Entries by Lance Weaver

Esplanade Sandstone & Cutler Cedar Mesa Sandstone (Geology of The Grand Canyon)

Exposure: The Esplanade Sandstone is the upper member of the Supai Group and forms a prominent bench visible throughout the Grand Canyon. It is time equivalent to the upper Culter Group units, the Cedar Mesa & Elephant Canyon Formations. Age:  Early Permian, 290–294 million years ago. Depositional Environment: deposited in a nearshore eolian, or wind-blown, environment. […]

Hermit/Organ Rock (Geology of The Grand Canyon)

Age:  Early Permian (Cisuralian); approximately 285 to 275 million years ago (Ma). Exposure: Easily identified as the wide, brick-red slope below the Coconino Sandstone. Best seen along the Bright Angel Trail at the “Hermit Basin” or from the Desert View Watchtower. It is also well-exposed in the Hurricane Cliffs of Southern Utah. Age:  Early Permian […]

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)

Age:  Early Permian, 250 million years ago. Lateral Equivalents: Park City Formation (Northern UT, WY); Phosphoria Formation (ID, MT, WY); San Andres Limestone (NM, TX); Toroweap Formation (underlying/intertongued). Exposure: It forms the rim of the Grand Canyon and the surface of the Kaibab Plateau. Exceptional exposures occur at Zion National Park (the base of the cliffs), the […]

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 […]