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Multi-Layered Low-Angle Ductile Detachment System in Dabie-Sulu UHPM and HPM Belts, china

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Journal of earth Science 1999年第3期18卷 187-193页

作者： Suo Shutian Zhong Zengqiu(faculty of earth sciences, china university of geosciences, {4. 4.0074. faculty of earth sciences China University of Geosciences Wuhan 430074

The present-day observed crustal-scale tectonic style of ultrahigh-pressure metamorphic (UH-PM) and high-pressure metamorphic (HPM ) belts in the Dabie-Sulu region was dominantly formedby extensional processes, postdating the Triassic collision between the Sino-Korean and Yangtze cratons. The extensional structures overprinting the previous structures related to contraction that produced the thickened continental crust of the UHPM and HPM belts, in particular display the typical features of a Cordilleran-type metamorphic core complex, in which at least four regionalscale, low-angle ductile shear zones that constitute a detachment system, are recognized in the Dabie region. In the Sulu region, the extensionaI structures show in the form of small-scale domes or a regional-scale SE-dipping pseudo-monocline. The geometry and the kinematics of tbe detachment zones are briefly described and their significance for the exhumation of UHPM and HPM rocks is discussed. It is iniliated that the subhorizontal crustal-scale extensional flow in the middle-lower crust, under amphibolite- to greenschist-facies conditions, was an important tectonothermal process at 200- 170 Ma and the exhumation or the UHPM and HPM rocks was achieved at least in part along multi-layered detachment zones. The regional detachment system has been the main factor enabling UHPM and HPM rocks to be brought from middle-lower crustal levels to middle-upper crustal levels.

关键词： detachment system UHPM and HPM rocks exhumation ductile shear zone,Dabie massif Dabie-Sulu region

Depositional Model and Tectonic Evolution of Tertiary Transform-Extensional Basins in Northeast china: Case Study on Yitong and Damintun Grabens

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Journal of earth Science 1997年第1期16卷 62-67页

作者：  Xie Xinong Huang Yanqiu faculty of earth Resources, china university of geosciences, wuhan 4.0074.Lu Zongshengfaculty of earth sciences, china university of geosciences, wuhan 4.0074.

? The formation and evolution of the Tertiary transformextensional basins in Northeast china are controlled by extensional and strikeslidding combinational processes because the giant strikeslip fault system, TanchengLujiang fault, cut through the basement or margin. Two kinds of structural styles have been identified in Northeast china: Yitong and Damintun styles. The former shows a clear asymmetry, in which sediments came mainly from two lateral sides and thick filling sediments were adjacent to the main strikeslip fault. The latter shows symmetry filling, in which sediments came from the long axial ends in addition to from two lateral sides. The tectonic evolution of Tertiary transformextensional basins in Northeast china underwent three stages: Eocene extensional, Oligocene transformextensional and Neogene transpressional stages.

关键词： transformextensional basin Tertiary Yitong graben Xialiaohe basin.

Distributions of fatty acids in a stalagmite related to paleoclimate change at Qingjiang in Hubei,southern china

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Science china earth sciences 2005年第9期48卷 1463-1469页

作者： XIE Shucheng1,HUANG Junhua1,WANG Hongmei2,YI Yi1,HU Chaoyong1, CAI Yanjun3 & CHENG Hai4.1. faculty of earth Science,china university of {4.,wuhan 4.0074.china 2. School of Environmental Studies,china university of {4.,wuhan 4.0074.china 3. SKLLQG,Institute of earth Environment,Chinese Academy of {13.,Xi’an 710075,china 4. Department of Geology and Geophysics,university of Minnesota,MN554.5,USA faculty of earth Science China University of Geosciences Wuhan China School of Environmental Studies China University of Geosciences Wuhan China SKLLQG Institute of Earth Environment Chinese Academy of Sciences Xi’an China Department of Geology and Geophysics University of Minnesota USA

