Using hearths for temper: petrographic analysis of Middle Woodland charcoal-tempered pottery in Northeast Florida

Charcoal-tempered pottery is uncommon in North America, but was produced with notable frequency in Northeast Florida from ca. AD 300–600. Thirty-six thin sections of pottery were analyzed by petrographic analysis and compared to 10 clay samples in order to characterize the paste of charcoal-tempered wares in terms of charcoal and mineralogical composition and abundance, assess the number of clay sources used to make the pottery, identify the species of wood represented in charcoal inclusions, and infer techniques of ceramic production. This analysis identified four temper categories, three texture groups, and three distinct clay resources used to make charcoal-tempered pottery, all of which were likely local to Northeast Florida. Identified wood taxa include pine (Pinus sp.), cedar (cf. Juniperus sp.), cypress (cf. Taxodium sp.), and sassafras (Sassafras albidum), with pine suspected to be the most common. These genera of charred wood, which exhibit minimal shrinkage in the samples, along with the prevalence of bone and grog inclusions, indicate that hearth contents were processed as temper, sometimes in combination with quartz sand. Potential reasons for the use of hearth contents as temper are considered.

► Charcoal tempered pottery was examined by petrographic analysis.
► Charcoal and mineralogical composition and abundance was recorded.
► Number of clay sources was inferred from natural inclusions in clays.
► Identified wood taxa include pine, cedar, cypress, and sassafras.
► Charred wood, bone and grog indicate that hearth contents were added to paste.