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Late Caledonian Ductile Thrusting Deformation in the Central East Kunlun Belt, Qinghai, china and Its Significance: Evidence from Geochronology

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Acta Geologica Sinica(English Edition) 2003年第3期77卷 311-319页

作者： WANG Guocan, CHEN Nengsong, ZHU Yunhai and ZHANG Kexin faculty of earth sciences,{3., Wuhan, Hubei 43.074 E-mail: wgcan@*** Ren Xifei, Liu Ruixun and Xie Guanglian faculty of earth sciences China University of Geosciences Wuhan Hubei 430074

A high-angle ductile thrusting deformation with top-to-the-north movement penetratively developed in the Proterozoic-Early Paleozoic metamorphic rocks along the Central East Kunlun belt. The deformed rocks suffered epidote-amphibolite facies metamorphism. On the basis of our previous study, we present more data in this paper to further support that the ducdle thrust deformation occurred in the later Caledonian and more detailed information about the deformation. A zircon U-Pb concordant age of 446±2.2 Ma of a deformed granodiorite in the ductile thrust zone was obtained and can be interpreted as the lower limit of the deformation. A syntectonically crystallized and also strongly deformed hornblende Ar/ Ar dating gives an Ar/Ar plateau age of 426.5±3.8 Ma, which represents the deformation age. A strongly orientated muscovite gives an Ar/Ar plateau age of 408±1.6Ma, representing the cooling age after the peak temperature, constraining the upper limit of the ductile thrust deformation. This ductile thrust deformation can be interpreted as the result of the closing of the Central East Kunlun archipelago ocean. To the north, Ar/Ar plateau ages of 3.2.9±0.2 Ma and 3.6.8±0.8 Ma of muscovite in the deformed Xiaomiao Group represent the uplift cooling ages of deeper rocks after the thrusting movement. The original thrusting foliation has a low angle. A rotation model was put forward to explain the development of the foliation from the original low-angle to present high-angle dipping.

关键词： ductile thrust deformation geochronology Central East Kunlun Belt Qinghai china

Behavior Mechanism on Sulfide Solid-Liquid Interface and Its Application

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Journal of earth Science 1998年第3期17卷 42-43页

作者： Jia Jianye Pan Zhaolu faculty of earth sciences,{3., Wuhan 43.074

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关键词： surface mineralogy interface between sulfide and solution adsorption physical chemistry of interface treatment of sewage water heavy metal ion genesis of gold ore.

Stratigraphic Succession,Source-Rock Distribution and Paleoclimatic Zone in Meso-Cenozoic Basins,Eastern china

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Journal of earth Science 1997年第1期16卷 11-15页

作者： Lu Zongsheng Huang Qisheng faculty of earth sciences,{3., Wuhan 43.074 Li Sitianfaculty of earth Resources,{3., Wuhan 43.074

?The unequal spacetime distribution of the source rocks resulted from the mutual superimposition of the biota evolution, basin type, and paleoclimatic change. The basin type is the most important in controlling the distribution of source rocks. The effect of the paleoclimate on the source rocks varied with different basins. In the rift basin, the source rocks were accumulated in the humid, semihumid and semiarid climates; however, in the flexural basin, only in the humid and semihumid climates. The biota features may control, to a great extent, the distribution pattern and the sourcerock quality. The abundance of the terrestrial flora and lacustrine phytoplankton was essential for the generation of the Meso-Cenozoic source rocks on a large scale.

关键词： petroleum source rock paleoclimatic zone Meso-Cenozoic basin eastern china.

Location of Triassic Tectonic Suture Between Collided Sino-Korean and Yangtze Cratons in Dabie-Sulu Region, china

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Journal of earth Science 1999年第4期18卷 281-286页

作者： Suo Shutian Zhong Zengqiu You Zhendong(faculty of earth sciences,{3., Wuhan 43.074) faculty of earth sciences China University of GeosciencesWuhan 430074

The regional extent and spatial distribution of ultrahigh pressure metamorphic(UHPM) and high pressure metamorphic (HPM) rocks, and the geometrical relationships of various petrotectonic units in the Dabie-Sulu region indicate that the Triassic collisional suture line between the Sino-Korean and Yangtze cratons is situated at the northern margin of the Dabie massif, that is,along the Balifan-Mozitan-Xiaotian fault in the Dabie region, and possibly is linked to the Wulian-Yantai fault in the Sulu region to tbe east. The suture line has been strongly modified duriug and subsequent to UHPM aud HPM events.

