Journal Title
Title of Journal: Contrib Mineral Petrol
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Abbravation: Contributions to Mineralogy and Petrology
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Publisher
Springer Berlin Heidelberg
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Authors: Shun Guo Kai Ye Yueheng Yang Yi Chen Lingmin Zhang Jingbo Liu Qian Mao Yuguang Ma
Publish Date: 2014/02/14
Volume: 167, Issue: 2, Pages: 975-
Abstract
This study presents in situ strontium Sr isotope and Sr content data on multistage epidote crystals from ultrahighpressure UHP eclogites and omphacite–epidote veins therein at Ganghe Dabie terrane China determined using LAMCICPMS The Ganghe eclogites occur as lenses in mainly leucocratic UHP gneisses and therefore our data provide insights into the origin composition and transport scale of the discrete multistage fluids in UHP eclogites during the subduction and exhumation of a continental crust Four textural types of epidote that record compositional and isotopic signatures of fluid at various metamorphic P–T conditions have been distinguished based on petrographic observations and compositional analyses They are 1 finegrained highpressure HP epidote inclusions EpIn in omphacite that define the earliest stage of epidote formation in the eclogite 2 coarsegrained UHP epidote porphyroblasts EpP that contain omphacite with EpIn inclusions in the eclogite 3 finegrained HP epidote in omphacite–epidote veins EpV as well as 4 the lateststage epidote in disseminated amphibolitefacies veinlets EpA which crosscut the EpP or matrix minerals in the eclogite and HP vein Both EpP and EpV crystals exhibit significant and complex chemical zonations with respect to the XFe = Fe/Fe + Al ratio and Sr content In contrast to the varying Sr contents EpIn EpP and EpV have similar and narrow ranges of initial 87Sr/86Sr ratios from 070692 to 070720 for EpIn from 070698 to 070721 for EpP and from 070668 to 070723 for EpV which are significantly different from those in EpA from 070894 to 071172 The initial 87Sr/86Sr ratio of EpA is closer in value to the initial Sr isotopic composition of the gneisses from 0710790 to 0712069 which enclose the UHP eclogite These data indicate different sources of the eclogitefacies fluids and retrograde amphibolitefacies fluid in the Ganghe eclogites The HP–UHP fluids responsible for the large amounts of hydrous minerals in the eclogites were internally derived and buffered The omphacite–epidote veins were precipitated from the channelized soluterich HP–UHP fluids released from the host eclogite However hydrated amphibolitefacies metamorphism during exhumation was mainly initiated by the lowSr and high87Sr/86Sr external fluid which infiltrated into the eclogite from the surrounding gneisses The eclogitefacies fluids in the Ganghe eclogites were locally derived whereas the infiltration of the retrograde amphibolitefacies fluid from the gneisses required a long transport most likely longer than 80 m This study highlights that the in situ Sr isotopic analysis of multistage epidote can be employed as a powerful geochemical tracer to provide key information regarding the origin and behavior of variousstage subductionzone metamorphic fluidsThis study was supported by The National Basic Research Program of China 973 Program 2009CB825001 and The National Science Foundation of China Nos 41102034 41372079 and 41090371 We gratefully acknowledge the constructive comments and suggestions from Drs Feineman M and KonradSchmolke M which considerably improved the manuscript Careful editorial handling by T L Grove is highly appreciated We thank Liewen Xie Zhichao Liu Qin Zhou and Jing Sun for assistance in the LAMCICPMS analyses Chaofeng Li and Xianghui Li for assistance in the TIMS analyses Professors WeiPing Wu and YongHong Shi for help in the field
Keywords:
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Other Papers In This Journal:
- Precise estimation of pressure–temperature paths from zoned minerals using Markov random field modeling: theory and synthetic inversion
- Formation of cordierite-bearing lavas during anatexis in the lower crust beneath Lipari Island (Aeolian arc, Italy)
- An Early Cretaceous garnet pressure–temperature path recording synconvergent burial and exhumation from the hinterland of the Sevier orogenic belt, Albion Mountains, Idaho
- Crystal reaming during the assembly, maturation, and waning of an eleven-million-year crustal magma cycle: thermobarometry of the Aucanquilcha Volcanic Cluster
- Origin of phlogopite-orthopyroxene inclusions in chromites from the Merensky Reef of the Bushveld Complex, South Africa
- An empirical garnet (YAG) – xenotime thermometer
- Magma storage and mixing conditions for the 1953–1974 eruptions of Southwest Trident volcano, Katmai National Park, Alaska
- In situ Re–Os isotopic analysis of platinum-group minerals from the Mayarí-Cristal ophiolitic massif (Mayarí-Baracoa Ophiolitic Belt, eastern Cuba): implications for the origin of Os-isotope heterogeneities in podiform chromitites
- Reply to comments by Sengupta, Raith and Dasgupta on S. B. Bhattacharya and R. K. Kar (2002)
- Trace element mapping by LA-ICP-MS: assessing geochemical mobility in garnet
- Metasomatized lithospheric mantle beneath Turkana depression in southern Ethiopia (the East Africa Rift): geochemical and Sr–Nd–Pb isotopic characteristics
- In situ observations of bubble growth in basaltic, andesitic and rhyodacitic melts
- NanoSIMS mapping and LA-ICP-MS chemical and U–Th–Pb data in monazite from a xenolith enclosed in andesite (Central Slovakia Volcanic Field)
- Phosphorus-controlled trace element distribution in zircon revealed by NanoSIMS
- Hydroxyl in olivines from mantle xenoliths in kimberlites of the Siberian platform
- Electrical conductivity of orthopyroxene and plagioclase in the lower crust
- Chromite in komatiites: 3D morphologies with implications for crystallization mechanisms
- Source components of the Gran Canaria (Canary Islands) shield stage magmas: evidence from olivine composition and Sr–Nd–Pb isotopes
- The stability and origin of sodicgedrite in ultrahigh-temperature Mg-Al granulites: a case study from the Gondwana suture in southern India
- Plagioclase in the Skaergaard intrusion. Part 1: Core and rim compositions in the layered series
- The Campanian Ignimbrite (southern Italy) geochemical zoning: insight on the generation of a super-eruption from catastrophic differentiation and fast withdrawal
- Melting of clinopyroxene + magnesite in iron-bearing planetary mantles and implications for the Earth and Mars
- Immiscible separation of metalliferous Fe/ Ti-oxide melts from fractionating alkali basalt: P - T - f O2 conditions and two-liquid elemental partitioning
- Experimental calibration of a garnet–clinopyroxene geobarometer for mantle eclogites
- A case for hornblende dominated fractionation of arc magmas: the Chelan Complex (Washington Cascades)
- Melting phase relations of a mica–clinopyroxenite from the Milk River area, southern Alberta, Canada
- Shoshonite and sub-alkaline magmas from an ultrapotassic volcano: Sr–Nd–Pb isotope data on the Roccamonfina volcanic rocks, Roman Magmatic Province, Southern Italy
- The role of slab melting in the petrogenesis of high-Mg andesites: evidence from Simbo Volcano, Solomon Islands
- Evolution of the Taupo Volcanic Center, New Zealand: petrological and thermal constraints from the Omega dacite
- Multi-stage metasomatism of diamondiferous eclogite xenoliths from the Udachnaya kimberlite pipe, Yakutia, Siberia
- Hercynian, Pan-African, Proterozoic and Archean ion-microprobe zircon ages for a Betic-Rif core complex, Alpine belt, W Mediterranean – consequences for its P - T - t path
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