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Restoration of eroded stratal thickness in key periods of tectonic change in a multi-stage superimposed Tarim Basin in china

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Journal of Palaeogeography 2012年第2期1卷 149-171页

作者： Liu Hao1, Wang Yingmin2.1. School of Marine Sciences, china university of geosciences (beijing),{2., china 2. School of geosciences, china university of Petroleum (beijing), beijing 102.49, china School of Marine Sciences China University of Geosciences (Beijing) Beijing 100083 China School of geosciences China University of Petroleum (Beijing) Beijing 102249 China

With an area of 56×104km2. the Tarim Basin is the largest inland basin in china and is also generally acknowledged as one of the most important areas for potential oil and gas exploration. On the basis of data from 2. regional seismic profiles and 40 drilling wells, 15 important first-order and second-order regional unconformities were *** all the main unconformities are superimposed unconfomities. Since the Cambrian, 5 key periods of tectonic change have occurred during the evolution of the Tarim Basin. The total eroded stratal thickness of the above-mentioned unconformities was calculated by using the method of virtual extrapolation of seismic reflection. The results indicate that the total eroded stratal thickness of different periods is quite different in different locations of the basin. Taking the Upper-Middle Ordovician as an example, its thickness restoration of eroded strata was calculated into individual stages i.e. its thickness restoration of eroded strata was calculated to different tectonic periods. Otherwise, as for the specific period of tectonic change, the underlying strata were, respectively eroded and thus the thickness restoration of eroded strata was calculated into individual intervals. Taking the Early Hercynian period as an example, the eroded stratal thickness was calculated into individual intervals to calculate the ratio of intervals of various ages occupying the total eroded thickness. The results show that for the same stratum, its degree of erosion is quite different in different periods and at different locations, due to the varying influence of tectonic movement. The unconformities of some key periods of tectonic change have different controls on the degree of erosion and the eroded range of the individual period of the underlying strata which are the typical characteristics of multi-stage superimposition of unconformities in the Tarim Basin.

关键词： Tarim Basin extrapolation of virtual surface key period of tectonic change superimposed unconformity restoration of eroded stratal thickness

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In situ reproductive organs of Early Cretaceous ferns from Northeast china

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Chinese Science Bulletin 1997年第23期42卷 1977-1980,2026页

作者： DENG Shenghui and CHEN Fen1. Research Institute of Petroleum and Development, beijing 100083 2. china university of geosciences, beijing 100083, china Research Institute of Petroleum and Development Beijing china university of geosciences Beijing China

FILICOPSIDA is a predominant group of the Early Cretaceous floras of Northeast china, whichapproximates 100 species and accounts for more than one third of the floras. The majority ofthis group are of great importance and significance in stratigraphy. The previous studies ofthese ferns are mainly morphological, with only a few concerning the in situ spores andsporangia. In recent years. the authors have carried out a research project on the in situreproductive organs of the Early Cretaceous ferns from/ basins of Inner Mongolia, Liaoning,Jilin and Heilongjiang of Northeast china. The study focuses on 35 species of 17 genera be-longing to 10 families. The present note briefly introduces the results of this study by listingsome representative species.

关键词： Northeast china Early Cretaceous Filicopsida in situ reproductive organs.

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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,{2., china 2. School of Earth Sciences and Mineral Resources, china university of geosciences,{2., china Key Laboratory of Lithospheric Tectonics and Lithoprobing Technology China University of Geosciences Ministry of Education of China Beijing China School of Earth Sciences and Mineral Resources China University of Geosciences 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.

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The Thermal Structure of the Upper Mantle in Eastern china——Inferred from the Petrological Model

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Acta Geologica Sinica(English Edition) 1991年第2期65卷 195-201页

作者： Deng Jinfu and Zhao Hailing china university of geosciences, beijing 100083, {2. china university of geosciences Beijing 100083 China

Cenozoic basalt in eastern china contains abundant ultramafic xenoliths which are specimens of pyrolitesreleased during basaltic magma eruption. A total of 405 P-T data of pyroxene in the ultramafic rocks have beencollected, which present a more precise pyroxene geotherm. The average geothermal gradient in the upper man-tle represented by the pyroxene geotherm is about 3.3℃ / km, which is much less than that derived from theconductive thermal model (≈14℃ / km), implying the great significance of convective heat transfer. The calcu-lation shows that the contributions of convective and conductive heat transfers are 79% and 2.%, *** perturbation in the thermal structure of the upper mantle is an important manifestation of thetectonothermal event of Cenozoic continental rifting and intense basaltic volcanism in eastern china. Based onthe pyroxene geotherm and its comparison with the current geothermal field derived from the measurements ofthe surface heat flows, it is suggested that the Moho may be a secondary thermal boundary. The currentgeothermal field and the thermal structure of the lithosphere in eastern china may mainly reflect the result ofthe tectonothermal disturbance in the Neogene-Quaternary, in other words, the lithosphere has just begun toCool.

