Shifts in exchange patterns provide a new perspective on the fall of inland Maya centers in Mesoamerica approximately 1,000 years ago.
Related reading on the Obsidian Trail: http://phys.org/news164896641.html
Related reading on Maya Collapse: http://phys.org/news/2012-02-maya-civilization-collapse-modest-rainfall.html
For the Maya, who did not have metal tools, obsidian (or volcanic glass) was highly valued because of its sharp edges for use as cutting instruments. Maya lords and other elites derived power from controlling access to obsidian, which could be traded for important goods or sent as gifts to foster important relationships with other Mayan leaders.
The Field Museum researchers found that prior to the fall of the Maya inland centers, obsidian tended to flow along inland riverine networks. But over time, this material began to be transported through coastal trade networks instead, with a corresponding increase in coastal centers' prominence as inland centers declined.
The shift in trade might have involved more than obsidian. Field researcher Mark Golitko said, "The implication is that other valuable goods important to these inland centers were also slowly being cut off." Golitko led the Social Network Analysis that graphically depicts the change in trade patterns.