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Genesis of ^(230)Th excess in basalts from mid-ocean ridges and ocean islands:Constraints from the global U-series isotope database and major and rare earth element geochemistry

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Science China Earth Sciences 2010年第10期53卷 1486-1494页

作者： ZHANG GuoLiang1.2 & ZENG ZhiGang1.1.Key Laboratory of Marine geology and Environment,{1. of Oceanology,chinese Academy of Sciences,Qingdao 266071.China 2 Graduate University of chinese Academy of Sciences,Beijing 1.0049,China 1. Key Laboratory of Marine geology and Environment Institute of Oceanology Chinese Academy of Sciences Qingdao 266071 China2. Graduate University of Chinese Academy of Sciences Beijing 100049 China

Based on 230Th-238U disequilibrium and major element data from mid-ocean ridge basalts(MORBs) and ocean island basalts(OIBs),this study calculates mantle melting parameters,and thereby investigates the origin of 230Th excess.(230Th/238U) in global MORBs shows a positive correlation with Fe8,Po,Na8,and Fmelt(Fe8 and Na8 are FeO and Na2O contents respectively after correction for crustal fractionation relative to MgO = 8 wt%,Po=pressure of initial melting and Fmelt=degree of melt),while 230Th excess in OIBs has no obvious correlation with either initial mantle melting depth or the average degree of mantle ***,compared with the MORBs,higher(230Th/238U) in OIBs actually corresponds to a lower melting *** suggests that the 230Th excess in MORBs is controlled by mantle melting conditions,while the 230Th excess in OIBs is more likely related to the deep garnet *** vast majority of calculated initial melting pressures of MORBs with excess 230Th are between 1.0 and 2.5 GPa,which is consistent with the conclusion from experiments in recent years that DU>DTh for Al-clinopyroxene at pressures of >1.0 *** initial melting pressure of OIBs is 2.2-3.5 GPa(around the spinel-garnet transition zone),with their low excess 226Ra compared to MORBs also suggesting a deeper mantle ***,excess 230Th in MORBs and OIBs may be formed respectively in the spinel and garnet stability *** addition,there is no obvious correlation of K2O/TiO2 with(230Th/238U) and initial melting pressure(Po) of MORBs,so it is proposed that the melting depth producing excess 230Th does not tap the spinel-garnet transition *** and MORBs in both(230Th/238U) vs.K2O/TiO2 and(230Th/238U) *** plots fall in two distinct areas,indicating that the mineral phases which dominate their excess 230Th are ***/Yb-Ce curves of fast and slow ridge MORBs are similar,while,in comparison,the Ce/Yb-Ce curve for OIBs shows more influence from *** mechanism

关键词： excess 230Th clinopyroxene garnet spinel-lherzolite mid-ocean ridge ocean island

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FORMATION AND EUOLUTION OF TETHYS IN THE TIBETAN PLATEAU

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地学前缘 2000年第S1期7卷 334-335页

作者： Pan Yusheng[WT5,5”BX](institute of geology and geophysics, {1. Academy of Sciences, Beijing 1.0029,China)

The formation of the Tibetan Plateau is closely related to the evolution of Tethys. There have been many researchers and articles concerning the Tethys since *** proposed the concept in 1.93. It means a large ocean which lies between Eurasia and Gondwanaland. With the development of Tethyan research, some new terms, appeared such as Neo\|Tethys, Paleo\|Tethys, and Proto\|Tethys, representing the Tethys in Mesozoic—Cenozoic, late Paleozoic and early Paleozoic respectively. The trace of an ocean from Sinian to Ordovician was discovered during the scientific expedition and Proto\|Tethys was proposed to name the ocean. Therefore, the Tibetan Plateau is the main scope of the Eastern Tethys. It can be divided c losely related into three zones which represent the main oceanic locations in th ree different *** Northern Tethyan Region lies in the Kunlun and Qilian Mountains, its remnant is the Fifth Suture Zone. It is also the northern boundary of the Tibetan Plateau The rift initiated after the continental basement had been formed in Sinian and gradually developed into an ocean, which was named Proto\|Tethys, the earliest Tethyan ocean known up to now. The petrochemical compositions of pillow lava in this zone show the characteristics of mid\|ocean ridge tholeiite basalt and the pelagic ophiolitic flysch were well developed, indicating a matured ocean. It was closed in Ordovician and Silurian.

