SEDIMENT PROVENANCE STUDY OF THE CRETACEOUS DAKOTA SANDSTONE AND MODERN KANSAS RIVER SEDIMENT AS AN INTEGRATED EXPERIENTIAL PROJECT IN THE UNDERGRADUATE MINERALOGY AND PETROLOGY COURSES AT KANSAS STATE UNIVERSITY

Sedimentary provenance studies provide undergraduate students with a way to apply key geoscience skills (e.g. observation and data manipulation/synthesis) while linking to aspects of coursework (e.g. mineralogy, petrography and geochronology). We developed a provenance-based project for the two-course, yearlong Mineralogy & Petrology sequence at Kansas State University focused on two different local clastic materials: Cretaceous Dakota sandstone and modern Kansas River sediment. The Dakota Fm. crops out across portions of KS, NE, IA, MN and SD; it was sampled at Coronado Heights, KS. Dakota sandstone grains were previously thought to be derived from western sources as the Western Interior seaway contracted, but a recent detrital zircon-based provenance study indicates their source was to the east (e.g., Appalachian Mtns.; Finzel, 2014). Kansas River sediment, from Manhattan, KS, is primarily sourced from western KS and eastern CO and includes a substantial component of reworked Cenozoic Ogallala Fm. sediment derived from crystalline rocks in the Rocky Mtns. Mineralogy students were tasked with identifying the mineralogy of the samples visually and using powder XRD analysis. Petrology students further classified the Dakota sandstone sample using standard clastic rock classification schemes. Splits of both samples were sent to the U of AZ for detrital zircon U-Pb dating; ca. 200 grains from each sample were analyzed. Ages for the KS river sediment range from 0.01 to 2.7 Ga, with prominent discrete peaks at 1.1, 1.4 and 1.7 Ga; Dakota Sandstone ages range from 0.29 to 2.8 Ga, with a broad peak spanning Grenville ages of 1.0 to 1.5 Ga. Students were then provided with the Finzel (2014) paper and asked to find other literature resources that would help them interpret the U-Pb ages and determine the provenance of the Dakota Fm. Students concluded that our new U-Pb ages agree with the interpretation of Finzel (2014) for the Dakota. This project required constant interaction between group members in both classes and culminated in the production of a GSA presentable poster in Petrology. Students experienced firsthand what it is like to solve geological problems by analyzing real-world data from analytical methods discussed in the classroom and by working together to make their own observations and conclusions.