HR: 0800h
AN: T11B-0391    [Abstracts]
TI: Anatomy Of An Actively Evolving Foreland Basin Inferred From Bolivar Project 2D Seismic Lines And Merged 3D Seismic Volumes, Columbus Basin, Eastern Offshore Trinidad.
AU: * Garciacaro, E J
EM: emiliogarciacaro@mail.utexas.edu
AF: The University of Texas at Austin. Jackson School of Geosciences, 4412 Spicewood Springs Rd. #600, Austin, TX 78759 United States
AU: Mann, P
EM: paulm@utig.ig.utexas.edu
AF: The University of Texas at Austin. Jackson School of Geosciences, 4412 Spicewood Springs Rd. #600, Austin, TX 78759 United States
AU: Escalona, A
EM: escalonaa@mail.utexas.edu
AF: The University of Texas at Austin. Jackson School of Geosciences, 4412 Spicewood Springs Rd. #600, Austin, TX 78759 United States
AU: Wood, L
EM: Lesli.Wood@beg.utexas.edu
AF: The University of Texas at Austin. Jackson School of Geosciences, 4412 Spicewood Springs Rd. #600, Austin, TX 78759 United States
AB: Eastward migration of the Caribbean plate relative to the South American plate is recorded by a 1100-km-long foreland basin which is oldest in the west (Maracaibo basin, 65-55 Ma) and youngest in the east (Columbus basin, eastern offshore Trinidad, 15-0 Ma). The composite foreland basin exhibits a characteristic wedge shape that varies from tens of meters above the South American craton to more than 15 km in thickness to the north adjacent to fold-thrust belts. We have integrated approximately 775 Km of deep 2D seismic lines acquired in the study area as part of the 2004 BOLIVAR project, 8,000 km2 of shallow industry 3D seismic data and published well data from the submarine Columbus basin (CB) to reveal the active tectonic processes that controlled the older, now subaerial and inactive foreland basins to the west. The late Tertiary basin fill of the CB was divided into 7 unconformity-bound sequences which thicken northward to oblique-slip faults bounding the submarine Darien Ridge. Deep wells and seismic data show that the Darien Ridge is composed of an imbricated prism of late Cretaceous and early Tertiary deepwater limestone and clastic rocks that are bounded to the north by an active right-lateral strike-slip fault and metasedimentary rocks of the exotic Caribbean plate. The CB fill itself varies in age from Late Miocene to Recent with a Pleistocene section exceeding 4 km in thickness. Unconformities indicate a pulsed deformation of the CB extending over a period of 15 Ma rather than a single sharp closure event. Plio-Pleistocene depocenter migration toward the east indicates continuing advance of the Caribbean plate relative to South America during this time. Active mud diapirism in the CB is widespread and is related to overthrusting and loading of upper Miocene - lower Pliocene age shales. 3D visualization of mapped surfaces allow appreciation of the magnitude of Miocene to recent thrusting along the Darien Ridge and control on wedge-shaped sequences.
DE: 8105 Continental margins: divergent (1212, 8124)
DE: 8150 Plate boundary: general (3040)
DE: 8185 Volcanic arcs
SC: Tectonophysics [T]
MN: Fall Meeting 2005