Document Type
Thesis
Abstract
The Roanoke Rapids Terrane, containing metasedimentary and metavolcanic rocks, also includes a small pluton in the Purdy 7.5’ quadrangle composed of medium grained grey rocks. These rocks consist mainly of quartz and plagioclase along with trace minerals hornblende, epidote, and biotite. All of the samples contain no K-spar with the exception of two samples taken from a probable shear zone. All rocks modally classify as tonalites. Chemical analysis of the rocks categorize two of the samples as trondhjemites, while all samples consist of SiOz ranging from 60-66%, and K20 <2%. This is not typical of granites and is unlike the reported compositions of the Petersburg granite. This could be the remnants of a volcanic arc setting during sea floor subduction, directly related to quartz keratophyres of the Roanoke Rapids Terrane.
Date Awarded
2010
Department
Geology
Advisor 1
Brent E. Owens
Recommended Citation
Hess, Steven P., "Petrology of a Possible Trondhjemitic Pluton in the Roanoke Rapids Terrane, Virginia" (2010). Geology Senior Theses. William & Mary. Paper 231.
https://scholarworks.wm.edu/geologyseniors/231
