Mineral Fork Formation

Last updated
Mineral Fork Formation
Stratigraphic range: Proterozoic
Diamictite Mineral Fork.JPG
Boulder of diamictite of the Mineral Fork Formation, along the Elephant Head Trail, Antelope Island, Utah.
Typesedimentary
UnderliesMutual Formation (Big Cottonwood Canyon), Tintic Formation (Santaquin-Provo), or Kelly Canyon Formation (Antelope Island) [1]
OverliesFarmington Canyon Complex (Antelope Island), Big Cottonwood Formation (other locations) [1]
Thickness1000 to 3000 feet
Lithology
PrimaryTillite, Shale, Quartzite, Conglomerate
Location
RegionSouthern Rocky Mountains
Extent Wasatch Mountains, Antelope Island
Type section
Named forMineral Fork, Salt Lake County, Utah
Named byGranger et al., 1952 [2]

The Mineral Fork Formation is a mapped Proterozoic bedrock unit in Utah.

Contents

Description

Granger et al. (1952) describe the Mineral Fork Formation as black tillite consisting of boulders, cobbles and pebbles of quartzite, limestone, or granitic rocks in a black sandy matrix, with dark-gray to black varved slate or shale, dark-gray quartzite, and occasional channel fillings of boulder conglomerate. [2]

Exposures

According to Yonkee et al. (2000), the Mineral Fork is exposed at the following locations in Utah: [1]

And also:

Fossils

Abundant microfossils of planktonic alga of Bavlinella faveolata. [3]

Age

The presence of Bavlinella faveolata in the formation indicates a likely age of 750–650 Ma, because this fossil occurs elsewhere where it is well-dated radiometrically. The Mineral Fork Formation is no older than 1,250 Ma and no younger than 540 Ma. Thus it is likely Neoproterozoic but possibly Mesoproterozoic. [3]

Related Research Articles

Wasatch Range Mountain range in Utah, United States

The Wasatch Range or Wasatch Mountains is a mountain range in the western United States that runs about 160 miles (260 km) from the Utah-Idaho border south to central Utah. It is the western edge of the greater Rocky Mountains, and the eastern edge of the Great Basin region. The northern extension of the Wasatch Range, the Bear River Mountains, extends just into Idaho, constituting all of the Wasatch Range in that state.

Quartzite Hard, non-foliated metamorphic rock which was originally pure quartz sandstone

Quartzite is a hard, non-foliated metamorphic rock which was originally pure quartz sandstone. Sandstone is converted into quartzite through heating and pressure usually related to tectonic compression within orogenic belts. Pure quartzite is usually white to grey, though quartzites often occur in various shades of pink and red due to varying amounts of hematite. Other colors, such as yellow, green, blue and orange, are due to other minerals.

Colorado Plateau

The Colorado Plateau, also known as the Colorado Plateau Province, is a physiographic and desert region of the Intermontane Plateaus, roughly centered on the Four Corners region of the southwestern United States. This province covers an area of 336,700 km2 (130,000 mi2) within western Colorado, northwestern New Mexico, southern and eastern Utah, northern Arizona, and a tiny fraction in the extreme southeast of Nevada. About 90% of the area is drained by the Colorado River and its main tributaries: the Green, San Juan, and Little Colorado. Most of the remainder of the plateau is drained by the Rio Grande and its tributaries.

Uinta Mountains Mountain range in northeastern Utah and northwestern Colorado in the United States

The Uinta Mountains are an east-west trending chain of mountains in northeastern Utah extending slightly into southern Wyoming in the United States. As a subrange of the Rocky Mountains, they are unusual for being the highest range in the contiguous United States running east to west, and lie approximately 100 miles (160 km) east of Salt Lake City. The range has peaks ranging from 11,000 to 13,528 feet, with the highest point being Kings Peak, also the highest point in Utah. The Mirror Lake Highway crosses the western half of the Uintas on its way to Wyoming.

Geology of the Death Valley area Geology of the area in California and Nevada

The exposed geology of the Death Valley area presents a diverse and complex set of at least 23 formations of sedimentary units, two major gaps in the geologic record called unconformities, and at least one distinct set of related formations geologists call a group. The oldest rocks in the area that now includes Death Valley National Park are extensively metamorphosed by intense heat and pressure and are at least 1700 million years old. These rocks were intruded by a mass of granite 1400 Ma and later uplifted and exposed to nearly 500 million years of erosion.

