New models of early cretaceous source-to-sink pathways in the Eastern Gulf of Mexico
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During the early Cretaceous (Valanginian-Hauterivian stages), there were significant basin- to regional scale changes in the Gulf of Mexico affecting marine tectonics, terrestrial erosion, and sedimentation on the Florida shelf and in the eastern Gulf of Mexico deep-water areas. Termination of Gulf of Mexico (GOM) sea-floor spreading left its tectonic mark at the beginning of the Valanginian stage. Subsequent uplift of the Florida Ocala Arch caused a source terrane to perch above the landscape, leading to erosion and transport of siliciclastics across the shelf and into the GOM deep-water as a sandy progradational delta-fed slope apron. Contemporaneous supply from an Appalachian source terrane brought additional siliciclastic material into the GOM DeSoto Canyon- Mississippi Canyon deep-water off the Florida coast. To augment the results of seismic mapping of 2D and 3D narrow azimuth (NAZ) seismic reflection surveys, the Hosston interval of the onshore Florida Stanolind Sun Perpetual Forest #1 well was sampled and U-Pb detrital zircon analysis performed at Dr. Danny Stockli’s geochronology lab at The University of Texas at Austin. Results indicate Hosston siliciclastics were derived from the Suwannee Terrane and the Trans-Amazonian/Eburnean craton, rather than the Grenville Province of the Appalachian Mountains. For this Valanginian-Hauterivian-age Hosston sand grains to reach the deepwater and deposit a progradational sandy delta-fed apron of 200 km in length, we interpret submarine canyons incised the shelf edge, bringing both the carbonate reef rim material and siliciclastic material from where open shelf passages exist, down to the deep-water through turbidity flow processes. The Mississippi Canyon protraction block asymmetric expulsion rollovers, salt tectonic features which preserve direction of large-scale sedimentary progradation and basin filling, indicate the Hosston material was deposited in an ENE-WSW direction, or derived from an Appalachian source terrane. Scaling relationships between river channel length and fan length help constrain the possible extent of the Appalachian-sourced fan, resulting in the most likely fan runout length of approximately 70 km. Seismic observations, new interpretations of onshore and offshore Gulf Basin Depositional Synthesis project-digitized wells, and results of U-Pb detrital zircon dating support construction of an updated Hosston paleogeographic map, focusing on the eastern Gulf of Mexico where both economic and scientific interests coincide.