The Depositional Environments of the Jurassic Carmel Formation of Northeastern Utah

The Jurassic Carmel Formation of northeastern Utah was deposited during a major marine transgressive-regressive sequence with numerous alternating lithologies of minor, cyclically varying deposits that can be divided into three facies that represent distinct stages of deposition. The Lucerne Valley Facies represents the initial inundation of Carmel seas over dunes of the Glen Canyon Sandstone. Environments in the facies ranged from a broad supratidal flat to suspension deposits formed on the marine shelf below the wave base. The Boars Tusk Facies represents the initial regression of the Carmel seas. Environments of this facies are similar to the Lucerne Valley Facies except that an offshore carbonate bar and lagoon had formed in front of the prograding shoreline. The Dutch John Facies contains cyclical variations of supratidal intertidal environments and development of a sabkha that deposited thick, bedded gypsums with nodular gypsum and dolomite rhombs. These formed within the wet sediments around the edge of the sabkha. Regressive trends continued during Dutch John deposition until the sand dune and stream deposits of the Entrada Sandstone prograded over the Carmel Formation. The depositional characteristics of the Carmel Formation closely resemble the deposits along the modern day Persian Gulf which is proposed here as a modern correlative to the depositional environments of the Carmel Formation.