CONTINENTAL BREAKUP
Dynamic aspects of continental breakup: Why do continents break ?
Passive rifting can also be achieve through compression in front of collisional orogen. Continental extension and break-up can be initiated via normal faults oriented parallel to the direction of compression. The Siberian continent is breaking apart due to the indentation of India into Asia. The Lake Baikal, in the 2000 km long Baikal depression, is the product of crustal extension. This process is occurring at barely detectable rates, but with enough energy to produce earthquakes. SPOT scene showing an active fault escarpment in the Baikal region (crossing the picture from the bottom left to the upper right corner). Such a feature is very difficult to map with such a level of detail from field observations but appears very clearly on the satellite image.
The first suggestion that extension and thinning of the continental crust may be responsible for the upwelling of hot upper mantle material was brought forward by Artemjev and Artyushkov (1971) to explain the high heat flow in Lake Baikal. Salveson (1978) extended this model to continental shelves by interpreting shelves as rift basins that had extended so far that pure oceanic crust had formed.