The magnitude and distribution of convergence during the India–Asia collision remain debated, largely due to a mismatch between post-collisional convergence and observed crustal shortening. Resolving this discrepancy requires constraining the tectonic framework of the southern Asian margin immediately prior to collision, which is commonly assumed to have been an Andean-type convergent margin. Here, we report Late Cretaceous–Paleocene meta-mafic rocks from the eastern segment of the Lhasa–Tengchong terrane, showing coeval arc-like and back-arc basalt-like geochemical signatures. The arc-like samples crystallized between 87 and 47.3 Ma with initial 87Sr/86Sr = 0.7042–0.7091 and εNd(t) = −3.4 to +4.8, whereas the 71–55 Ma back-arc basalt-like samples display initial 87Sr/86Sr = 0.7053–0.7178 and εNd(t) = −5.0 to +8.4. These rock associations indicate the development of an active arc-back-arc system along the southern Asian margin prior to the India–Asia collision. When integrated with regional observations from the Lhasa–Tengchong terrane, including lithospheric thinning, moderate crustal thickness, back-arc magmatism, and widespread extension, these data suggest that southern Asia was characterized by a markedly extensional, thin continental lithosphere, fundamentally challenging the long-held view of an Andean-type southern Asian margin. More importantly, this extensional framework broadens the north–south extent of the pre-collisional Asian continent, implying that a substantial proportion of India–Asia convergence was accommodated by intra-Asian shortening after collision, rather than by subduction of the Indian plate.

Despite extensive research on the Comei large igneous province (LIP) in the Tethyan Himalaya, that has significantly enhanced our understanding of early Cretaceous tectonic evolution on Gondwana's northern margin, comprehensive studies on the complete magma-tectonic evolution of the Tethyan Himalaya during this period remain limited. Situated on East Gondwana's passive margin at mid-to-high southern paleolatitudes (39.6°–54.7°S), the Early Cretaceous Comei LIP (147–117 Ma) exhibits three main magmatic pulses (~140, 132, 119 Ma). The magmatic activity shows spatial and temporal variations, with the oldest ages in the central-east and the youngest in the central regions, indicating a complex distribution pattern beyond simple east-to-west progression. Its minimum erupted volume of 144,000 km3 and area of 180,000 km2 satisfy the defining criteria of a LIP. Peak emplacement (~132 Ma) reached ~50,400 km3/Myr assuming 70% volume emplaced within ≤2 Myr. The province comprises gabbroic intrusions, basaltic lavas, mafic sills/dikes, subordinate ultramafic intrusions, and felsic rocks. ΔNb values reveal two distinct mantle sources for the Comei LIP: an enriched plume source with recycled oceanic components (positive ΔNb) and a hydrated mantle source containing recycled continental crust (negative ΔNb). The Comei LIP also includes intermediate (diorite/tonalite) and silicic (A-type granite) rocks, which formed via amphibole separation during mafic magma fractionation and lower crustal melting, respectively. The Kerguelen mantle plume (~147–145 Ma initiation) influenced the Tethyan Himalaya via vertical and lateral spread of its plume head, centered in the Cuona-Kada-Tage-Longzi region. Its influence waned after ~120 Ma due to Indian Plate northward drift, ceasing plume magmatism and initiating rifting. The emplacement of the entire Comei LIP was controlled by E–W faults and facilitated by lithospheric thinning (60–80 km) and plate drift. This localization of plume activity exclusively in the Tethyan Himalaya contrasts with the plume-absent magmatism in coeval SW Australia, which is attributed to its thick lithosphere, compressional setting, and interior position within the LLSVP. Our revised geodynamic model for Eastern Gondwanas breakup integrates plume dynamics and plate kinematics, emphasizing the Indian Plate's rapid northward drift in driving plume-lithosphere interactions through three phases: pre-breakup plume coupling, conduit migration/rift nucleation, and oceanic breakup with the Southern Kerguelen Plateau formation. Future studies require resolving plume-lithosphere interactions via high-P experiments and diffusion chronometry, quantifying pyroxenite contributions, tracking deep carbon cycles (Ca-Mg isotopes), and integrated geodynamic modeling using ΔNb/FCKANTMS frameworks to decipher how plumes exploit lithospheric heterogeneity to drive supercontinental breakup.

