Southwestern Chihuahua, Mexico
Discovered in 2002 by John Roney, Art MacWilliams, and Robert Hard. This marekanite source is located about 10 km west of Norogachi and a kilometer west-southwest of the community of Ejido Siquirichi in the Sierra Madre Occidental of southwestern Chihuahua (UTM Zone 13, 278989E/3017363N).
Text submitted by John Roney:
"The nodules were collected from a 20 meter diameter area in a ridge top. The were essentially resting on rhyolitic tuff bedrock, and we believe that they are weathering out of the bedrock at this location [similar to Cow Canyon]. The largest nodule we collected here is 4.34X4.0XX2.8 cm and weighs 59 grams. However, we only spent a few minutes at this location and with additional time we might have found larger nodules. Furthermore, the local people who were with us indicated that grapefruit-sized nodules can be found on another ridge about a kilometer to the southwest of this location." (emphasis mine).
Even though the obsidian in nearly opaque even in the thinnest flakes, like many in the Sierra Madre, it is not a peralkaline rhyolite. The knapping quality seems fine. Using bipolar on the marekanites was very predictable, and relatively thin flakes could be removed easily. So far (Fall 2014) this source has not been located in archaeological contexts.
Table 1. Raw elemental concentrations for Ejido Siquirichi
Table 2. Mean and central tendency for the data in Table 1.
This page maintained by Steve Shackley (email@example.com).
Copyright © 2014 M. Steven Shackley. All rights reserved.
Revised: 19 August 2015
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