(tyafite* 5 



INSOLUBLE 

 RESIDUES 



H. A. Ireland 



An insoluble residue may be defined as the material remaining after rock 

 fragments have been digested in acid. Hydrochloric acid is generally used, but 

 acetic acid is occasionally used if the preservation of delicate fossils or other 

 structures is desired. Residues, such as shale, pyrite, gypsum, anhydrite, and 

 glauconite, are not siliceous; therefore, the term siliceous residues cannot be 

 applied correctly. The chief residues are quartz and various types of chert, with 

 chert the most diagnostic for identification and correlation. 



McQueen (1931) and Martin (1931) published methods of preparation, 

 terminology, and practical application of insoluble residues to surface and 

 subsurface correlation and identification of calcareous rocks. The work of 

 Martin is not known so well as that of McQueen although it is a significant 

 contribution. Ireland (1936) expanded the application of insoluble residues to 

 a regional basis by correlating outcrops in the Arbuckle Mountains through the 

 subsurface to outcrops in northeastern Oklahoma and adjacent areas. The use 

 of insoluble residues was not widespread prior to 1938. After 1940 rapid ad- 

 vances were made with the application of residue work to petroleum geology. 

 The United States Geological Survey and many state surveys now have 

 numerous publications based wholly or in part on insoluble residue work (for 

 a comprehensive list of publications and active workers who have not published 

 see Ireland, 1947) . A diversity of nomenclature resulted because most of the 



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