MINNEAPOLIS – ST. PAUL

This fifteen-mile-wide view looks north toward Minneapolis on the left and St. Paul on the right, with the Mississippi River flowing between them. The image extends approximately 1,400 feet in depth, representing more than one billion years of geologic history.

While living in the Upper Midwest for the first time, I became curious about the rock beneath this landscape. I wanted to understand the deeper structure below the Twin Cities and the groundwater systems that sustain such a densely populated area.

The lowest layer of the image is a thick, reddish sandstone deposited within the Midcontinent Rift, where North America nearly split apart more than one billion years ago. Above this rift-related rock are alternating sandstone and limestone layers deposited between roughly 500 and 460 million years ago, when an inland sea repeatedly advanced and retreated across the region. Over the past one million years, multiple glacial advances gouged deep bedrock valleys and left behind sediments of sand, gravel, and clay that now blanket the bedrock surface.

In more recent time, urban development has added its own materials—concrete, asphalt, steel, and fill—forming a thin but distinct layer at the surface. In one version of this image, vertical lines depict water wells drilled into underlying sandstone aquifers that continue to supply the metropolitan area. A second version removes the wells, presenting only the geologic layers beneath the city.

Photo-geologic composite created through field photography, geologic interpretation, and digital compositing.