When and how the plateau lithosphere commenced to expand southeastwards and then induced the fast uplift and exhumation in the SE Tibetan Plateau during the India - Asia collision remain controversial. Here we present zircon U-Pb, mica Ar-Ar, and apatite (U-Th)/He and fission track ages of the granites together with kinematic observations in the Nujiang tectonic zone of the SE Tibetan Plateau. An integrated analysis indicates the earliest pulse of shearing strike slip induced by the southeastward lithospheric expansion in the SE Tibetan Plateau and the establishment of tectonic framework of the SE Tibetan Plateau during 45 - 40 Ma. In addition, the SE Tibetan Plateau, from south to north, had experienced the differential extrusion and uplift during the early Miocene to Pliocene. An integrated analysis suggests that the south and north SE Tibetan Plateau (the boundary line at ca. 26 degrees N) stopped growth at Middle Miocene and Pliocene, respectively. This study provides the most detailed resolution for the southeastward expanding processes of the plateau lithosphere and the exhumation mechanisms of the SE Tibetan Plateau during Cenozoic times to date.

The distribution and episodic magmatism of the southern Asian continental arc since the Cretaceous remains unclear. Here, we systematically compiled zircon U-Pb ages and Hf isotopic data sets, including magmatic rocks exposed on surface, detrital zircons from erosion of magmatic rocks, and xenocrystal zircons entrapped by Cenozoic volcanics from deep magmatic rocks, to elucidate these questions. Magmatic flare-up at 140-110 Ma occurred from central and northern Lhasa through eastern Tengchong to Shan Scraps, which resulted from the combination of diachronous closure of Bangong-Nujiang Tethys Ocean and subduction of a consolidated NeoTethys Ocean from Lhasa to Shan Scraps. During late Cretaceous-Eocene times, an extended Neo-Tethyan continental arc was built on the southern Asian margin from southern Lhasa, through Tengchong-Shan Scarps to Sumatra, excluding West Burma. The continental arc shows spatiotemporal variations in magmatism across different sections. Magmatism in eastern southern Lhasa and Sumatra is dominated by juvenile crust growth with flare-ups at 105-85 Ma and 65-45 Ma. In contrast, magmatic flare-ups at 75-45 Ma and ancient crust reworking are recorded in western southern Lhasa, Tengchong, and Shan Scraps. The spatial and temporal variations in magmatic flare-ups of Neo-Tethyan continental arc are probably related to asynchronous rollback of the NeoTethyan slab under different sections. During late Cretaceous-early Paleocene times, the multi-stage changes of Neo-Tethyan slab dip caused asynchronous extension-compression cycles on southern Asian continental margin.

Greisen-type tin (Sn) mineralization has traditionally been attributed to the interaction between granite and reduced Sn2+-bearing fluid (with Sn oxidation). In this study, we present the magnetite-bearing and evolved mineral assemblages from topaz-fluorite (Zones 1-3) to primary greisen (Zone 4, quartz-muscovite-cassiterite) in the Paleocene Kalonta Sn-W deposit, southern Myanmar. Together with the typical unidirectional solidification textures (UST), melt/fluid inclusions in topazes and their low OH/(OH + F) ratios (< 0.04) indicate that the fluorine (F)-rich minerals from Zones 1-3 were likely crystallized from fluid-saturated and extremely F-rich melts. In addition, abundant magnetite grains (replaced by hematite) in Zones 1-4 strongly suggest that the oreforming melts and fluids are highly oxidized, which may have been achieved by fluid exsolution and/or "self-oxidation (H2O dissociation)" in the late-stage evolution of F-rich magmas. Therefore, the precipitation of hydrothermal cassiterite (Fe + Mn of 0-0.05 apfu and Nb + Ta of 0-0.003 apfu) in oxidized fluids (Sn dominated by Sn4+) could result from the reduction of HCl activity and hydrolysis of fluoride without Sn oxidation. This study thus points to a mechanism for cassiterite precipitation in greisen-type Sn mineralization that differs from the traditional model and may be more abundant than previously thought.

