Paleoecology and biostratigraphy of early Mississippian foraminifera and carbonate petrology and sedimentology of strata from southern Idaho, western and north-central Wyoming.

摘要

The Early Mississippian Strata of southern Idaho, western, and central Wyoming were deposited on a warm carbonate shelf or platform. After deposition, the strata underwent deformation during the Sonoma, Sevier and Laramide orogenies culminating in uplift which exposed the strata to view. The three sections studied for this dissertation are located at Gardner Canyon, south-eastern Idaho, Strawberry Creek, western Wyoming, and Little Tongue River, north-central Wyoming.;The Gardner Canyon strata consist of lime mudstones, wackestones, packstones and grainstones deposited predominantly above stormwave base. Strawberry Creek rocks were deposited in deeper water and consist of pelletal lime mudstones and wackestones at the base, and fossiliferous lime wackestones packstones and grainstones at the top. The Little Tongue River section is dominated by dolo grainstones with small amounts of intercalated oolitic and pelletal lime packstones and grainstones.;The foraminiferal fauna, although of patchy vertical distribution exhibits a typical Early Mississippian assemblage. The Kinderhookian-Osagean foraminiferal boundary marker, Tuberendothyra tuberculata is found in the Strawberry Creek and Gardner Canyon sections, while the closely associated Spinotournayella sp. is found at Little Tongue River.;The Early Mississippian foraminifera from this area are found to have lived in shallow water environments usually above storm wave base and lacking crinoidal remains suggesting segregation via sedimentological or biological processes.