Entries by Lance Weaver

Toroweap/Coconino/White Rim Sandstone (Geology of The Grand Canyon)

Exposure: The Toroweap & White Rim Sandtones are best seen in Southern Utah and Northern Arizona. Age:  Early Permian, 280 million years ago. Depositional Environment: Coastal dune field (eolian with some marine transgressions). Marine transgressions, terrestrial wind-blown sand, coastal environments laid down the Kaibab, Toroweap, and Coconino formations. At different time, the marine waters came from […]

Kaibab Limestone (Geology of The Grand Staircase)

Exposure: The Kaibab Limestone forms the caprock of most of the Grand Canyon. Great exposures exist west of Zion National Park. Age:  Early Permian, 250 million years ago. Depositional Environment: Shallow Marine Shelf Deposit. Paleogeography: Sediment deposition was influenced by the Uncompahgre Uplift (ancestral Rocky Mountains), but by the end of the Permian, the Uncompahgre mountains […]

Moenkopi Formation (Geology of Utah’s Grand Staircase)

Exposure: The Moenkopi formation can be found throughout the Colorado Plateau. But its thickest extent stretches from southwest Utah to Northern Arizona. Age:  Lower Triassic to possibly lower Middle Triassic Depositional Environment: Tidal sabkha (also with nearshore shales, shallow marine limestones, and some floodplain) Paleogeography: The Moenkopi Formation was deposited along the western portion of the […]

Chinle Formation (Geology of Utah’s Grand Staircase)

Exposure: The Chinle formation can be found throughout the Colorado Plateau. From the Flanks of the Uintas to Petrified Forest National Park in Arizona. Age:  Late Triassic. Depositional Environment: Non-marine fluvial channels, floodplains, paleosols, marshes, and small lakes. Paleogeography: The Chinle Formation was deposited during the Late Triassic when the supercontinent Pangea had landmass on both […]

Kayenta Formation (Geology of Utah’s Grand Staircase)

Exposure: The Kayenta is exposed throughout the state of Utah, but is especially visible in Zion National Park, Capital Reef and Glen Canyon NRA. Age:  Early Jurassic, 199.6 million years ago to 175.6 million years ago. Depositional Environment: Fluvial (river) environment The Navajo Sandstone was deposited in an eolian environment composed of large sand dunes, similar […]

Navajo Sandstone (Geology of Utah’s Grand Staircase)

Exposure: The Navajo is exposed throughout the state of Utah, but reaches maximum thickness near Zion National Park and Red Rocks Recreation area near Las Vegas. Age:  Early JurassicThe Navajo Sandstone is dated as Early Jurassic, although precise dating is typically difficult due to a lack of age diagnostic fossils, a common problem in eolian […]

Carmel Formation (Geology of Utah’s Grand Staircase)

Exposure: Within the Grand Staircase, the Curtis Formation is best exposed in east of Capital Reef National Park just south of Goblin Valley State Park. Age:  Middle Jurassic, 160 Ma Depositional Environment: Full marine, shallow marine to sabkha (and supratidal) Paleogeography: Frequent, but short-lived sea level fluctuations during the Middle to Late Jurassic caused periodically flooding […]

Entrada Formation (Geology of Utah’s Grand Staircase)

Exposure: Without a doubt the most striking exposures of the Entrada Formation are in Arches National Park. Other great exposures exist in Canyonlands, Goblin Valley State Park and Lake Powell NRA. Age:  Upper Jurassic, 80 and 140 ma Depositional Environment: Eolian, sabkha, and tidal flat. The Entrada Sandstone preserves terrestrial environments.  Within the field trip area, the deposits […]