Linking magmatism with collision in an accretionary orogen

Area of Science:

• Geochemistry
• Isotope Geochemistry
• Tectonics

Background:

• The southern Central Asian Orogenic Belt (CAOB) provides a crucial window into the complex interplay of magmatism and orogenesis.
• Understanding the Paleo-Asian oceanic closure and continental amalgamation is key to deciphering the region's geological history.

Purpose of the Study:

• To evaluate the interaction between magmatism and orogenesis in the southern CAOB.
• To analyze U-Pb age, geochemical, and isotopic data of granitoid plutons.

Main Methods:

• Compilation of U-Pb age, geochemical, and isotopic data.
• Geological evidence analysis.
• Interpretation of magmatic and tectonic regimes.

Main Results:

• Collision-related calc-alkaline granitoid and mafic magmatism occurred from 255–251 Ma along the Solonker-Xar Moron suture zone.
• End-Permian magmatism suggests final orogenic contraction and weak crustal thickening, possibly due to slab break-off.
• Early-Middle Triassic adakite-like granitoids and S-type granites resulted from crustal anatexis post-collision.
• A shift from compression to extension occurred between 235–220 Ma, linked to lithospheric extension and orogenic collapse.

Conclusions:

• Magmatism in the southern CAOB is a prime example of the link between magmatism and orogenic contraction/collision.
• The study highlights the significance of magmatic events in understanding accretionary orogen evolution.
• The findings contribute to the broader understanding of continental amalgamation processes in the CAOB.