The Dendroarchaeology Of Cagle Saltpetre Cave: A 19th Century Saltpeter Mining Site In Van Buren County, Tennessee, U.S.A

Abstract

During the historic mining episodes at Cagle Saltpetre Cave, wooden leaching vats needed for the lixiviation of calcium nitrate from mined sediments (from which saltpeter was then produced) were constructed and used in the cave. When mining operations ceased, these features were abandoned and preserved in situ, some remaining virtually intact. Their remarkable preservation enabled tree-ring dating of timbers associated with these vats to be accomplished. Tree rings from oak planks used in the construction of the leaching vats were measured to 0.001 mm precision on a Velmex measuring system. Using COFECHA software, we crossdated the measurement series to both the Norris Dam State Park and Piney Creek Pocket Wilderness white oak reference chronologies, spanning the years from 1633 to 1982, obtained from the International Tree-Ring Data Bank. Graphical comparisons via scatter plots were inspected to ensure correct temporal placements. The final chronology developed from 39 dated series correlated very highly with the Norris Dam State Park reference chronology (r = 0.49, n = 170 yrs, t = 7.29, p < 0.0001) and verified that our site chronology extends from 1692 to 1861. The results of our analyses indicate that saltpeter was mined and processed at the site during separate episodes throughout the 19th Century. Additionally, saltpeter-processing technology changed throughout the course of the mining operations.