关键词： The Thermal Structure of the Upper Mantle in Eastern china

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Mineralogy and crystal structure determination of Mg-fillowite

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Science china Earth Sciences 2005年第5期48卷 635-646页

作者： MA Zhesheng 1 , SHI Nicheng 1 & YE Danian 2.1. china university of geosciences, beijing 100083, {2. 2. Institute of Geology, Chinese Academy of Sciences, beijing 10002., {2. china university of geosciences Beijing China Institute of Geology Chinese Academy of Sciences Beijing China

Accurate crystal structure determination of complex phosphate Mg-fillowite ? Na2.a(Mn4Mg2.e)7[PO4]6 has been finished. Mg-fillowite occurs in muscovite-pegmatite in the Altay area, Xinjiang, china. It is of the trigonal lattice, with space group R-3, unit cell a=1.5143(3) nm, c=4.3191(2. nm, V=8.5736 nm3, Z = 18. The R-factor of the determination accuracy is R (I > 2. ( I )) = 0.0776. The cationic polyhedra consist of two kinds of structural units: compound col- umn and screw column. In three-dimensional space, they are linked with each other through corner sharing or edge sharing to build the entire structure. There are 45 atoms in an asymmetric unit and 72. atoms in a unit cell. In terms of types and connection manners of the coordination polyhedra, the degree of complicity is rarely seen in all mineral crystal structures. Study of such a structure is significant for the classification of phosphate and the building rule of coordination polyhedra in a complex crystal structure.

关键词： Mg-fillowite, complex phosphate, crystal structure, coordination polyhedron.

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Origin,evolution and extinction of Cathaysia flora

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Chinese Science Bulletin 1999年第2期44卷 100-108页

作者： SUN Keqinchina university of geosciences, beijing 100083, {2. china university of geosciences Beijing China

Recent research results showed that the Cathaysia flora originated and developed from the global uniform Lepidodendropsis flora of the Early Carboniferous, which had already become an independent flora in the early Late Carboniferous (Namurian B to C). The center of origin of the Cathaysia flora is restricted to the North china Plate. On the basis of the successional characteristics of the Cathaysia flora in different geological ages, it may be divided into seven evolutionary stages. The evolutionary trend of the Cathaysia flora, as a whole, was characterized by the gradual increase of the typical Cathaysian elements in the sequence from the early Late Carboniferous to the early Late Permian, which began to decline during the late Late Permian. The climatic differentiation, tectonic movement,oceanic circulation, palaeogeographical environment, extraterrestrial event and plant evolution caused the mass extinction of the Cathaysia flora on a large scale by the end of the Permian.

关键词： Asia Cathaysia flora origin evolution extinction Late Carboniferous Permian.

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Identifying rock blocks based on hierarchical rock-mass structure model

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Science china Earth Sciences 2009年第10期52卷 1612-1623页

作者： XU NengXiong School of Engineering and Technology, china university of geosciences, beijing 100083, {2. School of Engineering and Technology China University of Geosciences Beijing China

Rock-masses are divided into many closed blocks by deterministic and stochastic discontinuities and engineering interfaces in complex rock-mass engineering. Determining the sizes, shapes, and adjacent relations of blocks is important for stability analysis of fractured rock masses. Here we propose an algorithm for identifying spatial blocks based on a hierarchical 3D Rock-mass Structure Model (RSM). First, a model is built composed of deterministic discontinuities, engineering interfaces, and the earth's surface, and the deterministic blocks surrounded by these interfaces are traced. Then, in each deter-ministic block, a network model of stochastic discontinuities is built and the stochastic blocks are traced. Building a unitary wire frame that connects all interfaces seamlessly is the key for our algorithm to identify the above two kinds of blocks. Using this algorithm, geometric models can be built for block theory, discrete element method, and discontinuous deformation analysis.

