Writ in stone

The rock used in campus construction tells tales of social history

By David Williams

Dave Knoblach ’94 is not your typical geologist. Instead of examining faults or volcanoes, Knoblach heads for the nearest building. He looks hard at the structure’s walls. He gets on his knees and examines the floors. He may even dig out a pair of binoculars to scan the roof. What he sees can tell a story as ancient and informative as any range of mountains piled up by plate tectonics.

“Looking at building stones is a great way to learn about geology as well as human history,” says Knoblach, who was a geology major at Puget Sound and is now working on his master’s at UW-Tacoma. “Too few people understand where our geologic materials come from, and without that knowledge it is impossible to appreciate how land use decisions may affect our economic and social future.”

Knoblach shared his passion for building-stone geology on a recent tour of campus. His first stop was the new UPS entry sign at North 18th and Union Avenue. The lower part consists of a gray basalt, known as the Boring Lava, quarried just down the Columbia River from Vancouver, Wash. It was deposited 2 million years ago.

“The Boring had three key characteristics that made it a popular building material,” says Knoblach. “One, it split well into slabs. Two, it could also be worked into large, competent boulders, and perhaps most important, the rock could easily be transported from the quarries along the Columbia,” The rock, known in the building trade as Columbia Gray, was a popular building stone in Portland and was the premier rock for seaside jetties from Alaska to California.

The top of the stone marker is Wilkeson Sandstone, a whitish, 40-million-year-old rock deposited in deltas in what would become Puget Sound. At the time, neither the Cascades nor the Olympics had risen and the local climate was tropical with palms and tree-sized ferns. The Wilkeson, quarried near Mt. Rainier, is the most commonly used building stone on the Puget Sound campus, especially in the earlier buildings, such as Thompson Hall and Collins Library, where its light color contrasts gracefully with the red brick. (The Wilkeson characterizes so many UPS buildings that when architects designed Phibbs Hall, many years after the original quarry closed, they won an award for creating faux Wilkeson out of concrete.)

Inside Thompson, Knoblach pointed out small stones—serpentine, magnesite, and dolomite—in the terrazzo floor in the entry way. They come from eastern Washington, from a mine that was once the principal American source of magnesium, an essential ingredient in refractory materials in furnace linings for producing iron and steel. Terrazzo floors in the Denver and Chicago airports incorporate this rock, too. The Thompson floors also contain tiles made out of clay found near the town of Taylor, a long- abandoned community in Seattle’s Cedar River Watershed.

As the tour continued, Knoblach, who grew up in Minnesota swimming in abandoned granite quarries and skiing around the tailings piles, talked about the topic of his master’s thesis. “Take clay as an example. In Seattle, brick became important after the Great Fire. Unfortunately, the local clays were not that good for making bricks, which led to developers not using fireproof building materials. It wasn’t until 1905 when people discovered good clays in Renton, Taylor, and eastern Washington that you see big growth of brick and terra cotta architecture in Seattle,” he says. UPS also shows this influence. The campus was built during the heyday of the Wilkeson quarries.

Not that UPS only uses local materials. The fireplace on the ground floor of Wyatt Hall has Vermont slate and Montana argillite. The recently built Benefactors Plaza incorporates granite from the Sierras, as does the obelisk just west of Jones Hall. “Part of the fun of building- stone geology is the mystery. The rocks could be from anywhere. These materials are not only beautiful and culturally significant, but also record important events in Earth’s history. What a great combination!” he says.