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Formation · Jurassic · sandstone

Navajo Sandstone

The pale, cross-bedded slickrock of the Colorado Plateau — an Early Jurassic fossil dune sea that builds Zion's big walls and Glen Canyon's bald domes.

Also known as: Navajo

Jurassic — the golden age of dinosaurs

The world back then

Early Jurassic, about 190 million years ago. You're standing in one of the largest deserts the planet has ever built — a sand sea the size of a subcontinent, dunes towering hundreds of feet, monsoon winds hauling grains for a thousand miles, a rare wet pond glinting between them. Vast, hot, and almost empty. Sand to every horizon and then some.

That endless desert is Zion's walls and the slickrock you can't stop scrambling on. The dunes ran a thousand miles for a hundred thousand years; your trip runs a week and ends at a shuttle. History's biggest sandbox, handed to its smallest, softest visitor for an afternoon.

Recognize it in the field

Typical color
white to pink, salmon, and red-tan — white where bleached, red where iron-stained
Weathers as
Massive cliff-former and rounded slickrock — domes, beehives, cuestas, and Zion's sheer walls; weathers into bald, cross-bedded rock.
Grain
fine to medium, well-sorted, well-rounded frosted quartz

Look for

  • huge sweeping eolian cross-bedding, meters to tens of meters tall
  • bald, rounded slickrock domes and cliffs
  • white-to-red color banding
  • frosted, well-rounded, well-sorted wind-worked sand

How this rock was made

One of the largest sand seas in the geologic record, on the arid western margin of Pangaea in the Early Jurassic, with seasonal/monsoonal winds and interdune ponds.

The setting: wind-blown dune sea (eolian erg) (wind-blown dune sea)

Thickens to the northwest; over 2,000 ft in Zion (NPS) and up to ~2,300 ft (700 m) at its maximum (Wikipedia).

In the rock record

Part of the Glen Canyon Group.

↑ Younger — rests above

Carmel Formationa gap in time (unconformity) · much of the Colorado Plateau, where the Page Sandstone is absent
Navajo Sandstone you are here
Kayenta Formationinterlocks like fingers (interfingering) · southwestern Utah (intertonguing)
Kayenta Formationblends into it (gradational) · Glen Canyon area and generally

↓ Older — sits beneath

See the full regional rock columns →