Insights into Caribbean tectonics from a detrital zircon U-Pb provenance study of siliciclastic strata in western and central Cuba

Abstract

The tectonic affinity and origins of the Jurassic, siliciclastic San Cayetano and Constancia formations exposed in western and central Cuba in the Caribbean region remain debated. The scarcity of modern geochronologic studies on these Cuban units hampers both sedimentary provenance and palinspastic reconstructions, resulting in Caribbean models that tend to oversimplify the formation of Cuba and correlate the Jurassic strata to various regions such as North America, South America, the Yucatán margin, or the conceptual Caribeana domain. Using laser ablation−inductively coupled plasma−mass spectrometry (LA-ICP-MS), we conducted a detailed detrital zircon (DZ) U-Pb provenance study of these Cuban siliciclastic strata that provides critical insights into understanding the formation of Cuba during the Early Jurassic rifting stages of Pangea. Results from 19 San Cayetano Formation samples show a dominant Oaxaquia (ca. 1 Ga) and Chiapas batholith (ca. 250 Ma) signature, while six Constancia samples display variable ca. 1 Ga and ca. 250 Ma grains. The Lower Cretaceous Polier Formation and the Paleocene Moncada Formation also display the same ca. 1 Ga and ca. 250 Ma signatures. After comparing these Cuban data with data from other regional DZ studies, we propose that that the San Cayetano and Constancia formations are correlative to the Todos Santos Formation located in the southwestern Yucatán region of Mexico. These Cuban units were predominantly deposited adjacent to the Chiapas batholith during the Early Jurassic in northwest−southeast-trending basins created by Pangean rifting. They were eventually sheared during eastward migration of the Caribbean plate and transported northward until they collided with the North American continent in the Paleogene. This DZ study provides new constraints on the tectonic provenance of western and central Cuba and improves plate tectonic reconstructions of the Caribbean.