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Dehydration melting of solid amphibolite at 2.0 GPa: Effects of time and temperature

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Science china Earth sciences 2005年第8期48卷 1120-1133页

作者： ZHOU Wenge1, XIE Hongsen1, LIU Yonggang1, ZHENG Xiaogang1, ZHAO Zhidan2 & ZHOU Hui3.1. Laboratory of Material in the Earth’s Interior, institute of Geochemistry, chinese academy of {3., Guiyang 550002, china 2. Department of geology, china University of Geo{3., beijing 100083. china 3. Department of geology, Peking University, beijing 100871, china 1. Laboratory of Material in the Earth’s Interior Institute of Geochemistry Chinese Academy of Sciences 550002 Guiyang China 2. Department of geology China University of Geosciences 100083 Beijing China 3. Department of geology Peking University 100871 Beijing China

Two sets of dehydration-melting with a natural solid amphibolite, collected from North Himalayan structure zone, Tibet, have been carried out in multi-anvil apparatus at 2.0 GPa and 800―1000℃, for 12―200 h. One is keeping the pressure at 2.0 GPa and the annealing time of 12 h, changing the temperature (800―1000℃). The other is keeping the pressure at 2.0 GPa and temperature at 850℃, varying the annealing time (12―200 h). The products are inspected with microscope and electron probe. The results indicate that at 2.0 GPa, annealing time of 12 h, garnets, melts and clinopyroxenes occur in amphibolite gradually with increasing temperature and the chemical compositions of melt vary from tonalite to granodiorite, and then to tonalite. However, at 2.0 GPa and 850℃, with the annealing time increasing, the garnets, melts and cli-nopyroxenes also occur in amphibolite gradually and the chemical compositions of melt vary from tonalite to granodiorite. In both cases, melts interconnect with each other when the contents of melt are over the 5 vol.%. the viscosities of the melt produced in amphibolite at temperature higher than 850℃ are on a level with 104 Pa·s. The interconnected melt with such a viscosity may segregate from the source rock and form the magma over reasonable geological time. Therefore, it is believed that at the lower part of the overthickened crust, the tonlitic and grano-dioritic magma may be generated through the dehydration melting of amphibolite.

关键词： solid amphibolite, high pressure, high temperature, time, partial melting.

中国大陆地壳“镶嵌与叠覆”的结构特征及其演化

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地质通报 2004年第9期23卷 986-1004页

作者： LI Jinyi(institute of geology, chinese academy of geological sciences,{3., china) 中国地质科学院地质研究所北京100037

初步探讨了中国大陆地壳“块带镶嵌多层叠覆”的结构特征和多阶段的构造演化过程。中国大陆地壳新元古代中期以来的一级构造单元有中朝、塔里木、扬子、敦煌4个陆块和中央、西北、东北、西南、东南5个造山区(带)。中朝陆块的形成源于古... 详细信息

初步探讨了中国大陆地壳“块带镶嵌多层叠覆”的结构特征和多阶段的构造演化过程。中国大陆地壳新元古代中期以来的一级构造单元有中朝、塔里木、扬子、敦煌4个陆块和中央、西北、东北、西南、东南5个造山区(带)。中朝陆块的形成源于古元古代期间发生的古大陆裂解;扬子、塔里木和敦煌陆块的形成源于新元古代早期发生的古大陆裂解。西北造山区的形成源于古生代晚期洋盆关闭、大陆碰撞并叠加新生代陆内再造山;东北造山带的形成过程包括古生代碰撞造山及中生代增生、碰撞造山;中央造山带至三叠纪大陆碰撞才最后形成并叠加有新生代再造山;东南造山带的形成经历了古生代至新生代的多次造山作用;西南造山带主要是中—新生代造山作用的产物。这些单元都具有“块带镶嵌多层叠覆”的结构特征和多阶段构造演化的特点。中国大陆地壳的形成与演化可以划分为太古宙—古元古代、中元古代—新元古代早期、新元古代中期—古新世和始新世以来4个构造阶段,每个阶段都对应不同的超大陆裂解-聚合旋回。其中新元古代中期以来的地壳形成演化与全球洋陆格局中的古亚洲洋、古特提斯洋、古太平洋、特提斯洋和太平洋5个动力学体制有关,相应地可以归结为古亚洲、古特提斯、古太平洋、特提斯和太平洋5个造山域。

