Document Type
Thesis
Abstract
Jamestown was founded in 1607 along the James River estuary on the Virginia Coastal Plain as the first permanent English settlement in America. Archaeological digs at James Fort have unearthed numerous cobbles to boulders of andesite and limestone in the foundations and fireplace hearths of structures dating to 1611. These stones were not locally sourced in Virginia, but were ballast stones transported to the colony and then incorporated into structures. The purpose of our study is to determine the provenance of ballast stone at Jamestown and to provide a better understanding of the early English colonists’ voyages to the New World. We analyzed 13 ballast stones from the James Fort site for this study: 9 andesites and 4 limestones. Samples were analyzed using hand samples, thin sections, and whole-rock geochemistry. Andesite samples are porphyritic with 20-40% phenocrysts of plagioclase and hornblende in a glassy matrix. Samples contain 58 — 62% SiO2, ~17% Al2O3, and 6 — 7% Fe2O3 and plot as calc-alkaline medium-K andesites. The geochemistry of the Jamestown andesite ballast is similar to andesites from the Lesser Antilles particularly the islands of Martinique, Dominica, and Guadeloupe, which are known stops made by colonists en-route to Jamestown. Limestone samples are fine- to medium-grained unsorted biosparites with abundant Halimeda, bryozoans, mollusks, and gastropods. Limestone ballast at Jamestown is similar to Pleistocene/Holocene limestones in Bermuda and likely arrived with the Deliverance and Patience, the replacement ships for the Sea Venture that was wrecked in Bermuda in 1609.
Date Awarded
2015
Department
Geology
Advisor 1
Christopher M. Bailey
Recommended Citation
Watson, Kelsey D., "Provenance of Ballast Stone Used in Early 17th Century Foundations at Jamestown, Virginia" (2015). Geology Senior Theses. William & Mary. Paper 349.
https://scholarworks.wm.edu/geologyseniors/349
