WIDTH OF CONTINENTAL RIFTS AND RHEOLOGICAL LAYERING OF THE LITHOSPHERE

A review of some well-known continental rifts shows that rift features such as maximum basin depth are dependent on the amount of extension. Conversely, the initial rift width appears to independent of the amount of extension. A comparison is made with laboratory models of rifts developed in a brittle-ductile lithosphere. Experimental models show that normal faults which bound a graben initially meet at the brittle-ductile interface. A relation between initial rift width and the depth of the brittle-ductile transition is thus suggested. Implications for natural examples are discussed.