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Science China Earth Sciences 2005年第3期48卷 353-363页

作者： R. Matsumoto Geology Institute Tokyo University Tokyo 113 Japan

According to high-resolution analyses on multi-proxy of sediment core from the Er- hai Lake, Yunnan province. the sequence of climatic and environmental change since the Holo- cene has been reconstructed based on accurate dating. The results show that climate had tran- sited from cold-wet to warm-wet during ca. 12950-8399 aBP in this area, and the transition happened in ca. 10329 aBP. Due to the enhancing southwest Asian monsoon and increasing precipitation, the lake-level of the Erhai Lake began to rise after ca. 10329 a BP. Climate in the catchment was warm and wet during the mid-Holocene, and the warmest stage appeared in ca. 8399-6371 a BP. The lake-level descended in the mid-Holocene because of the decrease of effective moisture in the basin. Human activities appeared in ca. 6371 a BP, and the initial man- ner mainly focused on deforestation. Up to ca. 2139 a BP, due to the amount of immigration into this area, the cultivation was developed widely, which was followed by mining (coal mine).

关键词： climate change, human activity, Holocene, lake sediment, Erhai Lake in Yunnan province.

Numerical modeling of the formation of Indo-Sinian peraluminous granitoids in Hunan province.Basaltic underplating versus tectonic thickening

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Science China Earth Sciences 2002年第11期45卷 1042-1056页

作者：王岳军 Y.Zhang 范蔚茗席先武郭锋林舸 Guangzhou Institute of Geochemistry Chinese Academy of Sciences Guangzhou China CSIRO Division of Exploration ⇐p Mining Perth Australia

The genesis of Indo-Sinian granitic plutons with peraluminous and potassium-rich affinities from Hunan province. China has been investigated by numerical modeling using the numerical code FLAC. On the basis of the regional geological evolution in South China, we employed a realistic numerical model in an attempt to unravel the influences of basaltic underplating and tectonic crustal thickening on the crustal anatexis. Heat production derived from basaltic underplating (e.g. ca. 220 Ma gabbro xenoliths) can result in dehydration melting of fluid-bearing minerals in crustal rocks such as gneisses and metapelites, but its effect is limited in a relatively short time span (5-15 Ma) and on a small scale. Accordingly, it is very difficult for basaltic underplating to generate the large-scale Indo-Sinian granitic bathliths unless voluminous mafic magmas had been underplated at the lower/middle crust during this period. Alternatively, crustal thickening induced by tectonic compression can also lead to geothermal elevation, during which the temperature at the boundary between lower and middle crusts can be up to or greater than 700°C, triggering dehydration melting of muscovite in gneiss and metapelite. The proportion of melts from muscovite-induced dehydration melting is close to critical melt percentage (?20%) once the thickening factor reaches 1.3. These melts can be effectively transferred to the crust-level magma chamber and form large-scale granitic batholiths. In combination with the Indo-Sinian convergent tectonic setting in South China as well as sparse outcrops of contemporary mafic igneous rocks, we consider that tectonic crustal thickening is likely to be the predominant factor controlling the formation of the Indo-Sinian peraluminous and potassium-rich granitoids in Hunan province.

关键词： Indo-Sinian granitoids, dehydrated melting, basaltic undedrplating, tectonic thickening, numerical modeling,Hunan province.

Effect of Mesozoic volcanic eruptions in the western Liaoning province. China on paleoclimate and paleoenvironment

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Science China Earth Sciences 2003年第12期46卷 1261-1272页

作者：郭正府刘嘉麒汪筱林 Institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100029 China Institute of Vertebrate Paleontology and Paleoanthropology Chinese Academy of Sciences Beijing 100044 China

Well-preserved Mesozoic vertebrate fossils were found from lacustrine deposits inter-bedded with tuff and tuffites in the lower part of the Yixian Formation, western Liaoning province. China. The fossil-rich layers were preserved in the intermediate-acid volcanic deposits in Sihetun excavating profile. Based on the petrographic studies of samples of the tuff and tuffites collected from the profile, this paper determines major element concentrations and volatile compositions of the melt inclusions in phenocrysts and matrix glasses with electron microprobe analysis. Volatile (S, F, Cl and H2O) contents emitted into the atmosphere were estimated by comparing pre- and post-eruptive volatile concentrations. Amount of volatiles (except for water) emitted in western Liaoning are much higher than those in the historic eruptions which had a substantial effect on climate and environment. Based on the nature and amount of the gases emitted in the eruptions of western Liaoning, we present a hypothesis that volatile-rich volcanism could result in mass mortal-ity of vertebrates in the study area by injecting a large amount of volatiles (e.g., SO2, H2S, HCl, HF and H2O) into the stratosphere that would have triggered abrupt environmental and climate changes and altered lake chemistry. In terms of contents of volatile emissions, the eruptions in western Liaoning can be subdivided into the following three categories. The first group is domi-nated by HF emission, which had a fatal but possibly short-lived effect on paleoclimate and pa-leoenvironment and finally caused the mass mortality of the primitive birds. The second group presents the highest halogen concentrations emitted. However, contents of chlorine erupted is higher than those of fluorine emitted. The reactive chlorine compounds probably led to the ozone layer depletion and, therefore, caused mass mortality of most of all vertebrates including fishes, turtles and dinosaurs. The third one consists mainly of sulfur gases (pri

关键词： volcanic eruption, paleoclimate, mass mortality, ozone layer, acid rain, western Liaoning province.

