Xiumian Hu

The Triassic Songpan‐Ganzi basin, located in northeastern Tibet, is one of the world's largest preserved ancient deep‐marine siliciclastic basins, yet its tectonic origin remains contentious. While often regarded as a remnant‐ocean basin, it has also been interpreted as a stretched and thinned continental margin. To resolve this debate, we investigated the basin's northeastern side in the West Qinling Mountains through integrated stratigraphic, sedimentological, petrographic, heavy‐mineral, and detrital zircon U‐Pb analyses. Our results show deepening from coastal depositional environments in the Early Carboniferous to widespread submarine‐fan sediments in the Middle Triassic. The Triassic deep‐sea turbidites were mainly sourced from the southern North China block, including the East Kunlun, Qilian, and Qinling orogens, rather than from the eastern Dabie orogen. These findings support the interpretation that the Songpan‐Ganzi region represents the hyper‐extended continental margin of the North China block rather than a remnant‐ocean basin. Such a revised tectonic framework has major implications: it redefines the Triassic magmatism in the Songpan‐Ganzi basin as post‐collisional rather than related to oceanic subduction and, critically, explains the high thermal gradients and extensive fault networks typical of extensional settings that favored the formation of the region's world‐class Carlin‐type gold deposits.

The East Anatolian Plateau is a major collisional feature within the Tethyan realm formed as a late‐stage result of the collision between East Anatolia and the Arabian Platform. The timing of this collision is highly debated, with estimates from the Late Cretaceous to the Miocene. This study presents new biostratigraphic and detrital zircon U–Pb–Hf data from upper Campanian and Danian siliciclastic rocks of the Arabian Foreland Basin, ∼40 km south of the Bitlis Suture. Upper Campanian rocks contain a dominant zircon age cluster (100–83 Ma) with εHf(t) values ranging from −7 to +6, whereas overlying Danian sandstones yield broader age spectra with clusters at 100–65 Ma, 750–500 Ma, and 1,100–800 Ma. The absence of Late Cretaceous magmatism on the Arabian Plate indicates derivation from the magmatic arc north of the Bitlis Suture. The late Campanian–Danian provenance shift likely reflects erosion of the upper arc and exhumation of metamorphic massifs representing middle‐ to lower‐crustal levels of the magmatic arc and the subducted Arabian margin, indicating that the Arabia–Eastern Anatolia collision began in the late Campanian (∼74–71 Ma). Reassessment of published detrital zircon data from the Iranian foreland suggests later collision along the Zagros Suture (Maastrichtian‐early Paleocene in the Kermanshah and Khorramabad areas). Final Eurasia–Arabia suturing occurred along the İzmir–Ankara–Erzincan and Zagros sutures, linked across West Azerbaijan (Iran), providing a coherent explanation for the pronounced Mesozoic–early Cenozoic geological contrasts between Eastern Anatolia and NW Iran.

The amount of detrital zircon U-Pb geochronology data and Lu-Hf isotopic data has doubled in the past two decades with the continuous improvement of analytical methods, and has developed into the most closely integrated research field in earth science with big data methods. However, how to effectively construct giant databases in geoscience has become a challenge. Here, we present OneDZ, a global comprehensive detrital zircon U-Pb geochronology and Lu-Hf isotope database, which includes diverse samples with data source, location, stratigraphy, depositional age, and various elemental and isotopic information. OneDZ collected corresponding regions, stratigraphic and lithological information to facilitate quick access for users. Comparing with current zircon databases, until now, OneDZ complies 2 550 738 grains of detrital zircon U-Pb and 297 527 grains of detrital zircon Lu-Hf records from 275 971 publications. Furthermore, the construction of OneDZ leverages artificial intelligence (AI) and programming scripts and offers insights into managing large-scale unstructured data in geosciences. This paper further discusses the perspective of applying big data methods in the research of zircon-related areas. This database exemplifies the power of big data in Earth sciences, providing a platform for investigating zircon data in deep time. It serves as a springboard for research, offering new insights in understanding Earth's past, present, and future. The database (Li et al., 2026) is freely available via Zenodo at https://doi.org/10.5281/zenodo.19690702.

