Xiaoran Zhang

Chinese Academy of Sciences | CAS · Institute of Geology and Geophysics

The Junggar ocean, once situated north (present coordinate) of the Yili and Central Tianshan blocks during early Paleozoic to Late Carboniferous time, was a major southern branch of the Paleo-Asian Ocean whose opening, expansion, and final closure led to the development of the Central Asian Orogenic Belt between Eastern Europe-Siberia and Tarim-Nor...

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 co...

Late Ordovician (ca. 451 Ma) calc-alkaline adakitic granodiorite and granite, associated with coeval S-type granites, were discovered in the Central Tianshan block, NW China. They are characterized by high Sr (526–620 ppm), but low Y (6.8–8.6 ppm) and HREE (e.g., Yb = 0.7–0.8 ppm) contents, thus with high Sr/Y (66–86) ratios. The granodiorite has S...

Sibumasu is inferred to have developed as a united terrane in East Gondwana, with West Sumatra linked to Cathaysia. New detrital zircon U-Pb and Hf isotopic data from Sumatra, complemented by literature data, challenge the above views. The scarcity of early Neoproterozoic zircons in West Sumatra argues against a direct connection between West Sumat...

Magmatic arcs typically exhibit non-steady-state evolution with episodic flare-ups and lulls, yet the main drivers remain contentious. Situated in the southwest margin of Southeast Asia, Sumatra records a long-lived magmatic arc that is still poorly constrained in age and tempo. Detrital zircon data from Sumatra delineate major arc magmatic pulses...

Situated in the heart of the Indonesian archipelago, Sulawesi records well-developed Cenozoic magmatism, yet its Cretaceous magmatic evolution remains enigmatic. Here, we report new U-Pb-Hf isotopic data of detrital zircons from West Sulawesi, Indonesia to constrain its Cretaceous to Eocene magmatic tempo. Detrital zircons aged at ca. 105−80 Ma and...

Combined U-Pb-Hf-O isotopic analyses of zircons are useful probes to investigate the origin and temporal evolution of long-lived magma reservoirs feeding large eruptions. This study presents a complete dataset of zircon Hf-O isotopes of the latest five Toba eruptions in the Quaternary. The new isotopic data differ slightly within and between erupti...

Subduction of oceanic lithosphere is the main driving force of plate tectonics on Earth, yet, how subduction began (i.e. subduction initiation; SI) remains enigmatic, due to limited SI examples. Here, we report new whole-rock geochemical and zircon U-Pb-Hf isotopic data of arc magmatism from the North Sulawesi Arc, Indonesia, to constrain the petro...

Incremental accretion of continental fragments from East Gondwana to Eurasia resulted in the growth of Asia and rise of the Tibetan Plateau, yet its detailed evolution remains uncertain. Argoland, a continental fragment that rifted from NW Australia during the Late Jurassic, played a key role in the initial opening of the Indian Ocean and the evolu...

Cenozoic magmatism occurs throughout West Sulawesi, Indonesia, yet its detailed evolution remains enigmatic due mainly to the scarcity of precise dating. Here, we report new whole-rock geochemical and zircon U-Pb-Hf isotopic data of plutonic/volcanic rocks and river sediments from West Sulawesi to constrain the petrogenesis and magmatic tempo. The...

This study reports new LA‐ICP‐MS U–Pb zircon ages from the Xinghuadukou Complex from the Erguna Block, NE China. A suite of the Palaeoproterozoic orthogneiss and a suite of the Vendian to Cambrian paragneiss are recognized with the co‐magmatic age of 2,464 ± 26 Ma and the maximum depositional age of 561 ± 10 Ma for their igneous and sedimentary pro...

Advancing and retreating subduction zones at convergent margins, primary sites of continental crust growth and loss, are the cornerstones of tectonic evolution of accretionary orogens. Yet, distinguishing the tectonic mode (advancing, retreating, or switching) of subduction zones in fossil orogens is not always straightforward due to the scarcity o...

The main site and timing of the final closure of the middle segment of the Paleo-Asian Ocean (PAO) has been an issue of hot debate, which hampers us from better understanding the late-stage tectonic evolution of the Central Asian Orogenic Belt (CAOB). Synthesizing the available geological records for the ophiolitic mélanges in the Beishan Orogenic...

The Central Asian Orogenic Belt (CAOB) was built up through protracted accretion and collision of a variety of terranes/micro-continents during Neoproterozoic–Mesozoic time. To understand potential links among Paleozoic subduction and accretionary processes that were operative during the development of the southeastern CAOB, we conducted a combined...

