November Meeting
Farmer Brown's Steak House
Waterloo, NE
We will order from the menu, and each attendee is responsible for their own bill. Professionals, please remember to honor the NGS tradition and add a student to your bill!
Happy hour! (5:30pm)
Bring some cash and pick up your 2025 NGS Calendar!
Dinner & Program (6:00pm)
Program:
“Stratigraphy of the Graneros Shale and Greenhorn Limestone of Eastern Nebraska"
Jon Schueth, PhD, Assistant Professor, University of Nebraska - Omaha
Abstract: The stratigraphy of Cretaceous rocks in Eastern Nebraska has been enigmatic due to the lack of good outcrops, with the closest being exposures in central and northern Kansas. The lack of good rock data has led to rough correlations with known stratigraphy in Kansas and Colorado, but there has not been a detailed stratigraphic study of the Cretaceous in Nebraska to see how these units compare to the type sections elsewhere. I will describe new cores recently drilled by the UNL Conservation and Survey Division, and a few others discovered in their core depository, that have complete sections of the Graneros Shale and Greenhorn Limestone. The cores were described and had elemental geochemistry and calcareous nannofossil biostratigraphy done to assess their stratigraphy and depositional lithofacies. I will suggest that what is largely considered "Graneros Shale" in Nebraska is part of the Greenhorn Limestone. The Graneros contains heterolithic sandy and muddy units characteristic of deposition in a deltaic to pro-deltaic setting. The presence of sand in the Graneros makes it difficult to discern from the underlying Dakota Formation, and its gradational contact with overlying Greenhorn makes the upper contact equally difficult to determine. I will describe how the use of elemental chemostratigraphy and biostratigraphy helps to define these units clearly and place them in the broader regional stratigraphic context. I will then discuss how the Greenhorn differs from its equivalent strata elsewhere and the implications for that with regards to the Western Interior Seaway. Importantly, this study has updated our understanding of the Cretaceous of eastern Nebraska and finally starts to fill in the blank space on our understanding of the ancient Cretaceous seaway that once covered the state.
Business Meeting Agenda