一种新的地质地貌景观类型——西藏札达盆地古格地貌的特征与成因初探  

A new type of geological-geomorphological landscape: Discussion of the Guge forest geomorphological features and its origin in the Zanda basin, Ngari, Tibet, China.

作　　者：孟宪刚[1] 朱大岗[2] 邵兆刚[2] 杨朝斌[3] 韩建恩[2] 余佳[2] 孟庆伟[2] 

机构地区：[1]中国地震局地质研究所,北京100029 [2]中国地质科学院地质力学研究所,北京100081 [3]西藏国土资源厅,西藏拉萨850000

出　　处：《地质通报》2006年第1期295-301,共7页Geological Bulletin of China

基　　金：中国地质调查局国土资源调查项目<青藏高原第三纪重点古湖泊环境演变序列>(任务书编码:科2003007-02;工作项目编码:200313000066)资助。

摘　　要：札达盆地位于西藏西南边陲,构造上处于喜马拉雅断块挠起带头部内侧,呈NW—SE走向,长约1000km,宽约70km,总面积约40000km2,海拔约4500m。盆地中地层呈明显的二元结构特征。基底岩石为三叠纪—侏罗纪灰岩、砂岩和板岩,盖层为上新世—早更新世早期沉积的固结和半固结岩石,因受喜马拉雅断块挠起运动的影响,形成NW、NE和近EW、SN向等多组节理裂隙。晚新生代以来,盆地上升,在构造节理的主导下,穿越盆地的象泉河及其支流对岩石地层进行侵蚀、切割,在雨水的淋蚀、寒冻风化的剥蚀作用下,逐渐形成现今大小不同和形态奇特的半固结砂泥岩塔林地貌景观—古格地貌,这是中国地质地貌景观的一种新类型。Located in the Ngari area, southwestern Tibet, the NW-SE-trending Zanda basin, -1000 km long and -70 km wide with a total area of 40000 km^2 and an elevation of -4500 m above sea level, is tectonicaUy located at the inner side of the tilted head of the Himalayan block. The strata of the basin evidently have a binary structure. The basement rocks are Triassic-Jurassic limestone, sandstone and slate and the cover rocks are Pliocene-earliest Pleistocene consolidated and semi-consolidated rocks. Due to the influence of tilting of the Himalayan block, the NW, NE and nearly E-W and N-S sets of joints and fi＇actures are formed. During the Late Cenozoic, the basin was uplifted. Under the guidance of tectonic joints, the Xiangquan River and its distributaries traversing the basin eroded and dissected rocks and strata. Then leaching by rains and erosion by frost weathering gradually gave rise to the present semi-consolidated arenaceous-argillaceous rock tower forest landscape--Guge geomorphology, which has different sizes and grotesque shapes.

关 键 词：古格地貌 河湖相沉积 固结—半固结 喜马拉雅运动 节理 西藏札达盆地 

分 类 号：P931[天文地球—自然地理学]