THE CO-OCCURENCE OF TRYPANITES AND GLOSSIFUNGITES SUBSTRATE-CONTROLLED TRACE-FOSSIL ASSEMBLAGES IN A TRIASSIC MIXED SILICICLASTIC-CARBONATE DEPOSITIONAL SYSTEM: BALDONNEL FORMATION, WILLISTON LAKE, BC, CANADA

摘要

Detailed outcrop analysis of an Upper Triassic, shallow marine, mixed siliciclastic-carbonate ramp succession in northwestern Canada reveals numerous disconformities that are characterized by substrate-controlled trace-fossil assemblages. Although Glossifungites assemblages, and to a lesser extent, Trypanites assemblages, are common in the Upper Carnian Baldonnel Formation, in several horizons, a pattern of paired Trypanites-Glossifungites-demarcated discontinuity surfaces occurs. These paired surfaces occur in the same overall environmental setting and are interpreted to have the same general stratigraphic implications in each case.