Abstract: Multivariate Coal Rank Trends and Anomalies in the Eastern Kentucky Coalfield and Their Relation to Orogenic Fluids and Basement Features

COLLINS, STEVEN L.

The Kentucky Geological Survey provided data on 372 full bed channel samples representing 35 coal beds of Early and Middle Pennsylvanian (Namurian through Westphalin D) age. Principle components (PC) analysis was performed on eight rank parameters. PC scores were regressed on sample position, then rank anomalies were identified by mapping regression residuals (the actual PC score minus the score estimated by regression).

The first principle component (R1) explains 43% of the variance of the eight rank parameters. It has large positive loadings on mean maximum vitrinite reflectance, heating value, and free swelling index; and large negative loadings on volatile matter and elemental ratios O/C, H/C, and S/C. (N/C has a small loading.) Regression of R1 on easting, northing, and bed number (assigned to quantify stratigraphic position) explains 53% of the variance of R1. R1 increases toward S43(E and downward, as calculated from regression coefficients, consistent with the trend to greater burial depths. Ba, Sr, Mg, and Yb also increase southeastward within 5 degrees of S43E, and Na increases toward S51E.

R1 is anomalously high immediately northwest of the Pine Mountain thrust fault. This and the coincident directions of increase of elements expected to be present in orogenic fluids are interpreted as being the effects of hot orogenic fluids channeled under the Pine Mountain thrust fault as they moved northwestward during the Alleghany orogeny.

R1 is anomalously low over the Floyd County channel and adjacent parts of the Rome trough. Evidently thicker Lower Paleozoic shales insulated overlying Pennsylvanian coals from escaping heat.

AAPG Search and Discovery Article #90939©1997 AAPG Eastern Section and TSOP, Lexington, Kentucky