Why the Valles Caldera National Preserve?
For one thing, it’s federal land: “I love working in a place that is owned by the people and creating opportunities for them to come to know the place. I really like creating opportunities to learn with the public, not just for the public,” Dr. Steffen told Earthwatch.
Then, of course, there’s the science: “I’m very interested in creating opportunities to use the Valles Caldera as a laboratory for obsidian analysis. There’s a lot more that needs to be done on assessing and applying what’s called obsidian hydration dating. This is geochemical method is used to figure out the age of obsidian artifacts. When a piece of obsidian is fractured during tool manufacture, water gradually absorbs into the surface. The longer the artifact was exposed to water, the deeper the water penetrates.”
An exciting find:
“So far, archaeologists have found thousands of artifacts with obsidian from the Valles Caldera in 12 states,” says Dr. Steffen. “That tells us that prehistoric peoples in the west-central U.S. used this caldera for obsidian starting about 10,000 years ago and continuing through until European contact in the 1600s. Inevitably, people ask me where the farthest flung artifact has been found: the answer includes Mississippi, Texas, northern Mexico, northern North Dakota, and eastern Nebraska."