STRATIGRAPHY AND SOILS OF FLUVIAL TERRACES ON THE CATAWBA RIVER, NC AND SC: LANDSCAPE EVOLUTION OF THE SOUTHEASTERN US
1 online resource (171 pages) : PDF
University of North Carolina at Charlotte
Few studies provide data that can document the long-term landscape evolution of the Piedmont of the southeastern United States. Here we present the results of field mapping and a soil chronosequence for fluvial terraces along a ~46 km reach of the Catawba River, NC and SC. Five terrace units (Qt1 – 5) have been mapped along the reach, and in certain regions a sixth surface (Qt0) was mapped. Observations of bedrock surfaces on Qt3 – Qt0 confirmed that these units are strath terraces. Longitudinal profiles of terrace units constructed from mapping data revealed static channel convexities in Qt5 – Qt1 in the lower reach of the study area at Landsford Canal State Park, and a lack of an obvious influence on terraces profiles within the Gold and Silver Hill shear zones in the middle reach. Age dating of terraces in this study included deriving ages based on surface height above the channel (Mills, 2000) and IRSL samples obtained from Qt3 exposures. Ages, reported in ka, are as follows: Qt0 - 4591 ± 404 ka, Qt1 - 1852 ± 365 ka, Qt2 - 1181 ± 194 ka, Qt3 (average of two IRSL ages) – 142 ± 32 ka, Qt4 – 50 ± 8 ka, and Qt5 – 5 ± 2 ka. Up to 3 soil pits were dug on each terrace unit Qt5 – Qt2, and soils described as per Birkeland (1999). Chronofunction trends of soil morphological properties include soil colors in the most developed B horizons reddening and clay films increasing in amount and prominence with surface age. Soil samples were analyzed for particle size, pedogenic iron (AAS), bulk density and major elements (XRF). Some of these analyses show expected trends with respect increasing surface age for terraces of the Catawba River, such as increases in clay content (%) and decreases in iron activity ratios in most weathered B horizons with increasing surface age. Overall the history Catawba River is one of five distinct periods of lateral planation of the valley, possibly driven by transitions to interglacial periods, punctuated by periods of incision, whose cause is currently unknown. The soil chronosequence, ages, and data derived from mapping, however, provide a strong foundation that can be used in further studies of the long-term landscape evolution of the SE Piedmont of the SE United States.
Diemer, JohnBobyarchick, Andy
Thesis (M.S.)--University of North Carolina at Charlotte, 2018.
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