Geoarchaeological investigation of lithic resources in the central Mesa Verde region, Colorado, USA

Abstract

An important question in Southwestern archaeological research is how social and economic ties between prehistoric groups changed through time. The chemical and mineralogical matching of stone tools and ceramics to source areas is one approach to addressing this question. Here we challenge the assumption that igneous rocks used for manufacturing stone tools and ceramics in the Mesa Verde region of Colorado were originally derived from the Chuska Mountains of New Mexico. Recent geological surveys suggest that small igneous features present in and around Mesa Verde National Park and Ute Mountain Ute Tribal Park contain similar lithologies and may represent a local source. We systematically visited seven of these igneous exposures and nine downstream gravel deposits, looking for geological sources and quarry sites matching the lithology of analyzed debitage from this region. Our results suggest that the ancestral Puebloans could have procured such igneous rocks as aphanitic minette and trachybasalt pottery temper from local areas. Because the trachybasalt is usually thought to have been imported from the Chuska Mountains, this discovery may require a revision of interpreted trade networks based on pottery temper and lithic raw material distinctions.

Petrographic and Geochemical Constraints on the Provenance of Sanidine‐Bearing Temper in Ceramic Potsherds, Four Corners Region, Southwest USA

“…The variability of textural features and chemical signatures in trachybasalt temper tend to support the hypothesis of Arakawa and Miskell-Gerhardt (2009) that ancient people who inhabited the region during the ninth to thirteenth centuries probably procured some raw materials from different rock sources rather than relying entirely on trade with the Chaco Canyon trade network. In spite of this, however, the petrographic data do provide evidence against Narbona Pass as a potential source, and the chemical data reveal that rocks exposed at Newcomb and Black Cone are not strong candidates.…”

“…In spite of this, however, the petrographic data do provide evidence against Narbona Pass as a potential source, and the chemical data reveal that rocks exposed at Newcomb and Black Cone are not strong candidates. The variability of textural features and chemical signatures in trachybasalt temper tend to support the hypothesis of Arakawa and Miskell-Gerhardt (2009) that ancient people who inhabited the region during the ninth to thirteenth centuries probably procured some raw materials from different rock sources rather than relying entirely on trade with the Chaco Canyon trade network. There is, however, no compelling evidence that constrains which particular source or sources of trachybasalt were used in the production of the pottery.…”

“…Rock samples used in these investigations, however, were collected at only 10 locations over a narrow geographical extent in the Chuska Mountains. Arakawa and Miskell-Gerhardt (2009) argued that poikilitic-sanidine trachybasalt exposed near Mesa Verde National Park in southwestern Colorado was another potential source of sanidine-bearing temper. Our regional investigations also reveal that poikilitic sanidine is found in rocks at numerous locations in the NVF (indicated by stars on Figure 2).…”