Stable calcium (Ca) and iron (Fe) isotopes could provide a new way to investigate granite petrogenesis, and their isotope fractionation mechanisms in felsic magmas have been increasingly understood through continuous efforts in recent years. However, comprehensive Ca and Fe isotope fractionation during highly fractionated magmas is still unclear. This study presents Ca and Fe isotope data for some fractionated granites from Southern Myanmar. The S56/54Fe values of the less fractionated Eocene granites range from 0.11 f 0.03 %o to 0.23 f 0.04 %o. The highly fractionated Late Cretaceous and Paleocene granites clearly exhibit 0.15 %o and 0.42 %o variations in S56/54Fe values, respectively. These S56/54Fe values are negatively correlated with those of Fe2O3T, TiO2 contents and (La/Yb)N ratios, suggesting that more evolved melts are enriched in heavy Fe isotopes, primarily as a result of fractional crystallization of Fe-rich minerals enriched in light Fe isotopes (e.g., biotite and ilmenite). Some Late Cretaceous granites with low Nb/Ta and Zr/Hf ratios display relatively low S56/54Fe values, which may be modified by exsolved fluids enriched in light Fe isotopes. Moreover, the S44/40Ca values of the Late Cretaceous, Paleocene, and Eocene granites range from 0.71 f 0.07 %o to 0.90 f 0.06 %o, 0.62 f 0.08 %o to 0.89 f 0.06 %o, and 0.66 f 0.06 %o to 0.75 f 0.05 %o, respectively. Most of the studied granites have relatively consistent Ca isotopic compositions with those of the continental crust. Combined with high S44/40Ca values (up to 0.90 %o), the studied granites have a weakly negative correlation between S44/40Ca values and Eu/Eu* ratios. This evidence suggests that fractional crystallization of plagioclase with light Ca isotopes may also be a reason for Ca isotope fractionation during felsic magma differentiation, in addition to crustal magma sources and crustal contamination. Additionally, a Late Cretaceous granite with a high (Dy/Yb)N ratio has the lowest S44/40Ca value (0.52 f 0.06 %o), possibly reflecting the presence of residual garnet in the source. The affirmation of significant Ca and Fe isotope fractionation in highly evolved melts strengthens the utility of Fe and Ca isotopes as tracers of magma differentiation.

AbstractIt was recognized that two magmatic belts in the Lhasa‐Tengchong terrane formed due to the Mesozoic‐Cenozoic Tethyan evolution. Still, their spatiotemporal variations of magmatic flare‐ups/lulls are rarely discussed. Here we use the new U‐Pb and Lu‐Hf isotopic data of captured zircons and a comprehensive data set to show that the flare‐up of northern magmatic belt has peak ages of 110 Ma in central and northern Lhasa and 120 Ma in eastern Tengchong, possibly related to the tectonic transition from Meso‐ and Neo‐Tethyan double subduction to Neo‐Tethyan single subduction. For the southern magmatic belt, the flare‐ups at 100–85 Ma and 65–45 Ma in eastern southern Lhasa indicate obvious juvenile crustal growth, while flare‐ups at 75–45 Ma in western southern Lhasa and Tengchong record ancient crustal reworking. Such flare‐up variations in the southern magmatic belt possibly resulted from asynchronous changes in the Neo‐Tethyan slab dip.

