Subsurface structures along western Yucatan from integrated geophysical analysis

Integration of seismic, gravity and magnetic data revealed variations in crustal architecture along the Yucatan passive continental margin. The crust beneath the Yucatan salt basin is similar to 10 km thick and is primarily a lower continental crust. In contrast, the crust beneath the Campeche salt basin is thicker and comprises both the upper and the lower crustal layers. These variations in crustal architecture explain the strikingly different tectonic histories of these basins outlined by previous authors. The rifting of the Yucatan margin was associated with extensive magmatism expressed as voluminous igneous intrusions in the lower crust, one of which is manifested as the Campeche magnetic anomaly. The zone of extrusive volcanic flows is also interpreted in the northern Yucatan coincident with the Seaward Dipping Reflectors (SDR) in seismic data. Integrated analysis of potential fields and seismic data demands high density and magnetic susceptibility for the rocks of the SDR zone. The pre-salt sedimentary basin with up to 5 km of sediments overlies the stretched and intruded continental crust adjacent to the Ocean-Continent boundary (OCB). This pre-salt basin is up to 100 km wide and pinches out at the northeastern tip of the Yucatan peninsula. It appears to be compartmentalized with the width of individual segments up to 100 km. All the tectonic elements, namely OCB, SDR, pre-salt sedimentary basin, and magmatic intrusions within the stretched continental crust, have their counterparts in the northeastern Gulf of Mexico and therefore represent important constraints for the pre-breakup locations of individual crustal blocks.

Automated summary

The integration of seismic, gravity, and magnetic data reveals variations in crustal architecture along the Yucatan passive continental margin, particularly between the Yucatan salt basin and the Campeche salt basin. These variations explain the different tectonic histories of the basins, including pre-salt sedimentary basin, the pre-breakup locations of individual crustal blocks, and magmatic intrusions within the stretched continental crust.