R.T. Buffler, 1983. "Structure of the Sigsbee Scarp, Gulf of Mexico", Seismic Expression of Structural Styles: A Picture and Work Atlas. Volume 1–The Layered Earth, Volume 2–Tectonics Of Extensional Provinces, & Volume 3–Tectonics Of Compressional Provinces, A. W. Bally
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The lower Texas-Louisiana continental slope between Alaminos Canyon and De Soto Canyon is a unique geomorphic and geologic province (Figure 1). Between 1975 and 1977 the University of Texas collected regional multifold seismic data across the region (Figure 1). Examples of these data are included here to show some of the geomorphic and geologic features of the area (Figures 2 through 5). The figures are duplicates of most of the figures from an earlier paper presented at the 1978 Offshore Technology Conference (Buffler et al, 1978). The reader is referred to this paper for a more detailed discussion of (1) previous studies in the area, (2) the seismic data, and (3) preliminary conclusions. The lines are repeated here because this is such a unique province containing some very interesting structural and stratigraphic features.
The lower continental slope can be divided into two major provinces, the Sigsbee Bulge area and the Central Slope/Mississippi Fan area (Figure 1). The Sigsbee Bulge area is where the lower slope bulges seaward into the deep central Gulf. It forms a broad terrace-like feature about 50 to 75 km (164 to 246 ft) wide (Figure 2). Its southern boundary is marked by a prominent change in slope and geology known as the Sigsbee Scarp (Figures 1, 2). The Bulge area is characterized by a shallow, irregular high-amplitude reflector overlain by a relatively thin sedimentary section (Figure 2). The reflector is generally interpreted to be the top of mobilized salt. The geometry and extent of the mobilized mass beneath the lower slope is not clear on these seismic data (Figure 2). The leading edge of the mobilized zone forms the Sigsbee Scarp, which is characterized by material thrust up to 10 to 15 km (6.2 to 9.3 mi) seaward over flat-lying rise sediments (tongues, Figure 3).