Changes

===Stagnant lid===

===Stagnant lid===

A stagnant lid regime occurs when mantle driving forces do not exceed the lithospheric yield strength, resulting in a single, continuous rigid plate overlying the mantle. Stagnant lids only develop when the [[viscosity]] contrast between the surface and planetary interior exceeds about four orders of magnitude.<ref name=Reese_etal_1998>{{cite journal|last1=Reese|first1=C.C.|last2=Solomatov|first2=V.S.|last3=Moresi|first3=L.-N.|title=Heat transport efficiency for stagnant lid convection with dislocation viscosity: Application to Mars and Venus|journal=Journal of Geophysical Research|date=25 June 1998|volume=103|issue=E6|pages=13643–13657|doi=10.1029/98JE01047|url=http://onlinelibrary.wiley.com/doi/10.1029/98JE01047/pdf|accessdate=10 October 2014}}</ref>

A stagnant lid regime occurs when mantle driving forces do not exceed the lithospheric yield strength, resulting in a single, continuous rigid plate overlying the mantle. Stagnant lids only develop when the [[viscosity]] contrast between the surface and planetary interior exceeds about four orders of magnitude.<ref name=Reese_etal_1998>Reese, C.C.; Solomatov, V.S.; Moresi, L.-N. (25 June 1998). "Heat transport efficiency for stagnant lid convection with dislocation viscosity: Application to Mars and Venus". Journal of Geophysical Research 103 (E6): 13643–13657. doi:10.1029/98JE01047. Retrieved 10 October 2014.</ref>

===Episodic tectonics===

===Episodic tectonics===