TIMING AND SOURCE RELATIONSHIPS OF CAMPANIAN STRATA, KAIPAROWITS AND HENRY MOUNTAINS BASINS, SOUTHERN UTAH

The Henry Mountains and the Kaiparowits basins of southern Utah contain thick Campanian sequences. A proposed correlation between the “beds on Tarantula Mesa” in the Henry Mountains basin and the lower part of the Kaiparowits Formation in the Kaiparowits Basin has been suggested. A detailed petrologic and stratigraphic analysis was undertaken to determine if the two basins were sourced at the same time and with the same provenance. This study focuses on the relationship between the Tarantula Mesa Sandstone and the overlying “beds on Tarantula Mesa” in the Henry Mountains basin (~65m thick) and the capping sandstone member of the Wahweap Formation and the overlying Kaiparowits Formation in the Kaiparowits basin (~105m thick) with the goal of determining if the proposed correlation is correct. Distinctive, well-rounded, recycled eolian quartz grains in the capping sandstone member of the Wahweap Formation are absent in the overlying Kaiparowits Formation suggesting a change in source. The Tarantula Mesa Sandstone lacks eolian quartz grains yet they are present in the overlying “beds on Tarantula Mesa.” The arkose to lithic arkose sandstones of the Wahweap Formation and “beds on Tarantula Mesa” also are compositionally similar as compared to the litharenite sandstones of the lower part of the Kaiparowits Formation. The lithologic similarity of the capping sandstone member of the Wahweap Formation and the “beds on Tarantula Mesa” are further supported by shared east-southeast trending paleocurrents. This study suggests that the original correlation was incorrect and that the capping sandstone member of the Wahweap Formation and the “beds on Tarantula Mesa” were sourced by the same river system at the same time.