One of the fundamental geophysical observations made of the Earth is the stratified nature of the continental crust, in which the lower crust comprises denser, more mafic material and the upper crust comprises less dense, more felsic material. This chemically differentiated layered structure is developed and maintained by partial melting at depth and the ascent of magma to shallower crustal lev...

There is overwhelming and incontrovertible petrological and geophysical evidence for the significant role played by mantle-derived mafic magma in the generation and growth of continental crust. Likewise, intrusion of mafic magmas beneath or into continental crust is very likely the major source of enthalpy that drives intracrustal differentiation. A simple dynamical model has been constructed t...

Geologists are acquainted with the principle of uniformitarianism, which holds that present day processes are the key to those that operated in the past. But the extent this applies to the processes driving the growth and differentiation of the continental crust throughout the Earth history remains a major controversy in earth sciences. An important part of the discussion circles around the pre...

The potential effects of continental crust on mantle convection are explored using threedimensional numerical simulations. The simulations model the coupling between a thin, deformable layer of chemically buoyant crust and a deep layer of thermally convecting and chemically dense mantle. Simulations begin with a crustal layer embedded within the upper thermal boundary layer of a mantle convecti...

[1] Rifting of passive margins has, in some places, led to the development of extensive submerged continental platforms. Crustal thinning by a factor of two or more is at least partially accommodated by high-angle normal faults that extend through the brittle upper crust to the ductile parts of the lower crust. However, an approximately horizontal detachment zone has been postulated to explain ...

We derive expressions for computing the gravitational field (potential and its radial derivative) generated by an arbitrary homogeneous or laterally varying density contrast layer with a variable depth and thickness based on methods for a spherical harmonic analysis and synthesis of gravity field. The newly derived expressions are utilised in the gravimetric forward modelling of major known den...

Recycled oceanic crust, with or without sediment, is often invoked as a source component of continental and oceanic alkaline magmas to account for their trace-element and isotopic characteristics. Alternatively, these features have been attributed to sources containing veined, metasomatized lithosphere. In melting experiments on natural amphibole-rich veins at 1.5 gigapascals, we found that par...

The impact of mechanical layering and the strength of the Indian lower crust on the dynamics of the modern India-Asia collisional system are studied using 3-D thermomechanical modeling. The model includes an Indian oceanic domain, Indian continental domain, and an Asian continental domain. Each domain consists of four layers: upper/lower crust, and upper/lower lithospheric mantle. The Tarim and...

Systematic exploration of the continental lithosphere by deep seismic reflection profiling over the past 20 years has revolutionized our view of the deep crust and upper mantle. Major geological features have been traced to lower crustal depths. Certain deep crustal features have been traced into the underlying mantle (fossil subduction zones?). Some geotectonic boundaries, considered by genera...