The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
Field relations and whole-rock geochemistry indicate that magma mixing has been important in the genesis of the late Mesozoic I-type igneous complexes at Pingtan and Tonglu in SE China. Morphological and trace-element studies of zircon populations in rocks from each of these complexes have defined several distinct growth stages [Mineral. Mag. (2001)]. In-situ LAM-MC-ICPMS microanalysis shows large...
Geochemical and petrographical studies of lavas and ignimbrites from the Quaternary Nisyros–Yali volcanic system in the easternmost part of the Hellenic arc (Greece) reveal insight into magma generating processes. A compositional gap between 61 and 68 wt.% SiO 2 is recognized that coincides with the stratigraphic distinction between pre-caldera and post-caldera volcanic units. Trace element...
Granitic leucosome and pegmatite are widely distributed within biotite-bearing orthogneiss in the northern part of the Sulu ultrahigh-pressure (UHP) metamorphic terrane, eastern China. A combined study of mineral inclusions, cathodoluminescence (CL) images, U–Pb SHRIMP dates, and in situ trace element and Lu–Hf isotope analyses of zircons provided insight into the nature and timing of partial melting...
During the Late Mesozoic, extensive magmatism and associated ore deposits were developed in the southeast Hubei Province, Middle–Lower Yangtze River metallogenic belt (MLYRB), East China. To understand the petrogenesis of the intrusions in the area, we performed in situ zircon U–Pb and Hf isotopic analyses on 14 samples from the Fengshangdong stock, and from the Echeng, Tieshan, Wangbaoshan–Jinshandian...
In-situ zircon U–Pb ages, Hf isotopic compositions and whole rock geochemical and Sr–Nd isotopic compositions are presented for three Mesozoic syenitic–monzonitic intrusions from Shanxi province, central North China Craton. Zircons from these intrusions all show core–rim structures in that the oscillatory rims recorded their intrusive ages, whereas the cores are interpreted as xenocrysts. The U–Pb...
Zircon Hf isotopic data from six granite supersuites recognised in the New England Batholith of eastern Australia indicate that magma mixing is present in all plutons. Apart from the S-type supersuites, inherited zircons are rare to absent, suggesting that initial melt temperatures were above zircon saturation for the M-, I- and A-type granites. In all supersuites, the range of zircon Hf model ages...
The Late Carboniferous to Permian marks an important phase of terrane amalgamation through accretion–collision in the Central Asian Orogenic Belt (CAOB). The Tianshan Belt forms part of this sequence, where the post-collisional event generated an E–W trending bimodal volcanic zone that extends for ca. 500km from the southern Bogda Mt. to the easternmost Tianshan Belt. Here we report the petrology,...
Zircon U–Pb ages and Hf isotopic compositions of Mesozoic magmatic rocks from the Chizhou Area are systematically investigated to reveal the tectonic setting of magmatism and their relationship with Cu–Au mineralization in the Lower Yangtze River Belt, southeastern China. The samples cover nearly all types of magmatic rocks in a 30×50km 2 region, including 6 granite porphyries, 6 dacites and...
Recalculated whole rock major-, trace-element and isotope compositions from mineral analyses of Finsch mantle peridotites indicate a complex history of the South African sub-continental lithospheric mantle (SA-SCLM). According to the Lu–Hf whole rock isotopic data last depletion coupled with the final cratonization of the Kaapvaal craton underneath Finsch occurred at ~2.6Ga. The data of this study...
The Dunhuang Block, located in the eastern Tarim Craton, widely exposes Precambrian TTG gneisses and metamorphosed supracrustal rocks. A suite of metasedimentary rocks of the Dunhuang Group in the Hongliuxia area on the eastern margin of the Tarim Craton are characterized by moderate contents of quartz, plagioclase, and biotite, with minor amounts of garnet or kyanite, most of which have experienced...
The leucogranites in the Baoshan Block of the Tethyan belt in Western Yunnan, are composed mainly of two-mica granite with subordinate muscovite granite. Here we present zircon U–Pb ages from four intrusions that show ages of 448–476Ma suggesting that these rocks were emplaced during the Ordovician. The leucogranites are high-K calc-alkaline and strongly peraluminous, with K 2 O/Na 2 ...
Knowledge of the lower crust beneath the southeastern parts of North China Craton (NCC) is still sparse. The Junan basalts (67 Ma) in the southeastern NCC contain abundant xenoliths of lower crustal granulites, pyroxenites and mantle peridotites. We present integrated in-situ U-Pb ages and Hf isotopes of zircons from the Junan basalts and granulite xenoliths, to investigate accretion and modification...
The Late Paleozoic tectonic setting and location of the southernmost boundary of the Central Asian Orogenic Belt (CAOB) with respect to the Alxa Block or Alxa-North China Craton (ANCC) are debated. This paper presents new geochronological, petrological, geochemical and zircon Hf isotopic data of the Late Paleozoic intrusions from the Shalazhashan in northern Alxa and discusses the tectonic setting...
The Baoshan block is one of the important members in the southeastern margin of the Tibetan Plateau. Cambrian to Jurassic (meta-) sedimentary strata and their metamorphic counterparts were well preserved in the eastern part of the Baoshan block. Zircon U–Pb dating, trace elements, and Hf isotope data for both the Cambrian to Jurassic (meta-) sedimentary sequences and the Lincang granite were used...
The Junan granulite xenoliths and xenocrysts have a distinct overlap in U–Pb ages and Lu–Hf isotopic compositions with the Precambrian basement of the Yangtze craton. We thus believe that the Junan granulite cannot be derived from the North China lower crust. Moreover, broad deep seismic and magnetotelluric probing across the Sulu UHP terrane indicates the former is well coupled with the lower crust...
Here, we test the hypothesis that the rhyolitic lavas of the Rooiberg Group and granophyres associated with the roof of the Bushveld Complex are differentiation products of Bushveld-age mafic liquids. We present Lu-Hf isotopic compositions in zircons from roof rocks that have been interpreted to represent thermally metamorphosed and remelted Rooiberg Group lavas and from granophyres interpreted to...
The Xuting pluton, located at the north section of the Zanhuang Complex, contains potassic and sodic granite in both of which shallow level emplacement is shown by graphic texture feldspar and quartz intergrowth. Two potassic granite and one sodic granite samples yielded zircon 207Pb/206Pb ages of 2066±17Ma, 2092±14Ma, and 2071±14Ma, respectively, suggesting that the Xuting pluton emplaced between...
The Seleteguole Cu–Mo deposit in Jinghe County, Xinjiang is tectonically located on the northern margin of the Northwestern Tianshan. Three major intrusions including biotite granite, diorite porphyry and quartz diorite porphyry have been identified. The biotite granite, with a zircon U–Pb age of 307±3Ma, intruded carbonates and clastic rocks of the Middle Carboniferous Dongtujin Formation. The younger...
We present an integrated study of LA-ICP-MS U–Pb age, Hf isotopes, and trace element geochemistry of zircons from the Himalayan eclogites (mafic rocks) and their host gneisses (felsic rocks) from the Kaghan Valley in Pakistan in order to understand the source and mode of their magmatic protoliths and the effect of metamorphism. Zircons from the so-called Group I (high-pressure) eclogites yielded U–Pb...
We report new Hf isotopic data for basaltic glasses from seamounts flanking the East Pacific Rise (EPR) between 5° and 15°N that have been previously analyzed for Sr–Nd–Pb isotopes as well as major and trace elements. The Hf isotopic data offer new perspectives on the petrogenesis of these samples in a broader context on mantle dynamics. The Hf isotope compositions show significant correlations with...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.