Kaibab Limestone | |
---|---|
Stratigraphic range: Early to Middle Permian, Leonardian to Roadian [1] [2] [3] | |
Type | Geological formation |
Sub-units | Fossil Mountain and Harrisburg members |
Underlies | Moenkopi Formation |
Overlies | Toroweap Formation, Coconino Sandstone, and White Rim Sandstone |
Thickness | 300 feet (91 m)-500 feet (150 m) in Grand Canyon region. |
Lithology | |
Primary | fossiliferous limestone, sandy limestone, dolomite, and chert |
Other | gypsum, siltstone, and sandstone |
Location | |
Region | Arizona–(northern) California–(southeast) Nevada–(east-central) and, Utah–(southern) |
Country | United States – (Southwestern United States) |
Type section | |
Named for | It was named for the Kaibab Plateau, northern Arizona [4] |
Named by | Darton (1910) [4] |
The Kaibab Limestone is a resistant cliff-forming, Permian geologic formation that crops out across the U.S. states of northern Arizona, southern Utah, east central Nevada and southeast California. It is also known as the Kaibab Formation in Arizona, Nevada, and Utah. The Kaibab Limestone forms the rim of the Grand Canyon. In the Big Maria Mountains, California, the Kaibab Limestone is highly metamorphosed and known as the Kaibab Marble. [2] [3]
The Kaibab Limestone was named by Darton [4] in 1910 for the Kaibab Plateau, which is on the north side of Grand Canyon in Coconino County, Arizona. In his definition of the Kaibab Limestone formation, no type locality was designated. He also designated the Kaibab Limestone as the upper formation of the Aubrey Group, a now-abandoned stratigraphic unit. In 1921, Bassler and Reeside revised Darton's work and defined the Harrisburg Member of the Kaibab Limestone. [5] In his 1938 monograph on the Toroweap Formation and Kaibab Limestone of northern Arizona, [6] McKee split Darton's original Kaibab Limestone into the currently recognized Kaibab Limestone and Toroweap Formation. He also revised Kaibab Limestone's lower contact and divided it into informal (descending) alpha, beta and gamma members. Later in the 1970s, its upper contact was revised and its areal extent were defined. Also, unsuccessful attempts were made to raise the formation to group rank and divide it into several formations. In 1982, Warren Hamilton renamed it as the Kaibab Marble and determined its areal extent for California. [7] In 1991, Sorauf and Billingsley subdivided the Kaibab Limestone into (ascending) Fossil Mountain Member (new) and Harrisburg Member. [8] They designated the strata comprising McKee's alpha (or upper) member as the Harrisburg Member and the strata comprising McKee's beta (or middle) member as the Fossil Mountain Member. The Fossil Mountain Member was named for Fossil Mountain along the south rim near the Bass Trail. McKee's gamma member is considered to be part of the Fossil Mountain Member. Later research has further redefined the regional extent of the Kaibab Limestone. [1] [2] [3]
The Kaibab Limestone is an assemblage of sedimentary rock types. It consists of a complexity of inter fingering and inter bedded carbonate and siliciclastic sedimentary rocks. In addition, intense post-depositional (diagenetic) changes have produced a more composition variation by the alteration of limestone to dolomite and the silicification of limestone to form chert. In the western Grand Canyon region, the Fossil Mountain Member consists of fossiliferous and cherty limestone with an abundant and diverse normal-marine fossil fauna. Further east in the Coconino Plateau region, the lithology, mineralogy, and fauna of the Fossil Mountain Member changes drastically where it grades laterally into sandy dolomite and dolomite that contains a restricted-marine fossil fauna and subordinate amounts of sandstone. The Harrisburg Member, which forms the uppermost cliffs and receding ledges along both north and south rims of the Grand Canyon, consists of an assemblage of gypsum, dolomite, sandstone, redbeds, chert, and minor limestone. [1] [2] [3] [6]
Within the Grand Canyon region, the Kaibab Limestone overlies gypsum and contorted sandstones of the Toroweap Formation. Originally, geologists interpreted the lower contact of the Kaibab Limestone to be an unconformity based on the presence of local intraformational breccias and erosional surfaces. [6] However, additional research has concluded that these local intraformational breccias and erosional surfaces are the result of collapse following the dissolution of evaporite deposits within the upper part of the Toroweap Formation. As a result, this contact is inferred to be conformable or only locally a disconformity. South and east of the Grand Canyon, the evaporites and contorted sandstones (sabkha deposits) of Toroweap Formation interfinger with and are replaced by cross-bedded sandstones of the Coconino Sandstone. As a result, the Kaibab Limestone directly overlies the Coconino Sandstone in the Mogollon Rim region. The Kaibab Limestone directly overlies the White Rim Sandstone in northeastern Arizona and southeastern Utah. [1] [6]
