Kansas Geological Survey, Current Research in Earth Sciences, Bulletin 240,
Chert Gravel and Neogene Drainage in East-central Kansas--page 14 of 15
Based on this study of chert gravel, the following conclusions can be drawn:
- The Flint Hills were much less prominent and did not form a major drainage divide during the Neogene.
- Considerable erosion has occurred across all of eastern Kansas with up to 80 m (260 ft) of dissection during the Quaternary. The Flint Hills emerged at the same time as terrains to the east and west were eroded down.
- Exotic pebbles in chert gravels of eastern Kansas were derived from Tertiary and Cretaceous sources west of the Flint Hills.
- Modern rivers within the study region bear little resemblance to the oldest recognizable drainage routes.
- Regional valley asymmetry may be the result of long-continuing crustal tilting downward to the south and east.
I have benefitted from discussions with many colleagues, especially P. Berendsen, L. L. Brady, J. W. Harbaugh, P. L. Johnston, D. F. Merriam, and F. W. Wilson. The presence of exotic pebbles in chert gravel was first shown to me by W. Dort, Jr. Many students have contributed to the GIS compilation of data for this report: R. D. Byerley, M. Husain, R. Krueger, T. Peterson, L. L. Rand, R. O. Sleezer, and N. H. Wilkins. M. J. Guccione, J. Ratzlaff, and C. W. Martin reviewed an earlier version of this article and offered many valuable suggestions for improvement. I offer my thanks to all these individuals. This research was supported by grants from Kansas Geological Survey, Kansas Department of Wildlife and Parks, NASA, and Emporia State University.
Kansas Geological Survey
Web version March 18, 1998