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Experimental constraints on the genesis of Jadeite quartzite from Shuanghe,Dabie Mountain ultra-high pressure metamorphic terrane

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Science China Earth Sciences 2014年第1期57卷 104-116页

作者： ZHANG YanFei WU Yao WANG Chao JIN ZhenMin Hans-Peter SCHERTL State Key Laboratory of Geological Processes and Mineral Resources China University of Geosciences institut für geologie Mineralogie und Geophysik Ruhr-Universit t Bochum 44780 Bochum Germany

Jadeite quartzite,essentially a two-phase rock made up of jadeite and quartz,is one of the most important UHP lithologies occurring in the Dabie Mountain ultrahigh pressure metamorphic belt and forms layers in biotite-plagioclase *** pressurehigh temperature studies on natural albite from the country rock gneiss were undertaken to reveal the—in parts—complex mineralogical changes that occur in the jadeite quartzite during prograde *** were conducted at 800–1200°C,in the pressure range of 2.0–3.5 *** of the most intriguing results shows that the low pressure boundary of the jadeite+coesite stability field is located between about 3.2 GPa at 1000°C and 3.4 GPa at 1200°C,thus about(0.2–0.3)±0.1GPa higher than the quartz-coesite transition curve,given the uncertainty in the present *** amounts of sodium and aluminum entering the structure of quartz and the intimate intergrowth texture of the run products may contribute to the observed pressure *** petrological and mineralogical studies on the run products and the natural rocks yield the following prograde reaction sequence to have occurred:The protolith of the jadeite-quartzite from Dabie Mountain is an albitized siltstone/greywacke characterized by an albite+quartz *** prograde metamorphism albite breaks down to form jadeite+quartz and thus at this stage two types of quartz can be distinguished whereas type-I-quartz already existed in the protolith,type-II-quartz represents a newly formed reaction product of *** further P-T-increase the pure type-I-quartz was transformed to coesite,whereas type-II-quartz(together with jadeite)was still present as a stable phase because of its impurities of Na and *** a later stage during further subduction,type-II-quartz also decomposes to form *** studies represent an important puzzlement for a better understanding of the evolution of jadeite-quartzite from the Dabie Mountain during continental cru

关键词：超高压变质地体硬玉石英岩大别山翡翠实验黑云斜长片麻岩双河成因

Recycling process and proto-kimberlite melt metasomatism in the lithosphere-asthenosphere boundary beneath the Amazonian Craton recorded by garnet xenocrysts and mantle xenoliths from the Carolina kimberlite

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Geoscience Frontiers 2022年第5期13卷 89-105页

作者： Fernanda Gervasoni Tiago Jalowitzki Marcelo Peres Rocha Ricardo Kalikowski Weska Eduardo Novais-Rodrigues Rodrigo Antonio de Freitas Rodrigues Yannick Bussweiler Elisa Soares Rocha Barbosa Jasper Berndt Elton Luiz Dantas Valmir da Silva Souza Stephan Klemme Centro de Engenharias Universidade Federal de Pelotas(UFPel)PelotasBrazil Programa de Pós-graduação em Geociências Universidade Federal do Rio Grande do SulPorto AlegreBrazil Programa de Pós-graduação em Geologia Instituto de GeociênciasUniversidade de Brasília(UnB)BrasíliaBrazil Faculdade de Geociências Universidade Federal do Mato Grosso(UFMT)CuiabáBrazil institut für geologie und mineralogie Universität zu KölnGermany Faculdade de Ciências e Tecnologia Universidade Federal de Goiás(UFG)Aparecida de GoiâniaBrazil institut für mineralogie Universität MünsterMünsterGermany

