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The LA-ICP-MS zircons U-Pb ages and geochemistry of the Baihua basic igneous complexes in Tianshui area of West Qinling

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Science China Earth Sciences 2007年第z2期50卷 264-276页

作者： PEI XianZhi DING SaPing ZHANG GuoWei LIU HuiBin LI ZuoChen LI GaoYang LIU ZhanQing MENG Yong Key Laboratory of Western China's Mineral Resources and Geological Engineering Ministry of Education Faculty of Earth Science and Land Resources Chang'an University Xi'an 710054 China Key Laboratory of Western China's Mineral Resources and Geological Engineering Ministry of Education Faculty of Earth Science and Land Resources Chang'an University Xi'an 710054 China State Key Laboratory of Continental Dynamics Department of Geology Northwest University Xi'an 710069 China Key Laboratory of Western China's Mineral Resources and Geological Engineering Ministry of Education Faculty of Earth Science and Land Resources Chang'an University Xi'an 710054 China

Baihua meta-igneous complex consists mainly of pyroxenite-gabbro(diorite)-diorite-quartz diorite. They form a complete comagmatic evolutionary series. The geochemical characteristics of basic-interme- diate basic igneous rocks indicate that they belong to a tholeiite suite. The REE distribution pattern is nearly flat type and LREE is slightly enriched type, and their primitive mantle-normalized and MORB-normalized trace element spider diagrams are generally similar; the LIL elements (LILE) Cs, Ba, Sr, Th and U are enriched, but Rb, K and the HFSEs Nb, P, Zr, Sm, Ti and Y are relatively depleted. All these show comagmatic evolution and origin characteristics. The tectonics environment discrimination of trace element reveals that these igneous complexes formed in an island-arc setting. The LA-ICP-MS single-zircons U-Pb age of Baihua basic igneous complex is 434.6±1.5 Ma (MSWD = 1.3), which proves that the formation time of the island-arc type magmatite in the northern zone of West Qinling is Late Ordovician or Early Silurian, also reveals that the timing of subduction of paleo-ocean basin represented by the Guanzizhen ophiolite and resulting island-arc-type magmatic activities is probably Middle-Late Ordovician to Early Silurian.

关键词： basic igneous complex, island-arc setting, LA-ICP-MS, zircons U-Pb isotopic ages, Tianshui area, West Qinling

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Timing of the terrestrial Permian-Triassic boundary biotic crisis:Implications from U-Pb dating of authigenic zircons

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Science China Earth Sciences 2008年第11期51卷 1633-1645页

作者： YU JianXin LI HuiMin ZHANG SuXin YANG FengQing FENG QingLai Key Laboratory of Biogeology and Environmental Geology of Ministry of Education China University of GeosciencesWuhan 430074China Tianjin Institute of Geology and Mineral Resources Tianjin 300170China State Key Laboratory of Geological Processes and Mineral Resources China University of GeosciencesWuhan 430074China

The Late Permian to Early Triassic transition represents one of the most important Phanerozoic mass extinction episodes. The cause of this event is still in debate between catastrophic and gradual mechanisms. This study uses the U-Pb method on zircons from the uppermost Permian/lowermost Triassic clay deposits at Chahe (Guizhou Province, SW China) to examine time constraints for this event. The results of both this and previous studies show that the ages of Bed 68a and 68c (the upper clay bed of the terrestrial Permian-Triassic boundary (PTB)) respectively are 252.6±2.8 and 247.5±2.8 Ma. This age (within the margin of error) almost accords with the upper clay bed (Bed 28) age of Meishan and the eruption age of Tunguss Basalt, and is so far the most accurate age obtained from terrestrial PTB. The claystone of Bed 68 was formed in the earliest Triassic. The biotic crisis occurred at nearly the same time in terrestrial and marine environments during Permian-Triassic interval; however the extinction patterns and processes are different. The extinction pattern of the terrestrial plants shows a major decline at the PTB after long-term evolution, followed by a retarded extinction of the relicts in the earliest Triassic.