The upper contact of the Kaibab Limestone (Harrisburg Member) with the overlying Moenkopi Formation is an erosional unconformity and disconformity. Within northwestern Arizona, southeastern Nevada, and southwestern Utah this contact is an erosional unconformity that in part consists of paleovalleys, as much as several hundred feet deep, and paleokarst that were eroded into the underlying Kaibab Limestone before the deposition of the Moenkopi Formation. These paleovalleys are often filled with conglomerates and breccias that are known as the Rock Canyon conglomerate. Within the Marble Canyon and eastern Grand Canyon regions and south into Verde Valley, upper contact of the Kaibab Limestone with the Moenkopi Formation is an erosional disconformity. This disconformity exhibits little relief and is identified by marked differences in color, topography, and rock types between tan, ledge-forming, calcareous sandstones and of the Kaibab Limestone and red, slope-forming siltstones of the Moenkopi formation. The unconformity and disconformity are inferred to represent most of Permian time (including the Leonardian) and part of Early Triassic time. [1] [6] [8]
Although the Moenkopi Formation overlies the Kaibab Limestone, its redbeds have been removed almost entirely by erosion because they are less resistant to erosion than the strata of the Kaibab Formation. As a result, the Kaibab Limestone forms the surface of many of the vast plateaus that border the Grand Canyon. Within these plateaus, the uppermost beds of the Kaibab Limestone have also been largely removed by erosion. [1]
The Kaibab Limestone contains the abundant fossils of Permian invertebrates and vertebrates. The invertebrate fossils found within the Kaibab Limestone include brachiopods, conodonts, corals, crinoids, echinoid spines, mollusks, hexactinellid and other sponges, trilobites, and burrows of callanassid shrimp. The fossil cephalopods found in the Kaibab Limestone include giant football-sized nautiloids. [1] [6] Fossil shark teeth, which represent a diverse assemblage of chondrichthyans, occur within the Kaibab Limestone of Arizona. [6] [9] [10]
The complex intercalation of carbonate and clastic sediments within the Kaibab Limestone reflects the deposition of sediments within a gently sloping continental margin during a period of frequent, high-frequency sea level changes. Relatively minor changes in sea level caused major lateral shifts in the position of supratidal, subtidal, and shallow-marine environments during the deposition of the Kaibab Limestone. The shifting sea levels and associated depositional environments brought about a complex interlayering of different types of carbonate and clastic sediments in the strata that comprise the Kaibab Limestone. The gently sloping continental margin on which the Kaibab Limestone accumulated, extended seaward from northern Arizona to southern Nevada, at times exceeding 200 miles (125 km) in width. It is most likely that the high-frequency changes in sea level were caused by glacial sea level oscillations during this time period. [1]
Early paleontological studies of the Kaibab Limestone firmly established its age on the basis of the abundant fossils that it and the underlying Toroweap Formation contain. On the basis of its brachiopod and siliceous sponge faunas, it was initially concluded that it is Leonardian (approximately Kungurian / latest Early Permian) in age. [1] [6] [11] Later research concerning conodonts and associated megafossils obtained from western outcrops of the Fossil Mountain Member indicates that its age extends into the Roadian (latest Early Permian and earliest Middle Permian) age. [1] [12]
Geologic Province: [3]
Parklands (incomplete list):
Other:
The geology of the Grand Canyon area includes one of the most complete and studied sequences of rock on Earth. The nearly 40 major sedimentary rock layers exposed in the Grand Canyon and in the Grand Canyon National Park area range in age from about 200 million to nearly 2 billion years old. Most were deposited in warm, shallow seas and near ancient, long-gone sea shores in western North America. Both marine and terrestrial sediments are represented, including lithified sand dunes from an extinct desert. There are at least 14 known unconformities in the geologic record found in the Grand Canyon.
