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Geochemistry and Petrogenesis of Volcanic Rocks in the Yeba Formation on the Gangdise Magmatic Arc, Tibet

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Journal of China University of Geosciences 2005年第4期16卷 283-296页

作者： Geng Quanru pan guitang Jin Zhenmin Wang Liquan Liao Zhongli Faculty of Earth Sciences China University of Geosciences Wuhan 430074 China Chengdu Institute of Geology and Mineral Resources Chengdu 610082 China

The Early Jurassic bimodal volcanic rocks in the Yeba Formation, situated between Lhasa, Dagze and Maizhokunggar, composed of metabasalt, basaltic ignimbrite, dacite, silicic tuff and volcanic breccia, are an important volcanic suite for the study of the tectonic evolution of the Gangdise magmatic arc and the Mesozoic Tethys. Based on systematic field investigations, we carried out geochemical studies on representative rock samples. Major and trace element compositions were analyzed for these rock samples by XRF and ICP-MS respectively, and an isotope analysis of Rb-Sr and Sm-Nd was carried out by a MAT 262 mass spectrograph. The results show that the SiO2 contents in lava rocks are 41 %-50.4% and 64 % -69 %, belonging to calc-alkaline basalt and dacite. One notable feature of the basalt is its low TiO2 content, 0.66%-1.01%, much lower than those of continental tholeiite. The ∑REE contents of basalt and dacite are 60.3-135 μg/g and 126, 4--167.9μg/ g respectively. Both rocks have similar REE and other trace element characteristics, with enriched LREE and LILE relative to HREE and HFS, similar REE patterns without Eu anomaly. The basalts have depleted Ti, Ta and Nb and slightly negative Nb and Ta anomalies, with Nb = 0.54--1.17 averaging 0. 84. The dacites have depleted P and Ti and also slightly negative Nb and Ta anomalies, with Nb= 0. 74 -1. 06 averaging 0. 86. Major and trace elemental and isotopic studies suggest that both basalt and dacite originated from the partial melting of the mantle wedge at different degrees above the subduction zone. The spinal Iherzolite in the upper mantle is likely to be their source rocks, which might have been affected by the selective metasomatism of fluids with crustal geochemistry. The LILE contents of both rocks were affected by metamorphism at later stages. The Yeba bimodal volcanic rocks formed in a temporal extensional situation in a mature island arc resulting from the Indosinian Gangdise magmatic arc.

关键词： bimodal volcanic rock geochemistry petrogenesis Gangdise magmatic arc late Indosinian to early Yanshannian.

Zircon SHRIMP geochronology and Nd-Pb isotopic characteristics of the meta-basalt in the central part of Tibetan Plateau's Qiangtang region

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Science China Earth Sciences 2014年第5期57卷 428-438页

作者： PENG ZhiMin GENG QuanRu pan guitang WANG LiQuan ZHANG Zhang CONG Feng GUAN JunLei Chengdu Institute of Geology & Mineral Resources China Geological Survey

A small-sized meta-basic rock system is discovered in Qilongwuru Gully of Central Qiangtang’s Shuanghu region and contains a meta-basalt and garnet-bearing plagioclase *** zircon U/Pb age of this meta-basalt by SHRIMP analysis is463.3±4.7 Ma,suggesting that this lava formed in the Middle Ordovician,and is consistent with that of the meta-basic rocks in the Taoxing Lake and Guoganjianian Mountain ophiolite found in the Qiangtang *** this lava system bears similar geochemistry to N-MORB,it might be a component of ophiolite that represents the trail of the extinction of the Proto-Tethys,suggesting that the formation of Proto-Tethys oceanic basin in the Longmu Co-Shuanghu suture zone could date as far back as to the Middle *** geochemical analysis indicates that the magma source area consists of both depleted mantle(DM)and enriched mantle(EMII)end members and bears Dupal anomaly,similar to that of the Paleo-Tethys in the Neo-Tethys represented by the Yarlung-Tsangpo suture zone,the Paleo-Tethys represented by the Changning-Menglian suture zone,and the Paleo-Tethys in Sanjiang *** suggests that they have inherited the attribute of the Proto-Tethys mantle domain,and the Longmu Co-Shuanghu suture zone may be a representative of the northern boundary of Gondwana.

