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Evidence for metasomatic mantle carbonatitic magma extrusion in Mesoproterozoic ore-hosting dolomite rocks in the middle Kunyang rift, central Yunnan, china

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Progress in Natural Science:Materials International 2008年第8期18卷 965-974页

作者： Yongbei Zhanga,b,c, Hua Bia,*, Longshi Yua, Shihua Sunc, Jiaxiang Qiub, Chengyan Xub, Hao Wang b, Renjing Wang b a The Department of resources, Environment and Tourism, Hainan Normal University, No. 432, Yinpo Road, Longshepo, Haikou 57000, china b Key Laboratory of mineral resources, institute of geology and Geophysics, Chinese Academy of Sciences, beijing 10002., china c Faculty of Earth Sciences, china University of Geosciences, Wuhan 470074, china The Department of resources Environment and Tourism Hainan Normal University No. 432 Yinpo Road Longshepo Haikou 57000 China Key Laboratory of mineral resources Institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100029 China Faculty of Earth Sciences China University of Geosciences Wuhan 470074 China

The Kunyang rift lying on the western margin of the Yangtze platform is a rare Precambrian Fe-Cu mineralization zone. WudingLufeng basin that is an important part of the zone is located on the west edge in the middle of the rift. The most important ore-hosting rocks are Mesoproterozoic dolomite rocks in the basin controlled by a ring fracture system, which is a fundamental structure of the basin. Plenty of silicate minerals and acicular apatite, feldspar phenocrysts and small vesicular, flown line and flown plane structures, melt inclusion and high temperature fluid inclusion found in most ore-hosting dolomites suggest that this kind of rocks could not be sedimentary dolomite, marble or hydrothermal carbonate rocks. The Zr/Hf and Nb/Ta values of the rocks are identical with those of associated mantle-derived rocks, and vary widely. For the monomineral dolomite, d18OSMOW‰ = +5.99 to +18.4 and d13CPDB‰ = à3.01 to +0.94, which fall within the range for all carbonatitic volcanic rocks of the world. As for the accessory minerals, the values of d18OSMOW‰ of magnetite (=+3.47 to +5.99‰) are close to that of the mantle (34S‰ values of sul?des (à5.09 to +5.78, averaging +1.50) are close to that of meteorite. For all the ore-bearing dolomite rocks, eNd = +0.19 to +2.27, and the calculated ISr = 0.699143, while for the associated mantle-derived rocks, eNd = +3.18 to +3.72. All the data suggest that the mineral assemblage is not only igneous but also of metasomatic mantle origin. And the presence of acicular apatite indicates that the rocks were formed by magma rapidly cooling. And the phenocryst texture and vesicular, flown and ropy and pyroclastic structures suggest that the igneous rocks were extrusive. Therefore, the ore-bearing dolomite rocks are carbonatitic volcanic rocks. This conclusion implies that most iron and copper ore deposits hosted in the dolomite rocks should be of the carbonatite type.

关键词： Central Yunnan Kunyang rift Precambrian mineralization Carbonatitite Volcanic rocks Petrogenesis Iron and copper ore deposit

Study of Noble Metal Elements in Lower Cambrian Black Rock Series of Guizhou-Hunan Provinces, china

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Journal of Earth Science 1999年第1期18卷 93-96页

作者： Li Shengrong Department of geology and mineral resources, china University of Geosciences, beijing 100083 Gao Zhenmin institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002

Systematic analyses of noble metal elements in the Lower Cambrian black rock series of South china are reported. Correlations of w (Os)/ w (Ir), w (Au)/ w (Ir), w (Ag)/ w (Au), w (Pt+Pd)/ w (Os+Ru+Rh+Ir), relations of noble metal and platinum group element (PGE) distribution patterns reveal that the noble metals are not directly from extraterrestrial materials. Studying the data of 9 aspects, the authors conclude that the noble metals were mainly from ultramafic mafic igneous rocks and their enrichment in black rocks is mainly controlled by hydrothermal fluid.

关键词： black shale Au Ag PGE Lower Cambrian Guizhou Hunan provinces china.

