SULFUR 



617 



concentrations but provides a virtually unlimited 

 sulfur resource. 



In summary, the world position on sulfur resources 

 is good and will sustain rates of production many 

 times higher than present rates without strain. 



PROSPECTING FOR ELEMENTAL 

 SULFUR DEPOSITS 



Most caprock sulfur deposits were discovered 

 through wildcat drilling in search for oil, but some 

 were found by either wildcat or systematic drilling 

 in search for sulfur. Geophysical prospecting to date 

 has not been effective in locating sulfur deposits, 

 although it can be used to located caprock of unspe- 

 cified composition. 



It has long been known that on the gulf coast, 

 acid soil, known as sour dirt, occurs over known 

 caprocks ; such soil is acidified by leakage of hydro- 

 gen sulfide from below. This geochemical evidence 

 was instrumental in locating several caprock oil 

 fields and also provided the first clue to the presence 

 of a sulfur deposit in Boling Dome, Tex. (Haynes, 

 1942). Acid soil, hydrogen sulfide emissions, and 

 sulfuric acid springs also are known in west Texas 

 but do not necessarily coincide with underlying sul- 

 fur deposits. They cannot be infallible geochemical 

 indicators of sulfur deposits simply because they 

 show only that hydrogen sulfide was generated, not 

 that it was retained and oxidized to sulfur at depth. 



Regional stratigraphic features in the gulf coast 

 region and local structural features in the Delaware 

 Basin of west Texas could be applied to a greater 

 extent in exploration for sulfur. Particularly on the 

 outer continental shelf, study of stratigraphy could 

 be applied to block out favorable and unfavorable 

 areas for generation and retention of hydrogen sul- 

 fide within caprocks. Study of faulting in the Dela- 

 ware Basin may lead to targets overlooked in pre- 

 vious exploration programs. 



PROBLEMS FOR RESEARCH 



Geological problems still to be resolved include 

 determination of all the factors leading to the accu- 

 mulation of sulfur in coal, petroleum, natural gas, 

 and shale rich in organic matter. The various hy- 

 potheses advanced to date need to be tested and 

 evaluated over sufficiently broad areas to determine 

 their validity and hence their usefulness in explor- 

 ing for low-sulfur coal or, if sulfur is being sought, 

 for fossil fuels high in that element. 



A related geological problem needing further study 

 is the generation in coal mines of sulfuric acid, a 

 troublesome pollutant in streams traversing coal- 

 mining districts. A fuller understanding of the 



natural processes involved will lead to better meth- 

 ods of controlling acid generation. 



Perhaps more research has been devoted to meth- 

 ods of recovering sulfur or removing it as an un- 

 wanted element than to the recovery of any one 

 other mineral commodity. The wide variety of raw 

 materials now yielding sulfur as a byproduct attests 

 to the past successes of these efforts. Research is 

 continuing, nevertheless, to reduce the costs or to 

 increase the efficiency of sulfur recovery processes 

 applying to several of these raw materials. Major 

 research efforts now are being directed to the prob- 

 lem of removing sulfur from coal. Techniques are 

 being studied for removal of pyrite before ignition 

 of the coal, removal of sulfur dioxide from stack 

 gases, with or without the recovery of the sulfur it- 

 self, and removal and recovery of sulfur from coal as 

 it is being gasified or liquified. Until these techniques 

 are perfected, much coal must remain in the ground 

 because it contains too much sulfur to meet clean- 

 air requirements. 



The present excess sulfur production, particularly 

 in Canada, is stimulating research on new uses that 

 will exploit the unique physical properties of sulfur. 

 The element is remarkably low in thermal and elec- 

 trical conductivity, completely inert to attack by 

 acids, impervious to water, and it has high strength 

 at normal ambient temperatures ; it is easily applied 

 and workable when plasticized or in molten form, and 

 it hardens quickly. It thus promises to be a versatile 

 construction material. 



REFERENCES 



Adams, J. E., 1969, Semi-cyclicity in the Castile evaporite, 

 in Cyclic sedimentation in the Permian Basin — Sympo- 

 sium, Midland, Tex., 1967: West Texas Geol. Soc. Pub. 

 69-56, p. 197-203. 



Ambrose, P. M., 1965, Sulfur and pyrites, in Mineral facts 

 and problems, 1965 ed.: U.S. Bur. Mines Bull. 630, p. 

 901-917. 



Bodenlos, A. J., 1970, Cap-rock development and salt-stock 

 movement, in Geology and technology of Gulf Coast 

 salt — A symposium: Baton Rouge, School of Geoscience, 

 Louisiana State Univ., p. 73-86c. 



Borchert, Hermann, and Muir, R. O., 1964, Salt deposits — 

 The origin, metamorphism and deformation of evapo- 

 rites: London, Princeton, N. J., Toronto, D. Van 

 Nostrand Co., 338 p. 



British Sulphur Corp., Ltd., 1966, World survey of sulphur 

 resources: London, British Sulphur Corp., 135 p. 



Cote, P. R., 1971, Sulphur, in Canadian minerals yearbook, 

 1969; Canada Dept. Energy, Mines and Resources 

 Mineral Resources Div., Mineral Rept., p. 485-496. 



Davis, J. B., 1967, Petroleum microbiology: Amsterdam, 

 London, New York, Elsevier Pub. Co., 604 p. 



Davis, J. B., and Kirkland, D. W., 1970, Native sulfur deposi- 

 tion in the Castile Formation, Culberson County, Texas : 

 Econ. Geology, v. 65, no. 2, p. 107-121. 



