Granite subduction: Arc subduction, tectonic erosion and sediment subduction

Shinji Yamamoto,Hiroki Senshu,Shuji Rino,Soichi Omori,Shigenori Maruyama

doi:10.1016/j.gr.2008.12.009

Abstract

Continental growth has been episodic, reflecting the episodic nature of mantle dynamics as well as surface dynamics of the Earth, the net result of which is exhibited by the present mantle with two huge reservoirs of TTG rocks, one on the surface continents and the other on the D″ layer on the Core-Mantle Boundary (CMB). During the early half of the Earth history, the felsic continental crust on the surface which formed in an intra-oceanic environment has mostly been subducted into the deep mantle, except in the rare case of parallel arc collision. The growth history of continental crust shows that with its simultaneous formation, a considerable amount must have also been subducted. Such ongoing subduction processes can be seen in the western Pacific region, through tectonic erosion, arc subduction, and sediment-trapped subduction.

Highlights

Intra-oceanic arcs (IOAs) form at Pacific-type convergent margins, in the upper “stable” plate, when the subducting plate submerges to the depths of melting, i.e., to ca. 50–100 km
Geochemical and isotopic data obtained during the last 15 years the Central Asian Orogenic Belt (CAOB) was a major site of juvenile crustal growth during the Phanerozoic (e.g. [Jahn et al, 2000; Kovalenko et al, 2004; Safonova, 2017])
The IOAs of the CAOB formed in the Paleo-Asian ocean during a period from the late Neoproterozoic to the late Paleozoic

Summary

Introduction

Intra-oceanic arcs (IOAs) form at Pacific-type convergent margins, in the upper “stable” plate, when the subducting plate submerges to the depths of melting, i.e., to ca. 50–100 km. I. Safonova et al.: Intra-oceanic arcs of the Paleo-Asian ocean The IOAs of the CAOB formed in the Paleo-Asian ocean during a period from the late Neoproterozoic to the late Paleozoic.

Results

Conclusion