Pleistocene Drainage Reversal in the Upper Tuttle Creek Reservoir Area of Kansas

Abstract

A study of stream valley cross sections and longitudinal profiles indicates that the pre-Kansan drainage in the Upper Tuttle Creek Reservoir area was northward, from the Randolph Divide along a course now occupied by the Black Vermillion River, into an east-flowing pre-Kansan tributary of the hypothetical preglacial Grand River. The east-flowing tributary, now buried under 300 to 400 feet of Kansas Glacial Deposits, was part of a drainage system that included the east-flowing Little Blue and the south-flowing Big Blue Rivers.

During Kansan (Nickerson) time a lobe of the glacier blocked the eastward drainage of the Grand River and a proglacial lake formed in the tributary draining north from the Randolph Divide. Overflow from the lake was southward through a nickpoint in the divide. This reversal of drainage produced a 300 to 400 foot deep gorge across the Randolph Divide. Terraced bedrock of the gorge now buried under alluvium suggests two major erosional cycles. Additional evidence for more than one period of erosion is found downstream in the Lower Kansas River drainage below Manhattan where the Kansan, Illinoisan, and Wisconsin alluvial terraces have significant elevation differences. The nickpoint on the Randolph Divide, driven northward by headward erosion, currently appears to be in the vicinity of Blue Rapids.