Coal from the Swash Zone--Herrin (No. 11) Coal in Western Kentucky: ABSTRACT

Abstract

The Herrin (No. 11) coal in the southern portion of Moorman syncline in western Kentucky represents an important resource with relatively consistent properties and thickness. To the north, however, subsurface information reveals that the position of the coal is occupied by a limestone across a narrow (less than 0.5 km or 1,600 ft), east-west transition zone. The Herrin is typically a bright, banded coal, with abundant vitrain and bright clarain, and has a parting, the band, in the lower third of the seam. Herrin coal from a core in the transition zone, however, is largely a coarse breccia with calcite cement. The blue band is present in its usual position as a slickensided clay rather than as indurated siltstone as at nearby sites. A fossiliferous limestone is present in the upper third of the seam. Breccia lithotypes are duller than would be expected in the Herrin coal, but do include fragments with the appearance of vitrain and bright clarain. Microscopically, however, the predominate macerals of the lithotypes are not vitrinite, as would be expected, but rather semifusinite. Vitrinite group macerals are frequently pseudovitrini e or forms showing signs of degradation. The presence of limestone offshore and as a parting within the coal and the pervasive calcite cementing between breccia fragments points to the strong influence of marine conditions on the peat. Nonbrecciated bands indicate that at least some of the seam is autochthonous. The breccia suggests a high-energy environment where peat fragments were ripped up in place or transported in from elsewhere. Any peat transport was probably along the strike of the transition zone. The peat was oxidized during fragmentation and transport, resulting in alteration of humic macerals to semifusinite and fusinite. End_of_Article - Last_Page 488------------