Document Type
Thesis
Abstract
Over time the James River has been eroding its channel leaving behind remnants of ancient floodplains as fluvial terraces. Mapping terraces along the banks of the James River in Goochland and Powhatan Counties may offer some clues to the late stage geomorphic evolution of the river. Identification of terrace deposits was based largely on soil type and surface topography. Four terrace levels are distinguishable based on elevations of the terrace tread and strath assuming that the longitudinal profile of the river has remained constant over time. The oldest terrace level, Tg1, occurs between 218 and 283 feet above the current river profile. The Tg2 terraces occur between 170 and 253 feet above the river, while Tg3 terraces are located at altitudes 116 and 200 feet above the river. The lowest terrace level mapped, Tg4, occurs between 70 and 142 feet above the river. Terraces are concluded to be depositional based on the thickness of the deposits and represent four major cut and fill periods of the James River. Previously estimated ages of terraces along the James River to the west of the mapping area were used to calculate minimum incision rates of the James River. The rates range from 3 +/- 1 meters/million years to 8 +/-4 meters/million years over the last 13 million years.
Date Awarded
2001
Department
Geology
Advisor 1
Gregory S. Hancock
Recommended Citation
Johnson, Willow, "Fluvial Terraces of the James River, Powhatan and Coochland Counties, Virginia" (2001). Geology Senior Theses. William & Mary. Paper 84.
https://scholarworks.wm.edu/geologyseniors/84