Paleozoic tectonothermal history of the amalgamation of theTarim–North China and Mongolian collages

We use a wide database of pressure (P), temperature (T) and petrochronological data from late Neoproterozoic to early Mesozoic metamorphic rocks together with a review of compressive and extensional tectonic cycles to evaluate and correlate the tectonothermal and temporal evolutions of the Mongolian and the Tarim–North China collages forming the Central Asian Orogenic Belt. In the Mongolian Collage, metamorphic pressure–temperature (P–T) and timing reveal a one-stage evolution defined by a duality of late Neoproterozoic–Ordovician subduction-related low T/P metamorphism and suprasubduction high T/P metamorphism recorded in the Mongolia–Manchuria and Baikal–Sayan belts. This was followed by gradual prevalence of suprasubduction high T/P metamorphism towards the late Paleozoic corresponding to the Altai and South Altai cycles. In the Tarim–North China Collage, metamorphic P–T and timing reveal a two-stage evolution, from dominant intermediate T/P metamorphism possibly resulting from Ordovician–Devonian amalgamation and Andean-type evolution of the collage, to dual low and high T/P metamorphism in the Carboniferous–Permian reflecting subduction–collision processes along the South Tianshan suture in the west and a suprasubduction evolution along the Solonker suture in the east. Altogether, the Paleozoic tectonometamorphic evolution of the two collages shows remarkable differences, with the Mongolian Collage displaying features typical of peripheral accretionary cycle reflecting recurrent tectonic switches that can be regarded as a single orogenic system, and a two-stage evolution of the Tarim–North China Collage with features of both peripheral–accretionary and interior–collisional orogenic cycles, but mostly related to recurrent subductions of interior oceans. Furthermore, the Paleozoic tectonic cycles recognized in the Mongolian and Tarim–North China collages are tentatively correlated to distinct retreating and advancing subduction dynamics of Paleozoic oceanic domains.

 

Funding:  This research was funded in part by the Polish National Science Centre (Grant DEC-2023/51/D/ST10/02611/R). K.S. and P.S. acknowledge the support of the Czech Science Foundation (grant number 19-27682X to K.S.) and of an internal grant of the Czech Geological Survey (number 329805 to K.S.). J.S. acknowledges the support of project No. 2021/43/P/ST10/02996 co-funded by the National Science Centre and the EU H2020 research and innovation program under MSCA GA No. 945339.