Distribution and sources of secondary deposit archaeological obsidian in Rio Grande alluvium New Mexico, USA

Abstract

AbstractIn 2000, Tim Church published an excellent examination of the secondarily deposited obsidian in Rio Grande Quaternary alluvium for a relatively small section of the Rio Grande in southern New Mexico. Here, the goal is to complement Church's study to include six secondary deposits of a portion of the Rio Grande hydrological basin nearly 400 km in length, coupled with a comparison to 11 archaeological sites on or near the river basin. Additionally, the compositional and metric data on obsidian sources from the Jemez Lineament sources have also improved since 2000, providing useful data on nodule dimension as well as compositional data at the primary sources. By recording both nodule sizes against source provenance at these points along the Rio Grande, scholars can compare the results of nearby archaeological contexts and the source obsidian available at various points along the Rio Grande. It is often difficult to determine whether the raw material used to produce a chipped stone tool was originally procured at the source or in secondary contexts. That, however, can never be achieved anywhere in the world without firm secondary depositional data. This issue is the focus of this study.