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The AAPG/Datapages Combined Publications Database

Houston Geological Society Bulletin

Abstract


Houston Geological Society Bulletin, Volume 30, No. 4, December 1987. Pages 11-11.

Abstract: Structural Styles of Growth-Fault Trends in Texas: Some Cases in Point

By

Thomas E. Ewing

Within the overall theme of Gulf Coast growth Previous HitfaultingNext Hit significant regional variability exists. Detailed mapping and regional seismic interpretation of selected areas in growth fault trends of the onshore Texas area (primarily the Wilcox and Frio growth-fault trends) documents this variability, which can be related to the distribution of oil and gas fields and overpressure occurrence.

Several basic styles of growth Previous HitfaultingNext Hit are observed in the Tertiary sequence of the Texas Gulf Coast. The most distinctive are glide fault systems, which display a basal detachment below highly faulted and rotated, usually sand-rich and hydrocarbon-bearing, strata. Most glide systems show rap-migrating highs following the basal detachment (South Texas Vicksburg, Sarita, Corsair), but others involve domino-style extension akin to Great Basin examples (Yegua). Other areas show rotated blocks on listric faults which may sole into a deep glide plane at great depth (Frio system). Still other growth faults are only slightly listric, have slight block rotations, and may root at great depth (Dewitt Wilcox). Other major systems of growth faults occur over shale ridges (Zapata Wilcox). Localized growth Previous HitfaultingNext Hit also occurs along the margins of salt-or shale-withdrawal basins, or as compactional Previous HitfaultingNext Hit related to shale ridges.

Factors that control structural styles must include: the nature of the pre-progradation substrate, presence of salt-or shale-related bathymetric features of the paleocontinental slope, the rate and spatial variance of sediment loading of the shelf margin, and the relative excess of sedimentation over subsidence. Presence of thick mud sequences in the substrate favors shale-ridge development and glide-fault systems. Slope features localize the trend of Previous HitfaultingNext Hit and may concentrate it over the slip-face of the slope feature. The spatial variance of sedimentation may determine the geometry of Previous HitfaultingTop, and also initiate salt or shale movement. The relative excess of sedimentation over subsidence determines the magnitude and timing of the fault systems by determining the overall extent of shelf-margin progradation.

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