Extensional Tectonics from Continental Breakup to Formation of Oceanic Basins: A review

Since the wide acceptance of Plate Tectonics Theory in the 1970s, our understanding of Extensional Tectonics from Continental Breakup to Formation of Oceanic Basins has improved substantially based on geological, geophysical, geochemical studies, and analog and computer modeling. Although it is widely accepted that oceanic basins initiate during the continental breakup due to rifting, there are still many fundamental questions related to the transition from continental to oceanic basins, and associated oceanic crust formation. Initial breakup processes are a) Intracratonic sags; b) Continental rifting; c) Failed rifting; and d) Supra-detachment basins. How these processes lead to mature oceanic basins is poorly understood. Also important is the role of large-scale continental extension in continental break up and formation of mature oceanic basins.

The best examples of large-scale extensional tectonics are the Basins and Ranges of Western North America and the Aegean Region of Eastern Europe and Western Asia. These regions experienced extensional tectonics following a continent-continent collision. This type of tectonic and petrologic succession may be "normal" for collisional mountain belts due to gravitational collapse of over-thickened crust, or extension may be driven by other forcing factors, such as slab roll-back or continental escape.

We suggest that there is a need for interdisciplinary research projects to provide complete treatment of extensional tectonics and basin formation from continental breakup to mature oceanic basins; the role of large-scale continental extension in continental break up; failed rifts, and structural development of Aulacagens. This type of projects will also provide insight into the mechanism and geological evolution of rift zones, continental and oceanic core complexes, continental breakup, and the development of passive margins such as on both sides of the Atlantic Ocean. The geochemistry and sedimentary depositional environments of oceanic and continental extensional basins also need better understanding. This will also provide new insights into large-scale climate change experienced during the geological evolution of these basins.