Situated between the South Tianshan suture zone to the west and the Solonker suture zone to the east, the Yagan and Zhusileng-Hangwula arcs (YZHAs) in western Inner Mongolia in China occupy a critical place to investigate the tectonic history of the middle segment of the southern Central Asian Orogenic Belt (CAOB). In this work, field-based petrolo...

Triassic magmatic and tectonic reactivation has played a crucial role in remolding the tectonic framework of Eastern Tianshan, NW China, but is poorly understood. Triassic granites in Eastern Tianshan contain magmatic zircons with euhedral to subhedral shapes and concentric oscillatory zoning structures. These zircons have relatively high Th/U rati...

As a pivotal junction between the North China and Tarim cratons, the Alxa Terrane provides an ideal window to constrain the final closure of the middle segment of the Paleo-Asian Ocean (PAO). This study carried out petrological, whole-rock geochemical, and zircon U-Pb-Hf isotopic investigations on four major granitic plutonic complexes in the Alxa...

This article reports new geochemical data from Permian sandstones, most probably deposited during a period of postcollisional extension, from the Yamansu, Shaquanzi, and Xingxingxia areas in the Eastern Tianshan, northwestern China, to determine and characterize their provenance and source nature. The medium- to coarse-grained sandstones are compos...

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 fi...

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...

Connecting the North China Craton to the east and the Tarim Craton to the west, the Alxa Terrane is a key place in investigating the timing of the final closure of the Paleo-Asian Ocean (PAO). New LA-ICPMS zircon U–Pb dating results reveal ca. 300–268 Ma gabbros and diorites in the Bayan Nuru area in the eastern part of the Alxa Terrane. The ~ 300...

The southern Qiangtang magmatic belt was formed by the north-dipping subduction of the Bangong-Nujiang Tethyan Ocean during Mesozoic. To better understand the petrogenesis, time-space distribution along the length of this belt, 21 samples of several granitoid bodies, from west to east, in the Bangong Co, Gaize, Dongqiao and Amdo areas were selected...

The Central Asian Orogenic Belt (CAOB), as one of the largest accretionary orogens in the world, was built up through protracted accretion and collision of a variety of terranes due to the subduction and closure of the Paleo-Asian Ocean in the Neoproterozoic to Early Mesozoic. Located in the Uliastai continental margin of the southeastern CAOB, the...

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...

U-Pb and Lu-Hf isotopic data of detrital zircons from late Paleozoic and Mesozoic strata along the southern flank of the Chinese western Tianshan enable to identify provenance changes and reconstruct early stage uplift and denudation history of the Tianshan range. Detrital zircons from Permian and Early-Middle Triassic siliciclastic rocks show two...

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 t...

The Heilongjiang complex, extending along a suture zone between the Jiamusi and Songliao blocks in Northeast China, is composed mainly of blueschists, greenschists, meta-ultramafic rocks, quartzites, muscovite-albite schists and two-mica schists. Controversy has long surrounded the ages and tectonic settings of mafic rocks from the complex, which a...

Accretionary and collisional orogenesis in the Tarim and North China cratons during Paleozoic time can be correlated with events associated with the assembly and subsequent incipient dispersal of Gondwana. Zircon U-Pb and Hf isotopic data from the northern margins of the two cratons and neighbors have revealed comparable εHf(t)-time patterns. Zirco...

A B S T R A C T Once situated between the Central Tianshan and Junggar blocks during Paleozoic time, the Junggar ocean was a major southern branch of the Paleo-Asian Ocean. Thus, when and how it was closed are essential in understanding the final assembly of the Central Asian Orogenic Belt. However, the exact closure time of the Junggar ocean remai...

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...

Geochemical (including Re-Os isotopic) studies of the mantle rocks of ophiolites in the Bangong-Nujiang suture zone in central Tibet have provided a coherent picture of the evolution of the Bangong-Nujiang Tethyan oceanic mantle from mid-ocean ridge (MOR) to subduction-zone (SSZ) settings.

A detrital zircon U-Pb and Lu-Hf isotopic study was carried out on the Middle Silurian to Late Carboniferous sedimentary strata of the northwestern Tarim Craton in order to understand accretionary processes in the southern part of the Central Asian Orogenic Belt. Detrital zircons from these strata yielded U-Pb ages clustering around 2.8-2.3 Ga, 2.0...

