Geological and Geophysical Constraints Guide New Tectonic Reconstruction
of the Gulf of Mexico
Abstract
The Gulf of Mexico is a prolific petroleum basin with more than a
century-long exploration history. Tectonic models proposed for the basin
vary dramatically in many aspects, ranging from the pre-rift locations
of the crustal blocks, the timing of the break-up to even the order of
tectonic events. The reason for these disagreements is in a thick and
complex overburden that obscures seismic imaging of crustal structures.
To overcome that, we integrated seismic data with gravity and magnetic
fields to determine the crustal architecture in different parts of the
basin, as well as to map the location of the key tectonic features. The
subsequent spatial analysis of potential fields allowed us to trace the
tectonic structures outside of seismic coverage. As a result, a set of
new geological constraints was derived including the Triassic rifts,
regions of Seaward Dipping Reflectors (SDR), and Jurassic pre-salt
sedimentary basins in the eastern Gulf of Mexico and along the Yucatan
margin, and two distinct crustal zones in the oceanic domain. We ensure
the pre-breakup alignment of the crustal blocks based on the mapped
geological features on the conjugate margins. Our tectonic
reconstruction takes into account an apparent temporal variability of
the magmatic regime during basin formation that ranged from CAMP
(~200 Ma) to an ultra-slow amagmatic spreading during
the initial stage of the GoM opening (~ 165 Ma). Our
reconstruction also includes a major ridge reorganization
(~ 152 Ma) associated with increased magmatic supply.
This second phase of oceanic spreading ceased at early Cretaceous
(~ 135 Ma) based on published correlation analysis of
seismic and well data. Overall, the tectonic reconstruction presented
here takes into account previously known and newly derived geological
constraints and integrates various geophysical datasets, namely seismic,
gravity, and magnetics.