关键词： terrestrial Permian-Triassic boundary floral extinction pattern U-Pb age zircons

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Detrital Zircon U–Pb Geochronology and Provenance of Bayan Obo Group, Northern Margin of North China Craton: New Implications for the Position of NCC in Rodinia

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Acta Geologica Sinica(English Edition) 2019年第5期93卷 1397-1416页

作者： LI Changhai LIU Zhenghong XU Zhongyuan DONG Xiaojie LI Pengchuan SHI Qiang WANG Shijie College of Earth Sciences Jilin UniversityChangchun 130001China Key Laboratory of Mineral Resources Evaluation in Northeast Asia Ministry of Natural ResourcesChangchun 130026China

The paleoposition of North China Craton in Rodinia has long been in controversial. This paper mainly focuses on the U-Pb geochronological studies of detrital zircons obtained from Bayan Obo Group exposed in the Shangdu area, Inner Mongolia, aiming to provide more information for interprating this problem. Based on the acquired data, this paper comes to the following conclusions. Firstly, the depositional age of Bayan Obo Group might be from Meso- to Neoproterozoic according to the zircons U-Pb dating results. The lower succession of this group, namely Dulahala and Jianshan formations deposited between 1800 and 1650 Ma. The Halahuogete and Bilute formations deposited between 1500 and 1350 Ma. For Baiyinbaolage and Hujiertu formations, their depositional age was 1250-900 Ma. Secondly, for the provenance of Bayan Obo Group, this paper believes detrital zircons with age of 2.51-2.71 Ga and 2.00-2.48 Ga were from Guyang, Xi Ulanbulang and Zhuozi area;the Khondalite Belt provided detrital zircons with age of 1.95-1.80 Ga;zircons with age of 1.60-1.75 Ga might come from granitic rocks in Miyun Area. The magmatism after 1.60 Ga was rarely recorded in the NCC, therefore those zircons with ages younger than 1.60 Ga might come from outside of NCC. The magmatism with the same age existed in Baltic, Amazonia and Laurentia. Based on previous paleomagnetic researches, this paper proposes that NCC might receive detritus from Baltic during 1560-1350 Ma and had affinity with Laurentia and Amazonia at ~0.9 Ga in Rodinia. Baltic, Amazonia and Laurentia might be potential provenances for non-NCC detritus in Bayan Obo Group.

关键词： North China Craton Precambria Bayan Obo Group detrital zircons Rodinia

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Zircon chemistry and new laser ablation U–Pb ages for uraniferous granitoids in SW Cameroon

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Acta Geochimica 2020年第1期39卷 43-66页

作者： V.F.Embui C.E.Suh J.M.Cottle J.Etame J.Mendes C.M.Agyingi A.Vishiti E.M.Shemang B.Lehmann Department of Geology University of BueaP.O.Box 63BueaSouth West RegionCameroon Ore Treatment Laboratory Institute of Geological and Mining Research(IRGM)P.O.Box 4110YaoundeNlongkakCameroon Department of Geology Mining and Environmental ScienceUniversity of BamendaP.O.Box 39BambiliCameroon Department of Earth Sciences and Earth Research Institute Webb Hall 2028University of CaliforniaSanta BarbaraCA 93106-9630USA Laboratory of Geosciences Natural resources and Environment Department of Earth SciencesFaculty of ScienceUniversity of DoualaP.O.Box 24157DoualaCameroon Department of Civil Engineering University Institute of TechnologyUniversity of DoualaP.O.Box 8698DoualaCameroon Departamento de Geologia IGEOUniversidade Federal do Rio de JaneiroCidade UniversitariaRio de Janeiro 21910-949Brazil Department of Earth and Environmental Sciences Botswana International University of Science and TechnologyPrivate Bag 16PalapyeBotswana Mineral Resources Technical University of ClausthalClausihal-ZellerfeldGermany

The Ekomedion two-mica granite,southwestern Cameroon,has potential for uranium and molybdenum ***,we present LA-ICP-MS U-Pb ages,Lu-Hf isotope characteristics,trace element concentrations and Ti-geothermometry of zircon from this granite hosting U-Mo mineralization in pegmatitic *** majority of zircon are CL-dark though some CL-bright cores were also identified.U-Pb zircon age data range from 121±3 to743±11 Ma with only 5 of 34 ages being near *** concordant mean age of 603±12 Ma is similar to ages of granitic intrusions along the Central African Shear Zone in *** ages with mean of261±6 Ma reveal open system behavior with respect to Pb and/or *** e Hfi values range from-20.3 *** implies that U-Mo was remobilized during partial melting of the surrounding *** Th/U>0.1 as well as an increasing Hf with decreasing Th/U indicates that fractional crystallization was the main factor that controlled U-Mo mineralization in pegmatitic pods.Y and Y/Ho ratios cluster from 29 to 33 close to the chondritic ratio of 28 and indicate fractionation of Y and Ho with low F contents during the earliest stages of *** stage accumulation of F-rich magmatic-hydrothermal fluids impacted U-Mo mineralization as a *** contains a prominent negative Eu anomaly pointing to a fractionating system rich in *** Ti-in-zircon temperatures span 672℃to1232℃with the temperatures at the high end reflecting interference from mineral inclusions in the zircon grains while the lower temperature values are linked to crystallization.