Little Cottonwood Canyon

Little Cottonwood Canyon lies within the Wasatch-Cache National Forest along the eastern side of the Salt Lake Valley, roughly 15 miles from Salt Lake City, Utah. The canyon is part of Granite, a CDP and "Community Council" designated by Salt Lake County. The canyon is a glacial trough, carved by an alpine glacier during the last ice age, 15,000 to 25,000 years ago. A number of rare and endemic plant species are found in the canyon's Albion Basin. Mountain goats inhabit the surrounding mountains.

Sevier orogeny Mountain-building episode in North America

The Sevier orogeny was a mountain-building event that affected western North America from northern Canada to the north to Mexico to the south.

Traverse Mountains

The Traverse Mountains, or sometimes Traverse Range, are an anomalous, geologically complex, east-trending range that separates Salt Lake Valley and Utah Valley in Salt Lake and Utah counties in the U.S. State of Utah.

Cardenas Basalt

The Cardenas Basalt, also known as either the Cardenas Lava or Cardenas Lavas, is a rock formation that outcrops over an area of about 310 km2 (120 mi2) in the eastern Grand Canyon, Coconino County, Arizona. The lower part of the Cardenas Basalt forms granular talus slopes. Its upper part forms nearly continuous low cliffs that are parallel to the general course of the Colorado River. The most complete, readily accessible, and easily studied exposure of the Cardenas Basalt lies in Basalt Canyon. This is also its type locality.

Unkar Group

The Unkar Group is a sequence of strata of Proterozoic age that are subdivided into five geologic formations and exposed within the Grand Canyon, Arizona, Southwestern United States. The 5-unit Unkar Group is the basal member of the 8-member Grand Canyon Supergroup. The Unkar is about 1,600 to 2,200 m thick and composed, in ascending order, of the Bass Formation, Hakatai Shale, Shinumo Quartzite, Dox Formation, and Cardenas Basalt. Units 4 & 5 are found mostly in the eastern region of Grand Canyon. Units 1 through 3 are found in central Grand Canyon. The Unkar Group accumulated approximately between 1250 and 1104 Ma. In ascending order, the Unkar Group is overlain by the Nankoweap Formation, about 113 to 150 m thick; the Chuar Group, about 1,900 m (6,200 ft) thick; and the Sixtymile Formation, about 60 m (200 ft) thick. These are all of the units of the Grand Canyon Supergroup. The Unkar Group makes up approximately half of the thickness of the 8-unit Supergroup.

Grand Canyon Supergroup

The Grand Canyon Supergroup is a Mesoproterozoic to Neoproterozoic sequence of sedimentary strata, mostly exposed in the eastern Grand Canyon of Arizona. This group is composed of the Unkar Group, Nankoweap Formation, Chuar Group and the Sixtymile Formation, which overlie Vishnu Basement Rocks. Several notable landmarks of the Grand Canyon, such as the "Isis Temple and Cheops Pyramid" and the "Apollo Temple," are surface manifestations of the Grand Canyon Supergroup.

Grouse Creek block An accreted terrane west of the Wyoming craton

The Grouse Creek block is a Precambrian basement province of 2.45 to 2.70 billion year old orthogneisses. The Grouse Creek block is one of several Proterozoic and Archean accreted terranes that lie to the north and west of the Wyoming craton, including the Farmington Canyon Complex, the Selway terrane, the Medicine Hat block and the Priest River complex. Together, these terranes comprise part of the basement rock of the North American continent and have been critical to studies of crustal accretion in the Precambrian. Ongoing study of the Grouse Creek block will contribute to understanding the paleogeography of the Wyoming craton prior to its incorporation into the supercontinent Laurentia approximately 1.86 billion years ago. The name was proposed by David Foster and others.

Hakatai Shale

The Hakatai Shale is a Mesoproterozoic rock formation that outcrops in the Grand Canyon, Coconino County, Arizona. It consists of colorful strata that exhibit colors that vary from purple to red to brilliant orange on outcrop. The colors are the result of the oxidation of iron-bearing minerals in the Hakatai Shale. It consists of lower and middle members that consist of bright-red, slope-forming, highly fractured, argillaceous mudstones and shale and an upper member composed of purple and red, cliff-forming, medium-grained sandstone. Its thickness, which apparently increases eastwards, varies from 137 to 300 m. In general, the Hakatai Shale and associated strata of the Unkar Group rocks dip northeast (10°-30°) toward normal faults that dip 60° or more toward the southwest. This can be seen at the Palisades fault in the eastern part of the main Unkar Group outcrop area. In addition, thick, prominent, and dark-colored basaltic sills and dikes cut across the purple to red to brilliant orange strata of the Hakatai Shale.

