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Aoyitake plagiogranite in western Tarim Block, NW china: Age, geochemistry, petrogenesis and its tectonic implications

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Science china Earth Sciences 2006年第11期49卷 1121-1134页

作者： ZHANG Chuanlin1,2. YU Haifeng3, YE Haimin2. ZHAO Yu2.& ZHANG Dongsheng4 1. Key Laboratory of Isotope Geochronology and Geochemistry, Guangzhou institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, china {2., nanjing 210016, china 3. Tianjin institute of geology and mineral resources, Tianjin 300170, china 4. The 2.d Regional Geological Investigation Party, Xinjiang Bureau of geology and mineral resources, Changji 831100, china Key Laboratory of Isotope Geochronology and Geochemistry Guangzhou Institute of Geochemistry Chinese Academy of Sciences Guangzhou China nanjing institute of {2. and mineral resources Nanjing China Tianjin institute of geology and {2. resources Tianjin China The 2.d Regional Geological Investigation Party Xinjiang Bureau of Geology and Mineral Resources Changji China

SHRIMPP U-Pb zircon age and geochemical and Nd isotopic data are reported for the Aoyitake plagiogranite in western Tarim Block, NW china. The plagiogranite intruded the Middle Pro- terozoic and Lower Carboniferous with an exposure area of ca. 60 km2.and crystallized at 330.7±4.8 Ma. Rock types mainly include tonalite, trondhjemite and minor amounts of diorite and quartz-diorite. Feldspars in the rocks are dominated by oligoclase-andesine, and minor perthite observed locally. The granites are sodic with Na/K ratios (molar) between 4 and 87. Total REE (50-2.0 ppm) show a clear positive correlation with SiO2. There is no LRRE/HREE fractionation (LaN/YbN=0.5-1.5), me- dium negative Eu anomalies (δ Eu=0.3-0.6), high Y content and low Sr/Y ratio (~1.0). These granites exhibit relatively juvenile Nd T2.M model ages of 470 to 580 Ma and positive εNd(331 Ma) values of 6.2. to 7.65. The aforementioned characteristics are similar to those of ocean island or ocean ridge plagiogranites. However, the regional geology, especially its scale, precludes that the plagiogranite pluton was derived directly from fractionational crystallization of mantle-derived basaltic magma. We interpreted that the primary magma of the pluton might be tonalitic in composition generated by ca. 50% partial melting of the juvenile basaltic crust. The primary magma experienced intensive frac- tionational crystallization, and intruded into the middle to upper crusts to form the granite pluton. In combination with the previous regional geological data, it is concluded that the plagiogranite pluton was emplaced within the Tarim Block in respond to the Carboniferous continental rifting along the Tianshan orogenic belt.

关键词： western Tarim, Aoyitake plagiogranite, age, geochemistry, tectonic implications.

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The modes of gold-migration in the gossan-type gold deposit

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Chinese Science Bulletin 1999年第S2期44卷 32-33页

作者： HE Jurui and LI Ying nanjing institute of {2. and mineral resources, nanjing 210016, china nanjing institute of {2. and mineral resources Nanjing 210016 China

MORE than 30 gossan-type gold deposits have beed discovered in the Middle-Lower Yangtze River *** profile of gold-bearing gossan can be divided into four subzones from upper to lower: （i） gold-deficient or gold-leached gossan (Au contents （0.1-0.8）×10-6) transitonal subzone; （ii） secondary goldconcentration subzone (Au（4-2.）×10-6); （iii） oxide and sulfide transitional subzone (Au（0.5-1.5）× 10-6); （iV） Primary sulfide ore (Au（0.5-1） × 10-6). Au Concentration in the subzone （ii） is 2.2. times higher than that in subzone （iV）. Obviously migration and secondary concentration of Au hadhappened in the process of oxidation of primary sulfides. Some geologists indicated that there would be four modes of gold-migration and concentration:（1） gravity separation （mechanism）; （2. organic complex or adsorption; （3） colloidal

关键词： gold migration gossan-type gold deposit.

