Subduction erosion and arc volcanism

Abstract

Tectonic or subduction erosion refers to the removal of upper plate material from the forearc at convergent margins. Subduction erosion has been suggested to represent a major process associated with the transfer of crustal material into the Earth's mantle at subduction zones 1-4. However, few studies have attempted to trace the fate of eroded forearc crust beneath volcanic arcs, where the eroded crust might first emerge after mixing with the upper mantle, owing to the formidable challenge associated with quantifying the rate of subduction erosion and the contribution of eroded crust to arc magmas. In this Review, we summarize the evidence for subduction erosion at convergent margins and show that, through integration of geochemical and geological data in arc settings where critical crustal lithologies can be accessed, quantification of the contribution of eroded forearc crust to arc magmas is possible 5-8. We further emphasize the importance of establishing arc-forearc compositional links, and illustrate the role of arc petrogenetic models for determining whether the eroded forearc crust contributes substantially (that is, greater than a few percent) to the construction of new arc crust in subduction zones 5,9 , or whether it is primarily exported to the deeper mantle. [H1] INTRODUCTION

Recognition of trench basins in collisional orogens: Insights from the Yarlung Zangbo suture zone in southern Tibet

“…Not all sediments deposited in trench basins are preserved. In subduction zones characterized by tectonic erosion, there is no accretion and all sediments are swallowed into the subduction channel together with material scraped off the overriding plate through frontal or basal erosion (Noda, 2016;Straub et al, 2020). The amount of subducted sediment thus varies widely in modern oceanic subduction zones.…”

Reconstructing Jurassic‐Cretaceous Intra‐Oceanic Subduction Evolution in the Northwestern Panthalassa Ocean Using Ocean Plate Stratigraphy From Hokkaido, Japan

“…subduction zones can be accretionary, neutral, or erosive, and subduction zones can switch between the two modes when these characteristics change (Le Pichon et al., 1993). Present‐day subduction at the circum‐Pacific margins is mainly erosive (Straub et al., 2020), but throughout their history, many circum‐Pacific trenches have experienced episodes of subduction accretion, resulting in the formation of accretionary orogens. Such accretionary orogens generally consist of series of overall trenchward‐younging complexes, and these complexes typically contain sequences or fragments of Ocean Plate Stratigraphy (OPS; Isozaki, 2000; Isozaki et al., 2010).…”

Subduction Erosion Revealed by Late Mesozoic Magmatism in the Gangdese Arc, South Tibet

“…Subduction erosion is a common process not only in modern subduction zones (Clift & Vannucchi, 2004;Straub et al, 2020) but also in fossil convergent systems (e.g., Clift et al, 2000;Draut & Clift, 2013;Yang et al, 2021;Zhang et al, 2017;this study). It plays a significant role in long-term destruction and recycling of the continental crust.…”