The Obsidian Trail: A GIS model for obsidian trade routes in the West Mexican Aztatlán Tradition (AD 900-1350)

Author(s): Daniel Pierce

Year: 2017


The Postclassic Aztatlán Tradition of Western Mexico is well known for its expansive trade networks. Aztatlán merchants traded ceramics, shell, copper, and obsidian across vast distances. Obsidian provides us with a particularly unique opportunity to trace trade networks due to the compositional homogeneity of obsidian sources. Recent studies have identified the source of thousands of obsidian artifacts from numerous Aztatlán centers, allowing for an elaboration on themes such as access to exotic goods and socioeconomic relationships. The aim of this paper is to create a series of models of possible trade routes from seven Aztatlán centers to the most common obsidian sources identified in previous geochemical analyses. These routes have been established through a GIS least cost path using multiple cost surfaces and Tobler’s Hiker Function to estimate path distance accounting for variable walking speeds across differing terrain. Further variables used to estimate possible paths include landcover and various hydrological elements. Ultimately, separate models were created and compared that assume a preference for water and overland travel routes. The resulting models assess the possibility of convergence of trade routes to and from key obsidian sources and various Aztatlán centers and lend themselves to estimating relative import cost.

Cite this Record

The Obsidian Trail: A GIS model for obsidian trade routes in the West Mexican Aztatlán Tradition (AD 900-1350). Daniel Pierce. Presented at The 81st Annual Meeting of the Society for American Archaeology, Vancouver, British Columbia. 2017 ( tDAR id: 428946)

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Geographic Keywords

Spatial Coverage

min long: -107.271; min lat: 12.383 ; max long: -86.353; max lat: 23.08 ;

Record Identifiers

Abstract Id(s): 16611