Paper No. 11-4
Presentation Time: 2:40 PM
MARKER BEDS AND STRATIGRAPHIC MEMBERS OF THE LOWER MISSISSIPPIAN STRATOTYPE IN THE NORTH CENTRAL SECTION ARE TRACEABLE TO THE ROCKY MOUNTAINS FROM ARIZONA TO ALBERTA
At Kaser Quarry, IA and Gray's Quarry the Burlington begins above a disconformity (K/O) below the Dolbee Creek Member (White Ledge oolite). The hiatus occured when isostatic rebound led to erosion of Db 2, Db1, the Meppen Member,and Fern Glen which are still present at House Springs. The limonitic Haight Creek Member base is a glauconitic hardground below the silty DB marker. Three grainstone cycles with silt partings are next. The middle of the member is soft, cherty and tripolitic with three grainstone beds and silty parting above. The CF/HC marker is a coarse unit between two silty dolomite beds. The Cedar Fork Member starts with four feet of oolitic grainstone then a glauconitic wackstone. The middle of the member is a dark silty band then solution breccias below three coarse cycles and a "Blue band (glauconite) at the top. The Keokuk Member starts above a disconformity with clasts, chert (Montrose) and the conodont (Gnathodus texana). The Keokuk continues with 6" white coarse bed (Keo 1) and two thick coarse cycles (Keo 2 and Keo 3 (Short Creek Oolite) with quartz grains. The Warsaw Member has a thick gray dolomite lower unit, limonitic dolomite with geodes and a cap bed of orange-red chert marker. This marker is seen across the stratotype to Mount Vernon, KY and to Winkleman, AZ below the Delle Phosphate.