RE-EXAMINING THE PAST: COAL FROM THE COOS BAY, 70 YEARS LATER

Coal petrography has advanced significantly since Reinhardt Theissen and James Schopf pioneered the use of thin-sections to examine coals from Coos Bay Oregon. Thin-sectioning and examination of coals under transmitted light is becoming a lost art. To preserve this art, a re-examination of the Coos Bay thin section collection was undertaken. This particular collection was chosen in part because of the abundance of fungal material reported by Schopf. Fungal material in coal and its association with huminite/vitrinite macerals provides important information about the decompositional history of the coal and allows coal dominated by oxic processes to be differentiated from coal dominated by anoxic processes. In the Coos Bay samples, oxic intervals were dominated by oxic conditions and contain well-preserved fungi, including spores, sclerotia, and hyphae. Anoxic intervals contain no fungi. Where hyphae are present, the surrounding huminite macerals show unusual darkening. While darkening can be related to varations of section thickness, no thickness variations were noted in these cases.