Manufacturing Continental Crust in the Subduction Factory

Elemental composition of concentrated brines in subduction zones and the deep continental crust

It has been well established that fluids played an important part in determining chemical characteristics in many crustal terranes. Studies of fluid inclusions in eclogites have established that brines coexisted with the primary mineral assemblages during their metamorphic crystallization. These brines are currently multiply saturated in halide salts, carbonates, oxides, and sulfides. As a firs...

When the Continental Crust Melts

The continental crust is 41.4 km thick on average and covers 39% of the Earth’s surface. Information from the isotopic and trace element composition of >4-billion-yearold (Ga) zircon grains and the evolution of mantle isotopic reservoirs indicates that 75%, and possibly more, of the continental crust was created before 2.5 Ga (Harrison 2009; Belousova et al. 2010). Thus, the continental crust i...

Postcollisional mafic igneous rocks record crust-mantle interaction during continental deep subduction

Findings of coesite and microdiamond in metamorphic rocks of supracrustal protolith led to the recognition of continental subduction to mantle depths. The crust-mantle interaction is expected to take place during subduction of the continental crust beneath the subcontinental lithospheric mantle wedge. This is recorded by postcollisional mafic igneous rocks in the Dabie-Sulu orogenic belt and it...

Alpine and Pacific styles of Phanerozoic mountain building: subduction-zone petrogenesis of continental crust

The geological complexities of contractional orogenic belts have been studied for two centuries, yet our understanding of them is still rapidly changing. Most mountain belts form at or near the active edges of continents and/or fringing island arcs. Virtually all result from consumption of lithospheric plates, involving the underflow of oceanic crust, and the consequent transport and descent of...

Subduction erosion: Rates, mechanisms, and its role in arc magmatism and the evolution of the continental crust and mantle