关键词： UHPM and HPM belts suture line Dabie massif Dabie-Sulu region

Permian and Triassic Sequence Stratigraphy and Sea Level Changes of Eastern Yangtze Platform

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Journal of earth Science 1999年第2期18卷 71-79页

作者： Tong Jinnan Yin Hongfu Zhang Kexin faculty of earth sciences,{3., Wuhan 43.074

The Permian and marine Triassic of eastern Yangtze platform, situated in eastern china, involve 19 orthosequences lasting about 2.7 Ma on average, which can be combined into five orthosequence sets ranging from 8 Ma to 12.Ma. Affected by the regional Dongwu and Indosinian movements, the sequence stratigraphic pattern and sea level changes in the Permian and Triassic of this region are distinctive and obviously different from most other regions in the world, but typical in the broad eastern Tethys and its neighboring areas. In this region not only did the continuous marine Permian and Triassic boundary sequences cause the orthosequence crossing the boundary belonging to type Ⅱ sequence but also the mesosequence including these stratigraphic intervals had its basal boundary in the upper Longlinian (Artinskian) (ca. 278 Ma), that is, the traditional Carboniferous and Permian boundary, and its top boundary moved from the Permian and Triassic boundary upward into the Anisian of Middle Triassic.

关键词： Permian and Triassic sequence stratigraphy sea level change eastern Yangtze platform.

Characteristics of Bacillus cereus Spore Counts in Soils w ith Underlying Gold Mineralization in Northwestern Sichuan, china: Results from a Pilot Study

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Journal of china university of geosciences 2003年第1期14卷 8-15页

作者： Wang Hongmei Yang Fengqing Qiao Shengying faculty of earth sciences,{3., Wuhan 43.074 faculty of earth sciences China University of GeosciencesWuhan 430074

A pilot survey on a microbial mineral exploration method based on so il Bacillus cereus spore counts was carried out across three different gold mi ning regions, which vary in soil type, climate condition and geological setting in northwestern Sichuan, china. B horizon soils from these sites were analyzed for B. cereus spores, Au, Ag, Cu, Pb and Zn. The results show that the numbe rs of B. cereus spores generally increased in soils overlying gold mineraliz ation. Specifically, elevated spore counts were found in samples slightly offset from the outcrops of orebodies, whereas soils directly above the outcrops of or ebodies usually contained low spore counts. However, the background counts of B. cereus spores varied from place to place and were complicated by environmen tal and pedological factors, but the relative ratios of spore counts still were indicative of the underlying gold mineralization.

关键词： Bacillus cereus spores gold deposit soil china.

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Science china earth sciences 2004年第10期47卷 896-911页

作者： ZHANG Changhou1,2, WU Ganguo1,2, WANG Genhou2, ZHANG Weijie2 & SONG Honglin2 1. Key Laboratory of Lithospheric Tectonics and Lithoprobing Technology, china university of geosciences, Ministry of Education of china, Beijing 100083. china 2. School of {3. sciences and Mineral Resources, china university of geosciences, Beijing 100083. china 1. Key Laboratory of Lithospheric Tectonics and Lithoprobing Technology China University of Geosciences Ministry of Education of China 100083 Beijing China 2. School of earth sciences and Mineral Resources China University of Geosciences 100083 Beijing China