The geology of the Zion and Kolob canyons area includes nine known exposed formations, all visible in Zion National Park in the U.S. state of Utah. Together, these formations represent about 150 million years of mostly Mesozoic-aged sedimentation in that part of North America. Part of a super-sequence of rock units called the Grand Staircase, the formations exposed in the Zion and Kolob area were deposited in several different environments that range from the warm shallow seas of the Kaibab and Moenkopi formations, streams and lakes of the Chinle, Moenave, and Kayenta formations to the large deserts of the Navajo and Temple Cap formations and dry near shore environments of the Carmel Formation.
The Grand Staircase is an immense sequence of sedimentary rock layers that stretch south from Bryce Canyon National Park and Grand Staircase–Escalante National Monument, through Zion National Park, and into Grand Canyon National Park.
The exposed geology of the Capitol Reef area presents a record of mostly Mesozoic-aged sedimentation in an area of North America in and around Capitol Reef National Park, on the Colorado Plateau in southeastern Utah.
The Cutler Formation or Cutler Group is a rock unit that is exposed across the U.S. states of Arizona, northwest New Mexico, southeast Utah and southwest Colorado. It was laid down in the Early Permian during the Wolfcampian epoch.
The Moenkopi Formation is a geological formation that is spread across the U.S. states of New Mexico, northern Arizona, Nevada, southeastern California, eastern Utah and western Colorado. This unit is considered to be a group in Arizona. Part of the Colorado Plateau and Basin and Range, this red sandstone was laid down in the Lower Triassic and possibly part of the Middle Triassic, around 240 million years ago.
Coconino Sandstone is a geologic formation named after its exposure in Coconino County, Arizona. This formation spreads across the Colorado Plateau province of the United States, including northern Arizona, northwest Colorado, Nevada, and Utah.
The Hurricane Cliffs of southwest Utah and northwest Arizona are a red, limestone geographic feature, sets of cliffs along the western, eroded edge of the Kaibab Limestone; the cliffs are about 135-mi (217 km) long, with the south end terminus just north of the Grand Canyon. The cliffs are associated with the Hurricane Fault.
The Tonto Group is a name for an assemblage of related sedimentary strata, collectively known by geologists as a Group, that comprises the basal sequence Paleozoic strata exposed in the sides of the Grand Canyon. As currently defined, the Tonto groups consists of the Sixtymile Formation, Tapeats Sandstone, Bright Angel Shale, Muav Limestone, and Frenchman Mountain Dolostone. Historically, it included only the Tapeats Sandstone, Bright Angel Shale, and Muav Limestone. Because these units are defined by lithology and three of them interfinger and intergrade laterally, they lack the simple layer cake geology as they are typically portrayed as having and geological mapping of them is complicated.
The Muav Limestone is a Cambrian geologic formation within the 5-member Tonto Group. It is a thin-bedded, gray, medium to fine-grained, mottled dolomite; coarse- to medium-grained, grayish-white, sandy dolomite and grayish-white, mottled, fine-grained limestone. It also contains beds of shale and intraformational conglomerate. The beds of the Muav Limestone are either structureless or exhibit horizontally laminations and cross-stratification. The Muav Limestone forms cliffs or small ledges that weather a dark gray or rusty-orange color. These cliffs or small ledges directly overlie the sloping surfaces of the Bright Angel Shale. The thickness of this formation decreases eastward from 76 m (249 ft) in the western Grand Canyon to 14 m (46 ft) in the eastern Grand Canyon. To the west in southern Nevada, its thickness increases to 250 m (820 ft) in the Frenchman Mountain region.
The Middle Permian Toroweap Formation is a thin, darker geologic unit, between the brighter colored units of the Kaibab Limestone above, and Coconino Sandstone below. It is a prominent unit in Grand Canyon, Arizona, Southwestern United States, found through sections of the South Rim, Grand Canyon, and the North Rim, of the Kaibab Plateau; also the Kaibab's southeast extension to Cape Royal, the Walhalla Plateau. The Colorado River of the Grand Canyon makes its excursion from due-south to due-west around the Walhalla Plateau, as it enters the east end of the Grand Canyon's interior, Granite Gorge. The formation is also found in southeast Utah.