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The geological feature, geochemistry and origin of Jinya gold deposit in Fengshan, Guangxi

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Chinese Science Bulletin 1999年第S2期44卷 168-169页

作者： ZHOU Jiyuan~1, CUI Bingfang~1 and LU Yan~2.1. nanjing institute of {2. and mineral resources, nanjing 210016, china 2. Chengdu institute of Technology, Chengdu 610059, china nanjing institute of {2. and mineral resources Nanjing 210016 China Chengdu institute of Technology Chengdu 610059 China

1 Geological feature of deposit The Jinya gold deposit is a fine disseminated gold mine. It occurs in sandstone and mudstone ofMiddle-Triassic Baifeng Formation, which is located at the margin of Late Paleozoic carbonate platform. Itwas controlled by the fracture zone, cleavage zone and fissure zone. The gold deposit has 15 orebodies,which are displayed as beds, lens and veins. The dominating minerals with gold are pyrite and arsenopyrite. The gold mainly occurs as submicroscopic intergranular gold. Low-to-moderate temperature (130-305℃) wall-rock alterations are mainly silicification, pyritization and arsenopyrite, also includes realgarization, carbonation (calcite, dolomite), sericitization and argillation (kaolinite, pyrophyllite). It wasformed after undergoing the sedimentary diagenetic period, hydrothermal mineralization epoch (2.3 Ma)and supergene mineralization.

关键词： geological feature Jinya gold deposit Fengshan.

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Geochronology and Geochemical Characteristics of the Early Mesozoic Tangquan Pluton in Southwestern Fujian and Its Tectonic Implications

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Acta Geologica Sinica(English Edition) 2003年第3期77卷 361-371页

作者： MAO Jianren, HU Qing, XU Naizheng, XIE Fanggui and TAO Kuiyuan, nanjing institute of {2. and mineral resources, nanjing, Jiangsu 210016 E-mail: mjrmh@*** Hao Ziguo and Zhu Xiling nanjing Inst Geol & mineral {2. Nanjing 210016 Jiangsu Peoples R China

The Tangquan granodioritic pluton in Dalian County, southwestern Fujian, china, which extends in a NE direction with an exposed area of about 130 km2. used to be considered a product of Early Cretaceous magmatism. The present study suggests for the first time that the pluton was formed in the Early Jurassic by using multiple methods for isotopic dating, which give zircon U-Pb ages of 186.8 Ma and 179.0 Ma, Rb-Sr isochron age of 162.02.4.5 Ma, and biotite 40Ar/39Ar plateau age of 158.1±0.7 Ma. The cooling rate for the pluton was relatively low (4.76℃/Ma) during the early stage (183-162.Ma) because of the compressional environment. It was emplaced in a higher cooling rate (50℃/Ma) in an extensional environment during the later stage (162.158 Ma). The granodiorites are metaluminous-peraluminous, relatively enriched in Na2. and depleted in K2., and characteristic of I-type granites of crust-mantle mixed sources. They are moderately enriched in Rb, Th, Hf and LREE, and depleted in Ti, Nb, Ta and Sr, and have geochemical features of cal-alkaline rocks of an island arc or active continental margin. Their (87Sr/86Sr)i ratio varies from 0.70769 to 0.7082., εNd(t) from -9.68 to -10.07 and TDM from 1.52.to 1.55 Ga. They were formed by mixing of mantle-derived mafic magma with the granitic magma resulting from partial melting of crust-derived materials in an upwelling of the asthenospheric mantle in South china during the Early Mesozoic.

关键词： granodiorite Early Jurassic petrogenesis tectonic setting southwestern Fujian china

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Sources of Cretaceous Bimodal Volcanic Rocks in the Coastal Region of Southeastern china -- Constrains of the Sr content and its isotopes

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Acta Geologica Sinica(English Edition) 1999年第1期73卷 84-92页

作者： XING Guanfu YANG Zhuliang and TAO Kuiyuan nanjing institute of {2. and mineral resources, Chinese Academy of Geological Sciences,534 East Zhongshan Road, nanjing 210016 Chinese Acad Geol Sci Nanjing Inst Geol & Mineral Resources Nanjing 210016 Peoples R China

Cretaceous volcanism in the coastal region of southeastern china was characteristized by occurrenceof bimodal volcanics consisting of basalts and rhyolites, the geneses of which are still controversial. Based on the factthat their isotopic compositions are similar but the Sr content of the former is much higher than that of the latter, thispaper discusses the respective sources of the two end-member rocks, and concludes that basalts were derived fromthe subduction-related enriched upper mantle wedge and their isotopic compositions had not been affected by crustalassimilation, whereas rhyolites were formed by remelting of the old metamorphic basement, but they were mixed upwith the underplating basaltic magmas to various degrees so that their Sr isotopic compositions varied significantlyfrom the sources and tended to be homogeneous to the latter.

