As the first obsidian sourcing study from coastal Guerrero, these data contribute to a greater understanding of the development of exchange networks in Mesoamerica during the Formative Period. Weaker connections existed with Gulf coast obsidian trade networks that traversed the Isthmus of Tehuantepec. Rhyolite is an igneous rock with silica content in excess of 65 SiO 2. Obsidian is a form of volcanic glass produced by rhyolitic volcanism. Comparisons with sourcing studies from elsewhere in Mesoamerica indicate the development of a major Pacific coast trade network during the Formative Period that linked coastal Guerrero to the central Mexican highlands and the Valley of Oaxaca. Sheppard, in Encyclopedia of Archaeology, 2008 Obsidian. The results of portable X-ray fluorescence (pXRF) analysis of 456 obsidian artefacts imported to the Pacific coast site of La Zanja (Guerrero, Mexico) indicate that long-distance exchange of finished obsidian blades along the coast began during the Early Formative (c.1400–1000 cal BC) and remained constant into the Middle Formative Period (c.800–550 cal BC). Long-distance networks for the transport of exotic goods and the beginnings of specialized craft production first appear in Mesoamerica during the Formative Period. You can put any knife you want in your checked luggage at the airport.

Our results provide new insight into the stability of supply networks and markets well into the Colonial period as well as the homogenizing tendencies of the Aztec market system. Davis Creek Rainbow Obsidian Flint Knapped Primitive Skinning Knife Wicca Shaman. Alongside the 4 obsidian blade-cores, 43 blades and a quantity. Gun Metal Gray Obsidian Fox Ear Knife Flint Knapping Black Powder Mountain Man. Concave surfaces did decrease the accuracy of readings because of the greater distance between the artifact and the detector. three metal objects were found in contrast to the vast quantities of obsidian recovered, it. Additional tests of potentially confounding factors show that neither length of read time, presence of surface residue, nor incomplete detector coverage due to small artifact size compromised our ability to attribute sources to artifacts. Sources were assigned by comparing pXRF measurements with previously published source data and were verified using the standard techniques of laboratory XRF (lXRF) and instrumental neutron activation analysis (INAA). Obsidian sources were identified for a sample of 103 artifacts from the site of Xaltocan, which spanned the rise and fall of the Aztec empire and the first centuries of Spanish colonial rule (AD 900–1700).

This article demonstrates the accuracy of non-destructive portable X-ray fluorescence (pXRF) for the study of obsidian in central Mexico.

Obsidian knife metal detector