Marcus I. Goldman, 1926. "Petrography of Salt Dome Cap Rock", Geology of Salt Dome Oil Fields, E. DeGolyer, W. A. J. M. Van Waterschoot Van Der Gracht, Marcus I. Goldman, I. P. Voiteşti, S. L. Mason, Hans Stille, Donald C. Barton, Sidney Powers, W. C. Spooner, David Donoghue, Francis Edward Vaughan, R. H. Goodrich, Lyman C. Reed, P. K. Kelley, H. E. Minor, Roland B. Paxton, A. S. Henley, John R. Suman, George Sawtelle, George M. Bevier, W. F. Bowman, Alexander Deussen, Laura Lee Lane, D. S. Hager, E. Stiles, Paul L. Applin, William Kennedy, Albert G. Wolf, Ben C. Belt, W. F. Henniger, Raymond C. Moore, Wallace E. Pratt, Donald C. Barton, Alexander Deussen, J. P. D. Hull
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Two kinds of cap rock are differentiated: the gypsum anhydrite-cap and the calcite cap. The gypsum is derived from the anhydrite by hydration and is characteristic of the upper part of the cap, where it contains much calcite and sulphur. The deeper, less altered part of the anhydrite cap shows parallel banding, which may be the result of diffusion, and breccia fragments of a parallel-banded, finer-grained anhydrite, which give evidence of sedimentary origin. Therefore, although no detrital minerals have been found in specimens of anhydrite cap, this cap is believed to be of sedimentary origin, brought up by an intrusive salt plug from depth. Possible explanations of the presence or absence of anhydrite caps on salt domes are offered. The calcite cap is the product of replacement and penetration by calcite of the sedimentary beds adjacent to the gypsum-anhydrite cap and probably of the upper part of the gypsum-anhydrite cap itself. The sulphur in cap rock is characteristically associated with this calcite. The calcite and sulphur are probably the result of reduction of the outer parts of the anhydrite cap by hydrocarbons from adjacent beds. Constituents of minor importance are sulphides, carbonates of an early generation, barite, celestite, bipyramidal quartz crystals, and inclusions of sandstone in anhydrite.
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Coming from an AAPG meeting in 1924, this volume strives to present a comprehensive picture of American salt domes, and to collect and record in permanent form the infirmation that has accumulated during twenty years of exploration for petroleum around the salt domes of the Gulf coastal plain. The plan for the volume included a brief, accurate description of each of the known salt domes. Although the list is not yet quite complete, the facts concerning a number of typical salt domes are presented with sufficient detail to portray +adequately the true nature of this remarkable type of geologic structure. Along with these descriptive papers, and based largely on the data contained in them, are several theoretical and interpretative studies, together, also, with some discussion of European salt domes.