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TS6.5

Tectonics of the Central Asian Orogenic Belt and the geodynamics of arc systems along convergent plate boundaries
Convener: Pengfei Li  | Co-Conveners: Antoine Triantafyllou , Min Sun , Wenjiao Xiao , Karel Schulmann , Keda Cai , Julien Berger , Delphine Bosch , Pierre Bouilhol 
Orals
 / Fri, 22 Apr, 08:30–12:00  / Room L1
Posters
 / Attendance Fri, 22 Apr, 17:30–19:00  / Hall X2
Convergent plate boundaries are key sites for continental accretion and geochemical cycles within the solid Earth. They are favorable tectonic places for the development of intense magmatic activity in the lithospheric mantle and the overlying crust.

The Central Asian Orogenic Belt, as one of the largest accretionary orogens on earth, provides an excellent opportunity to investigate the continental growth and accretion mechanisms along convergent plate boundaries. The evolution of this orogenic collage involved both the vertical addition of mantle-sourced magmatic rocks via generation of juvenile crust at Pacific-type convergent margins and plume-related magmatism, and the lateral accretion of continental and oceanic crust via continuous subduction, trench migration, oroclinal bending, terrane accretion and strike-slip faulting. Recent works have highlighted many similarities between the accretionary processes in the Central Asian Orogenic Belt and the Circum-Pacific orogenic belts (e.g. Japan, Philippines, Indonesia and Tasmanides), which potentially shed new light on the origin of accretionary orogens and their contribution to continental growth.

The arc is a fundamental tectonic element along convergent plate boundaries. It is viewed as major factories contributing to crust generation, continental growth, explosive volcanism and the geochemical cycles through the solid Earth, via magma production, differentiation and crustal foundering. Nevertheless, few accreted arcs sections expose a complete crustal and upper mantle section emphasizing the crucial role of arc preservation during subduction and continental collision. Active arc settings, in turn, allow direct investigation of the upper crustal and volcanic dynamics, but very little is known about their deeper crustal section apart for indirect imaging or discrete sampling (xenoliths). Recent studies and results acquired on fossil and active arc systems have boosted our comprehension of subduction initiation, arc growth and accretion as well as their ultimate participation in crust production.

The study of various convergent tectonic scenarios and production rates of juvenile crustal material through Earth's history - from Archean to modern case studies - requires bringing together multidisciplinary communities across a wide range of disciplines and methods encompassing (i) igneous, structural, petrological, geochemical, geochronological studies in exhumed subduction-related relics, orogenic collage and active settings, (ii) new insights from recent advances in analogue and numerical modeling, (iii) geophysical studies of active settings, and (iv) deep drilling of active subduction-related complexes as recently accomplished by IODP expeditions in the western Pacific.

This session embraces all aspects of research on tectonics/geodynamics along convergent plate boundaries, and particularly welcomes contributions from research teams studying the Central Asian Orogenic Belt and the circum-Pacific orogens. The session is organized in cooperation with IGCP Project 592 “Continental Construction in Central Asia” supported by UNESCO-IUGS, and is co-sponsored by ILP CC4 and IRSES-MEDYNA.