Page "Tharsis" Paragraph 18

The key to understanding how a vast igneous province like Tharsis can itself be a volcano is to re-think the notion of volcano from one of simple conical edifice to that of an environment or " holistic " system.

According to the conventional view in geology, volcanoes passively build up from lava and ash erupted above fissures or rifts in the crust.

The rifts are produced through regional tectonic forces operating in the crust and underlying mantle.

Traditionally, the volcano and its magmatic plumbing have been studied by volcanologists and igneous petrologists, while the tectonic features are the subject for structural geologists and geophysicists.

However, recent work on large terrestrial volcanoes indicates that the distinction between volcanic and tectonic processes is quite blurry, with significant interplay between the two.