摘要
秦岭勉略带是中国大陆主体拼合的主要结合带和秦岭造山带的基本组成部分 ,康县 -高川段为其重要地段 ,研究程度较高 ,但对其现今结构与岩片性质目前仍存有争论。通过对这两个最基本问题的研究 ,认为其现今结构总体为以向南运动为主的双重逆冲推覆构造 ,南、北边界分别复合了以陡立的荷叶坝断裂、状元碑断裂为主断裂的两个正花状构造 ,缝合线南、北两侧分别与扬子板块和秦岭微板块为邻。其内部物质组成 ,按大地构造属性、地球化学特征及时代可分为七大岩片组 ,即基底岩片组 ,扬子北缘岩片组 ,洋壳岩片组 ,洋岛岩片组 ,岛弧岩片组 (含弧间裂陷组 ) ,碰撞构造沉积混杂岩片组和秦岭微板块南缘岩片组。各岩片组由多个空间上被断裂或基质分割的岩片或岩块实体组成。这些岩片性质的厘定对全面认识勉略洋盆结构起关键作用 ,其现今空间结构的形成又与该构造带碰撞过程密切相关。基于这两个基本点 ,提出了一个系统的构造演化模型。
The Mianxian Lueyang suture zone from Kangxian to Gaochuan is a very important tectonic belt formed during main stage of collision between the North China Plate and South China Plate and a basic component of the Qinling Orogenic belts. However, the slabs' property and the current architexture of the suture zone is in debate. It is considered that current architexture of the segment is a southward duplex thrust in the main part superimposed by two positive flower type structures whose main faults are steep Heyeba fault and Zhuangyuanbei fault at the south and north boundary, respectively. Seven slab groups have been distinguished according to tectonic property, geochemistry and geological era, including basement slabs, slab group belong to the north of the Yangtze Plate, oceanic crust slabs, oceanic island slabs, arc island slabs, tecto sedimentary mélange slabs related to collision and slabs belong to the south part of the Qinling micro plate. Every slab group can be subdivide into several slabs or blocks being disparted by faults in space. These slabs are important to recognize the architexture of the Mianxian Lueyang small ocean and their current spatial sites are key to study the suture zone and collision process between the two plates. A tectonic evolution model has also be put forward.
出处
《华南地质与矿产》
CAS
2001年第3期1-8,共8页
Geology and Mineral Resources of South China
基金
国家自然科学基金重点项目 ( 4 9732 0 80 )
青年基金项目 ( 4 0 0 0 2 0 15 )