关键词： formation and evolution Tethys Tibetan plateau suture zone structural deformation Gondwana land

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U-Pb dating of zircon from the bed parallel anatectic granitic intrusion in the Baoban group in Hainan Island and the tectonic implication

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Science China Earth Sciences 2005年第12期48卷 2092-2103页

作者： DING Shijiang1. HU Jianmin2, SONG Biao3,4, CHEN Mulun1. XIE Shengzhou1.& FAN Yuan1.1. Geological Surveying institute of Hainan, Haikou 570206, China 2. institute of Geomechanics, chinese Academy of Geological Sciences, Beijing 1.0081. China 3. Beijing Center of SHRIMP, Beijing 1.0037, China 4. institute of geology, chinese Academy of Geological Sciences, Beijing 1.0037, China 1. Geological Surveying institute of Hainan 570206 Haikou China 2. institute of Geomechanics Chinese Academy of Geological Sciences 100081 Beijing China 3. Beijing Center of SHRIMP 100037 Beijing China 4. institute of {1. Chinese Academy of Geological Sciences 100037 Beijing China

The petrological and geochemical features of the bed parallel granitic intrusion in the Pre-Cambrian Baoban group in Hainan Island attest to the anatexis origin of the granites. U-Pb dating analyses of zircons from the anatectic granite and the biotite two-feldspar gneiss in the Baoban group, using SHRIMP II in the Beijing Ion-probe Center, acquire 206Pb/238U ages of 368±3.5 Ma (of granite, 95% confidence level, MSDW=1.23) and 362.9±6.1.Ma (of gneiss, 95% confidence level, MSDW = 2.04) respectively. The two late Devonian ages indicate consistently a tectonic- thermal event experienced in Hainan Island, and are the first discovered record of the Devonian geological process in the district. This event possibly resulted from the deep ther-mal-dynamic process when the Gondwana continent began to break up in the Devonian period.

关键词： Hainan Island, Devonian period, anatectic granite, zircon SHRIMP U-Pb dating.

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TAKE ANOTHER VISION TO THE UPLIFT OF THE QING—ZANG (TIBETAN) PLATEAU BASED ON CENOZOIC VOLCANISM

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地学前缘 2000年第S1期7卷 370-371页

作者： Liu Jiaqi [WT5,5”BX](institute of geology and geophysics,{1. Academy of Sciences,Beijing 1.0029, China)

The emergence of the Qing—Zang plateau is among the most important geological events on the globe since the Cenozoic Era. Many geological issues can find answer from here. The major issues concerning plateau probably have three: (1. geodynamics, timing and speed of the plateau uplift;(2) The plateau uplift impact on surrounding environment;(3) mineral resources in the plateau. The authors want to focuses on first issue based on volcanisms occurred in interior and surrounding of the plateau, The new opinions are following:(1. Each volcanic eruptive episode corresponded to strong uplift stage;(2) The dynamic mechanism of the plateau uplift can not ignore another force from west beyond collision between Indian and Eurasia plates from South;(3) The surrounding volcanic chain is not only related to the collision from South, but also from west.