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 100081, china 3. beijing Center of SHRIMP, beijing 100037, china 4. institute of geology, Chinese Academy of Geological Sciences, beijing 100037, china Geological Surveying institute of Hainan Haikou China institute of Geomechanics Chinese Academy of Geological Sciences Beijing China beijing Center of SHRIMP Beijing China institute of geology Chinese Academy of Geological Sciences 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.

Tectonic setting of the Helong Block:Implications for the northern boundary of the eastern North china Craton

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Science china Earth Sciences 2005年第10期48卷 1599-1612页

作者： ZHANG Yanbin1, WU Fuyuan1, ZHAI Mingguo1 & LU Xiaoping1,2 1. institute of geology and Geophysics, Chinese Academy of Sciences, P.O. Box 9825, beijing 10002., china 2. Regional Geological and mineral resources Survey of Jilin Province, Changchun 130062, china Chinese Academy of Sciences Regional Geological and mineral resources Survey of Jilin Province

LA-ICP-MS zircon U-Pb dating indicates that the Bailiping granitic pluton was em-placed during Late Paleozoic to Early Cretaceous (285―116 Ma) by four distinct magmatic epi-sodes, arguing against the previous thought that the Bailiping granites were emplaced during Archean, Proterozoic or Early Paleozoic. It is suggested that the so-called Archean Jincheng-dong granite-greenstone belt, mainly composed of Bailiping granites, should be broken down. Sr-Nd isotopic compositions of the Bailiping granites are similar to those of the Phanerozoic granites in the Xing’an-Mongolian orogenic belt, suggesting that their parental magmas were mainly derived from a juvenile crust with some contamination of ancient crustal materials during magma rising and/or emplacement. Therefore, the basement of the Helong Block is similar to that in the northern Xing’an-Mongolian Orogenic Belt, but different from that of the North china Craton. It is proposed that the Archean Jinchengdong complex in this area is probably an exotic slice from the North china Craton, which indicates that the Fu’erhe-Gudonghe Fault, located in northern part of the Helong area, is not the boundary between the North china Craton and the Xing’an-Mongolian Orogenic Belt. The possible boundary should be located further southward more than 50 km and near the Baitoushan volcano.

关键词： LA-ICPMS ziron U-Pb dating, Bailiping complex, Helong Block, North china Craton, Sr-Nd isotope.

Laser probe ^(40)Ar/^(39)Ar dating of mica on the deformed rocks from Altyn Fault and its tectonic implications,western china

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Chinese Science Bulletin 2001年第4期46卷 322-325页

作者： LIU Yongjiang, YE Huiwen, GE Xiaohong, CHEN Wen, LIU Junlai, REN Shoumai & PAN HongxunCollege of Earth Sciences, Changchun University of Science and Technology, Changchun 130061, china Graduate School, china University of Geosciences, beijing 100083, china Laboratory of Isotopic Geochronology, institute of geology, Ministry of Land and resources of china, beijing 100037, china College of Earth Sciences Changchun University of Science and Technology Changchun China Graduate School China University of Geosciences Beijing China Laboratory of Isotopic Geochronology Institute of Geology Ministry of Land and Resources of China Beijing China

The samples of Caledonian mylonitized granite and Jurassic meta-sedimentary rocks were collected in the north of Dangjinshan Pass, Qaidam gate fault-valley and Gesi fault-valley. Detailed studies under the microscope and electronic microscope suggest that all the samples contain the syntectonic-growing minerals such as white mica, chlorite, sericite, biotite, etc. By dating these minerals, we got a group of 40Ar/39Ar laser probe isochronal ages of 89-92 Ma and apparent ages of (46.6±6.4) Ma. The ages ranging from 97 to 46 Ma were reported for the first time in the isotopic dating researches of the Altyn Fault The isochronal age group of (98-89) Ma indicates that a ductile strike-slip event, with low-grade metamorphism, began in late Cretaceous. This suggests that the strike-slip movement of the Altyn Fault should be related to the formation of the so-called west tectonic syntaxis in the Nepal-western Kunlun area.