关键词： zircons Uranium-molybdenum Cameroon

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SHRIMP zircon U-Pb dating of the intrusives in the Tongling metallogenic cluster and its dynamic setting

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Science China Earth Sciences 2008年第7期51卷 911-928页

作者： GanGuo Wu Da Zhang YongJun Di WenShuan Zang XiangXin Zhang Biao Song ZhongYi Zhang State Key Laboratory of Geological-Processes and Mineral Resources China University of Geosciences Beijing 100083 China Shijiazhuang University of Economics Shijiazhuang 050031 China Institute of Geology Chinese Academy of Geological S

This paper selected five typical Mesozoic intrusives from the Tongling metallogenic cluster (Xiaotongguanshan, Fenghuangshan, Xinqiao, Dongguashan, and Shatanjiao plutons), and made a systemic SHRIMP zircon U-Pb datin... 详细信息

关键词： intrusive rocks SHRIMP U-Pb dating of zircons geodynamics Neoproterozoic the Tongling metallogenic cluster area

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Detrital zircon U–Pb geochronology and Hf isotopic compositions of Middle–Upper Ordovician sandstones from the Quruqtagh area, eastern Tarim Basin:implications for sedimentary provenance and tectonic evolution

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Chinese Science Bulletin 2014年第10期59卷 1002-1012页

作者： Shunli Dong Zhong Li Jianqiang Xu Jian Gao Chuntao Guo Institute of Geology and Geophysics Chinese Academy of Sciences University of Chinese Academy of Science

Figuring out whether the sedimentary provenance regions of the thick deep-water turbidite systems deposited during Middle–Upper Ordovician in South Quruqtagh are the intracontinental uplifts or the peripheral orogenic belts is of great significance for us to understand the tectono-sedimentary nature of the northeastern Tarim Basin and basin-range coupling processes in the middle *** paper reports the in situ LA-ICP-MS U–Pb ages and Hf isotope data on detrital zircons from two Middle–Upper Ordovician sandstone samples which were collected from the Charchag Formation and the Zatupo Formation in South Quruqtagh,*** results show that the studied two samples have extremely similar U–Pb age patterns and Hf isotopic compositions,reflecting multiphase tectonothermal events with age groups of 527–694,713–870 Ma(peaking at 760 Ma),904–1,090,1,787–2,094 Ma(peaking at 1,975 Ma)and 2,419–2,517 *** previous studies,the presence of age groups of 713–1,090 and1,787–2,094 Ma,respectively,demonstrates that Tarim had ever been a part of Rodinia and Columbia ***,98%of 713–870 Ma detrital zircons are characterized by negative e Hf(t)values ranging from-38.07 to-0.61,which are highly consistent with those of Neoproterozoic granites from the Quruqtagh *** Early Paleozoic ages(*470–500 Ma)signifying subduction or collision events in Altyn Tagh were detected in the two samples,indicating that the Middle–Late Ordovician sediments in South Quruqtagh and northern Mangar depression were mainly derived from intracontinental uplifts,i.e.,the North Quruqtagh uplift or the Tabei paleo-uplift,rather than the Altyn *** conjunction with regional sedimentary-tectonic background and previous studies,we proposed preliminarily that the northeastern Tarim remained as a passive continental margin in Late Ordovician and changed into an active-continental margin in Silurian due to the southward subduction of the South-Tianshan Ocean.

关键词： Tarim Basin - Quruqtagh Middle-Upper Ordovician Detrital zircons Provenance Altyn Tagh

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The New Data on Stratigraphy of the Riphean Stratotype in the Southern Urals, Russia

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Journal of Geoscience and Environment Protection 2014年第3期2卷 108-116页

作者： V. N. Puchkov A. A. Krasnobaev N. D. Sergeeva 1Institute of Geology Ufimian Scientific Centre of RAS Ufa Russia 2Bashkirian State University Ufa Russia Institute of Geology and Geochemistry Uralian Branch of RAS Ekaterinburg Russia Institute of Geology Ufimian Scientific Centre of RAS Ufa Russia

A recent series of U-Pb age determinations of zircons (SHRIMP, IDTIMS) from volcanic flows of several levels permitted to refine stratigraphy of the Riphean of Bashkirian megaanticlinorium (Urals, Russia), and provide... 详细信息

关键词： Proterozoic Stratigraphy U-Pb Dating zircons International Stratigraphic Scale Riphean

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Do U/Pb-SHRIMP Dating and Pb Stepwise Leaching (PbSL) Analyses Confirm the Lack of Precambrian Basement Outcrops in Thailand?

