Mesozoic Rift Evolution and Crustal Structure of the Gulf of Mexico Basin from Integration of Multiple Geological and Geophysical Datasets

Date

2021-08

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Abstract

The Gulf of Mexico basin (GOM) is one of the most prolific, hydrocarbon-producing basins in the world. However, our understanding of the Triassic-Jurassic rift history and crustal structure of the GOM is limited. This dissertation integrates satellite free-air gravity data, full-tensor gravity gradient data, 104,000 line-kilometers of 2D reflection data, and publicly available refraction data and deep wells over 4.2 million km2 to improve our understanding of the GOM rift history. Chapter 1 summarizes the development of this study. In Chapter 2, 2D gravity models are used to constrain two zones of southward-dipping reflectors associated with 7-10 km, dense and magnetic material. The marginal rift width varies from 28 km to 42 km in both models and was formed during a progressive, tectonic transition from late Triassic-early Jurassic, northwest-to-southeast rifting to late Jurassic north-south rifting. In Chapter 3, I test two GOM opening models by integrating reflection data, refraction data, gravity data, and well data from the greater GOM area. Inversion of gravity data for crustal thickness used constraints from 178 refraction stations to produce a regional map of crustal domains. I restore rifted margins to produce an earliest Triassic full-fit reconstruction. The best full-fit restoration was achieved using the two-phase model that consists of a first phase of Triassic-early Jurassic, northwest-southeast continental rifting followed by a second phase of late Jurassic north-south rifting and oceanic crust formation. In Chapter 4, I use 12 2D seismic profiles from the northeastern GOM and northern Yucatan to map the 1056-km-long marginal rift system that is adjacent to the late Jurassic oceanic crust of the central GOM. Analysis of the seismic, gravity, and magnetic data shows the crust underlying the marginal rift is thinned continental crust formed by necking of the continental crust. 2D gravity models show that the marginal rift sedimentary fill consists of volcaniclastic and sedimentary rocks. In Chapter 5, full tensor gravity gradient was used to model the base of salt and geometry of the salt canopy in the north-central US GOM. A 3D model containing the salt canopy was built and inverted for the base of salt using the Tzz component. The components Txz and Tyz were used to interpret the edges of the salt canopy.

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Keywords

Gulf of Mexico, Crustal structure, Gravity inversion, Continental rift, Full-fit Reconstruction, Gravity model, Seismic interpretation

Citation

Portions of this document appear in: Liu, Mei, Irina Filina, and Paul Mann. "Crustal structure of Mesozoic rifting in the northeastern Gulf of Mexico from integration of seismic and potential fields data." Interpretation 7, no. 4 (2019): T857-T867.