Comments on Geologic Parameters
05 Percent Shale:
Percent shale was also digitized from percent-sandstone maps of the upper, middle, and lower as defined by Galloway and others (1982), which provides an index to the heterogeneity of the system.
Galloway, W. H., Hobday, D. K., and Magara, Kinji, 1982, Frio Formation of the Texas Gulf Coast Basin—depositional systems, structural framework, hydrocarbon origin, migration, distribution, and exploration potential: The University of Texas at Austin, Bureau of Economic Geology Report of Investigations No. 122, 78 p.