Subduction transference occurs when an existing subduction zone is choked by the arrival of buoyant crust, and a new subduction zone is generated on the down-going plate to accommodate continuing convergence. Although subduction transference triggered by microcontinent collision was conceptually proposed as a viable tectonic mechanism across several Tethyan oceanic branches, evidence remains controversial, and geodynamic controls are unclear. Here, we report geological data from central Tibet documenting the Early Jurassic northward subduction initiation of the Bangong-Nujiang Ocean, followed by collision with a presently ∼70-km-wide microcontinent, ophiolite obduction, foreland-basin development, and initiation of a new north-dipping subduction zone to the south of the microcontinent in the late Middle to Late Jurassic. According to numerical geodynamic simulations, such a process can be triggered by an increase in buoyancy and/or lithospheric mantle strength of the collided microcontinent. Our study provides a geological example of subduction transference triggered by a narrow microcontinent collision, able to explain the progressive suturing of microcontinents in the Tethyan realm.

The Tibetan Plateau is an assemblage of continental blocks rifted from Gondwana and accreted to Eurasia after the closure of several Tethyan oceanic branches. The Ganzi-Litang ocean, as an eastern branch of the Paleo-Tethys, has been subject to a long debate particularly regarding its opening time, nature, and relationship with the Emeishan mantle plume. Here we present detailed field investigation combined with petrographic, geochemical, and geochronological analyses on mafic and sedimentary rocks from the Ganzi-Litang mélange zone. The 281.9 ± 3.8 Ma cumulate gabbro and associated enriched mid-oceanic-ridge-type basalts in the Ganzi ophiolitic complex indicate the Ganzi-Litang ocean initially formed in the Early Permian. Then the Middle–Late Permian Emeishan plume generated seamounts in the Ganzi-Litang ocean, as recorded by newly identified ocean-island basalt (261–254 Ma) capped by radiolarian cherts in the Litang area. These mafic rocks are characterized by high TiO2 (3.1–4.2 wt%) and Ti/Y, with positive zircon εHf(t) of +5.0 to +10.3 and whole-rock εNd(t) of 0 to +1.0, closely matching the signature of high-Ti Emeishan basalts. The occurrence of continental margin-type cherts and of Emeishan basalts along the suture allow us to envisage the Ganzi-Litang embryonic ocean as part of the hyper-extended margin of the South China Block that underwent further extension related to the emplacement of the Emeishan plume. These findings not only shed new light on the paleogeographic evolution of the eastern Paleo-Tethys but also have important implications for the regional exploration of Emeishan plume-related Fe–Ti–V ore deposits.

The accurate identification of the degree of alkali reactivity of aggregates is crucial for preventing alkali–silica reaction (ASR) damage in concrete. Two siltstones were collected from the main stream and a tributary of the Yarlung Tsangpo River. The alkali reactivity of these siltstones was examined through a combination of the Petrographic Method, the Accelerated Mortar Bar Test (AMBT), and the Chinese Universal Accelerated Mortar Bar Test (CAMBT). The influence of the petrographic characteristics of siltstones on the applicability of two accelerated expansion tests was also evaluated. Results show that both siltstones exhibit blocky textures and contain cryptocrystalline–microcrystalline quartz. However, the major alkali reactive components in the two siltstones show significant differences in morphology, distribution and content, with cryptocrystalline–microcrystalline quartz contents of approximately 20% in FS-1 and 10% in FS-2. This study reveals that the CAMBT identified two siltstones as alkali-reactive, whereas the standard AMBT classified them as non-reactive. The petrographic structures of the siltstones and the microstructural distribution of reactive quartz constituents are the key factors governing their expansion behavior and the applicability of different testing methods. By employing a single-graded aggregate that preserves the original rock fabric, the CAMBT improves the reliability of the detection of alkali reactivity in siltstones.