The tidal heating of hypothetical rocky (or terrestrial) extrasolar planets spans a wide range of values depending on stellar masses and initial orbits. Tidal heating may be sufficiently large (in many cases, in excess of radiogenic heating) and long-lived to drive plate tectonics, similar to the Earth’s, which may enhance the planet’s habitability. In other cases, excessive tidal heating may r...

A variety of geophysical data indicates that long wavelength temperature variations of the asthenosphere depart from the mean by + 200øC, not the + 20øC adopted by plume theoreticians. The 'normal' variation, caused by plate tectonic processes (subduction cooling, continental insulation, smallscale convection) encompasses the temperature excesses that have been attributed to hot jets and therma...

[1] Temperature observations from the Northern Hemisphere reveal a warming since 1861 which is larger in winter than in summer. Possible explanations for a decline in seasonal spread are discussed using the Earth system model CLIMBER-2. Simulations forced by natural and anthropogenic factors (Milankovitch forcing, solar variability, volcanism, atmospheric CO2 concentration, deforestation) gener...

During its first two flybys of Mercury, the MESSENGER spacecraft acquired images confirming that pervasive volcanism occurred early in the planet's history. MESSENGER's third Mercury flyby revealed a 290-kilometer-diameter peak-ring impact basin, among the youngest basins yet seen, having an inner floor filled with spectrally distinct smooth plains. These plains are sparsely cratered, postdate ...

Introduction: Although Enceladus has garnered the greatest attention, Saturn’s other icy moons also betray a diverse range of phenomenon (e.g., Rhea‘s ring, Iapetus‘ ridge, Tethys’ fracture). Even in Voyager’s limited global mapping, some cryptic evidence of resurfacing was evident [e.g., 1, 2]. Global mapping by Cassini reveals that a large resurfaced terrain covers much of the leading hemisph...

We use hydrodynamic modelling combined with known data on mantle melting behaviour to examine the potential for decompression melting of lithosphere beneath a large terrestrial impact crater. This mechanism may generate sufficient quantity of melt to auto-obliterate the crater. Melting would initiate almost instantaneously, but the effects of such massive mantle melting may trigger long-lived m...

The controversial claim that El Niño events might be partially caused by radiative forcing due to volcanic aerosols is reassessed. Building on the work of Mann et al., estimates of volcanic forcing over the past millennium and a climate model of intermediate complexity are used to draw a diagram of El Niño likelihood as a function of the intensity of volcanic forcing. It is shown that in the co...

mud volcanoes are defined as main elements of geological structures and ways through and within which buried argillaceous loose sediments and lithified rocks. the gharniaregh tappeh and naftelijeh mud volcanoes are the most attractive geomorphological phenomena in continental which appear along the eastern coast of the caspian sea. the naftelijeh mud volcano is more active than gharniaregh–tapp...