SUTURE ZONE OF LAURENTIA AND GONDWANA ALONG THE ALAMITOS LINEAMENT ON CENTRAL-EASTERN CHIHUAHUA, MEXICO

The Alamitos Lineament, in central-eastern Chihuahua, is a N65ºE-trending tectonic lineament separating exposures of the Sierra Madre Oriental, a part of the North American Tectonic Belt, and an extensive area, covered by Cenozoic volcanic rocks, to the south. Lineament stratigraphic, tectonic and paleomagnetic characterization were determined by field- and lab-research with satellite images, vertical aerial photographs, litho-stratigraphic columns and structural sections, thin-polished sections were used for petrographic, mineragraphic and paleomicroontologic studies. Paleomagnetic sampling and interpretation were used to determine crust tectonic rotation and poleward transport. Published geophysical and geological papers were utilized for much of the information to formulate the hypotheses which best explain the development of the lineament. The Alamitos Lineament, a two behavior regime frontier along the North American Plate in central-eastern Chihuahua, represents a basement geological structure. It was born when Laurentia and Gondwana collided in Late Paleozoic time. The Alamitos Lineament was reactivated by: 1) Isostatic equilibrium affecting sedimentary and volcanic rocks with major sedimentary deposits north of lineament; 2) Farallon Plate subduction which applied tangential stress-strain to the North American Plate; and 3) Movements along preexisting Texas Lineament and Laramide structures. Neogene extensional faulting and intraplate volcanic activity applied and continue to apply tectonic rotation and latitudinal transport to the north and south crustal sectors of lineament.