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Early Mesozoic synrift Eagle Mills Formation and coeval siliciclastic sources, sinks, and sediment routing, northern Gulf of Mexico basin

Bruce C. Frederick, Mike D. Blum, John W. Snedden and Richard H. Fillon
Early Mesozoic synrift Eagle Mills Formation and coeval siliciclastic sources, sinks, and sediment routing, northern Gulf of Mexico basin
Geological Society of America Bulletin (April 2020) 132 (11-12): 2631-2650

Abstract

The sedimentary architecture and provenance of the early Mesozoic incipient northern Gulf of Mexico basin remains controversial due to both lack of outcrop exposure and sample scarcity across the southern United States with subcrop depths approaching 6 km. The Eagle Mills Formation and coeval deposition across the northern Gulf of Mexico provides both a stratigraphic foundation for some approximately 15-km-thick overlying Mesozoic and Cenozoic deposits, and a coeval pre-salt equivalent for southern synrift deposits, in one of the most economically significant hydrocarbon basins in the world. This study presents more than 3200 new detrital zircon U-Pb analyses from sixteen Late Triassic pre-salt, siliciclastic, subcrop well samples, and combines over 14,000 linear kilometers of 2-D multi-channel seismic reflection data, 1511 geophysical well logs, and biostratigraphic data from 2478 wells to construct basin-scale pre-salt isochore and structure maps spanning the northern Gulf of Mexico margin from Florida to the USA-Mexican border. The data show that incipient Gulf of Mexico paleodrainage pathways held individual distinctions between basement sources and tectonic controls in three primary regions across the northern Gulf of Mexico: (1) The western Gulf of Mexico paleodrainage extended from the Central Texas uplift highlands to the submarine Potosi Fan on the western margin of Laurentia with local tributary sources from the East Mexico Arc, Yucatan/Maya, and Marathon-Ouachita provinces as evidenced by inverse Monte Carlo unmixing of peri-Gondwanan (ca. 700-500 Ma), Appalachian/Ouachita (500-280 Ma), Grenville (1250-950 Ma), and Mid-Continent/Granite-Rhyolite Province (1500-1300 Ma) detrital zircon ages. Isochore and associated geophysical well and seismic data suggest that by Early Jurassic time this depocenter had shifted into the present-day western Gulf of Mexico as East Mexico Arc development continued. (2) Southerly drainage in the north-central Gulf of Mexico region bifurcated around the Sabine and Monroe uplifted terranes with southwestern flow characterized by peri-Gondwanan detrital zircon ages from late Paleozoic accreted basement or discrete flexural successor basins, and southeastern fluvial networks distinguished by traditional North American basement province sources including Grenville, Mid-Continent, and Yavapai-Mazatzal. (3) Eastern Gulf of Mexico regional paleodrainage, with regional southern flow dictated by the brittle extensional tectonics of the South Georgia Rift as well as the regional southern flexure of the South Florida Basin, resulted in almost all pre-salt detrital zircon siliciclastic ages from this region to be dominated by local Gondwanan/peri-Gondwanan aged sources including the proximal Suwannee terrane and Osceola Granite complex. These regional, synrift sediment provenance models provide the first critical allochthonous evidence of Late Triassic-Early Jurassic paleodrainage stemming from the Appalachian-Ouachita hinterlands into the incipient northern Gulf of Mexico basin with critical implications for pre-salt hydrocarbon exploration and carbon sequestration reservoir potential.


ISSN: 0016-7606
EISSN: 1943-2674
Coden: BUGMAF
Serial Title: Geological Society of America Bulletin
Serial Volume: 132
Serial Issue: 11-12
Title: Early Mesozoic synrift Eagle Mills Formation and coeval siliciclastic sources, sinks, and sediment routing, northern Gulf of Mexico basin
Affiliation: University of Kansas, Department of Geology, Lawrence, KS, United States
Pages: 2631-2650
Published: 20200424
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
References: 181
Accession Number: 2020-056531
Categories: StratigraphyGeochronology
Document Type: Serial
Bibliographic Level: Analytic
Annotation: GSA Data Repository item 2020161
Illustration Description: illus. incl. sects., strat. cols., geol. sketch maps
Secondary Affiliation: University of Texas-Austin, USA, United StatesEarth Studies Group, USA, United States
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2020, American Geosciences Institute. Reference includes data from GeoScienceWorld, Alexandria, VA, United States. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States
Update Code: 202034
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