李秋生2,,,
邓小娟1,
李井元4,
熊小松3,
卢占武2,
李文辉2,
王晓冉2,
吴庆宇2,
石金虎1
1. 中国地震局地球物理勘探中心, 郑州 450002
2. 自然资源部深地动力学重点实验室, 中国地质科学院地质研究所, 北京 100037
3. 中国地质科学院地球深部探测中心, 北京 100037
4. 中石化地球物理有限公司中南分公司, 湖南湘潭 411104
基金项目: 国家深地资源勘查开采重点专项（2016YFC0600302），国家自然科学基金项目（41574092，41674140）和自然资源部深地动力学重点实验室自主研究课题（J1901-3）联合资助
详细信息
作者简介: 酆少英, 男, 1967年生, 河南南阳人, 高级工程师, 长期从事地壳深浅结构的反射地震探测与研究.E-mail:fsy.ny@163.com
通讯作者: 李秋生, 男, 1958年生, 河北邢台人, 研究员, 博导, 长期从事大陆岩石圈结构探测与地球动力学研究.E-mail:lqs1958@163.com
中图分类号: P313;P315收稿日期:2019-09-18
修回日期:2020-01-17
上线日期:2020-03-05
Crustal skeleton structure of the lateral collision zone of the Qinghai-Tibet Plateau revealed by large-shot set of deep-reflecting profiling
FENG ShaoYing1,,LI QiuSheng2,,,
DENG XiaoJuan1,
LI JingYuan4,
XIONG XiaoSong3,
LU ZhanWu2,
LI WenHui2,
WANG XiaoRan2,
WU QingYu2,
SHI JinHu1
1. Geophysical Exploration Center, China Earthquake Administration, Zhengzhou 450002, China
2. Key Laboratory of Deep-Earth Dynamics of Ministry of Natural Resources, Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China
3. Deep Earth Exploration Center, Chinese Academy of Geological Sciences, Beijing 100037, China
4. Southcentral Branch of Sinopec Geophysical Co., Ltd, Hunan Xiangtan 411104, China
More Information
Corresponding author: LI QiuSheng,E-mail:lqs1958@163.com
MSC: P313;P315--> Received Date: 18 September 2019
Revised Date: 17 January 2020
Available Online: 05 March 2020
摘要
摘要:青藏高原东南缘处于印度板块与欧亚板块碰撞的侧翼，揭示该地区的岩石圈结构有助于完整理解青藏高原碰撞造山的动力学过程，对构建大陆碰撞成矿理论框架至为关键.本研究对横过青藏高原侧向碰撞带的一条深反射地震剖面的15个大炮资料，进行了针对性静校正、去噪等处理和单次叠加成像，结果剖面显示了侧向碰撞带岩石圈结构的骨架特征：（1）双程走时（TWT）8~10 s的强反射（Tc）将地壳分为上、下两层；Tc可能是大型滑脱构造的拆离面，其存在使上地壳的变形与下地壳解耦；（2）Moho间断面反射（Tm）为3~4个同相轴的窄带反射波组，横向不连续，与深大断裂交汇处被错断，但断距不大；（3）在兰坪—思茅地块下方TWT21 s和扬子克拉通西缘下方TWT22~24 s存在相向倾斜的反射波组（TL）；以Tc、Tm和TL构成的骨架结构，定性地描绘出剖面下方岩石圈地幔以汇聚为主、地壳块体以侧向滑移为主和上地壳为薄皮逆冲或滑脱的分层动力学模式.该岩石圈变形样式明显不同于以正向碰撞挤压、地壳缩短垂向增厚为主的"冈底斯模式".
关键词: 青藏高原侧向碰撞带/
深反射地震剖面/
大炮单次叠加剖面/
地壳结构骨架/
分层动力学模式
Abstract:The southeastern margin of the Qinghai-Tibet Plateau is located on the flank of the collision between India and Eurasian plate. Revealing the lithospheric structure in this area is helpful to understand the deep dynamic process of the collision orogeny and crucial to construct the theoretical framework of continental collision metallogenesis. In this study, 15 large-shots data of a deep reflection seismic profile across the lateral collision zone of the Qinghai-Tibet Plateau were processed by static correction, denoising and single coverage stack imaging. The results show that the skeleton characteristics of the lithospheric structure in the lateral collision zone are:(1) Strong reflection (Tc) appearing between TWT 8 to 10 s divides the crust into upper and lower layers; Tc may be a large scale detachment surface in the crust, which decouples the deformation of the upper crust from the lower crust; (2) Moho discontinuity reflection (Tm) is a narrow-band reflection wave with 3~4 coaxial axes, discontinuous lateral traceability, and recognizable offset at the position of regional faults across; (3) There are two reflection wave groups (TL) dipping opposite each other beneath the Lanping-Simao massif at TWT21 s and TWT22~24 s beneath the western margin of Yangtze craton. The crustal structure skeleton composed of Tc, Tm and TL outlines briefly the hierarchical dynamic model of lithospheric mantle convergence, crustal block lateral slip and upper crust thin-skinned thrust or slip under the section. This deformation pattern of the lithosphere is obviously different from the "Gangdise model", which is dominated by forward collision, crustal shortening and vertical thickening.
Key words:Lateral collision zone of Qinghai-Tibet Plateau/
Deep seismic reflection profile/
Single stack section of large-shot/
Crustal skeleton structure/
Hierarchical dynamics model
PDF全文下载地址:
http://www.geophy.cn/data/article/export-pdf?id=dqwlxb_15361