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Open Journal of Geology 2014年第10期4卷 505-517页

作者： Bent T. Hansen Klaus Wemmer Prinya Putthapiban Ilka C. Kleinhanns Franziska Wilsky Geoscience Centre of the Georg-August-University Gottingen Germany Geoscience Programme Kanchanaburi Campus Mahidol University Tambon Salaya Thailand Department of Geoscience University of Tuebingen Tübingen Germany

U/Pb-SHRIMP dating and Pb stepwise leaching (PbSL) experiments on zircons and garnets, respectively have confirmed the lack of Precambrian outcrops within the crystalline basement of Thailand. The obtained data for the high grade metamorphism show Indosinian ages ranging from 225 - 200 Ma as previously suggested for the vast majority of outcrops in NW-Thailand ([1]?and references therein), as well as a small group of ages in the range of 445 Ma in the Lampang Province. Further, the age of a thermal imprint around 60 Ma was confirmed near Surat Thani, Peninsular Thailand, and only a few indications of older ages for the unknown source areas were detected in detrital components.

关键词： SHRIMP Dating Pb Stepwise Leaching (PbSL) zircons Basement Thailand

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New detrital zircon U-Pb ages from BIF-related metasediments in the Ntem Complex (Congo craton) of southern Cameroon, West Africa

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Natural Science 2013年第7期5卷 835-847页

作者： Nelson N. Chombong Emmanuel C. Suh Charles D. C. Ilouga Department of Earth Sciences University of Yaoundé I Yaoundé Cameroon Economic Geology Unit Department of Geology University of Buea Buea Cameroon

Banded Iron Formations (BIFs) were formed by contemporaneous events of active sediments supply and the venting of a hydrothermal fluid source at the Mid-Ocean-Ridge. BIFs within the Ntem Complex at the northern edge of the Congo Craton are intercalated with metasandstones and siltstones. SHRIMP U-Pb analysis on detrital zircons obtained from these metasediments gave variable ages from over 3000 Ma to 1000 Ma with the maximum age of deposition clustered around 1200 Ma and the peak of deposition at 1800 Ma. This age range suggested that the sub-basin was opened sometime in the Archean and remained active up till the Neoproterozoic. zircons with Archean ages have a provenance linked to the charnockitic suite and the high-K granites within the Ntem Complex. The Paleoproterozoic ages are attributed to clastic inputs from the neigbouring Nyong Series west of the Ntem Complex. Also the peak of deposition in the Proterozoic could probably be explained by the globally recognized intense crust-forming processes in the Early Proterozoic time. The provenance of the younger Neoproterozoic ages is tied to various lithologies within the northern mobile belts of the Adamawa-Yade massifs and correlates with Neoproterozoic sedimentation ages in the Yaoundé, Lom and Poli series. The Neoproterozoic ages obtained are comparable to those obtained from metasediments of the Amazonian Craton and provide evidence of Pre-Gondwana assemblage of the Congo and the S?o Francisco Cratons.

关键词： BIFs Metasediments Ntem Complex SHRIMP U-Pb Age Detrital zircons

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SHRIMP U-Pb Geochronology of Ultrahigh-pressure Metamorphic Rocks of the Dabie Mountains,Central China

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Continental Dynamics 1998年第Z1期 74-87页

作者： S. MARUYAMA, H. TABATA Department of Earth & Planetary Sciences, Tokyo Institute of Technology, Tokyo 152, Japan A. P. NUTMAN Research Institute of Earth & Planetary Sciences, Australian National University, Canberra, Australia T. MORIKAWA

１ＩｎｔｒｏｄｕｃｔｉｏｎＴｈｅｔｈｅｒｍａｌｈｉｓｔｏｒｙｏｆｔｈｅＥａｒｔｈｈａｓｂｅｅｎｄｉｓｃｕｓｓｅｄｆｒｏｍｓｅｖｅｒａｌｄｉｆｅｒｅｎｔｖｉｅｗｐｏｉｎｔｓ，ｉｎｃｌｕｄｉｎｇｔｈｅｏｒｅｔｉｃａｌ... 详细信息

１ＩｎｔｒｏｄｕｃｔｉｏｎＴｈｅｔｈｅｒｍａｌｈｉｓｔｏｒｙｏｆｔｈｅＥａｒｔｈｈａｓｂｅｅｎｄｉｓｃｕｓｓｅｄｆｒｏｍｓｅｖｅｒａｌｄｉｆｅｒｅｎｔｖｉｅｗｐｏｉｎｔｓ，ｉｎｃｌｕｄｉｎｇｔｈｅｏｒｅｔｉｃａｌｃｏｎｓｉｄｅｒａｔｉｏｎｓ（ｅ．...

关键词： SHRIMP Ages zircons Ultrahigh P Metamorphism Dabie mountains China

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