关键词：中国大陆地壳块带镶嵌多层叠覆超大陆裂解-聚合旋回动力学体制造山域

Petrology and mineral chemistry of new ureilites found in Grove Mountains, Antarctica

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Progress in Natural Science:Materials International 2008年第4期18卷 431-439页

作者： Bingkui Miaoa,b,, Yangting Linb, Guiqin Wangc, Daode Wangc, Ziyuan Ouyangd a Key Laboratory of geological Engineering center of Guangxi Province, Guilin University of Technology, Guilin 541004, china b State Key Laboratory of Lithospheric Evolution,{3. and Geophysics, chinese academy of sciences, beijing 100029, china c Key Laboratory of Isotope Geochronology and Geochemistry, Guangzhou institute of Geochemistry, chinese academy of sciences, Guangzhou 510640, chinad National Astronomical Observatories, chinese academy of sciences, beijing 100012, china Key Laboratory of geological Engineering center of Guangxi Province Guilin University of Technology Guilin 541004 China State Key Laboratory of Lithospheric Evolution Institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100029 China Key Laboratory of Isotope Geochronology and Geochemistry Guangzhou Institute of Geochemistry Chinese Academy of Sciences Guangzhou 510640 China National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China

Petrography and mineral chemistry of two new ureilites, GRV 021512 and 02293., from the Grove Mountains, Antarctica, are reported in this paper. GRV 021512 exhibits a typical ureilite texture, and consists of 48.3. olivine, 9.4% pigeonite and 3..1% carbo- naceous interstitial material and/or reduction product. GRV 02293. has a cataclastic porphyritic texture, and consists of 19.1% olivine and 14.1% pigeonite embedded in 66.3. carbonaceous interstitial material and/or reduction product. The coarse-grained olivine and pigeonite in both meteorites have homogeneous cores, and they are FeO-rich within the range of the ferroan subgroup (subgroup I) of olivine-pigeonite ureilites. All olivine grains of the meteorites show reduction zones along boundaries and cracks. Abundant diamond coexists with graphite as graphite-rich patches and veins in the carbonaceous interstitial material. Petrogenesis of both meteorites and the origin of diamond are discussed.

关键词： Meteorite Achondrite Ureilite Diamond Antarctica

The Yadong-Golmud Geoscience Transect in the Qinghai-Tibet Plateau

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Acta Geologica Sinica(English Edition) 1990年第2期64卷 115-127页

作者： Wu Gongjian Xiao Xuchang Li Tingdong chinese academy of geological sciences, beijing Jia Zhongpeng chinese academy of geological {3. Beijing 1This project was financially supported by the National Natural Science Foundation of china and the Min-istry of geology and Mineral Resources.

On the basis of abundant geological and geophysical data. 6 terranes have been distinguished on theQinghai-Tibet Plateau. The plateau is a single integrated lithospheric unit although it is divided into blocks.With Amdo as a boundary. the crust may be divided into two parts with different crustal structures. The struc-ture in the southern part is complex, while that in the northern part is simple. The current study has revealedthat 8 factors such as slab subduction. overthrust and superimposition are responsible for crustal shorteningand thickening in the region. The uplift of this region is possibly due to northward compression of the Indianplate and southward compression of the Eurasian plate with the former predominating. The compression led tothe asthenospheric movements which were also influenced by thermal activity caused by doming at the bound-ary between the core and mantle.

关键词： The Yadong-Golmud Geoscience Transect in the Qinghai-Tibet Plateau

A challenge to the concept of slip-lines in extrusion tectonics

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Geoscience Frontiers 2011年第1期2卷 23-34页

作者： Yadong Zheng~(a,*),Erchie Wang~b,Jinjiang Zhang~a,Tao Wang~c a Key Laboratory of Orogenic Belts and Crustal Evolution,Ministry of Education,School of Earth and Space sciences, Peking University,beijing 100871,china b{3. and Geophysics,chinese academy of sciences,beijing 100029,china c{3.,chinese academy of geological sciences,beijing 100037,china [a] Key Laboratory of Orogenic Belts Crustal Evolution Ministry of Education School of Earth Space sciences Peking University Beijing 100871 China [b] Institute of Geology Geophysics Chinese Academy of Sciences Beijing 100029 China [c] Institute of Geology Chinese Academy of Geological Sciences Beijing 100037 China

