Obsidian was considered a very important resource by Mesoamericans and understanding the major source regions is a key step towards comprehense the economy of Mesoamerican regions. Mesoamerica is divided into nine sub‐regions according to the locations of major obsidian sources and Zaragoza obsidian source is the dominant supply in the Zaragoza‐Oyameles sub‐region. The aim of this paper is to present new investigations into the geology and geochemistry of the previously understudied Zaragoza obsidian source. Subsequent to this, comparisons between Zaragoza source and other major sources across central Mexico were made in order to understand the nature of Mesoamerican obsidian sources. During the study, we discovered three chemically different flows exited in the field with Zaragoza‐1 and Zaragoza‐2 match the previously reported Zaragoza obsidian with just some chemical variations possibly due to combined effects of fractional crystallization and some other magmatic process. However, Gomez Sur obsidian flow, which is exposed on the Northern part of the study area, displayed similar but not exactly same chemical signals has previously defined Altotonga obsidian, which was thought to be the product of the same magma system as the Zaragoza obsidian. Based on chemical similarities and the fact that the spatial relationship between previous altotonga sample collection points and our Gomez Sur outcrops, we hypothesize that Gomez Sur and Altotonga obsidians might both be products from earlier eruptive activities. The Heterogeneity Index (HI index) values of 12 obsidian sources across central Mexico indicates that the presence of another flow or sub‐flows in obsidian field might be a common scene across central Mexico. / 1 / Heng Hu
| Identifer | oai:union.ndltd.org:TULANE/oai:http://digitallibrary.tulane.edu/:tulane_45969 |
| Date | January 2015 |
| Contributors | Hu, Heng (author), Nelson, Stephen (Thesis advisor), School of Science & Engineering Earth and Environmental Sciences (Degree granting institution) |
| Source Sets | Tulane University |
| Language | English |
| Detected Language | English |
| Type | Text |
| Format | electronic |
| Rights | No embargo |
Page generated in 0.0014 seconds