Archaeological dig targets cave site

Digging for scholarly gold in Central Oregon.

Central Oregon has long been a crossroads for human visitors.

While recreation seems to be the chief draw in the 21st Century, visitors from a much earlier time sometimes depended on the region's resources for their survival.

To help explore and understand the phenomenon of Central Oregon's early visitors, the Forest Service sponsored an archaeological dig on the grounds adjacent to Lava River Cave, south of Bend.

The site, and an interpretative staff, were made available to visiting classes of schoolchildren as part of the program.

Called "Passport in Time," the project matches archaeological professionals with volunteers from as far away as Florida.

The site near the cave opening is one that has not previously been excavated.

Forest Service Archaeological Technician Jo Radeke, explained that many excavations are funded because of human activities that have the potential to disrupt a site.

As a result, she said, excavations often occur at sites for future logging operations, road building or other construction.

The cave area has always been protected, so there have been no archaeological studies ¤ until now.

Award winning Oregon archaeologist C. Melvin Aikens notes that "cultural heritage sites are the fundamental depositories of knowledge" for more than 99 percent of human history.

As a result, management of cultural resource sites, such as those in Central Oregon, is drawing increased attention.

Although short-term environmental cycles do impact Central Oregon, in another sense, says Aikens, Oregon's High Desert is unchanging.

"It has been a fundamentally arid region ever since the Sierra-Cascades rose up and cast their rain shadow over the interior," he said in a paper published in 1995.

Because of the region's aridity, early visitors ¤ naturally enough ¤ tended to be transitory.

According to Radeker, pre-European settlement visitors to the area included members of the Tenino, Klamath, Molalla, Sahaptin (Warm Springs), and Northern Paiute Tribes.

Natural obsidian deposits, which were laid down at Newberry Caldera 1,300 years ago, created a shared destination for many different native peoples who used the sharp-edged glass-like substance for weapons and tools.

The silica-based rock can easily be shaped into cutting points by a process of pressure flaking.

Early natives fashioned obsidian points by applying pressure from a pointed tool. The resulting flakes that popped off are among the most common native artifacts that leave a record of past human activities in the area.

The Lava River Cave excavation has produced countless such fragments, as well as a number of larger artifacts, including whole and broken points.

Radeker pointed out that the base (place of attachment) of a point is of greater archaeological significance than the point itself, since the design of the base can be traced to a particular time period.

Many found points are broken. Radeker said that the points were designed to break off, so the more valuable shaft could be easily recovered.

A good point could be fashioned in an hour, she said; but the shaping and curing of a perfectly straight shaft was a process that took many months.

One of the major finds at the site was a shaped hammerstone.

"None of us had ever found a groundstone tool before," Radeker told a seventh grade class from St. Francis School in Bend. "So, we were all dancing in the woods a little."

The site was chosen due to its proximity to the cave, which was apparently a popular stopping place for early natives.

It is thought that ¤ then, as now ¤ the ice and opportunity for natural refrigeration made the site a natural attraction for the area's seasonal visitors.

A typical excavation begins with the selection of a likely spot, and a square meter of ground is marked off with string. The excavation extends straight down for a meter, and the finished product leaves a perfect cube of dirt extracted from the earth.

The hole may be enlarged if evidence leads the searchers in a particular direction.

Each layer is meticulously scraped away in 10 centimeter increments, and the contents of the layer are catalogued.

Radeker said that artifacts taken from the ground without such careful documentation lose approximately 97 percent of their archaeological value because they are separated from the context of their origin.

According to Forest Service Archaeologist Lucy Hamilton, who is overseeing the project, the principal makeup of the soil in the excavation area is a two to three foot layer of volcanic ash from the Mt. Mazama eruption that created Crater Lake's caldera 7,600 years ago.

The Mt. Mazama eruption left ash deposits of 30 inches or more as far away as Idaho.

In contrast, the Mt. St. Helens eruption in 1980 left ash deposits of about one inch over a similar-sized area.

Passport in Time is part of a continuing program of archaeological projects that the Forest Service sponsors to promote a better understanding of history and the stewardship of public lands.