关键词： Tibetan plateau the Cenozoic volcanism volcanic chain surro unding plateau west collision uplift mechanism

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Pentacyclic triterpenoid ketones in peat from Gannan Marsh,China

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chinese Science Bulletin 2001年第17期46卷 1433-1436页

作者： DUAN YiLanzhou institute of {1., chinese Academy of Sciences, Lanzhou 730000, China Lanzhou institute of {1. Chinese Academy of Sciences Lanzhou China

Abundant terrigenous triterpenoid ketones and a series of hopanoid ketones were detected in a peat sample from the recent Gannan Marsh. The identifications of pen-tacyclic triterpenoid ketones are discussed in detail. Based on the compositional features of pentacyclic triterpenoid ketones in the sample, it is proposed that terrigenous triterpenoid kentones originate directly from organisms or are diagenetic oxidation products of their alcohols, and hopanoid ketones are formed from hopanoids (e.g. hopanoid alcohols and hopenes) by chemical and biochemical processes. These data provide evidence for the applied studies of pentacyclic triterpenoid ketones as biomarker compounds.

关键词： Gannan Marsh peat pentacyclic triterpenoid ketones identification biochemistry.

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MULTI-PERIODIC COLLISIONAL PROCESS BETWEEN INDIAN AND ASIAN CONTINENTS:A CASE OF EASTERN HIMALAYAN SYNTAXIS AND HENGDUAN MOUNTAINS

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地学前缘 2000年第S1期7卷 47-48页

作者： Zhong Dalai 1. Ding Lin 1. Zhang Jinjiang 1. Ji Jianqing 2(1.institute of geology and geophysics, {1. Academy of Sciences, Beijing 1.0029, China 2 Department of geology, Peking University, Beijing 1.0871. China)

Our study area covered the Eastern Himalayan Syntaxis (EHS) and its southern extension (Hengduan Mountain or western Sichuan and Yunnan (WSY)) which is located at the orthogonal and oblique collisional front between Indian and Asian continents during *** on geometric and kinematic mapping of the major boundary or regional faults (Dongjug—Mainling(1., Anigiao(2) and Jali(3), Guyu(4) faults in EHS, Ailaoshan—Red River(5), Lancangjiang(6), Gaoligong(7), Binlangjiang(8) and Magok(9) faults in WSY) (see Fig.1., especially on abundant geochronological dating of the mylonitic rocks along these faults, and coupled with magmato\|metamorphic sequences of this region, we try to deal with the temporal and spatial relationships of collisional process to answer questions such as: (1. when did collision start ? (2) is thrusting as a initial and dominant deformation mode to absorb the crustal shortening after suturing, or earlier thrusting usually followed by large\|scale strike\|slip faults? (3) are the two structural patterns coeval at times, or do they occur alternatively during deformation history? (4) are the collisional and associate uplift processes a continuous one or periodic? Insight into such questions is crucial for better understanding of the continental deformation and testing the models available or constraining a new one.

关键词： collisional process multi\|period tectonic events Eastern Himalaya

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The microtine distribution and its environmental significance since the Middle Pleistocene in Zhangping Caves of the Qinling Mountains

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Science China Earth Sciences 2008年第2期51卷 294-299页

作者： LI YongXiang1.& XUE XiangXu1.2 1.State Key Laboratory of Continental Dynamics, Department of geology, Northwest University, {1. of Cenozoic geology and Environment, Xi’an 71.069, China 2 {1. of Earth Environment, State Key Laboratory of Loess and Quaternary geology, chinese Academy of Sciences, Xi’an 71.075, China 1. State Key Laboratory of Continental Dynamics Department of Geology Northwest University Institute of Cenozoic Geology and Environment 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

Three microtine species are recovered from the Zhangping Caves of the Qingling Mountains, namely Microtus oeconomus, Caryomys inez and Caryomys eva. They are climate-sensitive ones with different ecological habits, therefore their distribution well corresponds to environmental variations. Statistical comparison of the distribution of fossil microtines and their counterparts nowadays displays that the climate variation of the studied area and its contiguity since the middle Pleistocene are: warm and humid at 493 ka ago, cool and humid at 259 ka ago―cold and humid at 205 ka ago―cool and humid at 28 ka ago, and warm and dry at present.

