔底部年龄约为6.2 Ma，属上中新统上部；ZK5孔中更新统底界为64.7 m，下更新统底界为241.5 m，钻孔底部年龄约为3.2 Ma，属上上新统.基于上述磁性地层年代标尺，通过沉积速率分析发现ZK3孔在3.0—3.6 Ma之间沉积速率明显增大，反映了塔里木盆地北部天山在此期间的快速隆升.通过东西部多个盆地地质剖面沉积速率的对比分析发现，这期构造活动在区域上具有准同期活动特征，在时代上与晚中新世以来青藏高原快速隆升的时代一致，可能与青藏高原的隆升扩展效应有关.

Magnetostratigraphic chronology of Late Cenozoic borehole sequences in the northeastern margin of the Tarim Basin and its tectonic significance

The high-resolution sedimentary records of the Tarim Basin (TRB) play a crucial role in understanding the uplift of the Tibetan Plateau, Asian drying as well as global climate changes. The establishment of reliable chronostratigraphic frameworks is very important to probe into sedimentary environments, tectonic movements and the paleoclimate evolution of the TRB sediments of the Late Cenozoic. In this study we present detailed rock magnetic and magnetostratigraphic investigations of the ZK3 and ZK5 borehole sequences from the Korla area of TRB. In the ZK3 borehole, the Mid/Lower Pleistocene boundary (0.78 Ma) is placed at 54.8 m depth, the Pliocene/Pleistocene boundary (2.58 Ma), at 167.0 m depth; and the Miocene/Pliocene boundary (5.33 Ma), at 432.0 m depth. The bottom of the ZK3 borehole is at around 6.2 Ma, belonging to the upper part of the Upper Miocene. In ZK5 borehole, the boundaries of the Mid/Lower Pleistocene and the Pliocene/Pleistocene are located at 64.7 m and 241.5 m, respectively. The bottom of the ZK5 borehole is at around 3.2 Ma, belonging to the Upper Pliocene. Age-depth-accumulation relationship of the ZK3 borehole sedimentary sequence indicates a period with relatively higher sediment accumulation rate during the period of 3.0-3.6 Ma, which suggests an episode of rapid tectonic uplift in the northern Tianshan Mountain. In terms of the comparison of sediment accumulation rates of different geological sections between eastern and western China sedimentary basins, we suggest that this tectonic movement has the character of quasi-synchronous activity in the region and shows synchronous changes with the rapid tectonic uplift of the Tibetan Plateau since the Late Miocene, which may be related to the tectonic uplift effect of the Tibetan Plateau.