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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...
Early Permian magmatism is one of the most important tectonothermal events in the Central Asian Orogenic Belt (CAOB). Early Permian granitic magmatism has been recognized from southern Beishan, NW China and they were emplaced between 275Ma and 279Ma according to LA-ICPMS zircon U–Pb dating. They are mainly metaluminous I-type and belong to the high-K calc-alkaline and shoshonitic series. The granitoids...
Late Mesozoic large-scale crustal extension occurred across the northeastern section of continental Asia, and metamorphic core complexes (MCCs) are the major features in this region. This paper presents new zircon U–Pb and Ar–Ar ages of biotite and hornblende for pre- or syn- (mylonitized) and post-kinematic (unmylonitized) intrusions from these MCCs, and attempts to determine the timing of initiation,...
Five Triassic granitic plutons have been identified from the Beishan orogen by zircon U–Pb dating that defines two age groups: 240–238Ma and 225–217Ma. They belong to the high-K calc-alkaline and shoshonitic series and have alkalic and alkali-calcic characteristics, and are weakly peraluminous–metaluminous. These granitoids are mainly highly fractionated I-type granite and A-type granite. They have...
Granitoids varying in composition from biotite–amphibole granodiorite to monzogranite with rapakivi textures have recently been recognized in the Qinling orogen (central China). The granitoids are magnesian, calc-alkalic and metaluminous (A/CNK=0.71–0.95). They contain many mafic to intermediate microgranular enclaves. The enclaves are quenched mafic melts in granitic host magma as evidenced by fine-grained...
North Xinjiang, Northwest China, is made up of several Paleozoic orogens. From north to south these are the Chinese Altai, Junggar, and Tian Shan. It is characterized by widespread development of Late Carboniferous–Permian granitoids, which are commonly accepted as the products of post-collisional magmatism. Except for the Chinese Altai, East Junggar, and Tian Shan, little is known about the Devonian...
Post-orogenic granitic and associated mafic rocks from northeastern (NE) China consist of granodiorite and gabbro intrusions. We report here upon new U–Pb zircon ages, geochemical data and Sr–Nd–Hf isotopic data for these rocks. LA-ICP-MS U–Pb zircon analysis yields an age of 262.8±1.0Ma for the granitic rocks, and a uniform age of 262.1±0.7Ma for the gabbro. Most of the granitic and mafic rocks are...
Geochronological, geochemical and whole-rock Sr–Nd isotopic analyses have been completed on a suite of alkaline ultramafic dykes from southwest (SW) Guizhou Province, China with the aim of characterising their petrogenesis. The Baiceng ultramafic dykes have a LA-ICP-MS zircon 206 Pb/ 238 U age of 88.1±1.1Ma (n=8), whereas two phlogopites studied by 40 Ar/ 39 Ar dating...
Late Mesozoic (122.5–127 Ma) mafic dykes (dolerite-porphyries) in the Beibo gold district, Shandong Province, eastern North China Craton, can be subdivided into two groups (high-K and low-K) based upon K 2 O content. They are characterised by enrichment in light rare earth element (LREE) and some large ion lithophile elements (LILEs) (e.g., Rb, Ba and Sr), similar concentrations of heavy rare...
The Chinese Altai orogen is a typical domain of the Central Asian Orogenic Belt and in previous syntheses was divided into six tectonic units (or terranes). In this paper, 41 new and 36 published whole-rock Nd and Sr isotopic data for granitoid intrusions and mafic dykes within units 2 and 3 of the central Altai and units 4 to 6 of the southern Altai were used for isotopic mapping. The age of the...
Post-orogenic alkaline intrusions and associated mafic dikes from the Sulu orogenic belt of eastern China consist of quartz monzonites, A-type granites and associated mafic dikes. We report here U–Pb zircon ages, geochemical data and Sr–Nd–Pb–Hf isotopic data for these rocks. The SHRIMP U–Pb zircon analyses yield consistent ages ranging from 120.3±2.1 Ma to 126.9±1.9 Ma for five samples from the felsic...
The Qinling orogen between the North China and South China cratons was intruded at 211–217 Ma by calc-alkaline quartz monzonitic to monzogranitic plutons characterized by I- to A-type geochemistry and in many places contain plagioclase-mantled alkali feldspar megacrysts (rapakivi texture sensu lato). The felsic rocks contain mafic to intermediate magmatic enclaves suggestive of mingling and mixing...
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