关键词： Sr content and its isotopes Cretaceous bimodal volcanics coastal region of southeastern china

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Identification of Hercynian shoshonitic intrusive rocks in central Hainan Island and its geotectonic implications

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Science Bulletin 2006年第20期51卷 2507-2519页

作者： XIE Caifu1, 2. ZHU Jinchu1, DING Shijiang3, ZHANG Yeming2. FU Tai’an2.& LI Zhihong2.1. State Key Laboratory for mineral Deposits Research and Department of Earth Sciences, nanjing University, nanjing 2.0093, china 2. Yichang institute of geology and mineral resources, Yichang 443003, china 3. Hainan Bureau of geology and mineral resources, Haikou 5702.6, china State Key Laboratory for mineral Deposits Research and Department of Earth Sciences Nanjing University Nanjing China Yichang institute of geology and {2. resources Yichang China Hainan Bureau of geology and mineral {2. Haikou China

An identification has been made of some shoshonitic intrusive rocks in central Hainan Island recently. These rocks are K-rich (K2.=2.9%―5.1%, K2./Na2.=0.95―2.12., distinctly enriched in LILE and LREE, strongly depleted in Nb, Ta, and moder- ately depleted in Sr and Ti, with (87Sr/86Sr)i = 0.70859―0.7142. and ε Nd(t) = (?2.77―?7.49). They were derived from an EMⅡ-type mantle source. The enrichment process is related to metasomatism of depleted mantle caused by a great amount of fluid-melt released from oceanic crust and terri- genous sediments at great depth (eclogite facies) during the subduction of the South china plate under the Indochina-South china Sea plate in the Carbon- iferous–Early Permian. A SHRIMP U-Pb zircon dating yields a crystallization age of 2.2.7 Ma for the sho- shonitic intrusions, which is coeval with the strongly peraluminous granites found in central Hainan Island. These two kinds of rocks generally possess syn-intrusion ductile deformation structures. Thus they are considered to have been generated during the early stage (syn-thrust phase) of a post-collisional event. The primary magma of shoshonitic rocks was produced at a depth > 80 km by decompression- dehydration melting of previously enriched litho- spheric mantle wedge, phlogopite-bearing garnet peridotite, which was in turn caused by the break-off of a descendent slab and upwelling of a hot as- thenosphere. The rising of melts was accompaniedby crustal contamination and crystallization fractiona- tion (AFC). Combining with other related data, it is proposed that the southwards subduction and amal- gamation of the South china plate with the Indo- china-South china Sea plate took place at ca. 2.7- 2.8 Ma, which was a part of the convergence proc- ess of the Pangea supercontinent. The suture zone was probably located along the line of Song Ma-Beibu Gulf-north margin of the Yunkai Moun- tains-Wuyi Mountains.

关键词： SHRIMP U-Pb dating Hercynian shoshonitic intrusive rocks post-collisional event enriched mantle Hainan Island.

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A sort of iron-manganese nodule developing in drowned platform margin

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Chinese Science Bulletin 1999年第S2期44卷 34-35页

作者： JIANG Yuehua, YE Zhizheng and YUE Wenzhe nanjing institute of {2. and mineral resources, Chinese Academy of Geological Sciences, nanjing 210016, china nanjing institute of {2. and mineral resources Chinese Academy of Geological Sciences Nanjing 210016 China

A sort of purplish red iron-manganese nodules was found in the Middle Ordovician Guniutan-Miaopu period limestone, Anhui Province. About their formational environment, there are two different viewpoints:Yue thought they were deep-water pelagic deposit and Huang et al. believed they were formed inshallow water tide. We think that these nodules were formed in drowned platform margin belonging to atransitional type between shallow-water and deep-water iron-manganese nodules, and different from shoalwater iron-manganese oolites and pelagic iron-manganese nodules in feature and origin. 1 Palaeogeographic setting of iron-manganese nodules

关键词： iron-manganese nodule drowned platform platform margin.