关键词： Tibetan Plateau's Qiangtang region meta-basalt zircon U-Pb age Tethys Nd-Pb isotope

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Discovery of seismites in Upper Sinian stratiform lead-zinc deposits in Dadu River valley, Sichuan, China: Implication for ore genesis

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Science China Earth Sciences 2006年第11期49卷 1135-1146页

作者： LIN Fangcheng1,2 & pan guitang2 1. Geoscience College, Chengdu University of Technology, Chengdu 610059, China 2. Chengdu Institute of Geology and Mineral Resources, Chengdu 610082, China 1. Geoscience College Chengdu University of Technology Chengdu 610059 China 2. Chengdu Institute of Geology and Mineral Resources Chengdu 610082 China

A number of lead-zinc sulphide deposits have been discovered in recent years in dolo- mitic rocks of the Upper Sinian Dengying Formation in the Dadu River valley region, Sichuan Province, China. The lead-zinc mineralization is closely associated with a black siliceous exhalite that has been traced over 50 km of strike. This makes Dadu River valley the most extensive stratiform non-ferrous sulphide horizon having been discovered to date in China. In a previous study by the first author (LIN), these deposits were recognised as belonging to the broad spectrum of lead-zinc sedimentary exhala- tive (SEDEX) deposits. In this paper, seismites and seismogenetic structures occurring in close association with the Dadu River valley mineralized zone are described. The close spatial and temporal relationship between the seismites and mineralization provides strong evidence for the hypothesis that the lead-zinc SEDEX deposits formed in direct response to earthquake activities around the Sinian-Cambrian boundary. The earthquakes are postulated to be an effective dynamic mechanism for triggering the upward migration of deep circulating ore fluids along synsedimentary growth faults and their exhalation onto the sea-floor to form the extensive deposits of stratiform lead-zinc sulphide ore.

关键词： seismites, earthquake, lead-zinc deposit, hydrothermal exhalation, Upper Sinian Dengying Age.

Research Progress and the Main Achievements of The Regional Geology of China Preface

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Acta Geologica Sinica(English Edition) 2020年第4期94卷 I0001-I0012页

作者： DING Xiaozhong ZHANG Kexin GAO Linzhi LU Songnian pan guitang XIAO Qinghui LIU Yong panG Jianfeng Institute of Geology Chinese Academy of Geological SciencesBeijing 100037China Institute of Geological Survey China University of GeosciencesWuhan 430074China Tianjin Center China Geological SurveyTianjin 300170China Chengdu Center China Geological SurveyChengdu 610081China Information Center of Ministry of Natural Resources Beijing 100830China

Introduction to The Regional Geology of China In 2008, a new project concerning the recompilation of The Regional Geology of China (RGC) was assigned by the Chinese Geological Survey (CGS) and undertaken by the Institute of Geology, Chinese Academy of Geological Sciences (CAGS). Li Tingdong, an academician of the Chinese Academy of Sciences (CAS), is the chief leader and chief scientist of the project. The last time The Regional Geology of China was compiled was in the 1980s (Cheng, 1994).

关键词： Regional concerning assigned

TRIASSIC SEQUENCE STRATIGRAPHY AND CORRELATION FROM POLY-ARC AND BACK-ARC SYSTEM IN EASTERN TIBET

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地学前缘 2000年第S1期7卷 292-293页

作者： Peng Yongming,pan guitang,Luo Jiangning,Wan Minjie(Chengdu Institute of Geology and Mineral Resources,Chengdu 610082,China)