Here we present new data on the major and trace element compositions of silicate and oxide minerals from mantle xenoliths brought to the surface by the Carolina kimberlite,Pimenta Bueno Kimberlitic Field,which is located on the southwestern border of the Amazonian *** also present Sr-Nd isotopic data of garnet xenocrysts and whole-rocks from the Carolina *** xenoliths are mainly clinopyroxenites and *** of the clinopyroxenites were classified as GPP–PP–PKP(garnet-phlogopite peridotite,phlogopite-peridotite,phlogopite-K-richterite peridotite)suites,and two clinopyroxenites(eclogites)and two garnetites are relicts of an ancient subducted *** and pressure estimates yield 855–1102℃ and 3.6–7.0 GPa,*** are enriched in light rare earth elements(LREE)(La_(N)/Yb_(N)=5–62;Ce_(N)/Sm_(N)=1–3;where N=primitive mantle normalized values),they have high Ca/Al ratios(10–410),low to medium Ti/Eu ratios(742–2840),and low Zr/Hf ratios(13–26),which suggest they were formed by metasomatic reactions with CO_(2)-rich silicate *** with high TiO_(2)(>2.0 wt.%),Al_(2)O_(3)(>12.0 wt.%),and FeOt(5.0–13.0 wt.%)resemble those found in the groundmass of kimberlites,lamproites and ***,phlogopite with low TiO_(2)(<1.0 wt.%)and lower Al_(2)O_(3)(<12.0 wt.%)are similar to those present in GPP-PP-PKP,and in MARID(mica-amphibole-rutile-ilmenite-diopside)and PIC(phlogopite-ilmenite-clinopyorxene)*** GPP-PP-PKP suite of xenoliths,together with the clinopyroxene and phlogopite major and trace element signatures suggests that an intense proto-kimberlite melt metasomatism occurred in the deep cratonic lithosphere beneath the Amazonian *** Sr-Nd isotopic ratios of pyrope xenocrysts(G3,G9 and G11)from the Carolina kimberlite are characterized by high ^(143)Nd/^(144)Nd(0.51287–0.51371)and eNd(+4.55 to+20.85)accompanied with enriched ^(87)Sr/^(86)Sr(0.70405–0.71098).These results suggest intera

关键词： Carolina kimberlite K-rich mantle xenoliths Ancient subducted slab Proto-kimberlite melt metasomatism

Thermal evolution of an ancient subduction interface revealed by Lue Hf garnet geochronology, Halilba■? Complex(Anatolia)

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Geoscience Frontiers 2019年第1期10卷 127-148页

作者： Amaury Pourteau Erik E.Scherer Simon Schorn Rebecca Bast Alexander Schmidt Lisa Ebert institut für Erd- und Umweltwissenschaften Universit?t Potsdam Earth Dynamics Research Group ARC Centre of Excellence for Core to Crust Fluid Systems (CCFS) The Institute for Geoscience Research (TIGeR) School of Earth and Planetary Sciences Curtin University Münster Isotope Research Centre Institut für Mineralogie Westf?lische Wilhelms-Universit?t Münster Department of Geological Sciences University of Cape Town institut für geologie und mineralogie Universit?t zu K?ln