关键词： Altyn Fault 40Ar/39Ar age strike-slip movement.

Megaclasts from the Carboniferous-Permian Rocks in the Langkawi Islands, Malaysia, and Their Implications

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Acta Geologica Sinica(English Edition) 1999年第1期73卷 120-122页

作者： Chen Tingyu institute of geology 26 Baiwanzhuang Road,Chinese Academy of Geological Sciences, beijing 100037,china Chinese Acad Geol Sci Inst Geol Beijing 100037 Peoples R China

The Ninth Regional Congress on geology, mineral andEnergy resources of Southeast Asia was held in KualaLumpur of Malaysia in August of 1998. After the Con-gress, the author participated in the geological fieldexcursion and investigation in the Langkawi Islands,and noted that the Carboniferous-Permian rocks con-tain megaclasts of metamorphic and pegmatitic rocks,which indicate the existence of pre-Carboniferousmetamorphism and magmatism. The observation resultsare as follows:

关键词： Malaysia and Their Implications Megaclasts from the Carboniferous-Permian Rocks in the Langkawi Islands

Megaripples from the Mesoproterozoic of the Kimberley region,northwestern Australia and its geological implications

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Journal of Palaeogeography 2012年第1期1卷 15-25页

作者： Lan Zhongwu 1,2,3,,Zhong-Qiang Chen 2,4,1.State Key Laboratory of Lithospheric Evolution,institute of geology and Geophysics,Chinese Academy of Sciences,beijing 10002.,china 2.School of Earth and Environment,The University of Western Australia,Australia 3.Key Lab of Petroleum resources research,institute of geology and Geophysics,Chinese Academy of Sciences,beijing 10002.,china 4.State Key Laboratory of Biogeology and Environmental geology,china University of Geosciences (Wuhan),Wuhan 430074,china State Key Laboratory of Lithospheric Evolution Institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100029 China School of Earth and Environment The University of Western Australia Australia Key Lab of Petroleum resources research Institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100029 China State Key Laboratory of Biogeology and Environmental geology China University of Geosciences (Wuhan) Wuhan 430074 China

Large ripples are described from the Mesoproterozoic Hilfordy Formation in the Kimberley region,northwestern *** ripple index (RI) and ripple symmetry index (RSI) suggest the Kimberley ripples were likely generated by storm *** wave height is up to 15 23 cm and wave length is up to 70 90 *** features,incorporated with other morphological characteristics such as symmetry,steepness,ripple spacing,and compositions,agree well with the megaripples previously reported from the intertidal-nearshore settings of modern seas and the geological *** Mesoproterozoic ripples were likely generated by the storm-induced *** survey of the global record of megaripples reveals that such structures have occurred through the geological past from the Archean to present *** were particularly common in the Neoproterozoic and had the largest ripple length and ripple height among the modern and geological *** is probably because extreme storms prevailed at that *** frequent occurrence in present day beach is probably due to the prevalence of extreme storms caused by the monsoon or tsunami/earthquake influenced climatic regimes.

关键词： megaripples palaeohydrodynamics extreme storms Mesoproterozoic Hilfordy Formation Kimberley northwestern Australia

Slope Debris Flows in the Wenchuan Earthquake Area

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Journal of Mountain Science 2010年第3期7卷 226-233页

作者： LI Yanfu WANG Zhaoyin SHI Wenjing WANG Xuzhao State Key Laboratory of Hydroscienee and Engineering Tsinghua University Beijing 100084 China beijing institute of geology for mineral resources Beijing 100012 China

Avalanches and landslides,induced by the Wenchuan Earthquake on May 12,2008,resulted in a lot of disaggregated,solid material on slopes that could be readily mobilized as source material for debris *** triggered numerous slope debris flows with great damage to highways and rivers over the subsequent two *** debris flows(as opposed to channelized debris flows) are defined as phenomena in which high-concentration mixtures of debris and water flow down slopes for short distances to highways and river *** on field investigations and measurements of 19 slope debris flows,their main characteristics and potential mitigation strategies were *** rainfall intensity is the main triggering *** rainfall intensities for simultaneous occurrence of single,several and numerous slope debris flow events were 20 mm/day,30mm/day,and 90 mm/day,*** investigations also revealed that slope debris flows consist of high concentrations of cobbles,boulders and *** are two-phase debris *** liquid phase plays the role of lubrication instead of transporting *** particles collide with each other and consume a lot of *** velocities of slope debris flows are very low,and their transport distances are only several tens of *** debris flows may be controlled by construction of drainage systems and by reforestation.

