Selected geochemistry and mineralogy of Paleozoic strata in northern and central Appalachian basin, U.S.A., 1994-2012

Publication Date

2017-12-07

Start Date

2007-01-01

End Date

2012-12-31

Enomoto, C.B., Dulong, F.T., and Milici, R.C., 2017, Selected geochemistry and mineralogy of Paleozoic strata in northern and central Appalachian basin, U.S.A., 1994-2012: U.S. Geological Survey data release, https://doi.org/10.5066/F7KW5DZ8.

Organic richness and thermal maturity data for source rocks help predict the amount of oil and/or gas that may be generated and provide the fundamental information for resource evaluation. Various indicators are used to assess the thermal maturity of source rocks; Tmax is one of the prime Rock-Eval measurements used for determination of thermal maturity. Certain parameters, such as the Hydrogen Index (HI) and the Production Index (PI), are derived from the Rock-Eval pyrolysis measurements and also provide a general indication of the source rock maturity. Other evaluation methods for assessing thermal maturity include vitrinite reflectance (%Ro), the thermal alteration index (TAI), and conodont alteration index (CAI). In general, measured Ro reported as “indigenous” or as “edited population groups,” together with the number of measurements per sample, can be considered the most reliable representation of thermal maturation. Calculated Ro values are considered to be approximations, and Ro values corrected for suppression utilize the methodology of Lo (1993) to correct for anomalously low values of vitrinite reflectance. Semi-quantitative mineralogy data may help determine the depositional environment, thermal maturity, and fracability of these formations.

• Geology, Energy & Minerals (GEM) Science Center
• USGS Data Release Products