It is dominantly characterized that arc and back\|arc basin occur mutually in arc\|basin systems, Jomda arc and Sinda back\|arc basin located in Qamdo area are typical(Fig.1). Jomda arc covered by Triassic with thickness about *** sediments predominate, and are Characterized by the largely thick turbidity rocks and arc volcanic rocks of calc\|alkali suite which frequent volcanic events raised. Sinda back\|arc basin with a land\|crust basement is filled by the Upper Triassic sedimentary strata of more than 5000m. The active marginal sediments are composed of terrigenous,basinal and volcanic turbidity deposits of bathyal to deep\|sea facies,Characteristic extensive alkali basalts and submarine spout hot water deposits. Based on investigation of the cutcrop pro\|file, isotime grillwork for Triassic sequence stratigraphy has been established. for example Jomda arc basin, including 6 type 1 and 4 type 2 boundaries.10 three\|order sequences are divided, including 6 type 1 and 4 type 2 sequences. These sequences evolves during 37Ma,the estimated average time of a sequences is 3～7Ma,with being generally 1～2Ma,the longest being about 10Ma. type 1 and type 2 sequence boundaries are identified, in Upper Triassic Sinda back\|arc basin two type 1 and one type 2 sequences are divided. Relations have been first concluded among mainly controlled factors of sequence stratigraphies in arc and back\|arc basin systems. First, more sequences product and three\|units of its structures are complete in arc systems of complicated tectonic\|volcanic topographies, for example Jomda arc area of island\|sea framework, because lots of deposits are supplied and accumulations are allowed. Secondly, tectonic control is very clear, type 1 boundaries of SQ1 and SQ7 are clearly unconformity interfaces stressed by ***,volcanic rocks is greatly related with sequences, and there are various volcanic rocks in mang sequences,for example Jomda sequence stratigraphies,volcanic rocks o

关键词： arc and back\|arc basin sequence stratigraphy sequence correlation eastern Tibet

PETROLOGY AND GEOCHEMISTRY OF CENOZOIC VOLCANIC ROCKS FROM THE CENTRE OF QIANGTANG,TIBET

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地学前缘 2000年第S1期7卷 170-171页

作者： Tan Fuwen, pan guitang, Xu Qiang[WT5,5”BX](Chengdu Institute of Geology And Mineral Resources, Chengdu 610082,China)

The Cenozoic volcanic rocks in Qinghai—Tibetan plateau mainly occur in Qiangtang, Kunlun,Kokshili and eastern Tibet to the north of Bangong\|Nujiang suture. The study area locates in the centre of Qiangtang (N34°00′\|34°50′;E87°30′\|89°00′),where is nearly a blank area of geological *** pieces of samples from Hehulin,Luanqingshan,Bandaohu and Donghu show that the K\|Ar ages of the Cenozoic volcanic rocks range from 32 6 to 44 1Ma, which are elder than the Cenozoic volcanic rocks from Kunlun,Kokshili and eastern *** are two types of occurrence for the volcanic rocks: volcanic lava and sub\|volcanic rock. The lava is dark grey, light purple or dark purple and unconformably covers up on the Jurassic,which interbeds with purplish red tertiary sandstone and pebble\|bearing sandstone and contains a small amount of phenocrysts (andesine,pyroxene,amphibole and biotite). three craters and four volcanic necks have been found in this area. The sub\|volcanic rocks expose as volcanic necks with appearance of isolated peaks,which intrude into Jurassic. The rocks,appearing grey white to light grey, have trachytic texture with the phenocrysts of plagioclase,biotite and amphibole. Besides above rocks,there are some lamprophyre dikes intruding into grey white tertiary lacustrine algal limestone in this area with its length up to 2km and width 3m. The rocks appear dark grey or dark green and contain the phenocrysts of pyroxene,orthoclase,biotite,olivine,and leucitite.

关键词： Tibet volcanic rocks geochemistry REE

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东昆仑西段晚古生代盆地系

地球学报 2008年第1期29卷 31-38页

作者：尹福光潘桂棠成都地质矿产研究所四川成都610081

东昆仑西段晚古生代从北向南分别为昆北弧后盆地、昆中岛弧及昆南弧前增生楔。在二叠纪,增生楔又转变成岛弧及弧后盆地。昆北弧后盆地石炭纪发育有陆缘到深海盆地的沉积,二叠纪由碎屑岩过渡为浅海碳酸盐岩。昆中岛弧带沉积盖层为一些碳... 详细信息

