20 Geoarchaeology (Posters)

Thursday, 28 March 2019
1:00 PM - 5:00 PM
Carolina Ballroom

MINEROLOGY OF NATIVE WESTERN NORTH CAROLINA CLAYS USED IN CERAMIC STUDIOS

Paper number: 20-4
Program: Theme Sessions
Time: 1:00 PM – 5:00 PM

Authors

Abstract

Western North Carolina has a long and fascinating history with pottery and the materials used to make it, from Cherokee potters developing hand-building techniques and firing methods that are still used today, to Wedgewood Potteries harvesting kaolinite in Cowee, NC. Even among modern potters, many still endeavor to preserve the tradition and source their clays locally. This project investigates what makes local Western North Carolina clays useable in a ceramic studio setting. To achieve this, the minerology and physical characteristics of two native clays from Cherokee, NC, and Cowee, NC were analyzed. The two clays varied widely in physical behavior and use. Examining the minerology and physical behavior of these local, unprocessed clays can start to uncover how the mineral content affects the physical behavior of the clay, what the clays lack that could make them more viable, and what depositional environment yields a better studio ceramic.

At the start of this study, clay samples were harvested from the bank of the Little Tennessee River in Cowee, NC, and the bank of an unnamed pond in Cherokee, NC. These sites had been previously identified by local potters as sources of viable clays. The clays were then refined using traditional methods, made into thin sections, and evaluated using a polarizing microscope. The analysis revealed that both clays contained significant amounts of quartz, muscovite mica, kaolinite, and iron oxides. While the types of minerals in the two clays are virtually the same, the proportions and specific characteristics of the grains varied between the two samples. Overall, the Cowee clay was more practical for use in the ceramic studio largely due to its fine texture and balance of minerals (high kaolinite content, abundant mica and oxides, small amounts of quartz). Analysis of the Cherokee clay revealed that it lacked sufficient flux and plasticity. This clay could be amended with soda feldspar, which would lower the firing temperature, and bentonite clay, which would improve plasticity. Continued tests during the amending process would reveal the impact of adding incremental amounts of supplements to the clay bodies. This would further contribute to the understanding of what mineral characteristics and proportions make a local clay a viable studio ceramic.

Geological Society of America Abstracts with Programs. Vol. 51, No. 3

doi: 10.1130/abs/2019SE-327384

© Copyright 2019 The Geological Society of America (GSA), all rights reserved. Permission is hereby granted to the author(s) of this abstract to reproduce and distribute it freely, for noncommercial purposes. Permission is hereby granted to any individual scientist to download a single copy of this electronic file and reproduce up to 20 paper copies for noncommercial purposes advancing science and education, including classroom use, providing all reproductions include the complete content shown here, including the author information. All other forms of reproduction and/or transmittal are prohibited without written permission from GSA Copyright Permissions.