Document Type
Thesis
Abstract
This research project investigates where chert occurs in the Valley and Ridge and the amount of chert reflected in river sediments of the James River drainage basin. In the past, the James River may not have been draining the Valley and Ridge so indicator sediment from the Valley and Ridge would not show up in sediment records on the Coastal Plain until after the time when the James River breached the Blue Ridge. Chert is believed to be indicator sediment for the Valley and Ridge; the focus of this project is on the occurrence of chert in river sediments. Four tributaries to the James River were selected based on the general geology, chert-bearing versus non-chert-bearing units, in the tributaries drainage area. Originally the sites were chosen in pairs, two tributaries draining regions of primarily Cambro-Ordovician chert-bearing units and the other two draining regions of primarily Siluro-Devonian units. Three sediment samples were collected at each site and the medium grained sand fraction were grain mounted and point counted to see the amount of chert being reflected in the samples. Catawba Creek had the highest average percent chert: 3.50%, Craig Creek had an average percent chert of 1.34%, Maury River had 0.29%, and South River had 0.26%. No connection can be drawn from the average percentage chert of the medium grained sand fraction for river samples taken from the tributaries draining primarily Cambro-Ordovician chert-bearing units and those draining primarily Siluro-Devonian chert-bearing units because the anomalously high average percent chert from Catawba Creek skews the data from this pair-perspective. However, the results pair the tributaries a different way: samples taken on the tributaries flowing from the southwest have a higher average percent chert than those taken from the tributaries flowing from the northwest.
Date Awarded
2001
Department
Geology
Advisor 1
Heather MacDonald
Advisor 2
Gregory S. Hancock
Recommended Citation
Markman, Kristen, "Chert as an Indicator in River Sediments of the James River Drainage Basin, Valley and Ridge Province, Virginia" (2001). Geology Senior Theses. William & Mary. Paper 85.
https://scholarworks.wm.edu/geologyseniors/85