Genetic interpretation of fish swimming trails and calculation of fish-body length in Late Triassic Hengshan, Shannxi province. China

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Science China Earth Sciences 2004年第3期47卷 272-279页

作者： LU Zongsheng HOU Jianxiang CHEN Bin HAO Chaokun LI Xiaoyan Faculty of Earth Sciences China University of Geosciences Wuhan430074 China Faculty of Earth Sciences China University of Geosciences Wuhan430074 China Faculty of Earth Sciences China University of Geosciences Wuhan430074 China Faculty of Earth Sciences China University of Geosciences Wuhan430074 China Faculty of Earth Sciences China University of Geosciences Wuhan430074 China

The fish swimming trail fossils are rare and, therefore, precious. The specimen de-scribed abroad are generally smaller or more poorly preserved. The specimens used in the pre-sent study and derived from the Mesozoic strata in Hengshan County, Shaanxi province. China, are rare because of their completeness (with the length of the specimen reaching 4 m), exquisiteness and largeness in trace body. These specimens, classified as four ichnospecies, including two new ones, show the morphological pattern of the fish swimming trails. The trace fish bodies are calculated to be 32—92 cm long.

关键词： fish swimming trails, calculation of fish-body length, Late Triassic, Shaanxi province.

Thermal structure and rheology of upper mantle beneath Zhejiang province. China

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Science China Earth Sciences 1998年第2期41卷 171-178页

作者：林传勇史兰斌韩秀玲陈孝德张小鸥 Institute of Geology State Seismological Bureau Beijing China Institute of Geology Chinese Academy of Sciences Beijing China

The paleogeotherm derived from spinel and garnet lherzolites xenoliths for the upper mantle beneath Zhejiang province. China is higher than the oceanic geotherm but is similar to the geotherm for the upper mantle beneath eastern China constructed by Xu et al. and the upper mantle geotherm of southeastern Australia. The crust-mantle boundary defined by this geotherm is about 34 km, while the lithosphere-asthenosphere boundary is about 75 km. This result coincides well with geophysical data. The study of rheological features of the xenoliths has revealed that at least two periods of deformation events occurred in the upper mantle beneath this region. The first event might be related to upper mantle diapir occurring in this region before or during late Tertiary, and the second might be related to the occurrence of small-scale shear zones in the upper mantle.

关键词： mantle xenolith upper mantle geotherm rheology of upper mantle Zhejiang province.

Negative carbon isotopic excursion on the Lower/Middle Cambrian boundary of Kaili Formation, Taijiang County, Guizhou province. China: Implications for mass extinction and stratigraphic division and correlation

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Science China Earth Sciences 2003年第9期46卷 872-881页

作者：杨瑞东朱立军王世杰 State Key Laboratory of Environmental Geochemistry Institute of Geochemistry Chinese Academy of Sciences Guiyang 550002 China Guizhou University of Technology Guiyang 550003 China

The stratigraphic division and correlation of the Lower/Middle Cambrian boundary is a global problem that has not yet been perfectly solved up to now. That is because there existed two global biogeographic regions during the period from Early Cambrian to Middle Cambrian. Although much work has been done from the angle of paleontology and great achievements have been acquired in this aspect, no biological assemblage has yet been established for global stratigraphic correlations due to the coexistence of the two global biogeographic regions —— the Atlantic biogeographic region and the Indian-Pacific biogeographic region during the Early-Middle Cambrian. So, to develop and establish other approaches to the stratigraphic division and correlation of the Lower/Middle Cambrian on a global scale is a possible way to solve the puzzling problem. This work systematically studied acritarch fossils from the Early-Middle Cambrian Kaili Formation at Taijiang County, Guizhou province. The Lower/Middle Cambrian boundary was divided in terms of acritarch fossil assemblage. The divided boundary is generally consistent with what was divided by trilobite and can be correlated with the Lower/Middle Cambrian boundaries divided by acritarch assemblage in Siberia and Europe. On this basis, the Lower/Middle Cambrian boundary is divided in terms of an obvious carbon isotopic excursion on a global scale during the transitional period from Early Cambrian to Middle Cambrian boundaries in Siberia and North America. The method for the stratigraphic division and correlation of the Lower/Middle Cambrian boundary in terms of carbon isotopic oscillations is helpful to solving the global problem on the division and correlation of the Lower/Middle Cambrian boundary. It is also evidenced that the extinction of a lot of trilobites at the end of Early Cambrian is closely related with this event of carbon isotopic excursion.

