摘要
The geometry of the Dabie Mountains is manifested in terms of the distribution of petro-tectonic units in three dimensions. It is identified into three segments from east to west, four horizons in vertical profiles and eight petro- tectonic units from north to south. Three segments are the east, middle and west segments. Four horizons, from top to bottom, are two different meta-tectonic mélange in the uppermost part, underthrust basement and cover below them, and mantle at the bottom of the profiles. Eight petro-tectonic units from north to south are: (1) the hinterland basin, (2) the meta -flysch, (3) the ultramafic rock belt (UM) + Sujiahe eclogite belt (SH), (4) eclogite belt 2 (Ec2) with most eclogites of continental affinity, (5) eclogite belt 1 (Ecl1) with some eclogite of oceanic affinity, (6) the Dabie complex or underthrust basement of the Yangtze continent, (7) the Susong and Zhangbaling Groups or underthrust cover of the Yangtze continent and (8) the foreland belt. The (3), (4) and (5) units belong to meta-tectonic mélange. Some ultrahigh pressure metamorphic minerals such as coesite and micro-diamonds have been found in (3) and (4) units; a possible ultrahigh pressure mineral, clinozoisite aggregate pseudomorph after lawsonite, was found in unit (5). The three tectonic units are speculated to be coherent initially; the UM and SH units are suggested to be the root belt in the east, middle and west segments respectively. The kinematics of the Dabie orogen is divided into three stages: top-to-south thrusting during the eclogite-granulite facies metamorphism, top-to-north extension during the amphibolite metamorphic stage, and faults or shear bands of brittle deformation and greenschist facies metamorphism were formed in the post-orogenic stage since the Late Jurassic and the movement pictures of these faults is different from each other.
The geometry of the Dabie Mountains is manifested in terms of the distribution of petro-tectonic units in three dimensions. It is identified into three segments from east to west, four horizons in vertical profiles and eight petro- tectonic units from north to south. Three segments are the east, middle and west segments. Four horizons, from top to bottom, are two different meta-tectonic mélange in the uppermost part, underthrust basement and cover below them, and mantle at the bottom of the profiles. Eight petro-tectonic units from north to south are: (1) the hinterland basin, (2) the meta -flysch, (3) the ultramafic rock belt (UM) + Sujiahe eclogite belt (SH), (4) eclogite belt 2 (Ec2) with most eclogites of continental affinity, (5) eclogite belt 1 (Ecl1) with some eclogite of oceanic affinity, (6) the Dabie complex or underthrust basement of the Yangtze continent, (7) the Susong and Zhangbaling Groups or underthrust cover of the Yangtze continent and (8) the foreland belt. The (3), (4) and (5) units belong to meta-tectonic mélange. Some ultrahigh pressure metamorphic minerals such as coesite and micro-diamonds have been found in (3) and (4) units; a possible ultrahigh pressure mineral, clinozoisite aggregate pseudomorph after lawsonite, was found in unit (5). The three tectonic units are speculated to be coherent initially; the UM and SH units are suggested to be the root belt in the east, middle and west segments respectively. The kinematics of the Dabie orogen is divided into three stages: top-to-south thrusting during the eclogite-granulite facies metamorphism, top-to-north extension during the amphibolite metamorphic stage, and faults or shear bands of brittle deformation and greenschist facies metamorphism were formed in the post-orogenic stage since the Late Jurassic and the movement pictures of these faults is different from each other.
基金
financed by 973 Chinese National Key Project for Basic Research(2003CB716500)
the Scientific Investigation of Chinese Continental Scientific Drilling Project(2001 CCB00900)
National Natural Science Foundation of China(Grant No.40172079),Anhui Bureau of Geology and Mineral Resources
