PETCAL (version 2.1), an expanded personal computer compatible BASIC language for petrologic calculations, by Donald M. Hudson, 1988.

Explains the uses of the program, petrologic indices, commonly used magmatic series, and IUGS volcanic rock names; appendices contain the PETCAL program, sample output, and the PETDAT program; references.

Supersedes R28.

Open-File Report 88-3, 26 pages, 11x8.5", 6 b/w drawings, 2 tables, 3 appendices, $8.00