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Vermiform trace fossils from the Precambrian Ruyang Group, western Henan

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Chinese Science Bulletin 1997年第3期42卷 251-254页

作者： HU Jianmin, MENG Qingren and LI Wenhou1 xi’ an College of geology, xi’an 710054. China 2. Institute of Geophysics, Chinese Academy of Sciences, Beijing 100101, China 3 {2. of geology, northwest university, xi’an 710069, China xi’an College of geology Xi’an China Institute of Geophysics Chinese Academy of Sciences Beijing China department of geology Northwest University Xi’an China

THE origin and evolution of Precambrian lives has been a long-standing controversial problem. It is now generally accepted by most paleontologists that the origin of metazoa can be traced back to more than 1000 Ma, because the Ediacara and latest pre-Ediacara fauna, such as the Huainan fauna, are featured by their diversification of forms, complicated structures

关键词： Precambrian trace fossil Ruyang Group.

Discovery of bipinnatifid fronds of Protoblechnum contractum(Gu et Zhi)

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Chinese Science Bulletin 1999年第4期44卷 381-383页

作者： SUN Bainian and SHEN Guanglong department of geology, Lanzhou {2., Lanzhou 730000, China department of geology, northwest university, xi’an 710069, China department of geology Lanzhou University Lanzhou China department of geology Northwest University Xi’an China

IN Permian floras of China, a dispute over the relationship among the Protoblechnum and other similar plants such as Compsopteris, Glenopteris and Supaia has been existing for a long time, and moreover it has not been completely solved up to now. Halle placed a few simple pinnate fronds from the Shihhotze Formation in the genus Protoblechnum and named them Protoblechnum Wongii Halle 70 years ago when he was studying the fossil plants from the Late Palaeozoic strata in Shanxi, China. He did not think forked or unforked fronds as an important dividing genus condition in discussing the distinction among Protoblechnum and other relative fossils. Zalessky alSO found some specimens similar to Chinese Protoblechnum while he studied the Permian fossil plants from Russia. However, he did not approve of

关键词： very over Discovery of bipinnatifid fronds of Protoblechnum contractum Gu et Zhi

Northernmost paleo-tethyan oceanic basin in Tibet:Geo-chronological evidence from ^(4.)Ar/^(39)Ar age dating of Dur'ngoi ophiolite

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Chinese Science Bulletin 2001年第14期46卷 1203-1205页

作者： CHEN Liang, SUN Yong, PEI xianzhi, GAO Ming, FENG Tao, ZHANG Zhongqing & CHEN Wen1. Laboratory of Continental Dynamics, northwest university, xi’an{2., China {4., northwest university, xi’an,{2., China 3. Institute of geology, Chinese Academy of Geological Sciences, Beijing, 100037, China Laboratory of Continental Dynamics Northwest University Xi’an China department of geology Northwest University Xi’an China Institute of geology Chinese Academy of Geological Sciences Beijing China

Whole rock 4.Ar/39Ar age dating has been conducted on a basalt sample from Dur’ngoi ophiolite, Qinghai Province, which was reported to be the northernmost pa-leo-tethyan oceanic basin in Tibet. A high temperature pla-teau age (34..3±7.9 Ma) with an isochorn age (336.6±7.1 Ma) has been obtained, representing the eruption time of oceanic crust Considering related geological settings, the new age provides constraints on the northernmost pa-leo-tethyan suture zone in Tibet and the tectonic evolution of Paleo-tethys in Northeast Tibet and adjacent areas.

关键词： Dur’ngoi ophlolite 4.Ar -39Ar age Paleo-tethys.

NEW MATERIALS OF DINOCROCUTA GIGANTEA FOUND IN FUGU COUNTY, SHAANxi PROVINCE

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古脊椎动物学报(中英文） 1996年第1期 25-26页

作者： Zhang Yunxiang Xue xiangxu(department of geology Institute of Cenozoic geology and Environment northwest university xi'an 710069)

Dinocrocuta gigantea was erected by M. Schlosser in 1903. Since then, there were very few materials of Dinocrocuta gigantea to be found, and most of them unknown provenances. In 1986, a large quantity of Hipparion fauna fossils were yeilded in Laogaochuan, Fugu County, Shaanxi Province, among which, there are some materials of Dinocrocuta gigantea, including a complete skull, an anterior part of skull with all teeth, broken lower jaws, 10 isolate teeth, humerus and proximal part of ulna of same individual, femur etc.

关键词： Fugu Shaanxi Late Miocene Dinocrocuta gigantea

Geochemical　Features　of　Ophiolite　in　Mianxian　Lueyang　Suture　Zone，Qinling　Orogenic　Belt

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Journal of Earth Science 1996年第2期15卷 165-172页

作者： Lai Shaocong Zhang Guowei(department of geology,{2., xi’an{4.)

The ultrahasic rocks in the Mianxian-Lueyang ophiolite belt are mainly harzburgite and dunite, and exhibit two types of REE distribution pattern: (1) LREE depletion, with remarkable Eu enrichment; (2. slight enrichment of LREE, with Eu deficiency. Both gabbros (accumulative gabbros) and diabasic dike swarms show a LREE enrichment but a slight Eu anomaly. The ratios of w (Ti) /w (V), w (Th) /w (Ta). w (Th) /w (Yb) and w (Ta) /w (Yb) indicate that the mid-ocean ridge basalts in this region originated from depleted mantle of asthenosphere, implying an association of MORB-type ophiolite and an ancient ocean basin between Qinling and Yangtze plates during Middle Paleozoic-Early Mesozoic era. The island arc volcanic rocks can be divided into tholeiitic and cafe-alkaline associations, which originated from the upper mantle wedge above slab by partial melting.