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Vermicular fossils in the Early Cambrian Xidashan Formation in the Quruqtagh region of Xinjiang, china

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Progress in Natural Science:Materials International 2006年第5期16卷 559-562页

作者： YANG Ruidong, ZHANG Chuanlin, SONG Guoqi and LUO Xinrong (Postgraduate School of Guizhou University, Guiyang 55002., china nanjing {2. of geology and mineral resources, nanjing 210016, china Geological Survey of No. 3 Geological Party, Xinjiang, Kurle 841000, china) Postgraduate School of Guizhou University Guiyang 550025 China nanjing institute of {2. and mineral resources Nanjing 210016 China Geological Survey of No. 3 Geological Party Xinjiang Kurle 841000 China

Large amounts of vermicular fossils and a minor amount of sponge animal fossils have been found in the Early Cambrian Xidashan Formation in the region of Quruqtagh, Xinjiang. Vermicular fossils are generally more than 50 mm long and 0. 3-1. 4 mm wide; their wrinkled lamellae are microfine with 3-10 pieces within the length of every each millimeter. The fossils are considered to be Sabellidites cambriensis Sokolov (1965) . The Xidashan Formation is the highest stratum in which Sabellidites occur, as has been so far reported.

关键词： vermicular fossil Early Cambrian Quruqtagh Xinjiang.

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Whole fossil plants of Ephedra and their implications on the morphology,ecology and evolution of Ephedraceae (Gnetales)

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Chinese Science Bulletin 2010年第15期55卷 1511-1519页

作者： WANG Xin 1,2.& ZHENG ShaoLin 3 1 nanjing institute of {2. and Palaeontology,Chinese Academy of Sciences,nanjing 2.0008,china 2.Fairy Lake Botanical Garden,Shenzhen 518004,china 3 Shenyang institute of {2. and mineral resources,Shenyang 110034,china nanjing institute of {2. and Palaeontology Chinese Academy of Sciences Nanjing China Fairy Lake Botanical Garden Shenzhen China Shenyang institute of geology and {2. resources Shenyang China

Although there are many reports of fossil Ephedraceae,whole plant fossil record remains *** to a lack of trust on partially preserved fossil materials,scholars working on molecular clock proposed a recent origin of Ephedra and cast doubt on the earlier origin time of *** better the understanding on this interesting group,here we report whole plants of Ephedra hongtaoi ***.(Ephedraceae,Gnetales) from the Yixian Formation (Early Cretaceous) in western Liaoning,*** whole plants of Ephedra demonstrate clearly the characters of Ephedra,including shrubby growth habit,decussate branching pattern,and terminal ovuliferous unit with micropylar *** whole-plant preservation of the fossils provides more convincing fossil evidence of Early Cretaceous Ephedra,helps to resolve the controversy over the origin time of Ephedra,and sheds light on the whole plant morphology,growth habit,ecology and evolution of Ephedraceae.

关键词：化石植物生态学麻黄形态学进化材料保存早白垩世生长习性

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Criteria for defining and recognizing the various orders of sequences in outcrop sequence stratigraphy

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Science china Earth Sciences 2004年第7期47卷 618-629页

作者： WANG Xunlian Faculty of Earth Sciences and mineral resources,{2. University of Geosciences, Beijing 100083,{2. State Key Laboratory of Palaeobiology and Stratigraphy, nanjing institute of geology and Palaeontology, Chinese Academy of Sciences, nanjing 2.0008,{2. Faculty of Earth Sciences and mineral resources China University of Geosciences Beijing China State Key Laboratory of Palaeobiology and Stratigraphy Nanjing Institute of Geology and Palaeontology Chinese Academy of Sciences Nanjing China

The regional distribution in different depositional facies belts is here regarded as an important criterion for defining and recognizing the various orders of sequences. The third-order sequence is possibly global in nature, which may be discerned in different depositional facies belts in one continental margin and can be correlated over long distances, sometimes even worldwide. Commonly, correlation of subsequence (fourth-order sequence with time interval of 0.51.5 Ma) is difficult in different facies belts, although some of them may also be worldwide in distribution. A subsequence should be able to discern and correlate within at least one facies belt. The higher-order sequences, including microsequence (fifth-order sequence) and minisequence (sixth-order sequence), are regional or local in distribution. They may reflect the longer and shorter Milankovitch cycles respectively. Sequence and subsequence are usually recognizable in different facies belts, while microsequence and minisequence may be distinguished only in shallow marine deposits, but not in slope and basin facies deposits. A brief discussion is made on the essential conditions for correct identification of sequences, useful methods of study, and problems meriting special attention in outcrop sequence stratigraphy.

关键词： outcrop sequence stratigraphy, facies belt, sequence, subsequence, microsequence, minisequence, meter-scale cyclothem, Milankovitch cycle.

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