Sedimentology of historic and prehistoric deposits in the drainage basin of Deep River and Muddy Creek on the Piedmont of North Carolina.

详细信息   

• 作者：Spurgeon ; Victoria Leanne.
• 学历：Master
• 年：2000
• 导师：Kite, J. Steven
• 毕业院校：West Virginia University
• 专业：Geology.;Anthropology, Archaeology.;Agriculture, Soil Science.;Environmental Sciences.;Mineralogy.
• ISBN：0493126309
• CBH：1403356
• Country：USA
• 语种：English
• FileSize：3956451
• Pages：162

文摘

Deep River and Muddy Creek flow across a granitic and volcanic terrain intruded by diabase dikes in the Piedmont physiographic province of central North Carolina. Geoarchaeological and sedimentological investigation of these Piedmont streams included fourteen trenches dug at four floodplain localities. Soils in these trenches were described using standard soil taxonomy and sampled for particle-size, magnetic susceptibility, and mineralogical analyses.;Increased upland erosion rates, after European settlement, left more than a meter of historic sediments in some areas of the floodplains. A paleosol, indicated by an Ab horizon, records the floodplain surface at the time of European contact. This paleosol, dated by Coastal Carolina Research of Tarboro, North Carolina, was used to differentiate historic and prehistoric deposits.;Although historic and prehistoric sediments have similar sedimentological characteristics, there are trends that differentiate the two populations. Historic sediments have a coarser mean particle size than prehistoric sediments. Historic deposits show a general increase in magnetic susceptibility as particle size decreases from sand to silt; a trend not apparent in prehistoric deposits. Analyses indicate mineralogy varies with particle-size and that the trends in mineralogy are different for historic and prehistoric sediments. The combined chemical and mineralogical analyses show Fe2O3, MnO, TiO2, Al2O3, MgO, epidote, hornblende, and 14 ? clays are associated with high magnetic susceptibility in fine-grained historic sediments. Magnetic susceptibility is higher in the interval from fine sand to fine silt in the prehistoric sediments. The magnetic susceptibility in prehistoric sediments is associated with MgO, TiO2, MnO, CaO, Na2O, and hornblende. Epidote, 14 ? clays, Fe2O 3, and Al2O3 are associated with high magnetic susceptibility in the clay fraction.