Abstract

Silurian fossil communities can be used as a tool to interpret depositional environments in the Great Basin. The Laketown Dolomite was deposited in a carbonate shelf sea along the Silurian margin of the North American plate. Initial deposition began in the Middle Llandovery and continued into the Wenlock. Shallow water communities include a time-sequence of pentamerid communities in shallow, rough water and a dasyclad algal community in shallow, calm water. Basins formed to the north and south of the Tooele Arch in the Late Llandovery. The northern basin was nearly filled by the end of the Late Llandovery. The southern basin continued to deepen during the early Wenlock, but was filled by the middle of the Wenlock. Analysis of communities from the basins reveal that the southern basin attained a greater water depth than did the northern basin. With increasing depth, brachiopod guilds were progressively more diverse while shell size and robustness decreased.