Fatty acids extracted from a subtropical stalagmite at Qingjiang in Southern china’s Hubei Province were analysed using gas chromatography-mass spectrometry. These n-alkanoic acids range from C14.to C26 in carbon number, maximizing at C16, with a second dominance at C22. In contrast to the stalagmite analysed, the overlying soils are characterized by the dominance of heavy-molecular-weight homologues (>C20). The n-fatty acids in the stalagmite were proposed to be contributed by both the soil ecosystems and the microbes harboring in the percolating water and the cave. The ratios of unsaturated to saturated n-fatty acids (C16:1i/C16:0, C18:1/C18:0) appear to show trends comparable with the oxygen isotope records of the stalagmite carbonate, with enhanced values associated with the cold episode such as Heinrich event 1. This paleoclimate-dependent record of the n-fatty acids might reflect microbial changes in physiology and activity in response to the temperature. This record shows somewhat difference from the previous paleoclimate signal extracted from n-alkanols and n-alkan-2-ones of the same stalagmite. The acid record fails to document the well-known Younger Dryas event which was effectively shown by the latter two biomarkers derived from soil ecosystems. This discrepancy might result from the changing biogeochemical impact on different lipid fractions as well as the varied organism populations in different ecosystems.

关键词： biomarker, ecosystem, microbe, speleothem, paleoclimate, Quaternary.

^(4.)Ar-^(39)Ar and U-Pb ages of metadiorite from the East Kunlun Orogenic Belt: Evidence for Early-Paleozoic magmatic zone and excess argon in amphibole minerals

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Chinese Science Bulletin 2001年第4期46卷 330-333页

作者： CHEN Nengsong, SUN Min, ZHANG Kexin & ZHU Yunhaifaculty of earth sciences, china university of geosciences, {4. 4.0074. china Department of earth sciences, The university of Hong Kong, Hong Kong SAR, china faculty of earth sciences China University of Geosciences Wuhan China Department of earth sciences The University of Hong Kong Hong Kong SAR China

Single-grain zircon U-Pb and amphibole 4.Ar-39Ar dating have been conducted on a deformed and metamorphosed diorite in the East Kunlun Orogenic Belt, which intruded into the middle Proterozoic Kuhai Group exposed in the south of Xiangride region, Dulan County, NW Qinghai Province. The zircon gives a concordant U-Pb age of (4.6.5±9.1) Ma. The amphibole yields Ar plateau age of (4.8.0±1.2) Ma and an isochronal age of (4.8.9±5.6) Ma. Age results of both stepwise released Ar and conventional K-Ar analysis are remarkably higher than that of zircon U-Pb, suggesting that the amphibole contains excess argon and the amphibole plateau age cannot be taken as the timing of metamorphism or deformation. The zircon age is interpreted to be crystallization age of the diorite pluton, which suggests that an Early-Paleozoic magmatic zone indeed existed in the East Kunlun Orogenic Belt stretching along the region south to the Golmud, Normuhong and Xiangride.

关键词： East Kunlun Orogenic Belt metadiorite geochronology excess argon.

Principle and Technique of Calculating Seismic Velocities from Lattice Preferred Orientation (LPO) Data of Minerals

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Journal of earth Science 1998年第2期17卷 60-66页

作者： Guan Xiaoping Department of Applied Geophysics, china university of geosciences, wuhan 4.0074.Jin Shuyan faculty of earth {4., china university of geosciences, wuhan 4.0074

Deducing seismic velocity anisotropy from LPO (lattice preferred orientation) data of deformed rock samples, a significant link between geology and seismology in geoscience researches, has extensive and promising application. In this paper, the principle and programming technique are highlighted to illustrate the comprehensive automatization procedure. In computer algorithm, two aspects of the programs commonly used in the world are improved: (1) the addition of a pre processing subroutine makes the straightforward calculation realizable from universal stage readings to geographic azimuths and thus to solution of all crystal axes, even for non orthorhombic a and c axes in monoclinic systems. (2) the simplification and perfection of programming can be implemented in the light of Visual Basic (VB) resource. The algorithm has been verified with results from practical data of omphacite samples.

