STRATIGRAPHY OF EL CHANATE GROUP (LATE CRETACEOUS) AND ITS IMPLICATIONS FOR THE TECTONIC EVOLUTION OF NORTHWESTERN SONORA, MEXICO

Abstract

The Late Cretaceous El Chanate Group is a clastic and volcanic sequence, ranging from 700 to more than 2,800 m in thickness, deposited in a continental basin. It disconformably overlies the Lower Cretaceous Bisbee Group and underlies the Late Cretaceous (71 Ma) Tarahumara Formation. On the basin of major upward-fining eyeles and different conglomerate composition, three stratigraphic units were identified in the Sierra El Chanate: the Pozo Duro (oldest), Anita, and Escalante (youngest) formations. El Chanate Group and its three formations are proposed herein as formal stratigraphic units… in order to continue, download the full paper in PDF.