Bruce K. Reitz¹

(1) Conoco Inc, Lafayette, LA

ABSTRACT: A Two Pole Gulf of Mexico Basin Origin Model: Implications for Oceanic Crust Architecture and Louann Salt Distribution

Magnetic and gravity data are used to refine regional depth to basement interpretations, to derive oceanic crust and microplate boundaries, and to constrain crustal restorations of the Gulf of Mexico Basin (GOMB). These data are the basis for a GOMB reconstruction that requires two poles of rotation. During the initial rift phase of GOMB Triassic deformation, the combined Yucatan and South Florida blocks rotated 26 degrees counterclockwise about a pole at 28.8 N, -82.7 W. This departure produced up to 565 KM of crustal extension in the western GOMB, and a 450 KM southeasterly translation of the Yucatan/South Florida block along the Florida Elbow fault. Non-rigid reconstructions using this pole produce a +/-30 KM misfit on the restored northern and southern GOMB margins. The drift phase of GOMB origin involved departure of the Yucatan block from the South Florida block and a 36 degree counterclockwise rotation about a pole at 22.75 N, -83.72 W. The tight pre-drift fit between the Yucatan and Florida margins is constrained by a series of gravity and magnetic anomalies of similar frequency and amplitude on the opposing margins. Therefore no shear is required near the Florida Escarpment. Magnetic data in the central GOMB show symmetric patterns that are interpreted as oceanic transform and ridge architecture. This architecture is kinematically consistent with the drift phase pole. Seismic interpretations of basement structure support the transform and ridge interpretations. This oceanic fabric influences autochthonous salt limits and thickness, which in turn has a major influence on GOMB deepwater structure and accommodation space.

AAPG Search and Discovery Article #90906©2001 AAPG Annual Convention, Denver, Colorado