Navajo Sandstone

through Jurassic stratigraphy of the Colorado Plateau area of southeastern Utah that makes up much of the famous prominent rock formations in protected areas such as Capitol Reef National Park and Canyonlands National Park. From top to bottom: Rounded tan domes of the Navajo Sandstone, layered red Kayenta Formation, cliff-forming, vertically jointed, red Wingate Sandstone, slope-forming, purplish Chinle Formation, layered, lighter-red Moenkopi Formation, and white, layered Cutler Formation sandstone. Picture from Glen Canyon National Recreation Area, Utah. The Navajo Sandstone is particularly prominent in southern Utah, where it forms the main attractions of a number of national parks and monuments including Arches National Park, Zion National Park, Capitol Reef National Park, Canyonlands National Park, Glen Canyon National Recreation Area, and Grand Staircase–Escalante National Monument. Navajo Sandstone frequently overlies and interfingers with the Kayenta Formation of the Glen Canyon Group. Together, these formations can result in immense vertical cliffs of up to . Atop the cliffs, Navajo Sandstone often appears as massive rounded domes and bluffs that are generally white in color. Appearance and provenance in Zion National Park is an example of white Navajo Sandstone in the Canyons of the Escalante, is formed from a layer of Navajo Sandstone. The opening is wide and high. Navajo Sandstone frequently occurs as spectacular cliffs, cuestas, domes, and bluffs rising from the desert floor. It can be distinguished from adjacent Jurassic sandstones by its white to light pink color, meter-scale cross-bedding, and distinctive rounded weathering. The wide range of colors exhibited by the Navajo Sandstone reflect a long history of alteration by groundwater and other subsurface fluids over the last 190 million years. The different colors, except for white, are caused by the presence of varying mixtures and amounts of hematite, goethite, and limonite filling the pore space within the quartz sand comprising the Navajo Sandstone. The iron in these strata originally arrived via the erosion of iron-bearing silicate minerals. Initially, this iron accumulated as iron-oxide coatings, which formed slowly after the sand had been deposited. Later, after having been deeply buried, reducing fluids composed of water and hydrocarbons flowed through the thick red sand which once comprised the Navajo Sandstone. The dissolution of the iron coatings by the reducing fluids bleached large volumes of the Navajo Sandstone a brilliant white. Reducing fluids transported the iron in solution until they mixed with oxidizing groundwater. Where the oxidizing and reducing fluids mixed, the iron precipitated within the Navajo Sandstone. Depending on local variations within the permeability, porosity, fracturing, and other inherent rock properties of the sandstone, varying mixtures of hematite, goethite, and limonite precipitated within spaces between quartz grains. Variations in the type and proportions of precipitated iron oxides resulted in the different black, brown, crimson, vermillion, orange, salmon, peach, pink, gold, and yellow colors of the Navajo Sandstone. The precipitation of iron oxides also formed laminae, corrugated layers, columns, and pipes of ironstone within the Navajo Sandstone. Being harder and more resistant to erosion than the surrounding sandstone, the ironstone weathered out as ledges, walls, fins, "flags", towers, and other minor features, which stick out and above the local landscape in unusual shapes. == Age and history of investigation ==

The age of the Navajo Sandstone is somewhat controversial. It may originate from the Late Triassic but is at least as young as the Early Jurassic stages Pliensbachian and Toarcian. The two major subunits of the Navajo are the Lamb Point Tongue (Kanab area) and the Shurtz Sandstone Tongue (Cedar City area). The Navajo Sandstone was originally named as the uppermost formation of the La Plata Group by Gregory and Stone in 1917. Its age was modified by Lewis and others in 1961. The name was originally not used in northwest Colorado and northeast Utah, where the name 'Glen Canyon Sandstone' was preferred. A 2019 radioisotopic analysis suggests that the Navajo Sandstone formation dates to the early Jurassic and began around 200-195 million years ago. Kevin Padian stated in 1989 that the Navajo Sandstone extended into the Toarcian Stage. == Depositional environment ==

The sandstone was deposited in an arid erg on the Western portion of the Supercontinent Pangaea. This region was affected by annual monsoons that came about each winter when cooler winds and wind reversal occurred. == Outcrop localities ==

, a rock formation in Capitol Reef National Park. Though the park is famous for white domes of the Navajo Sandstone, this dome's color is a result of a lingering section of yellow Carmel Formation carbonate, which has stained the underlying rock. Navajo Sandstone outcrops are found in these geologic locations: • Colorado Plateau • Black Mesa Basin • Great Basin province • Paradox Basin • Piceance Basin • Plateau Sedimentary Province • San Juan Basin • Uinta Basin • Uinta Uplift • Uncompaghre Uplift The formation is also found in these parklands (incomplete list): • Glen Canyon National Recreation Area • Grand Staircase–Escalante National Monument • Zion National Park • Canyonlands National Park • Capitol Reef National Park • Arches National Park • Dinosaur National Monument • Navajo National Monument • Colorado National Monument • Coral Pink Sand Dunes State Park, Kanab, Utah == Vertebrate paleofauna ==

Ornithodires Indeterminate theropod remains geographically located in Arizona, USA. Theropod tracks are geographically located in Arizona, Colorado, and Utah, USA. Ornithischian tracks located in Arizona, USA. == Iron oxide concretions ==

The Navajo Sandstone is also well known among rockhounds for its hundreds of thousands of iron oxide concretions. Informally, they are called "Moqui Marbles" and are believed to represent an extension of Hopi Native American traditions regarding ancestor worship ("moqui" translates to "the dead" in the Hopi language). Thousands of these concretions weather out of outcrops of the Navajo Sandstone within south-central and southeastern Utah within an area extending from Zion National Park eastward to Arches and Canyonland national parks. They are quite abundant within Grand Staircase–Escalante National Monument. These concretions are regarded as terrestrial analogues of the hematite spherules, called alternately Martian "blueberries" or more technically Martian spherules, which the Opportunity rover found at Meridiani Planum on Mars. == See also ==