Root zone processes for the formation and evolution of a large-scale granitic batholith:drip structures,potassic volcanism and Earth surface processes

Taking the Sierra Nevada batholith for example, the authors give a comprehensive review of the root zone processes and tectonogeomorphic responses during the formation and tectonic evolution of a large-scale granitic batholith. In a continental arc environment, the processes responsible for the formation and evolution of a large-scale batholith involve (1) basaltic magma underplating near the lower crust-upper mantle; (2) dehydration and partial melting of lower crustal material, production of a large volume of granitic magma and related high-density garnet pyroxenite at the root of a batholith; (3) occurrence of negative gravity instability; (4) removal of such high-density material beneath a granitic batholith as drips, either spontaneously or induced by nearby deformation; (5) potassic basaltic volcanism by low degrees of partial melting of the residual lithospheric mantle; (6) large-magnitude surface subsidence and tensional deformation directly above the drip structure; and (7) abrupt rise of mountain belts. Highly dynamic drip tectonics as imaged in the southern Sierra Nevada batholith may have been a major factor that maintains the high elevation of the Sierra Nevada mountain range.