AAPG Bulletin; May 2007; v. 91; no. 5;
p. 653-684; DOI: 10.1306/11280606002
© 2007 American Association of Petroleum Geologists (AAPG)
Chronology of Cenozoic tectonic events in western Venezuela and the Leeward Antilles based on integration of offshore seismic reflection data and on-land geology
David Gorney1,
Alejandro Escalona2,
Paul Mann3,
M. Beatrice Magnani4 and
BOLIVAR Study Group5
1 Institute for Geophysics, John A. and Katherine G. Jackson School of Geosciences, University of Texas at Austin, 4412 Spicewood Springs Road, Bldg. 600, Austin, Texas 78759; present address: Marathon Oil Company, 5555 San Felipe, Houston, Texas 77056; dgorney{at}marathonoil.com
2 Institute for Geophysics, John A. and Katherine G. Jackson School of Geosciences, University of Texas at Austin, 4412 Spicewood Springs Road, Bldg. 600, Austin, Texas 78759; present address: Institute for Petroleum Technology, University of Stavanger, 4036 Stavanger, Norway; alejandro.escalona{at}uis.no
3 Institute for Geophysics, John A. and Katherine G. Jackson School of Geosciences, University of Texas at Austin, 4412 Spicewood Springs Road, Bldg. 600, Austin, Texas 78759; present address: Institute for Geophysics, Jackson School of Geosciences, University of Texas at Austin, 10100 Burnet Road (R2200), Austin, Texas 78758-4445; paulm{at}ig.utexas.edu
4 Department of Earth Science, Rice University, Houston, Texas; present address: Center for Earthquake Research and Information (CERI), University of Memphis, 3876 Central Avenue, Memphis, Tennessee 38152; mmagnani{at}memphis.edu
5 Alan Levander, Gail Christeson, Paul Mann, Colin A. Zelt, M. Beatrice Magnani, Michael Schmitz, Stoney Clark, Maria C. Guedez, Maximiliano Bezada, Yemi Arogunmati, David Gorney, Trevor Aitken, and Amanda Beardsley
David Gorney is a development geologist at Marathon Oil Company in Houston, Texas. He received a B.S. degree in geology with honors from the College of Charleston in 2003 and an M.S. degree in geology from the University of Texas Jackson School of Geosciences in 2005. This article summarizes his M.S. degree research project at University of Texas Austin.
Alejandro Escalona is an associate professor of petroleum geology at the Institute for Petroleum Technology of the University of Stavanger in Norway. He received his Ph.D. in geology from the Jackson School of Geosciences of the University of Texas at Austin in 2003 for a reservoir to basin-scale study of the Maracaibo Basin, Venezuela (cf. April, 2006, issue of AAPG Bulletin). As a postdoctoral researcher at the University of Texas Institute for Geophysics from 2004 to 2006, he conducted a regional mapping study of offshore seismic and well data from the southern Caribbean.
Paul Mann is a senior research scientist at the Jackson School of Geosciences of the University of Texas at Austin. He received his Ph.D. in geology at the State University of New York in 1983, began as a researcher at the University of Texas in 1983, and has published widely on the tectonics of strike-slip, rift, and collision-related basins. Since 1983, he has served as the primary supervisor for 19 M.S. and Ph.D. students in the University of Texas Department of Geological Sciences. A current focus of his research is the interplay of tectonics, sedimentation, and hydrocarbon occurrence in Venezuela, Colombia, Trinidad and offshore areas.
M. Beatrice Magnani is an assistant professor at the Center for Earthquake Research and Information at the University of Memphis. She received her M.S. in structural geology and her Ph.D. in geophysics from the University of Perugia, Italy. Her research interests focus predominantly on the study of continental lithosphere formation, evolution, and modification through active source seismic investigation, both marine and on land.
Newly acquired, deep-penetration Broadband Onshore-Offshore Lithospheric Investigation of Venezuela and the Antilles Arc Region seismic reflection data from offshore western Venezuela (Bonaire Basin) and around the Leeward Antilles are combined with existing geologic and geophysical data sets to examine the chronology of Late Cretaceous–Cenozoic tectonic events in this part of the Caribbean–South American plate boundary zone. These tectonic events have controlled the maturation and structural trapping of known hydrocarbons in the offshore Bonaire Basin and the adjacent onland Falcón Basin. We infer three tectonic phases that are constrained using these combined data sets. (1) The late Eocene–early Oligocene, north-south opening of the 3–6-km (1.8–3.7-mi)-thick Falcón-Bonaire Basin occurred along east-west–striking normal fault systems that have locally been inverted by later tectonic phases. These Paleogene normal faults rifted the Upper Cretaceous arc crust and Paleogene marine depositional sequences within the offshore Bonaire Basin. (2) Northwest-striking normal faults crosscut the older normal faults of the Bonaire Basin and Leeward Antilles and form deep, submarine rifts that contain up to 4 km (2.5 mi) of sedimentary fill and form deep-water channels between islands of the Leeward Antilles. Offshore well data and age of onshore sediments in the Falcón Basin indicate that this second phase of rifting occurred mainly during the late Oligocene to early Miocene and remains active to the present. (3) Inversion of the subaerial Falcón Basin commenced during the middle Miocene. This inversion phase is reflected in the present-day pattern of an east-northeast–trending fold-thrust belt that can be traced over 200 km (124 mi) along strike in the Falcón Basin. A second offshore fold-thrust belt (La Vela) can be traced over a distance of 175 km (108 mi) along strike and parallel to the northeast-trending Falcón Basin coast. Restoration of imbricate thrusts seen on seismic lines perpendicular to the La Vela fold-thrust belt indicates a minimum of 7 km (4.3 mi) of northeast-southwest–directed, thin-skinned shortening. Geochemical work indicates that source rocks for scattered occurrences of hydrocarbons in the Falcón Basin and its coastal zone are Paleogene and Miocene marine shale. Reservoir rocks are Tertiary marine sandstone and shale deposited in Paleogene rifts formed during the first tectonic phase in the late Eocene to early Oligocene. Structural traps were formed by thrusting during the second tectonic phase in the late Oligocene to early Miocene.
Copyright © 2009 by American Association of Petroleum Geologists (AAPG)
