PRELIMINARY COMPOSITIONAL ANALYSIS OF HISTORICAL MATERIALS FROM EROSION-DESTROYED BUILDINGS ALONG THE MISSISSIPPI RIVER IN FULTON, TENNESSEE

Community dwellings along the Mississippi River in Fulton, Tennessee, have been collapsing since the late 19^th Century due to bank erosion. During droughts over the past decade, local citizens and archaeologists have collected historical remains from the site. This site appears to preserve multiple uses, each contributing artifacts. Despite these collections and observations, no geologic analyses of the artifacts have been conducted. Such analyses are useful because they provide important information about construction source materials and the community’s economic history.

To this end, we collected artifacts made accessible during the extreme drought of 2012. We performed X-ray fluorescence spectroscopy analyses on brick and mortar samples from destroyed homes that were constructed during the mid-to-late 19^th Century. Our preliminary results indicate that the mortar is composed of minerals rich in silica (57.17%), calcium (13.4%), and iron (6.6%), characteristic of Portland cement. Portland cement has been in use since the early 19^th Century and relies upon the dehydration of the mineral portlandite for strength. The local region likely provided a source of limestone and shale. The lack of sulfur in the analyses suggests the mortar predates the use of gypsum to slow setting times. Thin section analysis was difficult due to the intensely weathered nature of the sample, but relatively high aluminum (11.7%) and potassium (7.8%) content suggests addition of clay to the mix. The bricks, from Laclede Brick Company, are composed of high concentrations of silica (60.5%) and aluminum (23.4%). The brick source material was mined from clay pits outside of St. Louis, Missouri.