High-pressure, low-temperature metamorphism

Abstract

Petrology, structural geology, and numerical modeling of HPLT rocks commonly depict dynamic flows beneath forearcs with great vertical and lateral displacements of regional rock masses, which might be commonly ongoing in subduction zones. Such deductions have, however, not been well linked with seafloor geology of forearc areas. For example, stacks of thrust sheets (nappe piles) and hanging-wall low-angle normal faults (detachment) are ones of the typical structures of HPLT terranes exposed on land. However, such structures have not yet been detected in forearcs on the seafloors. Serpentinite diapirs and mud volcanoes that penetrate the Mariana forearc crusts are in turn not so suitable with dominantly flat-lying structures of HPLT terranes. Filling these gaps and comprehension of subduction zone dynamics will greatly owe to further investigations by marine geoscience.