关键词： omphacite fabric seismic velocity anisotropy contouring.

Carbon isotope composition of the Lower Triassic marine carbonates, Lower Yangtze Region, South china

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Science china earth sciences 2006年第3期49卷 225-241页

作者： ZUO Jingxun1,2, TONG Jinnan3, QIU Haiou4.& ZHAO Laishi3 1. Nanjing Institute of Geology and Palaeontology, Chinese Academy of sciences, Nanjing 210008, china 2. Henan Institute of Geological Survey, Zhengzhou 4.0007, china 3. State Key Laboratory of Geological Processes and Mineral Resources at china university of geosciences, {4. 4.0074. china 4. faculty of Material sciences and Chemical Engineering, china university of geosciences, {4. 4.0074. china Nanjing Institute of Geology and Palaeontology Chinese Academy of Sciences Nanjing China Henan Institute of Geological Survey Zhengzhou China State Key Laboratory of Geological Processes and Mineral Resources at china university of geosciences Wuhan China faculty of Material sciences and Chemical Engineering China University of Geosciences Wuhan China

Studies on three Lower Triassic sections located on the shallow water platform, the deep water slope and in the deep water basin in the Lower Yangtze Region, South china, show the similar trend of carbon isotope evolution. Biostratigraphic correlations among the Lower Triassic sections on the basis of standard conodont zones indicate that three negative shifts occurred in the Griesbachian, the Smithian and the late Spathian stages respectively, and one distinctly positive shift occurred in the early Spathian stage. Trend of carbon isotope evolution of the Lower Triassic reflects some significant changes in the global carbon cycle. Moreover, δ 13. background values are intensively controlled by palaeogeographic environment. In general, δ 13. values from deep-water slope carbonates are lighter than those from carbonate platform and heavier than those from deep-water basin carbonates. The positive carbon isotope excursion may be induced by a significant amount of organic carbon burial in marine sediments and increase in primary productivity. The large negative carbon isotope excursions during the Early Triassic in Lower Yangtze Region are interpreted to relate to volcano eruptions based on tuffaceous claystone interlayers observed near the Permian-Triassic boundary, the Induan- Olenekian boundary and the Lower Triassic-Middle Triassic boundary.

关键词： Lower Triassic, carbon isotope compositions, palaeogeography, volcanic eruptions, Lower Yangtze Region.

Magnetic Structure of Archean Kongling Group from Yangtze Craton,South china

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Journal of earth Science 1998年第2期17卷 52-59页

作者： Liu Qingsheng Department of Applied Geophysics, china university of geosciences, wuhan 4.0074.Gao Shan faculty of earth {4., china university of geosciences, wuhan 4.0074.Xu Qidong faculty of earth Resources, china university of geosciences, W

Densities and various magnetic parameters (susceptibility, saturation magnetization, saturation isothermal remanent magnetization and intrinsic coercivity) were measured for 20 representative rock samples of different lithologies from the Archean Kongling amphibolite to granulite facies terrain of the Yangtze craton. Metasedimentary rocks and tonalitic trondhjemitic granodioritic granitic (TTGG) gneisses show that values of susceptibility κ and saturation isothermal remanent magnetization SIRM are higher than those of amphibolites and gabbros. The felsic gneisses have averages of κ =(1 163±375)×10 -6 SI, SIRM =(18.23±8.38) A/m and R 1=0.083 3± 0.005 7 and the metasedimentary rocks κ =(1 236±823)×10 -6 SI, SIRM =(20.70±10.91) A/m and R I=0.071 4.0.025 2. In contrast, mafic rocks have average κ =(764.316)×10 -6 SI, SIRM = (10.4.±3.94.A/m and R 1=0.036±0.009 4. and are dominated by a mixed paramagnetic and ferrimagnetic behavior. Thermal magnetic analyses indicate that magnetite and maghemite of low coercivity are the major carriers of remanent magnetism in the metaclastic sedimentary rocks and TTGG gneisses. The amphibolite and gabbro contain minor amounts of magnetite and pyrrhotite. Magnetism of metaclastic sedimentary rocks and TTGG gneisses is highly heterogeneous; variation coefficients of κ and SIRM are as high as 67 % and 53 % for the former and 32 % and 4. % for the latter. Mineral compositions suggest that biotite may be responsible for the higher magnetism of the metasedimentary rocks. The highest variations in κ, SIRM and R I exhibited by metasedimentary rocks can also be interpreted by their largest absolute variations in biotite mass fraction relative to mafic rocks and felsic gneisses. The average ratio ( Q ) of natural remanent magnetization to induced magnetization of felsic gneisses and metasediments is 0.4. . Ratios ( REM ) of natural remanent to sat

