4 Devonian and Mississippian Strata of the Midcontinent North America: Sequence Stratigraphy, Paleontology, and Hydrocarbon Potential (Gas Shales, Carbonates, Cherts)

Sunday, 11 April 2010
1:30 PM - 4:25 PM
Cooper Creek 3

DIACHRONOUS PROGRADING CARBONATE WEDGES FROM THE BURLINGTON SHELF TO THE SOUTHERN DISTAL SHELF/BASIN IN THE SOUTHERN FLANKS OF THE OZARKS

Paper number: 4-2
Program: Theme Sessions
Time: 1:50 PM – 2:10 PM

Authors

Abstract

Thompson 1970 documented the first occurrence of a diachronous prograding shelf based on the Lower Mississippian-Osagean Pierson through the Burlington-Keokuk strata of the Ozark regions in SW Missouri, NW Arkansas, and NE Oklahoma.  In ascending order the following conodont zones are recognized in Osagean strata of North America: communis carina Zone, multistriatus Zone, anchoralis-latus Zone, distortus Zone, mehli Zone, bulbosus Zone, and the texanus Zone.

    In the Springfield Missouri region and northwards the Pierson  Formation is directly overlain by the “Burlington-Keokuk” Limestone.  In these regions the Pierson contains the communis carina Zone and the lower multistriatus Zone then the base of the Burlington-Keokuk is upper multstriatus Zone.  Southward from the Springfield region the Pierson expands in stratigraphic thickness and an additional formation (Reeds Spring-Elsey) occurs beneath the Burlington-Keokuk. At the first locality south of this region (Branson-Baird Mountain Quarry) the top of the Pierson belongs to the anchoralis Zone and the Reeds Spring-Elsey contains distortus and mehli zones. Still further south at Marble Falls, Arkansas and the Type St Joe in Boone County, Arkansas the top of the Pierson contains distortus. Thus, the top of the Pierson becomes significantly younger to then south.

    In a southwesterly direction an identical pattern is seen. The top of the Pierson at Roaring River State Park  contains the bulbosus Zone and still further southwest at Jane the top of the Pierson is marked by the topmost Osagean zone texanus.   In this region the base of the “Burlington-Keokuk” is younger texanus Zone making it younger than the base of the type Keokuk in Iowa.

    In summary, the change in age is due to prograding wedges from the shallow water high energy Burlington Shelf to the lower energy distal shelf to basin to the south and southwest.