Arches National Park

Delicate Arch '73
Delicate Arch '73

The natural arches at Arches National Park near Moab, Utah were a source of curiosity that entranced me. I wondered how were they formed? The ranger’s explanation of "wind erosion" seemed hopelessly naive.

Landscape Arch
Landscape Arch

The longest span at Arches is Landscape Arch, shown here. It stretches 291 feet across, just about the length of a football field. In 1973 Steve Tetreault and I managed to climb out onto it, finding it narrows to just 6 feet wide! Climbing on the arch is no longer permitted.

Paleoliquefaction features at Arches NP
Paleoliquefaction features at Arches NP

One of the most unusual features I mapped at Arches Park were these enormous paleoliquefaction structures, which looked like gigantic sand boils, petrified in time. 20 years later Walter Alvarez at U.C. Berkeley explained these as the result of a nearby meteorite impact during the Jurassic Period. I mapped similar features in upper Lake Powell, though more subdued.

Delicate Arch '73
Delicate Arch '73

The natural arches at Arches National Park near Moab, Utah were a source of curiosity that entranced me. I wondered how were they formed? The ranger’s explanation of "wind erosion" seemed hopelessly naive.

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