Refining The Geologic Time Scale An Integrated Biostratigraphic

Refining The Geologic Time Scale: An Integrated Biostratigraphic Approach Black Knob Ridge, OK: Graptolites Chitinozoans The GSSP for the Katian Stage of the Upper Ordovician Series one ca us Z udat nis bicor Zone Conodonts

Refining The Geologic Time Scale: An Integrated Biostratigraphic Approach Trail Creek Summit, Idaho Graptolites Sil / Ord Little Fall Creek, Idaho Graptolites = conodont collection Conodonts The Phi Kappa Formation can be integrated into a regional composite that represents one of the biostratigraphically longest and most complete exposures of Ordovician rocks in the world.

Year 1 Summary A) Black Knob Ridge Ø An integrated biostratigraphic framework that allows for precise global correlation was developed in Upper Ordovician rocks at Black Knob Ridge. This section was chosen as the Global Stratotype Section and Point (GSSP) for the base of the Katian Stage of the Upper Ordovician Series. Ø Conodonts collected from shale bedding surfaces at BKR suggest that the Climacograptus bicornis - Diplacanthograptus caudatus zonal boundary is located in the B. alobatus subzone of the Amorphognathus tvaerensis conodont zone. B) Trail Creek Idaho Ø The Trail Creek graptolite faunas have strong affinities with Australasian and Chinese successions. ØConodont assemblages are common on some bedding plane surfaces. ØThe Phi Kappa Formation can be integrated into a regional composite that represents one of the biostratigraphically longest and most complete exposures of Ordovician rocks in the world.