Trends in depth and extent of bioturbation in Cambrian carbonate marine environments, western United States

Cambrian carbonate strata of the Great Basin deposited below fairweather wave base but above mean storm wave base (inner shelf), and below mean storm wave base but above maximum storm wave base (middle shelf) were examined for extent and depth of bioturbation. Data indicate that initial extensive colonization of marine infaunal habitats occurred between Tommotian and Atdabanian time. Throughout the remaining 65 m.y. of Cambrian time bioturbation increased, although depth of bioturbation remained relatively constant at less than 6 cm. During this time, the amount of bioturbation in the inner shelf was greater than that in the middle shelf.