Chapter 6 The Rio Grande Rift

Publisher Summary This chapter discusses the Rio Grande rift, which is a part of a broad region of the western United States, including the Basin and Range province, that has undergone lithospheric thinning and crustal extension during the middle to late Cenozoic. The present extensional setting of the rift is generally related to plate boundary forces acting along the southwestern edge of the North American plate, a transform boundary along which right-lateral slip occurs. The rift follows a zone of crustal deformation formed during the Laramide and Ancestral Rocky Mountains orogenic events. Tertiary sedimentation in the rift area is characterized generally by continental basinal deposits, including interbedded epi- and pyroclastic rocks.