Rapid endogenic rock recycling in magmatic arcs

Jun-Yong Li,Ming Tang,Xiao-Lei Wang,De-Hong Du,Xiao-Ping Xia,Cin-Ty A Lee,Lin-Sen Li,Zhi-Dong Gu,Di Wang

doi:10.1038/s41467-021-23797-3

Abstract

In subduction zones, materials on Earth’s surface can be transported to the deep crust or mantle, but the exact mechanisms and the nature of the recycled materials are not fully understood. Here, we report a set of migmatites from western Yangtze Block, China. These migmatites have similar bulk compositions as forearc sediments. Zircon age distributions and Hf–O isotopes indicate that the precursors of the sediments were predominantly derived from juvenile arc crust itself. Using phase equilibria modeling, we show that the sediments experienced high temperature-to-pressure ratio metamorphism and were most likely transported to deep arc crust by intracrustal thrust faults. By dating the magmatic zircon cores and overgrowth rims, we find that the entire rock cycle, from arc magmatism, to weathering at the surface, then to burial and remelting in the deep crust, took place within ~10 Myr. Our findings highlight thrust faults as an efficient recycling channel in compressional arcs and endogenic recycling as an important mechanism driving internal redistribution and differentiation of arc crust.

Highlights

In subduction zones, materials on Earth’s surface can be transported to the deep crust or mantle, but the exact mechanisms and the nature of the recycled materials are not fully understood
The Yangtze Block in Eastern Asia consists of Archean–Paleoproterozoic crystalline basement surrounded by Neoproterozoic fold belts
The western margin of the Yangtze Block became tectonically active since the early Neoproterozoic; it started with intra-oceanic arc magmatism before 971 ± 16 Ma and transitioned to Andean-type magmatism at ca. 870 Ma

Summary

Introduction

Materials on Earth’s surface can be transported to the deep crust or mantle, but the exact mechanisms and the nature of the recycled materials are not fully understood. By dating the magmatic zircon cores and overgrowth rims, we find that the entire rock cycle, from arc magmatism, to weathering at the surface, to burial and remelting in the deep crust, took place within ~10 Myr. Our findings highlight thrust faults as an efficient recycling channel in compressional arcs and endogenic recycling as an important mechanism driving internal redistribution and differentiation of arc crust. Crustal materials from the surface are recycled to Earth’s interior This chain of processes in magmatic arcs play important roles in driving much of the mass exchange between Earth’s interior and surface. Geochronologic and geochemical studies of these samples to understand the nature of the recycled materials and evaluate how thrust faults may contribute to rock recycling in compressional arc settings

Methods

Results

Conclusion