Bass Formation

The Bass Formation, also known as the Bass Limestone, is a Mesoproterozoic rock formation that outcrops in the eastern Grand Canyon, Coconino County, Arizona. The Bass Formation erodes as either cliffs or stair-stepped cliffs. In the case of the stair-stepped topography, resistant dolomite layers form risers and argillite layers form steep treads. In general, the Bass Formation in the Grand Canyon region and associated strata of the Unkar Group-rocks dip northeast (10°-30°) toward normal faults that dip 60+° toward the southwest. This can be seen at the Palisades fault in the eastern part of the main Unkar Group outcrop area. In addition, thick, prominent, and dark-colored basaltic sills intrude across the Bass Formation.

Shinumo Quartzite

The Shinumo Quartzite also known as the Shinumo Sandstone, is a Mesoproterozoic rock formation, which outcrops in the eastern Grand Canyon, Coconino County, Arizona,. It is the 3rd member of the 5-unit Unkar Group. The Shinumo Quartzite consists of a series of massive, cliff-forming sandstones and sedimentary quartzites. Its cliffs contrast sharply with the stair-stepped topography of typically brightly-colored strata of the underlying slope-forming Hakatai Shale. Overlying the Shinumo, dark green to black, fissile, slope-forming shales of the Dox Formation create a well-defined notch. It and other formations of the Unkar Group occur as isolated fault-bound remnants along the main stem of the Colorado River and its tributaries in Grand Canyon.

Typically, the Shinumo Quartzite and associated strata of the Unkar Group dip northeast (10°-30°) toward normal faults that dip 60+° toward the southwest. This can be seen at the Palisades fault in the eastern part of the main Unkar Group outcrop area.

Dox Formation

The Dox Formation, also known as the Dox Sandstone, is a Mesoproterozoic rock formation that outcrops in the eastern Grand Canyon, Coconino County, Arizona. The strata of the Dox Formation, except for some more resistant sandstone beds, are relatively susceptible to erosion and weathering. The lower member of the Dox Formation consists of silty-sandstone and sandstone, and some interbedded argillaceous beds, that form stair-stepped, cliff-slope topography. The bulk of the Dox Formation typically forms rounded and sloping hill topography that occupies an unusually broad section of the canyon.

The Neoproterozoic Chuar Group consists of 5,250 feet (1,600 m) of fossiliferous, unmetamorphosed sedimentary strata that is composed of about 85% mudrock. The Group is the approximate upper half of the Grand Canyon Supergroup, overlain by the thin, in comparison, Sixtymile Formation, the top member of the multi-membered Grand Canyon Supergroup.

The geology of Utah includes rocks formed at the edge of the proto-North American continent during the Precambrian. A shallow marine sedimentary environment covered the region for much of the Paleozoic and Mesozoic, followed by dryland conditions, volcanism and the formation of the basin and range terrain in the Cenozoic. Utah is a state in the western United States.

Rinconada Formation

The Rinconada Formation is a geologic formation that crops out in the Picuris Mountains of northern New Mexico. Detrital zircon geochronology establishes a maximum age for the Rinconada Formation of about 1723 Mya, placing it in the Statherian period.

Marquenas Formation

The Marquenas Formation is a geological formation that crops out in the Picuris Mountains of northern New Mexico. Detrital zircon geochronology gives it a maximum age of 1435 million years, corresponding to the Calymmian period.

References

  1. 1 2 3 Yonkee, W.A, Willis, G.C., and Doelling, H.H., 2000, Proterozoic and Cambrian Sedimentary and Low-grade Metasedimentary Rocks on Antelope Island, in The Geology of Antelope Island, Davis County, Utah, eds. J.K. King and G.C. Willis, Utah Geological Survey, p. 37–47.
  2. 1 2 Granger, A.E., Calkins, F.C., Crittenden, M.D., Jr., and Sharp, B.J., 1952, Geology of the Wasatch Mountains east of Salt Lake City, IN Marcel, R.E., ed., Geology of the central Wasatch Mountains, Utah: Utah Geological Society, Guidebook to the geology of Utah, no. 8, p. 1-37.
  3. 1 2 Knoll, A.H., Blick, N., and Awramik, S.M., 1981, Stratigraphic and ecologic implications of late Precambrian microfossils from Utah: American Journal of Science, v. 281, no. 3, p. 247-263.