Trace fossils from the Panther Member, Star Point Formation (Upper Cretaceous), Coal Creek Canyon, Utah

In the Panther Member of the Star Point Formation, Coal Creek Canyon, Utah, 19 types of trace fossils were documented ammong 13 ichnogenera: Ancorichnus, Chondrites, Cylinrichnus, Muensteria, Ophiomorpha, Palaeophycus, Planolites, Rossleia, Schaubcylindricus, Skolithos, Teichichnus, Thalassinoides and Uchirites. Stratigraphic, lithologic, and ichnologic data suggest sediment deposition in a regressive, offshore sequence. Conditions considered to be most typical of this offshore facies include: 1) moderately high behavioural diversity and intense activity by endobenthic animals, 2) thorough biogenic reworking of sediments, 3) slow, more or less continuous deposition of quartzose silt under quiet-water conditions, and 4) moderately stable substrates containing abundant organic detritus and fecal and pseudofecal materials. In addition, bed-by-bed analyses of trace fossil diversity, ethology and relative abundance revealed significant, albeit subtle differences in local depositional environments through time. The basal section represents the most distal sedimentation yet recorded among Panther sequences. Overlying beds indicate gradual shifts toward slightly nearer shore deposition, although interrupted by minor environmental variations. Even the most shoreward depositional sites remained well below effective storm-wave base, however.