Catastrophic Resurfacing and Episodic Subduction on Venus

Resurfacing on Venus

“…The hypothesis of global episodic subduction events as a mechanism for cooling Venus proposed by Turcotte (1993Turcotte ( , 1995Turcotte ( , 1996 and Turcotte et al (1999) provides a simple explanation. It also explains why the large basal volcanic units where emplaced over a surface almost free of craters, a fact shown by Collins et al (1999) and can account for the tectonic evolution of the tessera terrains if those terrains were made up of differentiated crust that do not participate in the subduction events (Romeo and Turcotte, 2008).…”

“…The randomness of the crater population is analyzed using the pair-correlation statistics following the procedure of Turcotte et al (1999). The expected frequency distribution function for points uniformly randomly distributed over a sphere is…”

EnVision: taking the pulse of our twin planet

“…The episodic resurfacing model (Turcotte, 1993;Turcotte, 1995;Basilevsky and Head, 1998;Turcotte et al, 1999;Basilevsky and Head, 2000) proposes a short-lived but intense period of activity ~750 Ma ago, followed by a long period of quiescence that is consistent with the impact crater distribution but predicts minimal rates of volcanic and tectonic activity at the present day, apparently inconsistent with geological observations. Models involving some form of plate-like movement (e.g., Schubert and Sandwell, 1995;Gilmore et al, The extreme surface conditions on Venus require that these science goals must be addressed by orbital remote sensing, including interferometric synthetic aperture radar (InSAR) data, gravity data, altimetric data and multispectral infrared data.…”

Water, Life, and Planetary Geodynamical Evolution

“…The latter data suggest an elastic lithosphere of up to 100 km thickness and a crust of 90 km thickness. The necessity of removing the heat in the absence of plate tectonics leads to episodic scenarios as have been proposed by Turcotte (1993), Turcotte (1995), Turcotte et al (1999), Reese et al (1999), andOgawa (2000). Some authors (Turcotte 1995;Phillips and Hansen 1998;Nimmo 2002;and most recently Van Thienen et al 2005) suggest that present Venus may actually be heating up.…”