Seconds to Millions of Years: A Road Trip Through Juniper Mesa

Bettina's Trip Notes

1Over spring break, Bettina Oduya and her grandmother Florence drove through Juniper Mesa National Park, a dry plateau of red and tan sandstone. Ranger Lorenzo Pak gave them the park measurements in Tables 1 and 2. He explained that forces deep inside Earth have slowly raised the plateau more than 1 km over millions of years.

2Their first stop was the Impact Crater Overlook. About 50,000 years ago, a meteorite, a rock from space, struck the plateau at very high speed and blasted out a huge bowl in a few seconds. Since then, rain and wind have lowered the crater's rim by about 15 m, and sediment has partly filled its floor.

3Next they hiked into the Narrows, a slot canyon 30 m deep and in places only 1 m wide. Most of the year only a trickle of water runs through it, or none at all. Last August, a thunderstorm upstream sent a flash flood through the canyon. Within 20 minutes the water rose 3 m and rolled a boulder 2 m across about 150 m downstream. Where the canyon opens onto a flat plain, the flood dropped a fan of sand and gravel about 1 m thick.

4At the third stop, a pile of broken rock lies where Fin Arch stood until 2019. Rangers had photographed the arch for 40 years. The photos showed a crack across its top slowly getting wider, and flakes of rock falling from its underside after winters with many freeze-thaw cycles. Then, one night, the arch fell in a few seconds.

5The fourth stop was the dune field beside the park road. The wind there usually blows from the west. It pushes sand up the gentle west side of each dune and over the crest, and the sand slides down the steep east side, which faces the road. Every two years, rangers measure the distance from the crest of one 12 m dune to a marker at the road's edge.

6The last stop was the rim of the Great Canyon, 1,500 m deep. The Juniper River cut it over about 5 million years while the plateau around it was slowly rising.