The northwest trending tectonic belt in the middle part of the Mesozoic intraplate Yanshan Orogenic Belt, northeast Hebei Province, is composed of thrusts, extensional faults, strike-slip faults and syntectonic sedimentations as well. The northeastward basement-involved major thrusting deformation occurred between 174Ma and 168MaBP and was followed by an intrusion of the granitic plutonic rocks. As a part of the post-thrusting extensional deformations a northwest extending volcano-sedimentation system of Late Jurassic and Early Cretaceous formed in the southwest side of the belt. These volcano-sedimentary sequences are divided into Tuchengzi Formation, Zhangjiakou Formation, Yixian Formation and Jiufotang Formation re- spectively. They are characterized by southeastward migration as a result of the increasing down-dip slip displacement along the major extensional fault toward the southeast of the belt. The provenance area of the Jiufotang Formation north to it experienced southwestward thrusting during and after its later sedimentation. The thrusting in this stage resulted in the formation of an asymmetric footwall syncline with vergence to SW in the Jiufotang Formation in the NE side of the basin. Finally a dextral strike-slip deformation occurred along the NW tectonic belt. The striking tectono-geomorphological features and present seismic activities along this belt indicate that it has been being active since Cenozoic era and is still in the active state at present. This northwest extending tectonic belt was following the same direction and location as the existing fault systems within the basement as revealed by former geological and geophysical studies. So it is reasonable to infer the Mesozoic deformation along this belt to be a result of reactivation of the basement structures in a favorable tectonic stress field. The reactivation of basement struc- tures might be taken as one of the mechanisms of intraplate deformation and orogeny.

关键词： Yanshan Orogenic Belt, northwest extending tectonic complex, thrust system, geochronology.

High-Field-Strength Elements in Mafic Volcanics from North china Craton: Implications for Archean-Proterozoic Boundary and Source Composition

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Journal of earth Science 1998年第2期17卷 17-23页

作者： Liu Yongsheng Gao Shan Luo Tingchuan faculty of earth sciences,{3., Wuhan 43.074

Archean to Cenozoic mafic volcanic rocks from the North china craton are studied. They show Archean Proterozoic (Ar Pt) boundary and geochemical anomalies in Cenozoic basalts. Proterozoic mafic volcanics are enriched in most of the high field strength elements (HFSE) compared with Archean ones. Nb, Ta and Th show a distinct sequence of incompatibility in Archean and Proterozoic. The Cenozoic basalts are enriched in HFSE and Ni and their REEs are strongly differentiated with positive Eu anomalies ( δ (Eu)=1.14). The Ar Pt boundary could be related to change in oxygen fugacity and requires an increasing importance of enriched mantle source. The geochemistry of Cenozoic basalts implies a mantle source similar to OIB. Residuum from subducting partial melting of old basaltic oceanic crust and continental crust is likely to contribute to the formation of the enriched mantle.

关键词： mafic volcanic rocks high field strength element Archean Proterozoic boundary enriched mantle.

Relic UHP Structures in Dabie-Sulu Region, china: Structural Expression and Geodynamic Significance

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Journal of earth Science 2000年第3期19卷 40-46页

作者： Suo Shutian Zhong Zengqiu You Zhendong Zhou Hanwen faculty of earth sciences,{3., Wuhan 43.074, china

The present day observed tectonic framework of ultrahigh pressure (UHP) metamorphic belt in the Dabie Sulu region was dominantly formed by an extensional process at 200-170 Ma, under amphibolite facies conditions, following the Triassic collision between the Sino Korean and Yangtze cratons. UHP relic structures, including massive eclogites with a weak foliation, UHP shear zones and A type folds, that are preserved in less retrograde metamorphism and deformation overprinted eclogite lenses can be recognized using the tectonic analysis. Examples are drawn from the Chengmagang area and Hejiawan area, Hubei; Bixiling area, Anhui, and Donghai area, northern Jiangsu. A speculative kinematic model is proposed for the collision between the cratons based on the UHP relic structures studied, in combination with the data of petrography, geochronology and P T path of UHP metamorphic rocks in the studied region which were reported in literature. It is stressed that only the early UHP relic structures, particularly, regionally consistent foliation and stretching lineations, record and reflect the formation of the UHP metamorphic rocks, and the relative dynamic and kinematic process related to the Triassic NNE directed oblique collision between the Sino Korean and Yangtze cratons.

关键词： UHP relic structure extensional process compressional regime stretching lineation Dabie Sulu region.