Genesis of an Artifact Layer: Natural and Cultural Processes at the La Playa Archaeological Site, Sonora, Mexico - Reconstructing Human-Landscape Interactions: Interpreting Desert and Fluvial Environments - page 22

Keywords La Playa Sonora Mexico Artifact layer Deflation Fluvial
Early agricultural period
Introduction
Understanding landscape evolution of archaeological sites that record extended
human utilization and occupation is critical, especially with increasing interest in
assessing the role of paleoclimatic changes and the resulting impacts on human-
environment interaction. In particular, distinguishing deposits that are of a cul-
tural origin compared to those of an environmental origin is an important initial
step in a comprehensive site investigation. Site formation processes are exten-
sively discussed by Schiffer ( 1987 ), who distinguishes between primary (cultural)
and secondary (environment) processes in explaining the distribution of artifacts.
He defines cultural formation processes as the effects of human behavior on
artifacts and sites whereas non-cultural or environmental formation processes are
natural events that affect the distribution and condition of artifacts and features
(Schiffer 1987 ).
The western North American desert contains a long and rich record of human
occupation, one that is largely attributable to the arid environment and the superior
preservation of archaeological resources. Although archaeological sites occur in
nearly all ecosystems throughout the region, human settlements in the Sonoran
Desert were principally determined by the availability of water. This is particularly
salient to human-environment interactions during the Early Agricultural period
(3,700-1,900 cal BP) when humans began to modify the desert floodplains by
irrigating extensive field systems from reliable water sources (Mabry 1998 ).
Although this likely impacted the depositional process at many Early Agricultural
period sites, environmental processes were not completely controlled as large
flood events and extensive episodes of erosion have been documented to have
covered these field systems (Nials 2008 ). It is therefore important to identify the
human impact and subsequent response to these environmental challenges in
order to understand how landscape and human settlements evolved in this arid
environment.
This research project addresses questions regarding human-environment
interaction and the distinction between human versus environmental controls on
the resultant archaeological record as part of an on-going study at the La
Playa archaeological site (SON F:10:3), located in northern Sonora, Mexico.
Specifically, this research documents the extent and characteristics of a buried
artifact layer to better understand the interaction between landscape evolution,
surficial processes, and human activities that have modified the site since the last
occupation during the Trincheras period (1800-500 cal BP). The buried artifact
layer is a 2-6 cm interval that contains an assemblage of fire-cracked rock,
groundstone, pottery, projectile points, and human skeletal remains. Although