Wide-open V-shaped conjugate strike-slip faults in Asia are typically related to extrusion ***,the tectonic model based on the slip-line theory of plasticity has some critical problems associated with *** conjugate sets of slip-lines in plane deformation,according to the theory of plasticity should be normal to each another but,in reality,the angles between the conjugate strike-slip faults,which are regarded as slip-lines in extrusion tectonics in the eastern Mediterranean,Tibet-middle Asia,china and the Indochina Peninsular regions,are always more than 90°(on average～110°) in the direction of contraction. Another problem is that the slip-line theory fails to explain how,in some cases,e.g.,in the Anatolian area in the eastern Mediterranean,the extrusion rate is much higher than the indent *** two major problems are easy to solve in terms of the Maximum-Effective-Moment(MEM) Criterion that predicts that orientations of the shear zones are theoretically at an angle of 54.7°and practically at angles of 55°±10°with theσ- or contractional *** orientations of the strike-slip faults that accommodate extrusion tectonics are,therefore, fundamentally controlled by the MEM *** extrusion is along the MEM-orientations,the extruding rate is normally higher than the indenting rate.

关键词： Extrusion tectonics Slip-line Wide-open V-shaped strike-slip faults MEM-Criterion Strain rate

Age Assignment of the Lycoptera- bearing Bed

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Acta Geologica Sinica(English Edition) 1994年第3期68卷 329-347页

作者： Li Peixian, Su Deying, Li Yougui and Yu Jingxianinstitute of geology, chinese academy of geological sciences, {3. chinese academy of geological {3. Beijing

In the Yanliao area, the occurrence of the Nestoria-Keratestheria fauna and the Eoparacypris- Luanpingella-Darwinula assemblage in the Dabeigou Formation s.s., a Rb-Sr isochron age of 145.2 Ma for the Baiqi Formation and a complete stratigraphic sequence-all this proves that the Lycoptera-bearing bed overlies the Upper Jurassic. The Jehol fauna comprises the primitive Trigonioidids fauna, Eosestheria fauna, Lycoptera fauna et al., and their own laws of evolution expound that they belong to Cretaceous faunas. The associations of Eosestheria with Yanjiestheria, Lycoptera with Eosestheria, and Kuntulunia with Yanjiestheria as well as the occurrence of early angiosperms and sporo - pollen in the Fuxin Formation and its equivalents also demonstrate that the Lycoptera-bearing, bed should be assigned to the Cretaceous. The confirmation of the existence of Aucellina in the Jixi Group and the correlation of Trigonioidids and Cypridids with those in the equivalent strata of Japan and Western Europe have also been verified by corresponding marine strata. According to the magnetostratigraphic data from Zhejiang and Songliao, it has been preliminarily ascertained that M0 between the mixed polarity zone in the lower part and the normal polarity zone in the middle part of the Cretaceous is located in the upper member of the Huangjian Formation of the Jiande Group and the top member of the Denglouku Formation of the same group, and the isotopic age data of the Jehol and Jiande Groups show that the approximate geologic age of the Lycoptera bed is 13.-122 Ma. These prove that the Lycoptera bed should be assigned to the Cretaceous.

关键词： Cretaceous Jurassic-Cretaceous boundary Lycoptera- bearing bed Jehol fauna

The Evolution of Alpine Ultramafic Rocks and Partial Melting of the Upper Mantle

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Acta Geologica Sinica(English Edition) 1993年第1期67卷 43-61,122页

作者： Bao Peisheng, Wang Xibin, Hao Ziguo and Peng Genyong institute of geology, chinese academy of geological sciences, beijing Fei Zhenbi institute of geology Chinese Academy of Geological Sciences Beijing

Ultramafic rocks of Tibet and Xinjiang are the products of partial melting of the upper mantle. The evolution of their mineral composition is marked by two parallel evolutionary series: one is the progressive increase of the 100 Mg/(Mg+Fe^(2+) ratio of silicate minerals in order of lherzolite→harzburgite→dunite, i.e. the increase in magnesium; the other is the increase of the 100 Cr/(Cr+Al) ratio of accessory chrome spinel in the same order, i. e. the increase in Chromium. The above-mentioned evolutionary trends are contrary to that of magmatic differentiation. The evolution of fabrics of ultramafic rocks is characterized by progressive variation in order of protogranular texture→melted residual texture, symplectic texture and clastophyritic texture→equigranular mosaic texture and tabular mosaic texture. Experiments of partial melting of lherzolite have convincingly shown that the evolution of Alpine ultramafic rocks resulted from the partial melting of pyrolite. Various subtypes of them represent different degrees of partial melting. The vertical zoning marked by more basic rocks in the upper part and more acid rocks in the lower actually belongs to the fusion zoning of pyrolite.

