110 KANSAS ACADEMY OF SCIENCE. 



ORIGIN OF GYPSUM, WITH SPECIAL REFERENCE TO THE 

 ORIGIN OF THE MICHIGAN DEPOSITS.^ 



By Q. P. Geimsley, Assistant State Geologist, Morgantown, W. Va. 

 Read before the Academy, at Topeka, December 31, 1904. 



A VARIETY of theories have been advanced at various times to 

 -^-*- explain the origin of gypsum in various parts of the world. In 

 order to arrive at a satisfactoj^y explanation of the gypsum deposits 

 in the state oi Michigan, it may be well to give a resume of these 

 different theories. 



DEPOSITION OF GYPSUM BY ACTION OF SULFUR SPRINGS. 



Gypsum is deposited directly by some thermal springs, as in Ice- 

 land,^ where the mineral is formed by the decomposition of volcanic 

 tufa by acids dissolved in the water. The sulfurous acids become 

 oxidized to sulfuric acid, and thus convert the carbonates, especially 

 of lime and magnesia, into sulfates. Then, through evaporation, 

 the sulfate of lime is deposited, forming layers of fibrous and selen- 

 itic gypsum. 



Small gypsum deposits are found about the fumaroles of craters 

 and lava streams^ in Hawaii, where sulfurous acid (SO3) is con- 

 verted into sulfuric, and attacks rocks which contain lime. The 

 gypsum concretions in the Harz mountains are regarded as due to 

 action of sulfur vapors on lime. Dana explains the origin of part of 

 the New York gypsum as a secondary mineral, formed by the altera- 

 tion of limestone by action of sulfuric acid; the sulfuric acid 

 coming from sulfur springs by oxidation of the sulfuretted hydro- 

 gen. Such springs are to be found in New York, especially about 

 Salina and Syracuse. 



According to the French geologist Lapparent, the large deposits 

 of gypsum and anhydrite at Montiers, Bourg, and Saint Maurice, in 

 the western Alps and Switzerland, are due to a similar transformation 

 of lime. According to Lyell, the thermal waters of Aix, in Savoy, in 

 passing through the strata of Jurassic limestone, turn them into gyp- 

 sum. The springs of Baden, near Vienna, deposit a fine powder 

 composed of a mixture of gypsum, sulfur, and muriate of lime. 



Mr. R. S. Sherwin presented a paper before this Academy in 1901 

 in which he gave a series of arguments for this mode of origin of the 

 Oklahoma gypsum deposits. 



1. Published with permission of the director of the Michigan Geological Survey. 



2. Annalen der Chem. 1847, Bunsen. 



3. Iowa Geological Survey, vol. 12, p. 116, 1902. 