关键词： magnetic structure amphibolite granulite facies Yangtze craton.

Petrology of Igneous Rocks in Northern Golpayegan,Iran

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Journal of earth Science 1998年第1期17卷 24-29页

作者： Mohammad Ebrahimi Mohammad Reza HosseinNejad faculty of earth sciences, china university of geosciences, {4. 4.0074

A preliminary study on petrological features of igneous rocks was carried out in northern Golpayegan, Iran, in an area of about 60 km 2. According to the limited available data the sequence of the magma activity could be considered as follows: (1) Precambrian (?) granite connected with a continental continental collision event, (2) Precambrian (?) syenite emplaced at a post continental continental collision environment, (3) Cretaceous volcanic rocks generated by a local extensional system at an active continental margin and (4. Cenozoic doleritic veins generated in a post collision event. Geochemical characteristics of the granitic intrusion show that it originated from crust and belongs to S type one. Syenitic body consists of syenitic affinities ranging from alkali syenite to syenodiorite. These rocks were cut by Cenozoic doleritic veins, which consist of dolerite and olivine dolerite. Both syenite and dolerite are thought to originate from upper mantle but their ages are different. Cretaceous volcanic rocks include basalt, andesite, trachyandesite, trachyte and tuff. They are compositionally alkaline and erupted in a shallow graben basin. Their eruption has been in connection with deep seated faults, which brought out the magma from the source.

关键词： S type granite volcanic rocks syenite dolerite Golpayegan Iran.

Silurian Seismites in Hanxia,Yumen,North Qilian Mountains,and Their Tectonic Significance

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Acta Geologica Sinica(English Edition) 2001年第4期75卷 385-390页

作者： DU Yuansheng, GONG Shuyun, HAN Xin, WANG Jiasheng, GU Songzhuand LIN Wenjiao faculty of earth sciences, china university of geosciences, {4. 4.0074. Hubei china Univ Geosci Fac Earth Sci Wuhan 430074 Peoples R China

The Caledonian orogenic belt of the North Qilian Mountains is an intensely active structure belt. In the process of the Late Caledonian syn-orogeny, the North Qilian-Hexi Corridor area was situated on the tectonic background of a syn-orogenic basin. In response to the orogenic process of the North Qilian Mountains, typical earthquake event deposits—seismites of the Silurian were widely distributed around Hanxia of Yumen City, the Liyuan River of Sunan County and Biandukou of Minle County. In the Hanxia area, where seismites are typically developed, clastic deposits of tidal-flat facies are the background deposits of the Hanxia Formation. The earthquake event deposits are characterized by sandy mudstone veins, synsedimentary microfractures, micro-corrugated laminations and earthquake breccias, which in turn constitute complex seismites, featuring seismic corrugation, shattering and liquefied sandy mudstone veins, auto-clastic breccias and intraclastic parabreccias. The seismites and tidal flat deposits formed typical sequences of earthquake event deposits.

关键词： Gansu Province North Qilian orogenic belt Caledonian Stage Silurian seismites earthquake event deposits