Structural evolution of the La Trocha fault zone: Oblique collision and strike‐slip basins in the Cuban Orogen

Abstract

The La Trocha fault zone acted as a major left‐lateral transfer zone and is bounded by the La Trocha (LTF), Zaza‐Tuinicú (ZTF), Cristales (CTF) and Taguasco (TGF) faults. These faults were consistent with the clockwise rotation of convergence and shortening in central Cuba. From the Paleocene to the Early Eocene (65–48 Ma), a SSW‐NNE shortening produced transtension in the LTF and transpression in the ZTF. Subsequently, during the Middle Eocene (48–37 Ma), shortening shifted to a SW‐NE direction, resulting in the normal component of the LTF and transpression in the ZTF and CTF. Since the Late Eocene (37 Ma), central Cuba has been welded to the North American Plate. The post‐welding deformation gave rise to transtension of the LTF and TGF. This deformation is consistent with a WSW‐ENE shortening and reflects activity in the transform boundary of the Cayman Trough. Both the normal and thrust displacements of these previous faults are corroborated by structural data whereas left‐lateral displacement is deduced from the concordance between oblique collision and structural features. Plate‐kinematics and the structural evolution of the La Trocha fault zone indicate that the related Central Basin is a strike‐slip polygenetic basin and that the formation of this system (i.e., fault zone – strike‐slip basin) was a consequence of the Paleogene oblique collision between the Caribbean Volcanic Arc and the Bahamas Borderland (North American plate).