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Structural analysis and U–Pb geochronological study on zircons from the southern Chinese Altai (the Kalasu area, SE of the Altai city) show that the Cambro-Ordovician accretionary wedge (ca. 520–492 Ma) underwent four major geological events: 1) emplacement of Early Devonian magmas (ca. 410–400) associated with formation of a volcano-sedimentary cover, 2) major Middle Devonian (ca. 390–374 Ma) tectono-metamorphic...
The Songpan–Ganze terrane is mainly composed of a Triassic sedimentary sequence and late Triassic–Jurassic igneous rocks. A large number of plutons were emplaced as a result of tectono-magmatic activity related to the late stages of Paleo-Tethys ocean closure and ensuing collision. Granitoids and their hosted mafic enclaves can provide important constraints on the crust–mantle interaction and continental...
Intensive Devonian felsic magmatism is recorded within the southwestern Mongolian collage system of the Central Asian Orogenic Belt (CAOB). The voluminous magmas have isotopic compositions of juvenile materials from the mantle, thus manifesting significant mantle–crust interaction and continental growth at this time. Here, we present systematic Sr–Nd–Hf–Pb isotopic data for the Devonian mafic intrusions...
The Heilongjiang Complex is a blueschist facies metamorphic belt located within the Zhangguangcailing Orogen between the Jiamusi and Songliao blocks in Northeast China. This complex has been regarded as an accretionary belt related to the subduction of an intervening oceanic domain between the two blocks. However, the timing of ocean closure and final amalgamation has not been well constrained, with...
In Northeast China, oceanic subduction between the Jiamusi and Songliao blocks remains topic of hot debate. The Heilongjiang Complex has been regarded as an accretionary belt resulting from the subduction of an intervening ocean between the two blocks. In this study, we carry out extensive geological, geochemical and geochronological investigations on the sedimentary rocks, amphibolites and blueschists...
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...
Mesozoic intrusions, including MORB-type gabbros, high-Mg diorites, calc-alkaline diorites and granodiorites, were exposed in the Ando microcontinent that is bounded between the Qiangtang and Lhasa terranes. Discoveries of these Mesozoic intrusions have provided new petrogenetic constraints on our understanding of Bangong-Nujiang ocean evolution. Zircon U–Pb dating shows that these intrusions formed...
The Alxa Terrane is situated in a key area between the North China and Tarim cratons. Paleozoic magmatic records in this terrane place important constraints on the subduction processes of the southern Paleo-Asian Ocean. New data of zircon U-Pb ages and whole-rock elemental and isotopic data reveal two groups of intermediate to felsic plutons in the Alxa Terrane. One group consists of diorites and...
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...
The closure of the Junggar Ocean between the Central Tianshan and Junggar terranes is essential in understanding the final assembly of the southern Central Asian Orogenic Belt. This study presents new whole-rock geochemical, Sr–Nd and zircon U–Pb–Hf isotopic data for mafic–intermediate intrusions from the Central Tianshan block to provide robust constraints on the final closure of the ocean. LA-ICP-MS...
Granitoids and their hosted mafic enclaves may retain important information on crust–mantle interaction, and thus are significant for study of crustal growth and differentiation. An integrated petrological, geochronological and geochemical study on the granitoid plutons of the Yaloman intrusive complex from the Gorny Altai terrane, northwestern Central Asian Orogenic Belt, was conducted to determine...
The provenance of late Paleozoic siliciclastic sedimentary strata on the northern margin of the Tarim Craton and the South Tianshan Orogenic Belt provides important insights into subduction and collision processes during the formation of the southern Central Asian Orogenic Belt. Detrital zircons from Carboniferous and Permian sedimentary rocks in the South Tianshan belt show two predominant age populations...
Extensive Permian mafic–ultramafic intrusions crop out within the Central Asian Orogenic Belt (CAOB). Because the magmatic activity is spatially and temporally associated with the Tarim Large Igneous Province (LIP), a mantle plume has been invoked to explain the petrogenesis of these mafic–ultramafic rocks. In order to test this hypothesis, we present new geochronological and geochemical data for...
As a major Precambrian microcontinent in the southernmost Central Asian Orogenic Belt (CAOB), the Central Tianshan block (CTS) in the Chinese Tianshan is essential for understanding the final assembly of the southern CAOB. It experienced multistage Paleozoic magmatism and metamorphism, but the detailed processes are still controversial and far from being completely understood. This paper reports coupled...
The Gorny Altai terrane (GA) is a key area in understanding the crustal evolution of the Central Asian Orogenic Belt (CAOB). This paper reports U–Pb and Hf-isotope data for detrital zircons from Cambrian to early Devonian sedimentary sequences to constrain their provenance, as well as the tectono-magmatic events and crustal growth in this region. Nearly all the detrital zircons are characterized by...
An integrated U–Pb and Hf-isotope study on detrital zircons from the early Paleozoic meta-sedimentary rocks along the Charysh–Terekta–Ulagan–Sayan suture zone in Russian Altai was conducted in order to trace their provenance and tectonic setting. Most of the zircons possess oscillatory zoning and high Th/U ratios (>0.1), indicating their magmatic origin. The investigated samples yield similar zircon...
Granitoid magmatism is extensively developed in the Altai Superterrane, but the timing of magmatic events is not so well determined. In this study, twelve granitoid intrusions from Southwest Mongolia were dated by the zircon U–Pb method and analyzed for zircon Hf isotopic compositions. The new age data indicated three phases of magmatic emplacement: Middle Paleozoic (398–350Ma), Late Paleozoic (317–289Ma)...
Dunhuang Block is previously considered to be an eastern part of the Tarim Craton, but now it is proposed to be the western extension of the Alxa Block of the NCC as a result of displacement along the Altyn Tagh fault. The oldest basement rocks of the Dunhuang Block, named Aketashitage Complex, were mainly exposed in the northern Altyn Tagh. Migmatites of the Aketashitage Complex are sodic and subalkaline...
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