摘要
羌塘盆地位于青藏高原核心区域,具有显著的断裂构造活动特征。本文基于高精度航空重磁数据,采用匹配滤波位场分离技术,获得了不同深度场源的重磁异常信息,再利用位场边缘识别方法,确定了断裂和岩体边界,最终厘定了不同构造层断裂的展布特征。结果表明:(1)金沙江缝合带南缘、中央隆起带北缘、中央隆起带南缘、班公湖-怒江缝合带北缘等基底深大断裂构成北羌塘、中央隆起和南羌塘等块体的深部边界;(2)中央隆起带发育冈玛错-双湖等深切断裂,与北羌塘坳陷内万安湖等断裂表现为中等规模断裂特征,而南羌塘仅发育帕度错-其香错等中浅层断裂;(3)近地表发育大量晚期的近南北向隐伏断裂,切割早期东西向构造,与高原伸展作用相关。基于上述结果可知:南北羌塘断裂体系差异显著,南羌塘以近东西向中浅层逆冲断裂为主,深部构造变形较弱,主要集中于中浅层;北羌塘中南部发育北北西向断裂,北部可能受块体深部边界影响渐变为东西向;隆起带内多为深切断裂,这些深切断裂控制着羌塘盆地基底形态和盖层的演化。
The Qiangtang Basin is located in the central region of the Qingzang(Xizang)Plateau and has remarkable characteristics oftectonic activities.Based on high-precision airborne gravity and magnetic data,this study uses matched-filtering potential fieldseparation technique to obtain the gravity and magnetic anomaly information of field sources at different depths.Then,by using the potential field edge-detection method,the boundaries of faults and rock masses are determined,and finally the distributioncharacteristics of faults in different structural layers are defined.The results show that:(1)The deep,large-scale basementfaults-such as those along the southern edge of the Jinsha River suture zone,the northern and southern edge of the Central Upliftzone,and the northern edge of the Bangong Lake-Nujiang suture zone-constitute the deep boundaries separating the northernQiangtang,Central Uplift,and southern Qiangtang blocks.(2)In the Central Uplift zone,major deep faults such as the GangmaCo-Shuanghu are well developed.In the northern Qiangtang,faults like Wan'an Lake exhibit medium-scale fault characteristics,while in the southern Qiangtang,only middle-to shallow-level faults such as Padu Co-Qixiang Co have developed.(3)A largenumber of late-stage,near-north-south concealed faults have developed near the surface,cutting the earlier east-west structures,which is related to the plateau extension.Based on the above results,it can be known that the fault systems in the northern andsouthern Qiangtang are significantly different.The southern Qiangtang is mainly characterized by east-west oriented thrust faults inthe middle and shallow layers,and the deep structural deformation is relatively weak.In contrast,the central and southern parts of thenorthern Qiangtang are dominated by northwest-oriented faults,while toward the north the strike of faults gradually change to east-west due to the influence of the deep boundary of the block.Numerous deep-seated faults in the uplift zone exert strong control overthe evolution of the basement morphology and overlying strata.The formation and evolution of the present fault system arecontrolled by the block-assembly process associated with the Tethyan region.
作者
魏岩岩
周道卿
曹宝宝
胡悦
赵睿
郑宇舟
胡夏炜
肖梦楚
WEI Yanyan;ZHOU Daoqing;CAO Baobao;HU Yue;ZHAO Rui;ZHENG Yuzhou;HU Xiawei;XIAO Mengchu(China Aero Geophysical Survey and Remote Sensing Center for Nature Resources,Beijing 100083,China;TechnologyInnovation Center of Airborne Geophysics Survey,MNR,Beijing 100083,China;State Key Laboratory of Geological Processesand Mineral Resources,Beijing 100083,China)
出处
《沉积与特提斯地质》
北大核心
2025年第4期819-832,共14页
Sedimentary Geology and Tethyan Geology
基金
自然资源部“航空地球物理与遥感地质重点实验室青年创新基金”(2023YFL03)
中国地质调查局“重点地区航空地球物理调查”(DD20230012)。
关键词
地球物理
重、磁特征
边界位场识别
断裂格架
羌塘盆地
geophysics
aeromagnetic and gravity anomalies
edge detection
fault framework
Qiangtang Basin
