学术
西藏当雄-羊八井盆地的第四纪地质与断裂活动研究
吴中海[1] 赵希涛[2] 吴珍汉[1] 江万[1] 胡道功[1]
[1]中国地质科学院地质力学研究所,北京100081 [2]中国科学院地质与地球物理研究所,北京100029
摘 要:
在当雄-羊八井盆地进行的详细地质填图工作表明．该盆地中堆积了上新世或早更新世以来多套不同成因的沉积物。其中最显著的是形成于约700～500kaB．P．、250～125kaB．P．和75～12kaB．P．等三个阶段的冰川和冰水沉积物，它们指示念青唐古拉山地区在中更新世以来曾有过三次冰期。对念青唐古拉山东南麓断裂带的研究表明。该断裂带包含了三条次级断层带，它们具有不断向盆地内部迁移和多期活动的特点，其中中更新世以来的几次重要活动分别发生在700～500kaB．P．、350～220kaB．P．、140kaB．P．和70～50kaB．P．。断裂带错动中更新世以来地层所形成的断层崖高度随着地层时代的变新发生系统地减小，指示该断裂的垂直活动速率介于0．4mm／a～2mm／a之间，其中第四纪期间的长期的平均垂直活动速率为1．1±0．3mm／a，而全新世期间的垂直活动速率为1．4±0．6mm／a。[著者文摘]
文章出处:
《地质力学学报》-2006年12卷3期 -305-316页
栏目信息:
文献标识码:
A
文章编号:
1006-6616（2006）03-0305-12
QUATERNARY GEOLOGY AND FAULTING IN THE DAMXUNGYANGBAJAIN BASIN, SOUTHERN TIBET
WU Zhong-hai , ZHAO Xi-tao, WU Zhen-han , JIANG Wan , HU Dao-gong （ 1. institute of C.eomeehanics, Chinese Academy of Geological Sciences, Beijing 100081 ; 2. Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029）
Abstract:
Detailed geological mapping conducted in the Damxung-Yangbajain basin shows that several sequences of deposits of different origins have been accumulated since the Pliocene or early Pleistocene, of which the most prominent are glacial and fluvioglacial deposits formed in the about 700 ～ 500, 250 ～ 125 and 75 ～ 12 ka intervals, indicating that three glacial periods have occurred in the NyainqSntanglha Mountains since the middle Pleistocene. Study of a fauh zone at the southeastern piedmont of the NyainqSntanglha Mountains indicates that this fault zone consists of three secondary fauh zones, which have the features continuous migration toward the interior of the basin and repeated activities. The several important faultings since the middle Pleistocene occurred about 700 ～ 500, 350 ～ 220, 140 or so and 70 ～ 50 ka. The heights of fault scarps which have offset the sediments formed since the middle Pleistocene decrease with younging stratigraphic ages, suggesting that the rates of vertical movement of the fault change between 0.4 and 2 mm/a, of which the average rate of long-term vertical movement during the Quaternary is 1.1 ± 0.3 ram/a, while that during the Holocene is 1.4 ± 0.6 mm/a.[著者文摘]
Key words:
Qinghai-Tibet Plateau ; Nyainqantanglha Mountains; Quaternary glaciation ; N-S-trending graben ; active faults
基金资助:
自然科学基金（40501006）,中国地质调查局“西藏1：25万当雄幅区域地质调查”（编号DKD9901001）和“青藏铁路沿线活动断层词查与地应力测量”（编号1212010340302）项目资助.
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