关键词： Alpine ultramafic rocks upper mantle partial melting

The species diversity of fusulinaceans and high-frequency sea-level changes in the Carboniferous-Permian boundary section at Xikou, Zhen'an County,Shaanxi Province, china

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Science china Earth sciences 2006年第7期49卷 673-683页

作者： ZHANG Haijun1, WANG Xunlian2, DING Lin1, XIA Guoying3.& WANG Lei2 1. institute of Tibetan Plateau Research, chinese academy of {3., beijing 100085, china 2. Faculty of Earth {3. and Mineral Resources, china University of Geo{3., beijing 100083. china 3. Tianjin institute of geology and Mineral Resources, Tianjin 3.0170, china 1. institute of Tibetan Plateau Research Chinese Academy of Sciences Beijing 100085 China 2. Faculty of Earth sciences and Mineral Resources China University of Geosciences Beijing 100083 China 3. Tianjin institute of geology and Mineral Resources Tianjin 300170 China

The study on the interrelation between sea-level changes and biodiversity with its evolu-tion has great significance for understanding the impact of global changes on organic evolution and exploring the inherent laws of life-environment coevolution in geological history. In this paper, the stratigraphic distribution of fusulinacean fauna in the Carboniferous-Permian boundary section at Xikou, Zhen’an County, Shaanxi Province, is analyzed quantitatively, and the relationship between the species diversity of fusulinaceans and relative sea-level changes is discussed. As a whole, the spe-cies numbers of fusulinacean fauna experience a rapid increase and an obvious decline in Xikou, Zhen’an County, from the Late Carboniferous to the Early Permian. There is a significant increase in species diversity around the Carboniferous-Permian boundary, which is one of the biggest bio-events of the fusulinacean fauna, and represents the radiation of Pseudoschwagerininae subfamily in the studied area. Integrated fusulinacean species diversity into sequence stratigraphic framework, de-tailed study suggests that the species diversity of the fusulinaceans is closely related to its relative stratigraphic location, and is essentially controlled by the sea-level changes, especially by the high-frequency sea-level changes. Generally, the species diversity of fusulinaceans is low, and the number of first and last appearance datum is small in the lower unit of high-frequency depositional cycle formed during the quick rise of the sea level; whereas the species diversity of fusulinaceans is high, and the number of first and last appearance datum is large in the upper unit of high-frequency cycle formed during the slow fall of the sea level. Within the third-order depositional sequence, the species diversity of the fusulinaceans at the first flooding surfaces and the maximum flooding surfaces is low, and it increases upward. The fusulinacean species diversity is low within the transgressive syst

关键词： fusulinaceans, species diversity, high-frequency cyclothem, sequence stratigraphy, sea-level changes, Carboniferous-Permian boundary, Zhen'an, Shaanxi.

Storm Deposits of the Sinian Zhangqu Formation in Northern Anhui——An Upward Shallowing Carbonate Sequence

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Acta Geologica Sinica(English Edition) 1990年第2期64卷 129-145,234-235页

作者： Qiao Xiufu Xing Yusheng Gao Linzhi Yin Chongyu Yue Zhao Liu Guizhi institute of geology, chinese academy of geological sciences, beijing Jia Zhongpeng Gao Linzhi chinese academy of geological {3. Beijing

This paper studies. for the first time, the storm deposits of a carbonate sequence in the Sinian ZhangquFormation in northern Anhui. In the formation. a great number of calcareous trider sponge spicules were dis-covered in a distal storm turbidity sequence, which have provided further evidence for the correlation of theSinian Systems in North and South china from a view point of palaeontology.

关键词： Zhang Storm Deposits of the Sinian Zhangqu Formation in Northern Anhui An Upward Shallowing Carbonate Sequence