New Mexico Geological Society Annual Spring Meeting — Abstracts

Carthage and Jornada coal fields are both parts of the Jornada del Muerto Basin, New Mexico. However, because the basin has been intensely block-faulted, and because the areal distance between the two fields is sizable, a stratigraphic correlation between·the coals of Carthage and Jornadaby conventional methods without drill cores is difficult.

The coals of Carthage and Jornada occur in the Mesaverde Group. The assumption is made that the fields must have constituted a laterally continuous stratigraphic unit prior to the block-faulting that occurred in the Pleistocene. In this study, the petrology (petrographic composition, textures, vitrinite reflectance, and chemical composition) is used in an attempt to correlate the seams of the two fields. The following conclusions emerge from this work:

(1) Carthage lower coal bed (also known as the Carthage Bed) and Jornada lower coal seam have nearly identical petrographic and chemical compositions, and rank. They could be the same coal unit.

(2) Jornada and Carthage upper coal beds have also nearly identical petrographic and chemical compositions, and rank. These parameters are different from those observed for Carthage Bed and Jornada lower coal seam. Among other differences Jornada and Carthage upper coal seams are of lower rank than their analogs.

(3) The maceral content of the upper and lower seams are different enough to indicate different environments of deposition.