In hydrothermal tin (Sn) systems, it remains unclear whether cassiterite precipitates from reduced or oxidized fluids. To resolve this issue, the geochemistry of magmatic garnet and cassiterite separated from fractionated muscovite-garnet granite in the Paleocene Bawapin Sn-W deposit was systematically investigated. CaO contents in Mn-rich garnet (spessartine) decrease from core to rim in single crystals and are negatively correlated with MnO/(MnO + FeO) ratios. These features suggest that garnet CaO content may be a good differentiation index for granitic magma evolution. Moreover, the Sn content in Mn-rich garnet increases with increasing Ca content and then decreases sharply at Ca contents of approximately 4300 ppm. Combined with evidence of Ta-rich magmatic cassiterite, the decreasing Sn content likely reflects the crystallization of magmatic cassiterite from the more evolved Sn-rich melts under oxidized conditions (fO(2) > Delta FMQ +1.5), in contrast to the reduced characteristics of the less-fractionated biotite monzogranite (fO(2) = Delta FMQ - 0.5). Late-stage oxidation might be attributable to fluid exsolution in the water-rich and Fe-poor granitic melts. This further indicates that hydrothermal cassiterite could precipitate in exsolved Sn4+-bearing fluids without Sn oxidation. This conclusion may provide a new perspective to our understanding of granite-related hydrothermal Sn systems worldwide.

Since the Cenozoic, the Tibetan Plateau has experienced large-scale uplift and outgrowth due to the India–Asia collision. However, the mechanism and timing of these tectonic processes still remain debated. Here, using apatite fission track dating and inverse thermal modeling, we explore the mechanism of different phases of rapid cooling for different batholiths and intrusions in the southeastern Tibetan Plateau. In contrast to previous views, we find that the coeval granitic batholith exposed in the same tectonic zone experienced differential fast uplift in different sites, indicating that the present Tibetan Plateau was the result of differential uplift rather than the entire lithosphere uplift related to lithospheric collapse during Cenozoic times. In addition, we also suggest that the 5–2 Ma mantle-related magmatism should be regarded as the critical trigger for the widely coeval cooling event in the southeastern Tibetan Plateau, because it led to the increase in atmospheric CO 2 level and a hotter upper crust than before, which are efficient for suddenly fast rock weathering and erosion. Finally, we propose that the current landform of the southeastern Tibetan Plateau was the combined influences of tectonic and climate.

The present northwest-trending Altai mountains, as far as similar to 2000 km north of the Indian-Asian collision front, are dominated by a transpressional strike-slip fault system, and are generally considered as one of distant tec-tonic effects of the ongoing India-Asia collision. However, the Cenozoic reactivation of the Altai and its linkage with the tectonic evolution of the Tibet plateau remain mechanically challenging. Here, we constructed large-scale 2D numerical models with inherited lithospheric heterogeneities from India to Altai representing the onset of the India-Asia collision. The sensitivity of model results to variable thermo-mechanical and geometric properties of the orogen-like Tibet and Altai as well as variable thermal state of the craton-like India and Junggar reveals that both the particular lithospheric architecture of western Tibet and basement structural inheritance of central Asia regulate the long-distance deformation propagation from the India-Asia plate boundary to the Altai-Sayan region. The model results indicate that the direct collision of the underthrusting Indian lithosphere with the rigid Tarim block beneath western Tibet plays a dominant role in the ultra-long-distance deformation propagation to central Asia. As less-deformed rigid blocks, the Tarim and Junggar basins with Precambrian basements serve as secondary indenters that transfer the compressive stresses extensively to the Altai-Sayan region. Constrained by substantial surface geology and geophysical observations, this numerical study recognizes the linkage between the evolving lithospheric structure of western Tibet with the northward younging trend of reactivation of the orogenic belts in central Asia. By means of the rigid Indian-Tarim lithospheric mantle collision, the plate-convergence stress can be effectively transmitted through Tarim to Tian Shan and subsequently through Junggar to Altai, leading to successive reactivation of the Tian Shan and Altai mountains. The locations of reactivation are determined by the inherited structural zones of lithospheric weakness that formed during the Paleozoic assembly of the Central Asian Orogenic Belt.

