Quaternary stratigraphy and pedology of Clear Creek watershed in Iowa County, Iowa

Abstract

the geomorphic surfaces of Iowa has been dominated by fairly recent glacial action during the Pleistocene (Prior, 1991). The Pleistocene is defined by geologists as the time from about 2.6 million years ago until the end of the most recent ice age, about 10,000 years BP (Gibbard et al., 2005). The Quaternary period refers to both the glaciations during the Pleistocene and the period up to the present, the Holocene (Prior, 1991). Large continental glaciers advanced into Iowa many times during the Pleistocene. The periods of glaciation can be broken into periods according to age. The pre-Illinoian glaciation is the oldest, occurring from about 600,000 to 2,200,000 years ago (Boellstorff, 1978; Hallberg and Boellstorff, 1978). The pre-Illinoian glaciations were once known as the Nebraskan and Kansan stages, with the Aftonian interglacial period separating the two. These stages have been combined into the pre-Illinoian due to confusion about the number of glacial deposits present (Hallberg, 1980a). The Illinoian advance is the next oldest at

From soilscapes to landscapes: A landscape‐oriented approach to simulate soil organic carbon dynamics in intensively managed landscapes

“…The simulated BD values ranged between 0.92 to 1.40 g/cm 3 . This is in good agreement with observed BD values of 0.90 to 1.40 g/cm 3 , gathered from a collection of past and current research conducted within the study site [ O ’ neal , ; Papanicolaou et al ., ; http://criticalzone.org/iml/infrastructure/field-area/clear-creek-watershed].…”

“…The time series covers the period from 1930 to 2010 to reflect initiation of tillage. Field measurements of soil bulk density from the study watershed ranged from 0.90 to 1.48 g/cm 3 , which are in good agreement with simulated values [ Papanicolaou et al ., 2008; O ' Neal , ].…”

Bank erosion processes in streams in the U.S. Midwest

“…The two study sites, have been strategically selected because they represent dissimilar bank soil properties and correspond to different hydrologic regimes with implications on the frequency in which bank erosion occur and the magnitude of bank retreats at the two sites (e.g., Oneal, 2009;Wilson et al, 2012;Sutarto et al, in press). Clear Creek, at site 1, is a 2 nd order stream, whereas, at site 2 is a 4 th order (Abaci and Papanicolaou, 2009).…”

“…The bank soils in Clear Creek watershed area consist of a deep layer of glacial till overlain by a thin layer of silty colluvium or silty alluvium (e.g., Oneal, 2009). The bank soils tend to be dark gray to brown, noncalcareous, silt clay loam or loam that are associated with the Holocene channel belt of the Iowa River valley (Bettis, 1995).…”

“…Veeraraghavan (2007) for sites exhibiting relatively similar properties. For example, Lohnes et al (2001) reported values ranging between 6.91 ± 4.19 kPa and 7.65 ± 5.59 kPa, respectively, for loess with high plasticity and glacial till deposits found in Iowa (Prior,1976;Lohnes et al, 2001;Yang et al, 2005;Oneal, 2009). Yang et al (2005) reported values in the range of 2.7 to 12 kPa for glacial till soils with a texture of silt clay loam extracted across six (6) counties in southern Iowa.…”