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The early Cretaceous Fangcheng basalts were erupted in the peak stage of lithospheric thinning of the North China Craton (NCC). They have olivine phenocrysts with forsterite (Fo) contents ranging from 74 to 92, clinopyroxene with high Mg# from 76 to 89, and contain pyroxenite xenoliths. Both the basalts and pyroxenite xenoliths have coexisting high-Ca and low-Al clinopyroxene and high-Mg and low-Ca...
Microstructures indicative of silicate liquid immiscibility were identified in the groundmass of plagioclase–pyroxene-phyric andesites from the Mangikhuta Volcanics at the top of the ~2.5Ga Dongargarh large igneous province (LIP), central India. The bulk rock is an Fe-rich, Al-poor andesite (SiO 2 57–58wt.%, FeO≤9.86wt.%, Al 2 O 3 ~13wt.%) compositionally similar to icelandite...
Subduction zones not only return oceanic lithosphere into the mantle, but are also sites where chemical components are transferred from the downgoing plate back to the surface in arc crust and, to a lesser extent, fore-arc and back-arc basins. Understanding of subduction-zone processes has evolved significantly over a relatively brief 40-year research history, thanks to combined insights from experimental...
The Western Gneiss Region (WGR), Norway, is dominated by migmatitic gneiss that contains inclusions of eclogite, some of which contain evidence for ultrahigh-pressure metamorphism. To evaluate geochemical and age relationships between host migmatite and eclogite, we obtained LA–ICP–MS U–Pb dates and trace-element analyses for zircon from a variety of textural types of leucosome, from layer-parallel...
The Madeira and Canary island/seamount chains represent two adjacent hotspot tracks in the eastern North Atlantic, which were derived from mixed peridotite–pyroxenite mantle sources. They possess systematically different Sr–Nd–Pb, Os and Hf isotope signatures, implying mixing of DMM-, HIMU- and EM-type components from different mantle lithologies. The lithological nature of these postulated mantle...
The metamorphic rocks in the Neoproterozoic (Pan-African) Mozambique belt of southwestern Tanzania, around the town of Songea, can be subdivided into one- and two pyroxene bearing charnockitic gneisses, migmatitic granitoid gneisses and amphibolite-facies metapelites. Lower-grade amphibolite-facies rocks are rare and can be classified as sillimanite- and/or garnet-bearing metapelites. Most of the...
The Qiguling topaz rhyolite is present as a dike within the Qitianling biotite granite batholith of the Nanling Range of southern China. Here, the rhyolitic dike, 4.5m wide and 500m long, contains enclaves of topaz granite. These rhyolites contain up to 72wt.% SiO 2 , have alumina saturation index (ASI) >1.1, and have groundmasses with estimated fluorine contents of approximately 1.5wt...
Mashhad granitoids in northeast Iran are part of the so-called Silk Road arc that extended for 8300km along the entire southern margin of Eurasia from North China to Europe and formed as the result of a north-dipping subduction of the Paleo-Tethys. The exact timing of the final coalescence of the Iran and Turan plates in the Silk Road arc is poorly constrained and thus the study of the Mashhad granitoids...
Isotopic dating of metamorphic minerals places fundamental constraints on the rates and mechanisms of burial and exhumation in collisional orogens. The Eclogite Zone in the Tauern Window has been the focus of many studies on subduction-related high-pressure metamorphism. However, the age and duration of the high-pressure stage remains the subject of ongoing debate. 32Ma Sr-Rb ages interpreted to date...
The ±260Ma Panzhihua mafic layered intrusion is one of a suite of intrusions related to the Emeishan Large Igneous Province (ELIP), SW China. The Panzhihua intrusion hosts a large (±60m thick) FeTi oxide ore body at the base of the intrusion. This study provides new constraints on the genesis of FeTi oxide ore layers at the Panzhihua intrusion using: geochemistry, petrography, and modeling of parent...
As an important component of the Western Shandong Complex in the Eastern Block of the North China Craton, the Yishui Terrane consists of Neoarchean high-grade supracrustal rocks, granitoid gneisses and charnockites. LA-ICP-MS zircon UPb dating and Hf isotopic analyses on these lithologies have been carried out and the results provide new insights into the Neoarchean crustal evolution of the Eastern...
The Sistan Suture Zone (SSZ) in eastern Iran extends as a N–S trending belt over more than 700km along the border area between Iran and Afghanistan. The SSZ formed as a result of eastward-directed subduction of a Neotethyan ocean basin beneath the Afghan block and includes a tectonic mélange consisting of disrupted meta-ophiolitic rocks within a low-grade matrix of ultramafic, mafic and pelitic schists...
Zircon U–Pb dating and whole-rock geochemical analysis have been undertaken on Late Paleozoic–Early Mesozoic intrusive rocks of central Jilin Province, NE China, with the aim of constraining the tectonic evolution of the eastern segment of the northern margin of the North China Block (NCB) during the Late Paleozoic–Early Mesozoic. Zircon U–Pb dating indicates that Late Paleozoic–Early Mesozoic magmatic...
Several sulfide ore-bearing mafic–ultramafic intrusions occur along the southern margin of the Late Paleozoic Central Asian Orogenic Belt (CAOB) in north Xinjiang, NW China. Their origin, magma evolution and relationship with the Permian basalts in the region remain equivocal. In this study, we investigate the Xiangshanzhong mafic–ultramafic intrusion in eastern Tianshan, dominantly composed of diorite,...
Petrological, whole rock major element and mineral chemical analysis of mantle xenoliths from the Venetia kimberlite pipes (533Ma) in South Africa reveals an apparently stratified cratonic mantle beneath the Central Zone of the Limpopo Mobile Belt (LMB) that separates the Kaapvaal and Zimbabwe Cratons. Combined pressure–temperature (P–T) data and petrographic observations indicate that the mantle...
This paper attempts to clarify the complex nature of how and when the Rheic Ocean closed in what is now Central Europe and, with respect to the various terranes that were involved, offer a regional chronology for the associated structural, metamorphic and igneous processes that accompanied and followed this closure. The Variscan orogen in Europe originated from the multiple collisions of Gondwana-derived...
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