Earth is the only known planet with subduction zones and plate tectonics, and this fact demonstrates that special conditions are required for this mode of planetary heat loss. Sinking of cold, dense lithosphere in subduction zones is the principal plate-driving force, so plate tectonics could not have begun until Earth cooled sufficiently to allow lithosphere to collapse into the underlying ast...

S U M M A R Y The subduction of lithospheric plates is partitioned between subducting platemotion and lateral slab migration (i.e. trench retreat and advance). We use 3-D, dynamic models of subduction to address the role of a power-law mantle viscosity on subduction dynamics and, in particular, rates of trench retreat. For all numerical models tested, we find that a power-law rheology results i...

attributed directly to subduction. One option consistent with Hf–Nd This paper develops methods for using the integrated study of systematics is that the positive Hf anomalies in the Protoarc boninites Hf–Nd element and isotope covariations to define the nature and were caused by fusion of mafic veins in their shallow mantle sources. provenance of the mantle and subduction inputs to subduction ...

Subduction earthquakes on plate-boundary megathrusts accommodate most of the global seismic moment release, frequently resulting in devastating damage by ground shaking and tsunamis. As many earthquakes occur in deep-sea regions, the dynamics of earthquake faulting in subduction zones is poorly understood. However, the Integrated Ocean Drilling Program (IODP) Nankai Trough Seismogenic Zone Expe...

Much of the Earth's mantle was melted in the Moon-forming impact. Gases that were not partially soluble in the melt, such as water and CO2, formed a thick, deep atmosphere surrounding the post-impact Earth. This atmosphere was opaque to thermal radiation, allowing heat to escape to space only at the runaway greenhouse threshold of approximately 100 W m(-2). The duration of this runaway greenhou...

the kahnuj ophiolitic complex, a part of the jazmurian ophiolitic belt, is located on the western boundary of the jazmurian depression and is bounded by two major fault systems. there is a well-preserved, ophiolite pseudostratigraphy of early cretaceous to early palaeocene age and has a bearing on the mesozoic development of southeastern part of iran and adjacent region. the kahnuj ophiolitic c...

We propose a mechanism previously developed as a hypothetical cause of the initiation of subduction in the Earth's mantle, to describe a situation where such subduction may occur transiently, at irregular intervals of time. It has been suggested that tectonics on Venus may be described by such a scenario. In our model, a subduction event is followed by resumption of high Rayleigh number mantle ...