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Cenozoic adakitic rocks in the Lhasa block (southern Tibet) have been widely used to trace the lateral extent of crustal thickening. However, their petrogenesis remains controversial. Here, we report geochronological and geochemical data for the Napuri intrusive rocks in the core area of the Quxu batholith, southern Lhasa. Zircon U-Pb dating suggests that they were generated at approximately 48Ma...
Little is known about the detailed processes associated with the transition from oceanic to continental lithosphere subduction in the Gangdese Belt of southern Tibet (GBST). Here, we report zircon U–Pb age, major and trace element and Sr–Nd–Hf isotopic data for Late Cretaceous–Early Oligocene (~91–30Ma) intermediate-acid intrusive rocks in the Chanang–Zedong area immediately north of the Yarlung–Tsangpo...
The Jinan gabbroic intrusion from the North China Block (NCB) experienced complex differentiation from a reduced and Si-undersaturated magma to an oxidized and Si-saturated melt, with a mineral assemblage of olivine+pyroxene+plagioclase+biotite+ilmenite. New dating of baddeleyite and zircon yield a consistent U–Pb age range from 130 to 134Ma, confirming emplacement during the early Cretaceous. In...
Rapid Mesozoic–Early Cenozoic crustal growth in the Gangdese area, southern Tibet, has commonly been attributed to pre-collisional and syn-collisional underplating of mantle-derived magmas. Here, we report on adakitic magnesian charnockites (i.e., hypersthene-bearing diorites and granodiorites) near Milin, in eastern Gangdese, that provide new insights into the crustal growth process of the region...
At more than 500km in length, the mainly Jurassic–Early Eocene Gangdese batholith is one of the most important constituents of the southern Lhasa sub-block and provides an ideal site for study of Tibetan orogenesis. Recent studies on Gangdese intermediate-felsic intrusive rocks, mainly granites, demonstrate that remarkable crustal growth as well as an early Late Cretaceous (ca. 100–80Ma) magmatic...
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...
Metasedimentary granulite enclaves hosted in the Indo-Sinian Darongshan–Shiwandashan granite belt from the southeastern Guangxi province, South China, experienced a three-stage metamorphic evolution: (1) the early prograde metamorphism in the stability field of sillimanite at ~800°C; (2) the peak metamorphism with a mineral assemblage of spinel+quartz at 7.5–8.0kbar and 950–1000°C (260–250Ma); and...
The Mesozoic geology of southeastern (SE) China was characterized by emplacement of voluminous felsic magmas. We present zircon U–Pb–Hf isotopic compositions and whole-rock major and trace elemental compositions of a series of felsic volcanic rocks from the eastern Guangdong and Fujian provinces. The volcanic rocks have been divided into three formations (the Douling, Nanyuan and Shimaoshan Fms.)...
New Sr–Nd–Pb isotope dataset of Mesozoic igneous rocks shows that the NE China can be subdivided into four Sr–Nd–Pb isotope provinces: (1) the northern Hinggan Mountains (NHM) region; (2) the southern Hinggan Mountain (SHM)–Yanji-Liaoyuan (YL) region; (3) the Zhangguangcai Range–Jiamusi (ZGJ) Block; and (4) the exotic Wandashan massif (WDM). The Wandashan massif contains Mesozoic (high-μ)-type oceanic...
Paleocene (55–58 Ma) adakitic andesites from the Yanji area of NE China are subdivided into clinopyroxene andesites and amphibole andesites. Relative to the clinopyroxene andesites, the amphibole andesites contain higher SiO 2 , K 2 O and lower MgO, FeO T , Al 2 O 3 , CaO, TiO 2 , Cr, Ni, Sr, Y and Nb, and have evolved Sr–Nd–Pb isotope compositions....
The Emeishan flood basalts are part of an important large igneous province (LIP) along the western margin of the Yangtze Block, Southwest China. Mafic rocks interlayered with Permian sedimentary rocks in western Guangxi Province, on the southeastern margin of the Yangtze Block, have SHRIMP zircon U–Pb weighted mean ages of 259.6±5.9 Ma and 259.1±4.0 Ma, identical to mafic plutons associated with the...
K-Ar dating, major- and trace-element and Sr-Nd isotopic analyses were carried out for early Cretaceous (122-127 Ma) lamprophyres from the Sulu orogen in eastern China. The results show strong fractionation in rare-earth elements with (LREE) >100 times chondrite, but HREE <10 times chondrite, indicating the presence of residual garnet in the melting source. These rocks are characterized by significant...
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