Quantifying past hominin interactions with earth’s surface using the mass flux of artifacts
Abstract
Past and present hominin interactions with the environment have altered the production, erosion and storage of mass on Earth’s near-surface environment – the Critical Zone (CZ). Modeling hominin interaction with modern and paleo-CZs requires that we develop suitable proxies that track changes in mass transfer over time. Artifacts, hominin-modified material remains, serve as a suitable proxy for the direct mass transfer in paleo-CZs. This paper begins with the idea that artifacts and the archaeological record are a component of the CZ. It builds off previous archaeological and geomorphological concepts and argues that the artifact system (archaeological record) and an artifact mass-flux calculation can quantify the archaeological record in such a way that provides rate-estimates of hominin mass addition to CZs over time. The optimal approach requires precise mass and/or density measurements of artifacts recovered from well-dated and spatially-defined archaeological sites. Artifact mass-flux calculations for a ~0.0035 Ma archaeological stone tool site (Vineyards) from northeastern USA yield fluxes of 2.32*10−7 g cm−2 yr−1 based on surface collection results and 2.76 ± 6.11*10−7 g cm−2 yr−1 based on the median value of 91 shovel test pits. Simulations suggest that this latter value is a representative artifact mass flux for the site and could serve as a basis for comparison with mass flux values from other sites. Factors that place limits on these calculations include uncertainty in mass, reservoir and residence time estimates, the complexity of site-reuse and issues of site formation (i.e., post-depositional processes). The Vineyards artifact mass addition is well below the mean geologic erosion rate (mass loss) and suggests that the indigenous people at Vineyards did not discard inorganic mass ~3,500 years ago in a manner that exceeded background CZ processes of mass loss. Prehistoric mass transfer of lithic artifacts in this example do not have a pronounced impact on mass transfer at Earth’s surface. A quantified artifact system could add insight into the on-going debate of when and where on Earth’s surface the Anthropocene occurred.
Publication Title
Zeitschrift fur Geomorphologie
Recommended Citation
Stinchcomb, G. (2018). Quantifying past hominin interactions with earth’s surface using the mass flux of artifacts. Zeitschrift fur Geomorphologie, 62 (1), 57-71. https://doi.org/10.1127/zfg/2018/0585
