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The Early Permian Tarim large igneous province (Tarim LIP) consists mainly of basaltic lavas, mafic–ultramafic intrusions including dikes and, syenite bodies in the Tarim Basin, NW China. A major unit of the Tarim LIP, the Wajilitag intrusive complex, consists of olivine pyroxenite, clinopyroxenite and gabbro units (from bottom to top), diorite and syenite rocks occurred in the upper part of the complex...
The Early Permian magmatism in Tarim, NW China comprises diamondiferous kimberlites, lamprophyres, flood basalts, Fe–Ti oxide ore-bearing layered mafic–ultramafic intrusions, bi-modal dyke swarms, alkaline igneous complexes (including syenites and A-type granites), rhyolites and pyroclastic rocks. The extent of this intraplate magmatism exceeds 250,000km 2 , making it comparable to Large Igneous...
Assessment of the synchroneity between the Siberian Traps and the Permo-Triassic boundary (PTB) mass extinction has led to the proposition that the Siberian flood volcanism was responsible for the severest biotic crisis in the Phanerozoic. However, recent studies suggest that the Siberian Traps may have postdated the main extinction horizon. In this paper, we demonstrate, using stratigraphy, a time...
The age of the Emeishan lavas in SW China remains poorly constrained because the extrusive rocks are (1) thermally overprinted and so represent an open system unsuitable for 40 Ar/ 39 Ar geochronology and (2) in most cases devoid of zircon so that it is impossible for the application of U–Pb geochronology. Existing radiometric age constraints of Emeishan large igneous province are...
The Early Permian Tarim Large Igneous Province (LIP) in northwestern China contains a large area of silicic volcanics (~48,000km 2 ) which are spatially and temporally associated with mafic–ultramafic rocks. In order to understand the behavior of crust above a mantle plume, selected rhyolitic samples are investigated in terms of U–Pb zircon dating, geochemical and isotopic analyses. The Tarim...
Despite considerable efforts, the Paleozoic tectonic setting (subduction vs. post-collision vs. mantle plume) in the Central Asian Orogenic Belt (CAOB) remains controversial. With aims of solving this issue, we examined zircon saturation temperatures of granitoids emplaced in different settings, and demonstrated that zircon saturation thermometry of felsic igneous rocks, especially when integrated...
Late Carboniferous igneous rocks are widespread in the western Tianshan, but the tectonic settings for these rocks remain controversial. We report a plagioclase 40 Ar/ 39 Ar age, and geochemical, Sr–Nd isotope and LA–ICPMS clinopyroxene trace element data for gabbros in the Luotuogou region. The tholeiitic Luotuogou gabbros give a Late Carboniferous (312±1Ma) 40 Ar/ 39...
Petrology, geochemistry and Re–Os isotopes of peridotite xenoliths from Yantai (Shandong Province) are reported in this paper with aims of constraining the age and evolution of the lithospheric mantle beneath eastern North China Craton. The Yantai xenoliths contain predominant harzburgites and subordinate lherzolites. Although their highly incompatible element compositions have been modified by metasomatism,...
The juvenile component of accretionary orogenic belts has been declining since the Archean. As a result, there is often controversy regarding the contribution of oceanic basalts to Phanerozoic crustal growth, as in the case of the Central Asian Orogenic Belt (CAOB). Here we report on three groups of Late Carboniferous (316–305Ma) granitoids in the western Junggar region of northern Xinjiang, NW China,...
Zircon U–Pb ages and geochemical data are reported for the Piqiang oxide-bearing ultramfic–mafic complex, the Bachu mafic dyke swarm, the Yingan and Kaipaizileike basalts and the Halajun A-type granites in the Tarim Block, Northwest China. The Piqiang complex and the Halajun A-type granites were emplaced at ca. 276Ma and ca. 278Ma, respectively. Together with previously reported geochronological data,...
The ~260Ma Emeishan Large Igneous Province (ELIP) in southwest China has previously been demonstrated to provide compelling evidence for pre-volcanic crustal doming in support of the mantle plume hypothesis. However this has been questioned by Ukstins-Peate and Bryan (2008) by showing hydrothermal magmatic activity at the Daqiao section. To solve this argument, a detailed characterization of the contact...
There are several places in the Emeishan Large Igneous Province (ELIP) where highly magnesian volcanic or intrusive rocks accompany more abundant flood basalts. The high-Mg rocks vary in composition from LREE-depleted, low-Ti komatiites to LREE-enriched, high-Ti picrites. These magmas carried cognate olivine phenocrysts with Fo content higher than 91mol% indicating that these olivines crystallized...
The Emeishan large igneous province in SW China comprises a bimodal mafic–silicic suite with the silicic rocks occurring at the uppermost part of the thick lava sequence. The silicic rocks have an age of 257–263Ma, and are thus roughly coeval with the Guadalupian–Loping (G–L) boundary event. Most silicic rocks (trachyte and rhyolite) from the Emeishan province have rather uniform ε Nd values...
Previous studies on the temporal link between the end-Guadalupian mass extinction event and Emeishan flood volcanism were mainly based on geochronological and bio- and chemostratigraphic correlation techniques (Wignall et al., 2009). The absence of material-based hard evidence that directly links the extinction with the Emeishan volcanism remains a major obstacle regardless of the indication of coincidence...
A suite of picrites and basalts from the Muli area, in the northwestern part of the Emeishan continental flood basalt province, provides new and valuable information on the geochemistry of the Emeishan Large Igneous Province (LIP) and its source. The Muli picrites can be classified as type-1 or type-2. The former shows ocean–island basalt-like trace element characteristics, with γ Os (260Ma)...
The tectonic setting of South China during the Neoproterozoic remains a subject of debate. Neoproterozoic adakites from Xuelongbao and Datian along the western margin of the Yangtze Craton have been used to argue for an arc setting assuming that these rocks are the melting products of a subducted oceanic slab (Zhou, M.F., Yan, D.P., Wang, C.L., Qi, L., Kennedy, A., 2006a. Subduction-related origin...
Sr–Nd–Os isotopic analyses are presented for peridotite xenoliths from Tertiary alkali basalts in Yangyuan and Fansi with the aim of identifying and characterizing the relics of ancient lithospheric mantle that survived lithospheric removal in the western North China Craton (NCC). The analyzed samples are residual lherzolites and harzburgites, ranging from fertile to highly depleted (0.36–4.0 wt%...
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