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The AAPG/Datapages Combined Publications Database
Houston Geological Society Bulletin
Abstract
Abstract: Structural Styles of Growth-Fault
Trends in Texas:
Some Cases in Point
By
Within the overall theme of Gulf
Coast
growth faulting
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 faulting 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
faulting also occurs along the margins of salt-or shale-withdrawal
basins, or as compactional faulting 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 faulting and may concentrate it over the slip-face of the slope feature. The spatial variance of sedimentation may determine the geometry of faulting, 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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