东昆仑西段晚古生代从北向南分别为昆北弧后盆地、昆中岛弧及昆南弧前增生楔。在二叠纪,增生楔又转变成岛弧及弧后盆地。昆北弧后盆地石炭纪发育有陆缘到深海盆地的沉积,二叠纪由碎屑岩过渡为浅海碳酸盐岩。昆中岛弧带沉积盖层为一些碳酸盐岩孤立台地和小的山间盆地,并有火山熔岩、火山碎屑岩的堆积。昆南弧前盆地岩石类型非常复杂,石炭纪包括了陆源碎屑岩、火山熔岩、火岩碎屑岩、钙屑浊积岩、硅质岩等。二叠纪的弧间盆地从深海盆地演化为浅海碳酸盐岩沉积。前锋弧也逐渐露出水面,形成孤立灰岩台地。东昆仑西段晚古生代沉积整体特征具有沉积相分布不对称性及"盆岭"相间展布、沉积类型多样性、物源、古流向的双(多)向性、沉积序列的两层性、沉积物的成熟度低、近源等。盆地演化可划分为盆地扩张阶段、弧陆碰撞阶段两个阶段。总体表现为弧后盆地性质的沉积与演化特点。

关键词：东昆仑西段晚古生代盆地系

GEOTECTONIC OF NAMCHE BARWA SYNTAXIS IN EAST TIBET, CHINA

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地学前缘 2000年第S1期7卷 279-280页

作者： Liu Yuping, pan guitang, Geng Quanru, Zheng Lalin, Liu Jiaoji (Chengdu Institute of Geology and Mineral Resources,Chengdu 610082,China)

Eastern Himalayan Syntaxis consists of Namche Barwa and Assam syntaxis. Namche Barwa, located at south east edge Tibet plateau, is the least\|known place for geologist, because there are thick trees and more rains as well as difficult traffic condition, but Namche Barwa syntaxis is very important to Himalayan and Tibet plateau research. A Big Bend of Yalu Tsangpo and the deepest Grand Canyon in the word developed in Namche Barwa region. From core to surrounding Namche Barwa syntaxis may be divided into Himalayan,Yalu Tsangpo as well as Gangdise three tectonic units and three boundary fault *** core of syntaxis is Himalayan unit with Zircon U\|Pb age 1312±6Ma which is correlated to High Himalayan unit in central Himalayan, major rocks of core are garnet\|plagioclase gneiss and hornblende\|plagioclase gneiss as well as layered migmatites, some lens or band of high pressure granulite,garnet\|clinopyroxenite(ecologite) and rare marbles also exist in this unit. Research result indicates that rock of core may have experienced poly\|phase metamorphism and deformation, from early granulite or eclogite facies to late amphibole face.

关键词： Geotectonic Namche Barwa syntaxis wedge Grand canyon

洋岛-海山研究进展及其对于重建洋板块的意义

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地球科学 2020年第8期45卷 2826-2845页

作者：袁四化潘桂棠任飞防灾科技学院河北三河065201 中国地质调查局成都地质调查中心四川成都610081

在中国区域大地构造研究中,对洋岛-海山/洋底高原的识别尚未引起足够重视.为深入研究中国大陆洋板块构造,系统回顾了洋岛-海山/洋底高原的基本概念、基本特征和增生造山过程.洋岛-海山/洋底高原是在海底扩张、大洋壳演化过程中由于地幔... 详细信息

在中国区域大地构造研究中,对洋岛-海山/洋底高原的识别尚未引起足够重视.为深入研究中国大陆洋板块构造,系统回顾了洋岛-海山/洋底高原的基本概念、基本特征和增生造山过程.洋岛-海山/洋底高原是在海底扩张、大洋壳演化过程中由于地幔热点/柱作用形成的有异常厚度洋壳的区域,是大洋岩石圈的重要组成部分.洋岛-海山/洋底高原在垂向上具有典型的二元结构,下部以镁铁质、超镁铁质岩石为主,上部以碳酸盐岩建造为主.现今大洋盆地中大面积分布着正在演化中和正在俯冲的洋岛-海山,根据比较大地构造学原理,古洋岛-海山的存在指示古大洋盆地的存在,是研究造山带的重要载体.认为地史时期大洋盆地中有相当数量的洋岛、海山,在俯冲增生碰撞造山过程中保留下来的古洋岛-海山残块以构造岩片(块)形式夹持在俯冲增生杂岩中,随大洋盆地关闭;其作为缝合带的重要组成部分,是识别对接带的重要判别依据之一.

关键词：洋岛-海山洋底高原增生造山作用俯冲增生杂岩洋板块地质学