关键词： negative carbon isotopic excursion, extinction, Lower/Middle Cambrian boundary, Guizhou province.

Discovery and significance of microfossils from Qinbaikouian Dazhuang Formation in Luonan, Shaanxi province

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Chinese Science Bulletin 1997年第3期42卷 243-245页

作者： Chen, Z Hua, H Jian, WC Hu, YX Department of Geology Northwest University Xi’an China Xi’an Institute of Geology and Mineral Resources Chinese Academy of Geological Sciences Xi’an China

THE microfossils were obtained by using 5%—7% HF acid from Qingbaikouian Dazhuang Formation in Luonan County, Shaanxi province. with an age of 800—1000 Ma. The fossils may be one type of the oldest skeletal mierofos... 详细信息

关键词： microfossil Qinbaikouian Dazhuang Formation Shaanxi province.

Potash-rich volcanic rocks and lamprophyres in western Shandong province.^(40)Ar-^(39)Ar dating and source tracing

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Chinese Science Bulletin 2002年第2期47卷 91-99页

作者： QIU Jiansheng, XU Xisheng & LO Ching-HuaState Key Laboratory of Mineral Deposit Research of Nanjing University, Nanjing 210093, China Department of Earth Sciences, Nanjing University, Nanjing 210093, China Department of Geology, Taiwan Unive State Key Laboratory of Mineral Deposit Research of Nanjing University Nanjing China Department of Earth Sciences Nanjing University Nanjing China Department of Geology Taiwan University Taibei China

Highly precise 40Ar-39Ar dating results demon-strate that the ages of potash-rich volcanic rocks in western Shandong province.are 114.7-124.3 Ma, and that of the lamprophyres is 119.6 Ma. The potash-rich volcanic rocks have relatively high (87Sr/86Sr)i ratios ( 0.708715-0.711418) and distinctly negative εNd values ( -11.47--17.54), and are enriched in radiogenic lead (206Pb/204Pb=17.341-17.622, 207Pb/204Pb=15.525-15.538, 208Pb/204Pb=37.563-37.684). Similarly, the lamprophyres also have quite low εNd values (-11.57 - -19.64). Based on the fact that the Sr, Nd and Pb isotopic compositions of potash-rich volcanic rocks are very consistent with that of the clinopyroxene separates, and by integrating comprehensive analyses of their tectonic settings, and extensive comparisons of the Sr, Nd isotopic composi-tions with that of the related simultaneous rocks, it is con-cluded that the potash-rich volcanic rocks and lamprophyres in western Shandong province.were most possibly derived from the partial melting

关键词： potash-rich volcanic rocks lamprophyres 40Ar-39Ar dating Sr-Nd-Pb isotope tracing western Shandong province.

The first discovery of eclogite and Palaeoproterozoic granitoids in the Beishan area,northwestern Gansu province.China

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Chinese Science Bulletin 1999年第4期44卷 356-361页

作者： Hualin Mei Haifeng Yu Quan Li Songnian Lu Huimin Li Yicheng Zuo Guochao Zuo Dejin Ye Jincheng Liu Chinese Acad Geol Sci Tianjin Inst Geol & Mineral Resources Tianjin 300170 Peoples R China Gansu Bur Geol & Mineral Resources Lanzhou 730000 Peoples R China

The eclogite, discovered in Liuyuan, occurs as lenticular enclave within granitic gneiss. It has typical features of eclogite in petrology and mineralogy. The eclogite provides an important wirdow to reconstruct the tectonic border of the Tarim block. The granitoids, located in Baihu area, yield U-Pb zircon ages of 1 660—2 000 Ma (Palaeoproterozoic), which irrplies an early Precambrian basement in the area.

关键词： eclogite Palaeoproterozoic granitoids Beishan area Gansu province.

Studies of geothermal waters in Jiangxi province.using iso-tope techniques

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Science China(Technological Sciences) 2001年第S1期44卷 144-150页

作者：孙占学李学礼 East China Geological Institute Linchuan Jiangxi China

Isotope hydrogeological studies of thermal waters conducted in the Lushan hotspring area, northern Jiangxi province. the Maanping hotspring area, central Jiangxi, and the Henjing hotspring area, southern Jiangxi province.show that the local meteoric water line of Jiangxi province.is similar to the Craig line. The SD and δ18O values of geothermal waters in the province.are roughly in accord with the local meteoric line, which implies that the thermal waters are of meteoric origin. Variations of isotopic composition of natural waters in the study areas reveal that the recharge areas of the geothermal fields are the adjacent mountains. The ages of geothermal waters measured by different dating methods, such as Ra/Rn dating and tritium dating, range from several decades to several hundred years in the province.which suggests that the geothermal waters are undergoing active circulation. The 3He/4He ratios of gases from the hotsprings in the Hengjing hotspring area show that the hotspring gases originate from the depth, and probably partly from the mantle source.

关键词： geothermal water isotope Jiangxi province.