Paleomagnetic dating of the India-Asia collision hinges on determining the Paleogene latitude of the Lhasa terrane (southern Tibet). Reported latitudes range from 5°N to 30°N, however, leading to constrasting paleogeographic interpretations. Here, we report new data from the Eocene Linzizong volcanic rocks in the Nanmulin Basin, which previously yi...

The geological attraction of the Heilongjiang Complex, extending along a suture zone between the Jiamusi and Songliao blocks in Northeast China, resides in excellent exposures of blueschists, which occur in association with granitic gneisses, marbles, meta-ultramafic rocks, greenschists, quartzites, muscovite-albite schists and two-mica schists fro...

The Amdo terrane holds one of the important keys to understand the tectonic evolution of Central Tibet. Here we report the results from a combined study of Cathodoluminescence imaging, LA-ICPMS U-Pb dating, and trace element analysis of zircons from high-pressure (HP) mafic granulites from the Amdo terrane. Zircons from the mafic granulite are roun...

It is essential to obtain precise Os isotopic composition of convecting upper mantle before the application of Re-Os isotope system. However, published estimates for convecting upper mantle, especially calculation from mantle peridotites, are hindered by ubiquitous mantle heterogeneity. Given the ancient refractory domains contribute little to MORB...

The Shangcang Permian pillow basalts in Yunnan Province crop out on the bottom of the inner zone of the Emeishan Large Igneous Province(ELIP). They are belong to tholeiitic series with SiO2 contents between 49.36% and 51.36%, 1.28%~1.91% for TiO2, 13.91%~16.31% for Al2O3, 6.08%~10.79% for MgO, with Mg#[100 × Mg/(Mg+Fe)] of 53~69, and the Na2O conte...

Podiform chromitites in ophiolite usually are interpreted as the crystallization products of mafic magmas, contemporaneous with the generation of the ophiolite at mid-oceanic ridges or back-arc spreading centres. However, the real ages of the chromitites can rarely be determined directly, because their chemistry provides few opportunities for geoch...

Early-crystallizing chromian spinel (Cr-spinel) in the Nagqu ophiolite has high Os and low Re contents, and it is resistant to alteration during serpentinization, weathering and metamorphism. The chemical composition of primitive magma is preserved in Cr-spinel, which makes it suitable for determining the initial Os-isotope composition of the mantl...

Podiform chromite deposits occur in the mantle sequences of many ophiolites that were formed in supra-subduction zone (SSZ) settings. We have measured the Re–Os isotopic compositions of the major chromite deposits and associated mantle peridotites of the Dongqiao Ophiolite in the Bangong–Nujiang suture, Tibet, to investigate the petrogenesis of the...

Dali picrite in Yunnan Province occurs at the bottom of Emeishan basalt in the inner zone of Emeishan Large Igneous Province ( ELIP). The picrite is highly porphyritic with 20% ∼ 40% euhedral-subhedral olivine and clinopyroxenite phenocrysts, and the groundmass with diabasic texture is composed of microcrystalline olivine, clinopyroxenite and plagi...

High-pressure mafic granulites with a peak mineral assemblage of garnet + clinopyroxene + rutile + quartz were found in the Amdo basement, central Tibet. Two kinds of symplectites were identified that are composed of orthopyroxene + plagioclase ± spinel and hornblende + plagioclase around garnet, which were interpreted to develop during the retrogr...

在青藏高原安多微陆块中发现了高压基性麻粒岩, 其峰期矿物组合为石榴子石+单 斜辉石+石英+金红石. 该高压麻粒岩经历了两期退变质作用, 退变质矿物呈后成合晶产 状, 早期退变质矿物组合是Opx+Pl±Spl, 晚期退变质矿物组成是Hbl+Pl. 温度与压力计算 表明, 高压麻粒岩相峰期变质温度为860~920℃, 压力为14.6~15.6 kbar; 早期退变质的形 成温压为820~890℃和8.8~11.5 kbar; 晚期退变质条件为550~670℃和5.2~6.5 kbar. 其退 变质作用P-T 轨迹为顺时针型近等温降压到降温降压的过程, 指示该麻粒岩经历了俯冲至 深部地壳层位(~50 km), 之后又快速抬升到浅部地壳(~20 km)的变质过程. 该高压麻粒岩 的形成可能与安多微陆...

High-temperature and-pressure granulites containing garnet, clinopyroxene, hornblende and quartz have been first found in Amdo basement along Bangong-Nujiang suture in central Tibet (Fig. 1). Fine grained symplectites composed of orthopyroxene + plagioclase ± spinel/hornblende + plagioclase ± orthopyroxene developed during the decompressing stages...