关键词： geochemistry ophiolite Qinling

Synthesis of Cycloundecanone from Benzimidazole Methiodide Salt

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Chinese Chemical Letters 2000年第4期11卷 285-288页

作者： Zheng LI Zhen SHI (department of Chemistry. northwest university,{2. 710069) NW Univ xian Dept Chem Xian 710069 Peoples R China

The intra-molecular addition reaction of Grignard reagent with quaternary C=N bond of benzimidazole methiodide salt is reported, and a novel method for the synthesis of cycloundecanone is provided.

关键词： cycloundecanone benzimidazole methiodide salt synthesis

Synthesis of Symmetric Diketones from Imidazolinium Salt and Bis-Grignard Reagents

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Chinese Chemical Letters 2000年第9期11卷 757-760页

作者： Zhen SHI Lin Gang LU department of Chemistry, northwest university, xi an{2. NW Univ xian Dept Chem Xian 710069 Peoples R China

The reaction of 2.substituted imidazolinium salt with bis-Grignard reagents is reported and a new method for the synthesis of symmetric diketones from carboxylic acids and bis-Grignard reagents is provided.

关键词： diketones imidazolinium salt bis-Grignard reagents synthesis

TECTONIC SIGNIFICANCE OF THE WEST KUNLUN FOLD-THRUST-BELT AND THE TARIM SOUTHWEST DEPRESSION

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地学前缘 2000年第S1期7卷 84-86页

作者： Luo Jinhai (department of geology,{2., xi′an{4.,China)

The evolution of the Tarim southwest depression lying at the piedmont of the West Kunlun orogen differs completely from the evolution of the main part of Tarim basin after Later Palaeozoic because the former strongly subsides many times.. Subsidence is related closely to the West Kunlun fold thrust\|belt, thus the evolution of the Depression and the fold\|thrust\|belt reflects clearly the formation and evolution of the West Kunlun and even the Tibet.1 Evolution of the West Kunlun fold\|thrust\|belt\;Thrusting of the fold\|thrust\|belt can be classified into three stages:(1) Devonian thrusting:This is the oldest thrusting distinguished in the northern margin of the West Kunlun while the Silurian—Devonian thrusting was discriminated a few years ago by seismic data in the northern part of the East Kunlun. The Devonian thrusting is proved by the Upper Devonian dynamometamorphic rocks outcropping at the core of the anticline in the Sangzhu lying at the fold\|thrust\|belt. The rocks consist of slightly metamorphic clastic rock and have always been regarded as the Mid\|Proterozoic strata. But they are actually Upper Devonian strata according to the amount of perfect plant fossils that we found recently in the metamorphic rock, and they are overburdened `with an angular unconformity by another reliable Upper\|Devonian conglomerate in the core of the Aqike anticline. A possible explanation for this and its limited lined distribution parallel to the West Kunlun orogen is that they are subjected to metamorphism during the Later Devonian thrusting.

关键词： evolution West Kunlun fold\|thrust\|belt Tarim southw est depression correspondence

Paleoenvironments indicated by the fossil mammalian assemblages from red clay-loess sequence in the Chinese Loess Plateau since 8.0 Ma B.P.

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Science China Earth Sciences 2006年第5期49卷 518-530页

作者： XUE xiangxu1,2. ZHANG Yunxiang1,2.& YUE Leping1,2.1. State Key Laboratory of Continent Dynamics (northwest university), Institute of Cenozoic {2. and Environment, De- partment of {2., northwest university, xi’an 710069, China 2. Institute of Earth Environment, State Key Laboratory of Loess and Quaternary {2., Chinese Academy of Sciences, xi’an 710075, China 1. State Key Laboratory of Continent Dynamics (northwest university) Institute of Cenozoic Geology and Environment Department of Geology Northwest University Xi’an 710069 China 2. Institute of Earth Environment State Key Laboratory of Loess and Quaternary Geology Chinese Academy of Sciences Xi’an 710075 China

Information from eleven profiles of eolian earthy red silty clay and loess of the middle of the Late Miocene to Holocene age have been studied and correlated. A complete summary profile with projected isotopic ages and fossil-bearing beds has been assembled. The profile is subdivided into 12.stratigraphic units proceeding from the lower (older) to the upper (younger) one. The character of mammalian assemblages contained in each unit was analyzed and the corresponding pa- leo-climatic environments were deduced. The environmental character of each period and the change from the middle of the Late Miocene at about 8.0 Ma B.P. up to the Holocene progressed from the hot semiarid and semi-moist, warmer-moist, warm-moister of the Late Miocene. To slightly less warm moist, cool-dry, slight-warmer-moister of the Pliocene; later the cool to cold dry periods alternated frequently with the mild semiarid and semi-moist periods of the Quaternary. Vegetation progressed from the grasslands with sparse woods, wooded shrub-grasslands and subtropical forest-grasslands of the Late Miocene age to sparse grasslands and dry grasslands of the Pliocene; and to sparse grasslands, dry grasslands and tundras of the Quaternary. The climate changes in the Neogene were of low-amplitute in a generally warm-humid background. Those of the Quaternary were of higher am- plitude with a longer phase. Cool or cold dry and slightly warm semiarid and semi-moist climates al- ternated on a generally cool-dry background. The tendency since the start of the Quaternary was the change to more northern and western shift in the Loess Plateau, with progressively cooler and dryer conditions. The dramatic uplift of the Qinghai-xizang (Tibet) Plateau and the forming and expansion of the Arctic ice sheet might be the main reasons of the more pronounced changes in the Quaternary.

关键词： paleoenvironment, mammalian fossils, eolian red clay-loess sequence, Loess Plateau.