关键词： environmental variation since Middle Pleistocene microtine fossils Zhangping Caves of the Qinling Mountains

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The discovery of aeschnidiid nymphs (Aeschnidiidae, Odonata, Insecta)

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chinese Science Bulletin 2000年第11期45卷 1031-1038页

作者： ZHANG JunfengNanjing institute of {1. and Palaeontology, chinese Academy of Sciences, Nanjing 21.008, China Nanjing institute of {1. and Palaeontology Chinese Academy of Sciences Nanjing China

Aeschnidiid nymphs are here first identified and described, and its phylogenetic relationship and bioecological characteristics are deduced. The nymphs known from China, Mongolia, Russia and Brazil and arranged in the family Aeschnidiidae are, in fact, unrelated to this group. All the known five chinese species in four genera which were erected based on fossil nymphs and placed in the family Gomphidae may be transferred in Aeschnidiidae and merged into one alone, the Sinaeschnidia cancellosa. It is a geographically widespread species from the 'Jehol biota' of East Asia and appeared in the latest Late Jurassic age.

关键词： Jehol biota Aeschnidiidae dragonfly nymphs.

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High-temperature phases of pyrophyllite and their evolutionary characteristics

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chinese Science Bulletin 1997年第2期42卷 140-144页

作者： WANG Ling and ZHANG Zhenyu1. Changsha institute of Geotectonics, {1. Academy of Sciences, Changsha 41.01., China 2. institute of geology, {1. Academy of Sciences, Beijing 1.0029, China Changsha institute of Ceotectonics Chinese Academy of Sciences Changsha China institute of {1. Chinese Academy of Sciences Beijing China

WITH the increase of heating temperature, phase of pyrophyllite will undergo a series of transformations. Former scholars have done some work in this respect; the temperature spans,however, were normally not more than 1.50℃ and no relatively comprehensive results have been reported. Thus, the features of the phases from indoor temperature to melting point (1.1.℃±) for pyrophyllite and the entire evolutionary process of the phases are uncertain.

关键词： pyrophyllite high-temperature phase phase tranformation pyrophyllite anhydrite mullite cristobalite.

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Dating of the Karakorum Strike-slip Fault

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Acta Geologica Sinica(English Edition) 2001年第1期75卷 10-18页

作者： ZHOU Yong, XU Ronghua, YAN Yuehua, PAN Yusheng,Tsanyao Frank YANG, Wei LO and WU Chunming Laboratory of Lithosphere Tectonic Evolution, institute of geology and geophysics, {1. Academy of Sciences, Beijing 1.0029Department of geology, National Taiwan University, 245 Choushan Road, Taipei 1.6-1., TaiwanDepartment of geology, {1. Culture University, Hwa-kang, Yang-Ming-Shan, Taipei, Taiwan institute of geology, {1. Academy of Geological Sciences, Beijing 1.0037 Laboratory of Lithosphere Tectonic Evolution Institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100029 Department of geology National Taiwan University 245 Choushan Road Taipei 106–17 Taiwan Department of geology Chinese Culture University Hwa-kang Yang-Ming-Shan Taipei Taiwan institute of {1. Chinese Academy of Geological Sciences Beijing 100037 [?]5Zhou Yong Male born in 1.68 graduated from Chengdu College of geology with a master's degree in 1.91. From 1.91.to 1.95 he focused on ore deposit investigation. Since 1995 he has studied structural geology associated with the Qinghai-Tibet plateau. Tel: (010) 62008438.

This paper mainly discusses the timing of the Karakorum strike-slip fault, and gives a brief introduction of its structures, offset, and deformational style. This fault strikes NNW-SSE. Asymmetrical folds, stretching lineation, S-C fabrics, feldspar and quartz s?-porphyroclasts, domino structure, shear cleavages and faults in the fault zone are products of tectonic movements. They all indicate a dextral slip sense of faulting. Mylonitic bands are widely developed along this fault. Phengite appears, indicating rather high deformational pressure. Geochronological data indicate that the Karakorum strike-slip faulting occurred from 6.88±0.36 to 8.75±0.25 Ma. The cumulative displacement from Muztag Ata to Muji is about 1.5 km.

关键词： Karakorum fault kinematics timing displacement

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