Morphological and structural model of Mexican Volcanic Belt

Abstract

On the basis of geological, geomorphological and structural data, the main structural units forming the Mexican Volcanic Belt (MVB) were recognized. They have been generated during several tensional phases since Oligocene. Many of the structures connected with these units are still active. Three main sectors were recognized inside the MVB. The western sector, activated during Pliocene times, shows a NW-SE trending graben system, associated to the opening of the Gulf of California. The central sector is represented by a block-faulted and tilted WSW-ENE trending graben system, surrounding a central depression. In the oriental sector the disjunctive structures are represented by N-S fault systems affecting the rigid basement of Sierra Madre Oriental, and controlling the development of the largest strato-volcanoes of the MVB. The MVB intersects older N-S and NNE-SW block-faulted structures, belonging to the Basin and Range province. Reactivated tensional lineaments belonging to the same province were recognized inside the western and the central sector, and probably in the eastern one too. Along the southern margin of the same volcanic belt all the described distensive structures are interrupted, and huge E-W collapsed structures coincident with the Rio Balsas valley develop.