PRELIMINARY RESULTS OF PALYNOLOGICAL STUDIES OF THE CHUGWATER GROUP (TRIASSIC), WYOMING

The body and trace fossil record of the Chugwater Group has been improving steadily over the last few years, but no new paleobotanical work has been presented in nearly a century. This study reports the first paleopalynological findings from the Triassic Chugwater Group in Wyoming. These data will help strengthen paleoecological interpretations and provide the first glimpse of the flora from the Middle Triassic strata of Wyoming. The lowest units of the Chinle Formation and Dockum Group are proposed to be temporally equivalent to, if not slightly younger than, the upper-most Chugwater, the Popo Agie Formation. The Popo Agie Formation possesses a unique vertebrate fauna, but only limited paleobotanical work on poorly preserved impressions has been done so far. Two deposits of the Chugwater Group have yielded plant microfossil samples. The first deposit, DMB, is the from the ‘unnamed redbeds’ (?Middle Triassic: ?Anisian), which are located along the Redwall near Arminto, WY. The second deposit, L01, is from the upper purple beds of the Popo Agie Formation (Late Triassic: ?late Carnian) at the Sinks Canyon Center, Lander, WY. We investigated our palynological samples with reference to the Chinle and Dockum palynofloras. Like these two paleofloras, our Chugwater palynoassemblages are dominated by bisaccates such as Alisporites and Pityosporites, and trilete spore forms resembling Dictyophillidites, Calamospora and Kyrtomisporis. Other palynomorphs such as Duplicisporites are also found. Further investigation will allow us to reconstruct the overall ecology of these strata.