The thermal structure of subduction zones exerts a major influence on deep-seated mechanical and chemical processes controlling arc magmatism, seismicity, and global element cycles. Accretionary complexes exposed inland may comprise tectonic blocks with contrasting pressureetemperature(Pe T)histories, making it possible to investigate the dynamics and thermal evolution of former subduction interfaces. With this aim, we present new Lue Hf geochronological results for mafic rocks of the Halilbag?Complex(Anatolia) that evolved along different thermal gradients. Samples include a lawsoniteeepidote blueschist, a lawsoniteeepidote eclogite, and an epidote eclogite(all with counter-clockwise Pe T paths),a prograde lawsonite blueschist with a "hairpin"-type Pe T path, and a garnet amphibolite from the overlying sub-ophiolitic metamorphic sole. Equilibrium phase diagrams suggest that the garnet amphibolite formed at w0.6 -0.7 GPa and 800 -850℃, whereas the prograde lawsonite blueschist records burial from 2.1 GPa and 420℃ to 2.6 GPa and 520℃. Well-defined Lue Hf isochrons were obtained for the epidote eclogite(92.38 ± 0.22 Ma) and the lawsoniteeepidote blueschist(90.19 ± 0.54 Ma),suggesting rapid garnet growth. The lawsoniteeepidote eclogite(87.30 ± 0.39 Ma) and the prograde lawsonite blueschist(ca. 86 Ma) are younger, whereas the garnet amphibolite(104.5 ± 3.5 Ma) is *** data reveal a consistent trend of progressively decreasing geothermal gradient from granulite-facies conditions at ~104 Ma to the epidote-eclogite facies around 92 Ma, and the lawsonite blueschist-facies between 90 Ma and 86 Ma. Three Lue Hf garnet dates(between 92 Ma and 87 Ma) weighted toward the growth of post-peak rims(as indicated by Lu distribution in garnet) suggest that the HP/LT rocks were exhumed continuously and not episodically. We infer that HP/LT metamorphic rocks within the Halilbag?Complex were subjected to continuous return flow, with "warm" rocks being exhumed during the tectonic bur

关键词： Subduction Lu/Hf dating of garnet Metamorphic sole Eclogite Blueschist Lawsonite

麻粒岩的石榴石Sm-Nd和U-Pb同位素体系:欧洲华力西造山带实例

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科学通报 2002年第11期47卷 864-868页

作者：陈福坤 institut fuer mineralogie Petrologie und GeochemieUniversitaet Tuebingen

报道德国黑森林地区（BF）华力西造山带高级变质基底的基性麻粒岩中锆石和石榴石年龄,并讨论其同位素体系的封闭温度.采用锆石U-Pb和Pb-Pb蒸发法分析,得到340 Ma左右至414 Ma的207Pb/206Pb年龄,而且大部分集中在340Ma左右.而石榴石的Sm... 详细信息

报道德国黑森林地区（BF）华力西造山带高级变质基底的基性麻粒岩中锆石和石榴石年龄,并讨论其同位素体系的封闭温度.采用锆石U-Pb和Pb-Pb蒸发法分析,得到340 Ma左右至414 Ma的207Pb/206Pb年龄,而且大部分集中在340Ma左右.而石榴石的Sm-Nd和Pb-Pb等时线年龄分别为（398±3）和（411±14）Ma,老于大部分的锆石年龄.这一现象暗示,在340Ma左右的麻粒岩相变质作用（800℃左右）过程中,可能由于重结晶作用或蜕晶作用使大部分锆石丢失其放射成因Pb.而石榴石的Sm-Nd和U-Pb同位素体系保存了变质作用峰期之前的年代学信息.这一现象可能说明该变质作用是在无流体参与的条件下进行的.该实例表明,采用Sm-Nd和U-Pb方法对高级变质岩石定年,在某些情况下石榴石可能是更好的候选矿物.

关键词：麻粒岩石榴石 Sm-Nd U-Pb同位素体系华力西造山带

Metamorphic Characteristics and Tectonic Implications of the Kadui Blueschist in the Central Yarlung Zangbo Suture Zone,Southern Tibet

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Journal of Earth Science 2018年第5期29卷 1026-1039页

作者： Guangming Sun Xu-Ping Li WenYong Duan Shuang Chen Zeli Wang Lingquan Zhao Qingda Feng Shandong Provincial Key Laboratory of Depositional Mineralization and Sedimentary Minerals Shandong University of Science and TechnologyQingdao 266590China institut fur geologie Mineralogie und GeophysikRuhr-UniversitatBochum 44780Germany Center of Hydrogeology and Environmental Geology Survey China Geological SurveyBaoding 071051China