关键词： rock-mass engineering discontinuity block identification 3D Rock-mass Structure Model network model of stochastic discontinuities

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A new breakthrough in the tectonic studies of South china

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Chinese Science Bulletin 1999年第1期44卷 23-25页

作者： MA wenpuchina university of geosciences, beijing 100083, {2. china university of geosciences Beijing China

SOUTH china comprises geologically the Yangtze, Cathaysia Block and the collisional orogenic belt between them. Traditionally, it was considered as a post-Caledonian platform after these two blocks collided and became united since Late Paleozoic. According to the similarity of tectonic patterns of Alps and Appalachian with South china, Hsu et al. proposed different opinions from the early 1980s, in which the title of the article: 'Huanan Alps not South china Platform' clearly declared their viewpoints. After more than a decade’s practice, some important advances concerning the nature of South china during Late Paleozoic have been acquired, mainly including: based on the facts that the duration of late Devonian to late Permian thin dark chert and siliceous rock sequence in Guangxi are rather long whereas it is a little thick,associated with Mn, Ni and Co-bearing deposit but absent in terrigenous sediments, the containing radiolaria is of open sea type, could be extensive correlation and not endemic

关键词： South china Babu ophiolite Turkic type orogen.

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Oxfordian (Jurassic) mayaitid (ammonite) dispersal in the Tibetan Himalaya as the first signal of the establishment of the Indo-Austrai subrealm

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Progress in Natural Science:Materials International 2003年第4期13卷 44-49页

作者： YIN Jiarun(china university of geosciences, beijing 100083, {2.) china Univ Geosci Beijing 100083 Peoples R China

New fossil collections in the Lanongla area, Tibetan Himalaya enables the establishment of the Upper Jurassic ammonoidsuccession. Middle Oxfordian ammonite-fauna is characterized by endemic epimayaittds with a marine deepening event, suggesling a high stand of sea Ievel in the Tibetan Himalaya. Distribution of mayaitids around the Eastern Gondwana can be regarded as the first signal of the Indo-AustraI Subrealm that was progressively established during the Late Jurassic and Early Cretaceous times.

关键词： Jurassic Oxfordian ammonites Tibetan Himalaya Indo-Austral Subrealm.

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Indian Ocean-MORB-type isotopic signature of Yushigou ophiolite in North Qilian Mountains and its implications

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Science china Earth Sciences 2006年第6期49卷 561-572页

作者： HOU Qingye1,2. ZHAO Zhidan1,2. ZHANG Hongfei3, ZHANG Benren3 & CHEN Yuelong2.1. State Key Laboratory of Geological Processes and Mineral Resources, china university of geosciences, beijing 100083, {2. 2. School of Earth Science and Mineral Resources, china university of geosciences, beijing 100083, {2. 3. Faculty of Earth Sciences, china university of geosciences, Wuhan 430074, {2. State Key Laboratory of Geological Processes and Mineral Resources China University of Geosciences Beijing China School of Earth Science and Mineral Resources China University of Geosciences Beijing China Faculty of Earth Sciences China University of Geosciences Wuhan China

In order to explore the disputed issue concerning the tectonic affinity ofthe ancient ocean mantle of North Qilian Mountains (NQM), geochemical and Sr, Nd, Pb isotopiccompositions of pillow basalts of the Yushigou Ophiolite (YSGO) suite from NQM have been analyzedsystematically. The pillow basalts exhibit tholeiitic characteristics, with flatchondrite-normalized REE patterns ((La/Yb)_N = 0.98—1.2.). They display no Nb, Ta, Zr, Hf negativeanomalies, and show MORB features in 2.b-Zr/4-Y and Ti/100-Zr-YX3 tectonic discrimination *** results indicate that the Yushigou ophiolite is most likely to be formed in a mid-ocean ridgeor mature back-arc basin. Their isotopic data show a relatively broad and enriched ^(87)Sr/^(86)Sr(0.70509 — 0.70700), restricted ^(143)Nd/^(144)Nd (0.512.55-0.512.78). Pb isotopes are in the rangeof ^(2.6)Pb/^(2.4)Pb (18.054-2..562., ^(2.7)Pb/^(2.4)Pb (15.537-15.743) and ^(2.8)Pb/^(2.4)Pb(38.068-38.530). These isotopic data imply that the basalts originated from the depleted mantle(DMM), with the involvement of enriched mantle components (mainly EMII). Geochemical comparisonsbetween the basalts in YSGO and the MORB-type basalts of ophiolite suites occurring in the knownancient Tethyan tectonic domain indicate that the ancient oceanic mantle represented by YSGO suiteforming in early Paleozoic in the North Qilian Moutains is very similar to the Tethyan mantle inboth trace elements and isotopic compositions. The North Qilian Mountains should be a part of theTethyan tectonic domain in early Paleozoic. This further implies that the Tethyan tectonic domaincan be deduced to early Paleozoic in the study area, which will be helpful to discussing thetectonic affinity and evolution of the North Qilian Mountains.

关键词： geochemistry, Indian Ocean-MORB-type isotopic signatures, Tethyan tectonic domain, Yushigou ophiolite, North Qilian Mountains.

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