The article "Nature-Communication: Earth and Environment", where Xinjiang's birthplace is located, reveals that the ancient Asian Ocean finally closed in the early Triassic

Plate aggregation and oceanic expansion triggered by aggregation and cleavage in Pangea have been frontier hotspots in global plate tectonics research since the late Paleozoic
.
Located in the central and eastern part of Asia, the Central Asian orogenic belt (also known as the Altai orogenic belt), that is, the ancient Asian Ocean tectonic domain, records the collision and stitching process of various blocks of Eurasia caused by the closure of the ancient Asian Ocean, and is an important orogenic belt
for the construction of the current Eurasian pattern.
At the same time, it is the most significant area for the proliferation and transformation of the Crustal of the Phanerozoic in the world, and it is also the largest continental mineralization area in the world, and its mineralization process is closely related
to the growth and formation, tectonic system transformation and Cenozoic transformation.

The timing of the final controversy of the southern margin of the Central Asian orogenic belt and the formation of Pangea has been the focus of international academic debate (Triassic, Permian or Late Carboniferous?).
This has also led to considerable uncertainty
in the tectonic pattern of the northeastern margin of Pangea and the reconstruction of the ancient Asian continent (Proto-Asia).
Despite a great deal of work done on this scientific issue over the past decade, it has not been possible to gain a unified understanding
.
In addition, the long history of hyperplasia collage, the huge scale of distribution, and the superposition and transformation of huge magma/metamorphism/complex tectonic deformation in the Central Asian orogenic belt also add great difficulty
to solving this scientific problem.
Sedimentation runs through the ancient Asian Ocean from the opening and expansion of the ancient Asian Ocean to the subduction and subsidence of the oceanic crust until the closure of the basin and orogeny
.
Although stratigraphic sequences have been fragmented by the modification of tectonic movements, strata (and the fossil record) are still partially preserved, and the study of tectonic evolution is inseparable from the determination of geological time, and sedimentary tectonics has played (and will continue to be) important in
the study of the evolution of the ancient Asian Ocean.

In response to the above problems, the team of academician Xiao Wenjiao of the Xinjiang Mineral Resources Research Center of the Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences selected a pre-arc hyperplasia basin located in the Akyazi low-temperature-ultra-high pressure metamorphic hybrid belt of the South Tianshan orogenic belt (Figure 1), carried out research on the chronology of clastic zircon and the evolution of sedimentary geotectonics, and combined with the geochemical and chronological big data summary of the three major rock types in the region, systematically sorted out the sources of sedimentary detritus in the closure process of the southern Tianshan Ocean in the southwestern margin of the ancient Asian Ocean.
Spatial-temporal evolution between shell-mantle responses and regional geodynamic lattices
.

These studies show that the main clastic sources in the prearc proliferative basin do not come from the Kazakh-Ili-Zhongtianshan continent in the north or the Karakum-Tarim craton in the south, but may come from the Triassic arc magma of the eastern Tiantian Mountains (Fig.
2a, 2e).

Therefore, it is proposed that the main detritus source in this basin is likely to be transported by the Contour current from the more distant East Tian Shan Arc (Figure 1e), which can limit the time limit of the South Tian Shan Ocean closure time limit for the southwestern margin of the ancient Asian Ocean
.
Middle Permian MOR type snake greenstones (Glacial plates in the eastern Middle Tianshan Mountains) and Late Carboniferous and Late Permian radiolaria fossils (Kyrgyzstan and the Southern Tian Shan region of the territory) further hint at the possibility of a younger ocean basin (Figure 2f).

The basin is likely to extend into the early Triassic, and the isobaths were able to transport detrital material from the farther East Tian Shan arc to form the pre-arc hyperplasia basin seen today in the Aqyazi ultra-high pressure metamorphic hybrid zone (Figure 3).

This is also corroborated by the regionally widespread Triassic cryothermal chronology cooling "signal" associated with the eventual stitching of the southern margin of the Central Asian orogenic belt (Figure 2).

Combined with the reports of Triassic hyperplasia basins in the South Tianshan, East Tianshan, central Inner Mongolia and Solonkel suture belt regions, it is likely that the entire ancient Asian Ocean closed in the western, central and eastern parts of the Central Asian orogenic belt in the near same period
.
These studies further indicate significant differences in the spatial and temporal distribution of subduction-related magma in the western and eastern regions of the South Tian Shan orogenic belt (Figure 3).

Among them, due to the continuous subduction of the Devonian-Carboniferous seamount chain and the existence of cratonic microland masses in the west, the formation of slab subduction structures and their trapping of the subarc mantle wedge were formed, and their magmatic action basically stopped during 300-230 million years.
Eastern arc magmatic action persisted from 330 million years until basin closure
.

The relevant research results are titled Final closure of the Paleo Asian Ocean basin in the early Triassic, published in Communications Earth & Environment, a journal of Nature, and Tan Zhou, associate researcher of Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, is the first author and corresponding author of the paper.
Academician Xiao Wenjiao and researcher Mao Qigui are co-corresponding authors
.
This research was supported
by the National Natural Science Foundation of China and major science and technology projects in Xinjiang Autonomous Region.

Link to the paper:

Figure 1: Geotectonic background and sample characteristics
of the pre-arc hyperplasia basin of the Aktaz metamorphic heterogeneous rock belt in the southern margin of the Central Asian orogenic belt.

Figure 2: Summary of chronicle and geochemical big data in the Southern Tian Shan orogenic belt
.

Figure 3: Schematic diagram of the Permian-Triassic tectonic model of the Paleo-Southern Tianshan Ocean (STO
).
NTC: North Tarim Kraton; AC: pre-arc proliferative hybrids; KYCTC: Kazakhstan-Ili-Zhongtianshan Continent
.