关键词： Slope debris flow rainfall intensity Wenchuan Earthquake landslide avalanche

Origin of the Red Earth sequence on the northeastern Tibetan Plateau and its implications for regional aridity since the middle Miocene

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Science china Earth Sciences 2006年第5期49卷 505-517页

作者： WANG Xianyan1,7, LU Huayu1,2, JI Junfeg3, WANG Xiaoyong1,7, ZHAO Jingbo4, HUANG Baochun5 & LI Zhen6 1. SKLLQG, institute of Earth Environment, Chinese Academy of Sciences, Xi’an 710075, china 2. Department of Urban and resources Sciences, Nanjing University, Nanjing 210093, china 3. Department of Earth Sciences, Nanjing University, Nanjing 210093, china 4. Department of Geography, Shaanxi Normal University, Xi’an 710062, china 5. institute of geology and Geophysics, Chinese Academy of Sciences, beijing 10002., china 6 Department of Geography, Qinghai Normal University, Xining 810008, china 7. Graduate School of the Chinese Academy of Sciences, beijing 100039, china SKLLQG Institute of Earth Environment Chinese Academy of Sciences Xi’an China Graduate School of the Chinese Academy of Sciences Beijing China Department of Urban and resources Sciences Nanjing University Nanjing China Department of Earth Sciences Nanjing University Nanjing China Department of Geography Shaanxi Normal University Xi’an China institute of geology and Geophysics Chinese Academy of Sciences Beijing China Department of Geography Qinghai Normal University Xining China

The Red Earth deposit around Xining, northeastern Tibetan Plateau, has beenstudied in terms of soil micro-structure, grain-size distribution, major- and trace-elementchemistry and magne-tostratigraphy. Field investigations indicate that the Red Earth sequenceconsists of 25 visually definable yellow-brown and weakly-developed soils interbedded with reddishstrongly-developed soils, and has a similar structure to the aeolian Red Clay deposit on the ChineseLoess Plateau. Grain-size analysis shows that the Red Earth deposit is very fine-grained with anegligible sand fraction ( > 63 μm). Thin-section observations under light microscopy show that thedeposit has a clayey texture and the coarse fraction ( > 10 μm) mainly consists of quartz,feldspar and micas. Pyroxene and hornblende were also observed. This mineralogical composition ofthe coarse fraction is similar to that of the Quaternary loess. In addition, all of the mineralgrains are semi angular semi-angular and are generally finer than 63 μm. There is a good agreementbetween the major and minor trace element chemistry of loess-soil units and the Red Earth *** REE distributions of the loess-soil and the Red Earth deposit are similar in shape, withenriched LREE and fairly flat HREE profiles and a clear negative Eu anomaly. The geochemicalcharacteristics of the Red Earth deposit are also identical to those of upper continental crust,thus indicating a wind-blown origin. Magnetostratigraphic investigation shows that onset of the RedEarth deposition predates 11.4 Ma BP (13.6 Ma at a nearby site). The distribution of the reportedMiocene aeolian loess at Qin''an of the Loess Plateau is still unknown. Our results indicate thatthis aeolian deposit had extended to the northeastern Tibetan Plateau by at least the middleMiocene. The similarity of the element geochemistry between the Red Earth deposit and the overlyingloess shows that they may have similar sources and dynamic transport system, and may indicate thatthe

关键词： Red Earth deposit, Northeastern Tibetan Plateau, aeolian deposit, aridity of Asia, the middle Miocene.