CONODONT BIOSTRATIGRAPHY OF MARINE UNITS ABOVE THE TYPE TEBO COAL, HENRY COUNTY, MISSOURI

Historically the coal below the Tiawah Limestone has been called the Tebo Coal. The base of the coal is just above the lower sequence boundary of the Tiawah cyclothem of Oklahoma and Kansas, with the upper sequence boundary at the base of the overlying “Scammon” (Carruthers Coal of Iowa) Coal. In Missouri the Tebo Coal is placed at the top of the Tebo Formation, underlying the “Scammon” Formation. The type section for the Tebo Coal is along the West Fork of Tebo Creek, north of Lewis, Henry County, Missouri.

In 2009, Hanley described the marine units above the “Scammon”/Carruthers Coal as having the conodont Gondolella cf. pohli, a smooth platformed Pa element variant of G. pohli in which the platform is tapered on both ends, dominating over G. pohli. The next higher occurrence of abundant Gondolellas is in the Oakley Shale above the Croweburg Coal (Verdigris cyclothem), the fourth cycle above the “Scammon”/Carruthers (Upper Tiawah) cyclothem. Preliminary evidence from Iowa, indicates the Oakley Shale has G. pohli dominating over G. cf. pohli. A few Gondolellas are found in the post-Fleming marine units (the first cycle below the Verdigris), and above the stratigraphically lower Inola Limestone (Hackbery Branch Limestone of Missouri), above the Bluejacket Coal. The marine units directly overlying the Tebo Coal have never been known to contain Gondolella in the Midcontinent.

We have discovered that the black, fissile, phosphatic shale above the Tebo Coal at its type section, contain abundant Gondolellas with G. cf. pohli dominating over G. pohli. The preliminary conodont evidence indicates the type Tebo is equivalent to the “Scammon”/Carruthers coal, the next cycle above the historic Tebo. More stratigraphic and conodont work needs to be carried out in the Tebo type area to verify the exact cyclothem to which the type Tebo belongs, as in the past, the Tebo Coal has been correlated to the Croweburg Coal of the Verdigris cyclothem.