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 tan 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… download the full paper in PDF.