South China, India, and their derivative blocks preserve many similar magmatic and sedimentary records related to the tectonic transition from Rodinia to Gondwana. They provide crucial insights into not only the pa-leogeographic correlation between them but also the geodynamic mechanism for such a transition. Our new results, combined with published data from these blocks, reveal that South China remained linked with India at least from ca. 830 Ma to ca. 510 Ma and formed the South China-India Duo, which is located at the western margin of Rodinia. The identical magmatism and sedimenta-tion reflect that double late Neoproterozoic rift systems in the South China-India Duo developed owing to the rollback of subduct-ing oceanic slab beneath them. For example, an intracontinental rift developed along the Jiangnan-Aravalli-Delhi fold belt, which separated the Yangtze-Marwar block from the Cathaysia-Bundelkhand block. Another intra-arc rift developed contemporaneously along the northern and western margins of the Yangtze block, through the Marwar ter-rane of western India, and then into the Sey-chelles and Madagascar terranes. Such an intra-arc rift is the most feasible explanation for the common development of coeval arc -like and extension-related magmatic rocks and extensional sedimentary sequences on the western margin of the South China- India Duo, in Seychelles and Madagascar, and even at other subduction zones. South China was finally separated from Indian Gondwana at ca. 510 Ma due to the opening of the Proto-Tethys Ocean.

How the Neotethyan Ocean evolved and extended southwards into Southeast Asia remains controversial. The paleographical correlation between India and the SE Asian blocks and/or terranes before the opening of the Neotethys and the initial opening time of the Neotethys is still unknown. The lack of this knowledge hampers our further understanding of the tectonic evolution of global Neotethys. Here we present a combined study on Triassic magmatism in the Tengchong Block and Triassic sedimentation in the Myitkyina area, located on the two sides of the Tagaung-Myitkyina Ophiolite Belt of northern Myanmar. Our results coupled with previous data demonstrate that a Triassic continental magmatic arc developed in the Tengchong Block and that the Triassic Myitkyina sedimentary sequence was part of the Tethyan Himalayan Langjiexue Group in northern India. Moreover, the Tengchong Triassic magmatic arc provided important detrital inputs to the whole Langjiexue Group of northern India. Such a provenance is the best explanation for the Permian−Triassic detrital zircons of the Langjuexue Group. Together, we propose that the Tagaung-Myitkyina Ophiolites in northern Myanmar are the relics of the Neotethyan Ocean rather than the Mesotethyan Ocean (Bangong-Nujiang Ocean) in SE Asia, and that the initial opening time of the Neotethys was the Early Jurassic of 200−190 Ma. Then, the earliest (185−165 Ma) intra-oceanic arc akin to the Izu-Bonin-Mariana arc in the West Pacific, developed soon after the Late Triassic opening of the Neotethys.

Early Cretaceous magmatic rocks of the Tengchong and Baoshan blocks provide insight into the late Mesozoic evolution of southeastern Tibet-Yunnan. We present LA-ICP-MS U-Pb zircon age, zircon eHf(t) isotope, and whole-rock geochemical and Sr-Nd isotopic data for dioritic porphyrite and rhyolite, outcropping in the Eastern Tengchong Belt and the Gaoligong Belt, respectively. The dioritic porphyrite has a 123.0 +/- 1.3 Ma (2 sigma) age, negative whole-rock (epsilon Nd)(t) of 1.99 to 2.16, initial Sr-87/Sr-86 of 0.70690-0.70734, zircon (epsilon Hf)(t) of 1.42 to 4.11, and adakitic geochemical features, suggesting an origin from mixing of mantle- and crust-derived magmas; the rhyolite has a 122.2 +/- 1.0 Ma age, low whole-rock (epsilon Nd)(t) of 9.69 to 8.83, initial Sr-87/Sr-86 of 0.71104-0.71246, and zircon (epsilon Hf)(t) of 8.55 to 2.59, suggesting crustal derivation. Our data-along with the published data-suggest that the Early Cretaceous rocks (140-109 Ma) comprise two magmatic phases with a geochemical and isotopic transition at similar to 123 Ma. The 140-123 Ma phase-mainly outcropping in the Gaoligong Belt-is mainly peraluminous, highly silicic, and has negative zircon (epsilon Hf)(t) values, suggesting derivation from remelting of ancient crust in a postcollisional setting; the 123-109 Ma phase is mainly metaluminous, restricted to the Eastern Tengchong Belt, and formed in a continental-arc setting with mantle melt involved. We propose that the similar to 123 Ma geochemical and isotopic change marks the transition from contraction due to the Tengchong-Baoshan collision to extension resulting from slab rollback of the Neo-Tethyan lithospheric slab.

