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The disappearances of mafic shoshonitic and ultrapotassic magma prior to Late Oligocene in Western Anatolia post-collisional tectonic settings, and the sudden appearance of Early-Middle Miocene potassic lavas with orogenic geochemical signatures, indicate a striking change of mantle sources during the Early-Middle Miocene period, and require a special explanation. In this regard, the Simav (Kütahya)...
Precambrian mafic dykes in the North China Craton (NCC) consist of dolerite. Geochronological, geochemical, and whole-rock Sr–Nd isotopic analyses were performed on this suite of mafic dykes to characterise their ages and petrogenesis. Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry (LA-ICP-MS) U–Pb zircon analyses yield consistent ages ranging from 837.9±4.8Ma to 2510±18Ma for seven of...
The crystal-rich alkaline basalt of the Füzes-tó scoria cone in the Bakony-Balaton Highland Volcanic Field, western Pannonian Basin, Hungary has a unique mineral assemblage reflecting a mixture of diverse crystals of various origins. The pheno- and microphenocrysts are represented by olivine with chromian spinel inclusions, clinopyroxene and plagioclase. The basalt contains abundant (20–40vol.% on...
Two sets of Late Paleozoic, orthogonal, dioritic dyke swarms are defined in the eastern part of the Western Junggar accretionary collage in the southern Altaids. Dioritic dykes (hornblende+plagioclase) are characterized by relatively high SiO 2 , elevated MgO, Na 2 O, K 2 O, Mg # , Ni, Si and Cr contents, La/Yb ratios, very low Y contents, and enrichments in large ion...
We report SIMS U–Pb zircon, elemental and Nd–Sr–Pb isotopic data for the volcanic rocks and their subvolcanic units from the Xiemisitai Mountains in the West Junggar Region (Xinjiang, China), aiming to determine their ages, source regions and tectonic setting. Zircon U–Pb dating results of the volcanic rocks (422.5±1.9Ma–411.2±2.9Ma) indicate that the volcanic strata occurred in the Xiemisitai Mountains...
Equilibrium P–T conditions of garnet-facies or garnet-spinel transition facies mantle xenoliths are suggested to be best determined through a combination of the Taylor (1998) two-pyroxene thermometer either with the Taylor (1998) garnet-orthopyroxene barometer for TiO 2 -rich orthopyroxenes (Al/Ti<12.0), or with the Nickel and Green (1985) garnet-orthopyroxene barometer for TiO 2 ...
Whether the northern Tarim Craton was an active or passive continental margin during the Paleozoic is vital to our understanding of the subduction polarity of paleo-oceanic plates in the Tianshan Orogen and the accretion history of the southwestern Central Asian Orogenic Belt. We identified undeformed granitoids intruding into the Paleoproterozoic metamorphic rocks in the Korla area at the northern...
Mineral inclusions in diamonds from the Renard kimberlites, on the eastern Superior Craton, document an almost exclusively peridotitic inclusion suite with an unusually high abundance of SiO 2 phases (coesite and presumably retrograde quartz). Whilst coesite is often associated with eclogitic diamond sources, there is an almost complete absence of unequivocally eclogitic mineral inclusions...
Mesozoic granitoids are widespread in the southern margin of the North China Craton, and of particular geological interests because of their indication for lithospheric evolution and close association with porphyry Mo mineralization. In this contribution, in situ LA-ICP-MS U–Pb, Hf isotope and trace element analyses of zircon crystals have been combined to constrain the emplacement time and petrogenesis...
Western Turkey, which forms the eastern part of the Aegean region, was subjected to continental extension that led to formation of metamorphic core complexes and associated syn-extensional granitoids. This study deals with petrogenesis of the syn-extensional Early Miocene Alaçamdağ (AG) and Middle Miocene Salihli (SG) granitoids and associated mafic microgranular enclaves (MME) in order to better...
Early Cretaceous granodioritic host rocks with mafic microgranular enclaves (MME) in the Dabie orogen provide important insights into magma mixing between melts from delaminated eclogitic lower continental crust and mantle-derived magma. The Meichuan host granodiorites (132±1Ma) from the eastern margin of the Dabie orogen, adjacent to the Tan–Lu fault, are high-Mg adakitic rocks containing 63.5–69...
Subduction-related Mesozoic mafic dykes in eastern Palmer Land, Antarctic Peninsula, record the development of an intra-oceanic arc terrane, the Dyer Arc, probably of late Permian–Triassic age, represented by a tholeiitic dyke group. Arc rocks were deformed in late Triassic–early Jurassic and mid-Cretaceous times on the Gondwana margin. Eruption of syn- to post-mid-Cretaceous orogenesis magmatism...
Wu and Zhao (2011) argue that pressures and temperatures for mantle xenoliths are best determined by combining Taylor's (1998) garnet–orthopyroxene barometer and two-pyroxene thermometer. Here we show that this choice may lead to grossly erroneous P–T estimates for some peridotitic compositions and increased scatter around xenolith geotherms. We contend that the Nickel and Green (1985) barometer remains...
We present SHRIMP zircon ages and whole-rock geochemical data to identify mafic–ultramafic massifs of early Carboniferous and early Cretaceous ages from northern Inner Mongolia, China. The early Carboniferous massifs (Chongenshan–Xiaobaliang–Wusnihei) comprise predominantly lherzolite and minor gabbroic rocks. Zircons from a microgabbro (ε Nd (t) =9.8) and a plagiogranite (ε Nd (t) ...
The detailed petrogenesis of mafic sills occurring throughout southern Africa provides strong support for the development of an Umkondo large igneous province on the eastern margin of the Kalahari craton at 1.1Ga. The sills are most extensively developed in the Waterberg and Middelburg basins in northern South Africa and south-eastern Botswana. They are typical fractionated continental tholeiites...
Six samples of the Linglong granitic pluton from the southeastern margin of the North China craton yield similar Jurassic magmatic zircon U–Pb ages and evolved whole-rock Sr–Nd isotopic compositions. They are weakly peraluminous to strongly peraluminous, with A/CNK (molar Al 2 O 3 /[CaO+Na 2 O+K 2 O]) ratios of 1.05 to 1.3 except one sample with an A/CNK of 0.98. However,...
A suite of mantle–crust transition zone (Moho transition zone = MTZ) rocks are exceptionally well exposed in Gebel Mudarjaj area, southeastern desert of Egypt. The MTZ rocks were thermally metamorphosed by younger granitic intrusion, forming mafic–ultramafic hornfels with characteristic metamorphic mineral assemblages. The MTZ rocks are remarkably thin (30–50m thick) and are composed mainly of dunites,...
40–20Ma marks a fundamental interval in the evolution of the 70–0Ma Panamanian magmatic arc system. During this period, there is no evidence of Panamanian magmatic arc activity to the east of the Panama Canal Basin while to the west and in localized regions to the east of the Panama Canal Basin a phase of intrusive-only activity is recorded. Fundamentally, geochemical and geochronological evidence...
Gabbroic xenoliths and diverse megacrysts (e.g., clinopyroxenes, amphiboles and plagioclases), which correspond to the lithology ranging from gabbro-norite to gabbro, occur in the Pleisto-Holocene alkali basalts from Jeju Island, South Korea. The gabbroic xenoliths consist primarily of moderate-K 2 O plagioclase, Ti-Al-rich clinopyroxene and CaO-rich orthopyroxene; additionally, TiO 2...
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