Toolstohe Procurement Patterns on Wetherill Mesa, Mesa Verde, A.D. 600–1280

Abstract

Analysis of debitage from Wetherill Mesa in Mesa Verde National Park indicates dramatic changes in toolstone procurement patterns through time. For much of the early occupation of Wetherill Mesa, locally available igneous and indurated shale toolstones were the primary resources utilized. During the Pueblo II period, however, there was a shift to the use of Brushy Basin chert, which outcrops approximately 20 km away. By the end of the Pueblo II period, there is another change in procurement. Silicified mudstones from the Burro Canyon and Morrison formations, from approximately 10 km away, were used. These changes in toolstone provide important clues about the changing social landscape in the central Mesa Verde region over time. RESUMENAnalisis de retazos producidos en la elaboracion de herramientas provenientes de la Meseta Wetherill en el Parque Nacional Mesa Verde, indican cambios dramaticos en los patrones de adquisicidn de piedras para herramientas. Por la mayor parte de la ocupacion temprana del la Meseta Wetherill, rocas igneas y estilolita endurecidas, disponibles localmente, fueron la principal fuente de recursos utilizados. Sin embargo durante el periodo Pueblo II hubo un cambio a usar piedra silicea de la Cuenca de Brushy, que se encuentra aproximadamente a unos 20 km de distancia. Para el final del periodo Pueblo II hubo otro cambio en la adquisicidn de material. Piedras silicificadas del Canon del Burro y formaciones Morrison, ubicadas a 10 km, fueron utilizadas. Estos cambios en piedras para herramientas proveen indicios importantes sobre los cambios en el horizonte social, a traves del tiempo, de la region de Mesa Verde.

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

“…Previous studies indicate that toolstone procurement in MVNP and UMUR displays diversity by location and time period (Arakawa, 2006;Arakawa & Gerhardt, 2007; Figure 4, Table II). In MVNP, seven sites contained very large amounts of igneous (aphanitic minette) debitage during the Basketmaker III (BMIII) through Early Pueblo II (EPII) period, while procurement and utilization of indurated shale rapidly decreased from the Basketmaker III to Pueblo I period.…”

“…During the 1000s to 1100s (Late Pueblo II), these same inhabitants procured more Brushy Basin chert. During the late 1200s (Early Pueblo III-Late Pueblo III), lower-quality Morrison rocks (Jurassic Morrison silicified mudstone and Brushy Basin chert) were procured and used instead (Arakawa & Gerhardt, 2007). On the UMUR, the residents procured and utilized large amounts of igneous materials (aphanitic minette) during the late Pueblo II period, while the amount of Morrison materials increased slightly during the late Pueblo III period.…”

“…Although many quarries containing Jurassic and Cretaceous flakable sedimentary rocks and metamorphic materials are known in southwestern Colorado (Arakawa & Gerhardt, 2007), less is known of the occurrence of igneous aphanitic minette. In our research, we investigated possible igneous sources for both aphanitic minette and pottery temper materials in the central Mesa Verde region.…”

“…The lithic raw materials were derived primarily from Jurassic-and Cretaceous-age sedimentary formations and igneous intrusions. The sedimentary formations are exposed in the canyons of the central Mesa Verde region ( Figure 2) and contain many flakable lithologies, including quartzite, chert, chalcedony, silicified mudstone, and altered volcanic ash (Arakawa & Gerhardt, 2007). We divided the possible toolstone sources into the following categories for analysis: Morrison (Jm) rocks and Jurassic Brushy Basin chert …”

“…As part of a larger project to determine distances between lithic procurement and habitation sites in this region, Arakawa (2006) and Arakawa and Gerhardt (2007) found flakes of dense, black, aphanitic minette (micaceous basalt) present in collections of lithic debitage from seven habitation sites on Wetherill Mesa, Mesa Verde National Park, and nine sites on the Ute Mountain Ute Reservation ( Figure 1, Table I). Although many quarry sites for lithic materials in southwestern Colorado are known, heretofore there was not a known local source for these igneous flakes.…”