Since the Cenozoic, the India-Eurasia continental collision has caused large-scale uplift and lithospheric extrusion of the Tibetan Plateau. As the response to this collision, two Cenozoic alkaline magmatic belts developed along the Jinshajiang-Ailanshan and Himalayan tectonic belts which have been considered to be two boundaries for adjusting the compressional stress in the interior of the plateau. The genesis and rock-forming mechanism of these alkali-rich magmatic rocks are the key to explore the deep geodynamics during the India-Eurasia collision. In this paper,we present zircon U-Pb geochronology and Lu-Hf isotopic compositions, whole-rock major and trace elemental, and Sr-Nd isotopic results of the Liuhe syenite porphyries and their enclaves. Our dating results together with previous data indicate that the syenite porphyries formed at ca. 37 Ma, which is slightly earlier than the peak alkali-rich magmatism（36 Ma） along the Jinshajiang-Ailaoshan belt. The Liuhe syenite porphyries are geochemically rich in alkali and potassium, and low in magnesium, coupled with the enrichment of Light Rare Earth Elements（LREE） and Large Ion Lithophile Elements（Rb, Ba, Sr）, and depletion of Heavy Rare Earth Elements（HREE） and High Field Strength Elements（Ta, Nb, Ti）. Their high Sr contents and Sr/Y ratios along with weak negative Eu anomalies（δEu=0.84–0.85）show an affinity to adakitic rocks. Their overall geochemical signatures and the similarities in Hf-Nd isotopic compositions to those of the hosted garnet-bearing amphibolite enclaves indicate that the Liuhe syenite porphyries were derived from partial melting of the thickened lower crust rather than the enriched lithospheric mantle. Moreover, the Liuhe syenite porphyries featured by low oxygen fugacity and high water content have not the potential to form porphyry deposits. As for the low-grade metamorphic enclaves hosted in the Liuhe syenite porphyries, they have significantly different zircon U-Pb age, major-trace element and Sr-Nd isotopic characteristics from the host rocks,indicating that they were captured during the ascent of the host porphyric magmas and their involvement in the genesis of the host porphyries were negligible if any. Collectively, our results combined with previous data reflect that the distribution of the early Eocene alkaline magmatic rocks along the Jinshajiang-Ailaoshan tectonic belt does not show a younging trend from north to south as proposed before, and that this stage of magmatism was related to the lithospheric extrusion of the Tibetan Plateau in response to the India-Eurasian continental collision rather than the Eocene lithospheric delamination.

Whether the voluminous Early Cretaceous magmatism in the Tengchong and Baoshan blocks, western Yunnan, China, was related to subduction of the Meso-Tethys or the Neo-Tethys is controversial. Here, we report SHRIMP and LA-ICP-MS U-Pb zircon ages, bulk-rock major and trace elements, and Sr-Nd isotope data from volcanic rocks in the Lameng area of the Baoshan block, SW China, investigate their genesis, and discuss the evolution of the Tengchong and Baoshan blocks. These rocks yield U-Pb zircon ages of 120.3 +/- 1.7 and 120.8 +/- 1.4 Ma and constitute a bimodal volcanic suite (group 1 and group 2). Group 1 samples show alkaline basaltic signatures (SiO2 = 46.2-53.1 wt.%), enrichments in Zr, Hf, Ti, and light rare earth elements, and slight depletions in Nb, Ta, and heavy rare earth elements. They have epsilon Nd(t) = - 1.0-+3.7 and initial 87Sr/86Sr = 0.70503-0.70709. Group 2 samples display higher silica contents (SiO2 = 61.7-65.0 wt.%) and evolved epsilon Nd(t) (-4.3 to-3.6) and initial 87Sr/86Sr (0.70653-0.70678) values. These features suggest that the group 1 melts were derived from an asthenospheric mantle source mixed with subcontinental lithospheric mantle components and that the group 2 samples were produced by partial melting of the lower crust in a continental back-arc setting. From an affinity with widespread coeval magmatic rocks in the Tengchong and Lhasa blocks, we suggest that the Bangong-Nujiang Ocean between the Tengchong and Baoshan blocks had closed by 120 Ma and that the Early Creta-ceous magmatism in the Tengchong and Baoshan blocks formed in an arc-back-arc system associated with Neo-Tethyan slab rollback.