The Kadui blueschist is located in the central section of Yarlung Zangbo suture zone （YZSZ）, southern Tibet, and has been subjected to the subduction of the Neo-Tethyan Ocean below the Asian Plate and provides important clues for better understanding the evolution of the India-Asia convergence zone. In this paper, the systematical petrographic and mineral chemical studies were carried out on the Kadui blueschist, which reveal a mineral assemblage of sodic amphibole, chlorite, epidote, albite and quartz with accessory minerals of titanite, calcite and zircon. Electron microprobe analyses demonstrate that amphibole shows zoned from actinolite core to ferrowinchite/riebeckite rim composition indicating that the sodic amphibole has formed during a prograde metamorphic event. The protolith of the blueschist is an intermediate-basic pyroclastic rock. The calculated pseudosection indicates a clockwise P-T path and constrains peak metamorphic conditions of about 5.9 kbar at 345 ℃. This condition is transitional between pumpellyite-actinolite, greenschist and blueschist facies with a burial depth of 20-22 km and a thermal gradient of 15-16 ℃/km. This thermal gradient belongs to high pressure intermediate P/T facies series and is possibly related to a warm subduction setting of young oceanic slabs. Our new findings indicate that the Kadui blueschist in the central part of YZSZ experienced a rapid subduction and exhumation process as a response to a northward subduction of the Neo-Tethyan oceanic lithosphere during the initial India-Asia collision stage.

关键词： Kadui blueschist metamorphism P-T conditions accretionary complex southern Tibet.

CARBON ISOTOPE STRATIGRAPHY OF THE DEVONIAN OF CENTRAL AND SOUTHERN EUROPE

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CARBON ISOTOPE STRATIGRAPHY OF THE DEVONIAN OF CENTRAL AND S...

Hydrogeochemistry of the Bicaz storage lake, East Carpathians, Romania

第二届国际古生物学大会

作者： Werner BUGGISCH Michael M.JOACHIMSKI institut für geologie und mineralogie Universitt Erlangen-Nürnberg Schlossgarten 5 D-91054 Erlangen Germany

Carbonate rocks of the Rhenohercynian and Saxothuringian zones of the Variscan Mountains, the Prague Syncline, the Carnic Alps, the Montagne Noire, the Pyrenees, and the Cantabrian Mountains were investigated for δ13Ccarb Fig. 1. The values were measured on bulk carbonate, selected carbonate components and cements. Many of the studied carbonates are interpreted

关键词： carbon isotopes Devonian event stratigraphy sea-level.

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Chinese Journal Of Geochemistry 2006年第B8期25卷 157-158页

作者： Nathalie Gassama Constantin Cocirta Haino Uwe Kasper Neculai Al. Apetroaei GéEAC EA 2100 Université Francois Rabelais F-37200 Tours France institut fuer geologie und mineralogie Universitaet Koeln D-50674 Koeln Germany Laboratorul de Acvacultura si Ecologie acvatica Piatra Neamt Universitatea ALI. Cuza RO-700134 lasi Romania

Identification of greigite in lake sediments and its magnetic significance

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Science China Earth Sciences 2002年第1期45卷 81-87页

作者：胡守云 E.Appel V.Hoffmann W.Schmahl Nanjing institute of Geography & Limnology Chinese Academy of Sciences Nanjing 210008 China institut für geologie und Palaontologie Universitat Tübingen 72076 Tübingen Germany institut für mineralogie Ruhr-Universtitat Bochum 44780 Bochum Germany

Detailed rock magnetic investigations and mineralogical analysis were conducted on lacustrine sediments recovered from Zoigê Basin, eastern Tibetan Plateau. Greigite, with fine and homogenous grain size, is found as a main magnetic carrier, which is suspected to be of biochemical origin. In contrast to some reports, greigite within the sediments is not oxidized even after exposure to air for a few years, which could be due to the fact that greigite is sealed by silicate.

关键词： greigite 湖的沉积摇磁力 X 光检查衍射 SEM

38亿年地幔橄榄岩强亲硫元素组成与Zn同位素特征

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38亿年地幔橄榄岩强亲硫元素组成与Zn同位素特征