Rifts of the world


Sengor A., Natal'in B.

Symposium on Locating Old Mantle Plumes held at the Annual Meeting of the Geological-Society-of-America, Toronto, Canada, 01 October 1998, pp.389-482 identifier

  • Publication Type: Conference Paper / Full Text
  • City: Toronto
  • Country: Canada
  • Page Numbers: pp.389-482

Abstract

Rifts are fault-bounded elongate troughs, under or near which the entire thickness of the lithosphere has been reduced in extension during their formation. They form in most tectonic settings, including above mantle plumes, and at all stages of the Wilson Cycle of ocean opening and closing. The purpose of this paper is to present an updated inventory of the rifts of the world both in graphic and tabular form. We have identified 290 rifts in Eurasia, 101 in Africa (including Madagascar), 11 in Australia, 1 in New Zealand, 81 in North America, 68 in South America, and 16 in Antarctica. These numbers are clearly an underestimation, because of (1) the ones we missed and (2) the ones that were too small to be included here. The greatest majority of rifts formed through passive mechanisms, i.e., without active mantle participation. In the future, it would be more helpful to consider rifts in terms of taphrogens, i.e., regions of intense extension, in which many rifts and grabens occur as a result of general lithospheric stretching, to be able to understand the tectonic regimes that give rise to rifting.