This is the dataset for the paper "Contrasting Collision-induced Far-field Orogenesis Controlled by Thermo–rheological Properties of the Composite Terrane" that has been submitted to "Geophysical Research Letters".

由于哀牢山古特提斯洋盆精确闭合时间一直存在争议,从而制约了我们对该区古特提斯洋演化及印支造山运动过程的完整认识.碎屑岩作为造山作用在地壳浅表响应的产物,保存了其物源区深部岩浆作用的重要信息,可有效地约束洋盆演化和造山过程的精细时空格架.本文选择对哀牢山构造带及其东侧地区中-上三叠统碎屑锆石年代学和Hf同位素开展了系统的研究,结果显示:构造带内部三叠统样品除了缺少240～325 Ma年龄群外,与东侧地区同时代碎屑岩样品相似,均具有480～560 Ma和900～1200 Ma两个主要年龄群,对应的εHf(t)值分别为?16.75～+17.00和?15.39～+19.20;而两地区上三叠统样品具有基本相同的年龄频谱特征,均显示250～330 Ma、480～580 Ma和920～1240 Ma三个主要年龄群,对应的εHf(t)值分别为?10.67～+12.15、?10.06～+9.57和?12.25～+15.62.综合本次研究结果与前人数据,表明哀牢山构造带内中-上三叠统及其东侧地区三叠系碎屑物质主要来源于构造带内的岩浆岩,有少量老地层再循环的贡献.进一步的源区分析指出,哀牢山古特提斯洋在早三叠世已闭合.此外,基于哀牢山构造带及两侧地区普遍缺失下三叠统地层和大量发育早-中三叠世碰撞有关的岩浆岩的特征,显示我国哀牢山地区与越北地区印支造山运动在二叠纪末-早三叠世同时开启,中-晚三叠世,哀牢山构造带进入碰撞后伸展阶段.

Despite decades of research, the mechanisms and processes of subduction initiation remain obscure, including the tectonic settings where subduction initiation begins and how magmatism responds. The Cretaceous Mawgyi Volcanics represent the earliest volcanic succession in the Wuntho-Popa arc of western Myanmar. This volcanic unit consists of an exceptionally diverse range of contemporaneously magmatic compositions which are spatially juxtaposed. Our new geochemical data show that the Mawgyi Volcanics comprise massive mid-oceanic ridge basalt (MORB)-like lavas and dikes, and subordinate island arc tholeiite and calc-alkaline lavas. The Mawgyi MORB-like rocks exhibit flat rare earth elements (REEs) patterns and are depleted in REEs, high field strength elements (except for Th) and TiO2 concentrations relative to those of MORBs, resembling the Izu-Bonin-Mariana protoarc basalts. Our geochronological results indicate that the Mawgyi Volcanics formed between 105 and 93 Ma, coincident with formation of many Neotethyan supra-subduction zone ophiolites and intraoceanic arcs along orogenic strike in the eastern Mediterranean, Middle East, Pakistan, and Southeast Asia. Combined with its near-equatorial paleo-latitudes constrained by previous paleomagnetic data, the Wuntho-Popa arc is interpreted as a segment of the north-dipping trans-Neotethyan subduction system during the mid-Cretaceous. Importantly, our restoration with available data provides new evidence supporting the hypothesis of a mid-Cretaceous initiation of this >8000-km-long subduction system formed by inversion of the similar to E-W-trending Neotethyan oceanic spreading ridges, and that this was contemporaneous with the final breakup of Gondwana and an abrupt global plate reorganization.

This is the dataset for the paper "India–Tarim Lithospheric Mantle Collision beneath Western Tibet Controls the Cenozoic Building of Tian Shan" that has been published by "Geophysical Research Letters".