A Petrographic Examination of Early Ceramic Crushed Rock Tempers

Author(s): Ammie Mitchell

Year: 2016


As part of her ongoing dissertation research, the author conducted a series of experimental tests to examine the physical properties of coarse crystalline rocks. Common coarse crystalline rocks in the Northeast include granite, granodiorite, and gabbro. Earlier petrographic studies by the author identified these rocks as common tempering agents in early ceramic vessels in New York. The author hypothesized that these rocks were intentionally collected by potters from glacial land formations and the rocks were actively processed into temper through intense heating and crushing actions. Rocks may have been collected, placed and later recycled from high-temperature features, such as hearths and earth ovens for the purpose of creating temper. The null hypothesis of this study is that potters selected previously eroded and weathered rocks because they were easily obtainable and crumble with minimal effort into grit for temper. The author used petrography to examine individual mineral weathering, alteration and fracturing within each sample. Twenty coarse crystalline rock samples were fired in both closed kiln and open pit firing at various temperatures and durations. The minerals within the experimental samples were compared to archaeological samples of grit-tempered Vinette pottery from various sites across New York State.

Cite this Record

A Petrographic Examination of Early Ceramic Crushed Rock Tempers. Ammie Mitchell. Presented at The 81st Annual Meeting of the Society for American Archaeology, Orlando, Florida. 2016 ( tDAR id: 404318)

Spatial Coverage

min long: -80.815; min lat: 39.3 ; max long: -66.753; max lat: 47.398 ;