Correlation among the Ailaoshan–Song Ma–Song Chay orogenic belts and implications for the evolution of the eastern Paleo-Tethys Ocean

The timing and mechanism of the combination between South China Block (SCB) Indochina (IB) are controversial. Three ophiolitic mélange zones (Ailaoshan, Song Ma, Chay) have been proposed as suture within this collisional orogen. However, relationships among three corresponding tectonic belts unclear. In study, we present detailed structural data for belts. bulk architectures Ailaoshan, Chay correlate well with one another. This similarity is also revealed by our new zircon UPb geochronological results from Ma ophiolites. regional deformation age constrained to 250 240 muscovite 40Ar/39Ar ages, medium-low temperature conditions quartz c-axis fabric. Considering transformation effect Cenozoic large-scale sinistral strike-slip RRF DBF, Early Mesozoic should represent different segments same belt. Based on hypothesis, compiled ages magmatism in region, which allows us propose an evolutional model follows: i) ?380–310 continental rifting subsequent Ailaoshan–Song Ma–Song ocean spreading a branch Paleo-Tethys, ii) ?310–250 oceanic subduction coeval continental-arc magmatism, iii) ?250–240 collision, iv) ?240–220 post-collisional extension.