Multichannel Seismic Survey of the Colombia Basin and Adjacent Margins
Published:January 01, 1982
Twelve-fold multichannel seismic data reveal two types of seismic stratigraphy in the Colombia Basin: basin-floor-type and fan-type. Basin-floor-type stratigraphy occurs in areas with thin sediment cover in the central basin and parts of the lower Nicaragua Rise; whereas the fan-type stratigraphy with thick sediment cover occupies the western and eastern regions of the Colombia Basin. The reflection zone above acoustic basement in the basin-floor-type province and in each region of the fan-type province is divided into four seismic intervals separated by three laterally persistent reflectors of unknown ages.
The acoustic basement shoals toward the Costa Rica coast and dips down toward the Panama and Colombia margins. The Panama and Colombia margins at the southern boundary of the Colombia Basin consist of a convergence zone where basin sediments have been underthrust and deformed into active-margin-type structures. Structural detail of the deformed belt indicates that the directions of convergence at the northern Panama and Colombia coasts have been different from those of the present day relative motions between the Nazca, South American, and Caribbean plates.
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Studies in Continental Margin Geology
"Studies in Continental Margin Geology" contains papers from a research conference co-sponsored by AAPG and the University of Texas Institute for Geophysics held in Galveston, Texas in 1981. Rapid advances in the understanding of continental margin geology were taking place during the time period, based on major improvements in the quality and availability of regional seismic surveys plus other fields such as organic geochemistry. For the first time it was becoming common to have a visual characterization of tectonic processes at significant depths below the surface. Twenty-seven papers are presented that deal with field investigations of continental margin structure and stratigraphy. The geographic areas of study are global in nature and many of the descriptive results are derived from modern seismic investigations in areas where that type of data had not previously been available in commercial publications. Fifteen of the papers focus on rifted margins and the other twelve concern convergent margins. Twelve papers are model investigations of a variety of margin environmental processes, related to subjects such as depositional environments, biostratigraphy, organic matter deposition, and oil and gas occurrences as a function of the plate tectonic setting. An additional nine papers model the thermal and mechanical tectonic processes involved in the structural development along continental margins.