As used in the PDMS, a Geologic Unit is a general term that encompasses formally recognized stratigraphic terminology mixed with some informal petroleum and coal industry terminology. The physical petroleum records on file at the IGS have been collected for nearly 100 years, and over that time stratigraphic terminology has evolved. Some "outdated" terminology, both formal and informal, is still used by the IGS Subsurface Geology Section to maintain continuity within records.
In the PDMS, the term "formation" is generally used in informal petroleum industry parlance to refer to any named stratigraphic interval, and does not necessarily coincide with the use of the term "formation" as formally defined by the Stratigraphic Code.
See the Chart Showing Stratigraphic Terminology Used in the Indiana Geologic Survey's Petroleum Database Management System (PDMS).
See also, the Geologic Names Information System for a detailed explanation of stratigraphic terminology used in Indiana.
Keywords:
Stratigraphy
Stratigraphic Terminology
Stratigraphic Term
Formation
Formation Top
Pick
Strat Pick
StratPick
Geologic Name
Geologic Names