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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...
It is generally believed that Miocene adakitic rocks in the Lhasa terrane (block) of Southern Tibet were derived from a thickened lower crust, and that their compositions will therefore reflect the geochemical characteristics of their lower-crustal source(s). Adakitic rocks in the western part of the Lhasa terrane possess geochemical and Sr–Nd isotopic characteristics that are clearly different from...
Adakite was originally proposed as a genetic term to define intermediate to high-silica, high Sr/Y and La/Yb volcanic and plutonic rocks derived from melting of the basaltic portion of oceanic crust subducted beneath volcanic arcs. It was also initially believed that adakite only occurs in convergent margins where young and, thus, still hot oceanic slabs are being subducted. Currently, adakite covers...
We describe the whole-rock geochemistry, biotite Ar–Ar and zircon U–Pb geochronology, and in situ Hf–O isotopic compositions of the Linzhi two-mica granitoid in the southeastern Lhasa terrane. The granitoids are calc-alkaline to high-K calc-alkaline in composition, and they have geochemical affinities with adakites. The whole-rock geochemistry, with high SiO 2 and Al 2 O 3 ...
Volcanic–subvolcanic rocks and associated Cu-Au deposits in Yinshan are located in the eastern part of the Neoproterozoic Jiangnan orogenic belt between the Yangtze and Cathaysia blocks, constituting a large metallogenic district in southeastern China. This paper presents new laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) zircon U–Pb dating, element and Sr-Nd-Hf isotopic data...
In order to characterize the recycled lower continental crust (LCC) in the Dabie orogen, 17 Early Cretaceous low-Mg adakitic (LMA) and 9 normal (non-adakitic) granitoids have been investigated for SrNdPb isotopes. Combined with literature data, LMA have low Ɛ Nd (t) (−27.8 to −14.7) and 206 Pb/ 204 Pb(i) (15.69–17.16) and low to moderately high 87 Sr/ 86 Sr(i)...
Granitic rocks are a major component of the Earth's continental crust and occur in a wide variety of tectonic settings. Their chemical and isotopic characterization is crucial to the recognition of the potential sources and mechanisms involved in their generation. In this study, we present the first whole rock chemical and isotopic (Sr–Nd–O) data for the Pavia pluton (328–317Ma), located near the...
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...
Intra-oceanic subduction has been taken as one of the most important contributors to the crustal growth of the immense Central Asian Orogenic Belt (CAOB), however, the detailed geological processes of the development and growth of numerous island arcs still remain unclear. In order to explore the development history of representative ancient island arcs, we have conducted geochronological and geochemical...
The Early Paleozoic intracontinental orogenic belt in the South China Block (SCB) is composed of massive granitoids and high-grade metamorphic rocks. Compared to the widespread distributions of early Paleozoic S-type granites in the eastern SCB, coeval I-type granitoids are rare and consequently receive much less attention. Two spatially associated granodiorite plutons in the northwestern rim of the...
The questions of why the Late Cretaceous magmatism generated and how the nature of the lower crust evolves in central Tibet remain poorly constrained. In this paper, we report the presence of early Late Cretaceous adakitic rocks from the Azhang area, northern edge of the central Lhasa subterrane, central Tibet. These rocks are rhyodacites/dacites in composition and have geochemical characteristics...
The Bozshakol area is one of the most important copper resource concentrations in Central Kazakhstan. We report in situ zircon U–Pb age and Hf isotope data, whole rock geochemical and Sr–Nd isotopic data for the volcanics and intrusions from the Bozshakol area.Secondary ion mass spectrometry (SIMS) zircon U–Pb dating indicates that the volcanics erupted at 501.8±3.2Ma and the intrusions emplaced at...
This study presents new major and trace element, plus Sr–Nd and zircon U–Pb isotope data for the Zhongcang granitic plutons, which are located to the south of the Yongzhu–Asuo ophiolite belt within the northwestern part of the central Lhasa subterrane, Tibetan Plateau. These data provide new insights into the Late Cretaceous tectonic evolution of southern Tibet. The Zhongcang plutons are dominated...
The late Mesozoic magmatic record of SE China is dominated by felsic volcanics and intrusions. However, this magmatism mainly occurred in coastal areas at 110–80 Ma, in contrast to poorly researched dike swarms that were emplaced inland at 165–120 Ma. Here, we focus on Early Cretaceous mafic and felsic dike swarms that provide new insights into the tectono-magmatic evolution of SE China. The swarms...
A major magmatic flare-up is documented along the Bitlis–Zagros suture zone in Eocene–Oligocene times. The Cenozoic magmatism of intraplate Central Iran is an integrant part of this tectono-magmatic scenario. The Cenozoic magmatism of the Sabzevar structural zone consists of mostly intermediate to felsic intrusions and volcanic products. These igneous rocks have calc-alkaline and adakitic geochemical...
The Qumushan (QMS) syn-collisional granodiorite, which is located in the eastern section of the North Qilian Orogen at the northern margin of the Greater Tibetan Plateau, has typical adakitic characteristics and also contains abundant mafic magmatic enclaves (MMEs). This recognition offers an unprecedented insight into the petrogenesis of both the adakitic host granodiorite and the enclosed MMEs....
Understanding how adakitic magmas form is important for understanding the formation of the continental crust. Generating such high-Sr/Y rocks by crystal fractionation of basalts/basaltic andesites in magma chambers has been proposed in a wide range of tectonic settings. However, the complementary cumulates predicted by this scenario have rarely been observed. The late Triassic (~227Ma) Ningcheng complex...
To constrain the Phanerozoic crustal evolution of the Dunhuang Block, new whole-rock geochemistry, zircon U–Pb ages and Hf isotopic data were determined for three Paleozoic granitic plutons in the northern Altyn Tagh, northwest China. Zircon U–Pb dating of these plutons, including gneissic granite, mylonitic granite and augen gneiss, yielded Middle Devonian to Early Carboniferous crystallization ages...
Adakitic intrusions are supposed to have a close genetic and spatial relationship to porphyry Cu deposits. However, the genesis of adakitic intrusions is still under dispute. Here, we describe newly discovered intrusive complex rocks, which are composed of ore-bearing, layered magnetite-bearing gabbroic and adakitic rocks in Jiamate, East Junggar, NW China. These Jiamate Complex intrusions have diagnostic...
Magmatic records with high Mg and low Y signatures provide important insights into the deep mantle dynamics that dictate the evolution of ancient orogenic belts. This paper reports the presence of felsic intrusive dikes with high Mg and low Y signatures intruding the Baingoin Batholith (central Tibet) at ca. 94 Ma. These dikes show adakitic signatures, including high Sr and low Y and Yb contents and...
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