G. Huxford, 1983. "Ship Shoal Anticlinal Structure", 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 exhibited line "A" is displayed to show an anticlinal structure that has associated faults and hydrocarbon indicators. The data is presented as it has come from the contractor and the processing is routing. Line "A" is located in the Pliocene trend approximately 64 km (40 mi) off the coast of Louisiana and was shot in 1978. The geologic section is composed of sand-shale sequences with occasional thin limestones. The sand deposits in the area appear to be regular and predictable and exhibit uniform deposition across the structure.
Structurally this line exhibits an anticline starting at approximately 1.5 secs. The anticline is apparently related to deep-seated diapiric movement that occurred during several periods of time. Gravity supports a deep diapir, but deep seismic data does not resolve the salt outline. Complications associated with the complex faulting in the area also give credence to this concept. The structure can be seen to be developing between the event indicated at 1.4 secs and the deeper levels. Thinning across the structure can be seen between the shallow horizon at 1.5 secs and the deeper events that have been indicated. The deeper horizons that have been marked are not necessarily correlative. Dominant faulting in the area is normal faulting with the dominant faults being down-to-the-south and the antithetical down-to-the-north faulting setting up additional traps and a large graben system. Fault "A" is the dominant fault with fault "B" dying out into "A." Depositional thickening can be seen across the fault by comparing the throw of fault "A" at shotpoint 1385 (0.6 secs) and at shotpoint 1361 (1.3 secs). Correlations across the faults in this area are fairly reliable at shallower depths. Growth can also be seen on fault "B" and also on the smaller fault that is antithetic to "B."
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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
Until a few decades ago, structural and regional geology were traditionally the preserve of field geologists. They usually mapped areas of outcropping deformed rocks and supplemented their work by laboratory studies of rock deformation and by theoretical work. Structural geology became tied to the geology of uplifts, folded belts, and underground mines, all of which were accessible to direct observation. Since World War II we have witnessed a tremendous development of geophysics in oceanography and in petroleum geology. Academic geophysicists in oceanography led their geological colleagues into modern plate tectonics and industry geophysicists developed reflection seismology into a superb structural mapping tool that penetrated the subsurface.
Today we are facing a situation where instruction and textbooks in structural geology are almost entirely dedicated to rock deformation, analytical techniques in detailed field geology and summaries of plate tectonics. Illustrations based on reflection seismic profiles are virtually absent in textbooks of structural geology. These texts illustrate only the parts of the proverbial elephant, together with some conjecture, but without ever offering a glimpse of the whole elephant.
Some of the reason cited for the relative scarcity of published reflection profiles are: 1) the confidentiality of exploration data; 2) difficulties in the photographic reduction and reproduction of seismic profiles for a book format; 3) the two-dimensional nature of vertical reflection profiles; and 4) the obvious distortions in reflection profiles that are typically recorded in time.
The AAPG leadership felt that it was time to attempt to correct the situation and to produce this picture and work atlas. The first volumes, of what may become a series of volumes, are addressing an audience that includes: petroleum geologists concerned with structural interpretations; exploration companies that provide in-house training; the AAPG continuing education program; and academic colleagues interested in updating their curricula in structural geology by inclusion of reflection profiles from the “real world” in their teaching.
The atlas is not meant to be a textbook in reflection seismology (instead we listed some at the end of this introduction) nor a text in structural and/or regional geology. Our intent is simply to provide a teaching tool.