The Toroweap Fault of northwest Arizona and southwest Utah is part of a fault system of the west Grand Canyon region, Arizona, US; also the west perimeter regions of the Coconino and Colorado Plateaus. The Hurricane Fault originates at the Toroweap Fault, in the region of the Colorado River, and strikes as the westerly depression of the Toroweap Fault. The Toroweap strikes northerly from the Colorado at the east of Toroweap Valley, and enters south Utah; from the Colorado River, the Hurricane Fault strikes north-northwest along the west flank of the small, regional Uinkaret Mountains, the west border of Toroweap Valley. The Hurricane Fault, and the Hurricane Cliffs strike into southwest Utah as part of the west, and southwest perimeter of the Colorado Plateau. The Hurricane Cliffs are made of Kaibab Limestone, an erosion resistant, cliff-forming rock unit.
Isis Temple is a prominence in the Grand Canyon, Arizona, Southwestern United States. It is located below the North Rim and adjacent to the Granite Gorge along the Colorado River. The Trinity Creek and canyon flow due south at its west border; its north, and northeast border/flank is formed by Phantom Creek and canyon, a west tributary of Bright Angel Creek; the creeks intersect about 3 mi (4.8 km) southeast, and 1.0 mi (1.6 km) north of Granite Gorge. The Isis Temple prominence, is only about 202 ft (62 m) lower than Grand Canyon Village, the main public center on Grand Canyon’s South Rim.
The Lower Permian Esplanade Sandstone is a cliff-forming, resistant sandstone, dark red, geologic unit found in the Grand Canyon. The rock unit forms a resistant shelf in the west Grand Canyon, south side of the Colorado River, at the east of the Toroweap Fault, down-dropped to west, southeast of Toroweap Overlook, and west of Havasupai. The red, sandstone shelf, The Esplanade is about 20-mi long. At Toroweap Overlook region, Toroweap Valley with Vulcan's Throne, Uinkaret volcanic field, the resistant Esplanade Sandstone is described in access routes exploring the Toroweap Lake area.
The Supai Group is a slope-forming section of red bed deposits found in the Colorado Plateau. The group was laid down during the Pennsylvanian to Lower Permian. Cliff-forming interbeds of sandstone are noticeable throughout the group. The Supai Group is especially exposed throughout the Grand Canyon in northwest Arizona, as well as local regions of southwest Utah, such as the Virgin River valley region. It occurs in Arizona at Chino Point, Sycamore Canyon, and famously at Sedona as parts of Oak Creek Canyon. In the Sedona region, it is overlain by the Hermit Formation, and the colorful Schnebly Hill Formation.
The White Rim Sandstone is a sandstone geologic formation located in southeastern Utah. It is the last member of the Permian Cutler Group, and overlies the major Organ Rock Formation and Cedar Mesa Sandstone; and again overlies thinner units of the Elephant Canyon and Halgaito Formations.
The Shinarump Conglomerate is a geologic formation found in the Four Corners region of the United States. It was deposited in the early part of the Late Triassic period.
The Redwall Limestone is an erosion-resistant, Mississippian age, cliff-forming geological formation that forms prominent, red-stained cliffs in the Grand Canyon. these cliffs range in height from 150 m (490 ft) to 244 m (801 ft). It is one of the most fossiliferous formations exposed in the Grand Canyon region.
The Devonian Temple Butte Formation, also called Temple Butte Limestone, outcrops through most of the Grand Canyon of Arizona, USA; it also occurs in southeast Nevada. Within the eastern Grand Canyon, it consists of thin, discontinuous and relatively inconspicuous lenses that fill paleovalleys cut into the underlying Muav Limestone. Within these paleovalleys, it at most, is only about 100 feet (30 m) thick at its maximum. Within the central and western Grand Canyon, the exposures are continuous. However, they tend to merge with cliffs of the much thicker and overlying Redwall Limestone.
Fossil Mountain is a 6,729-foot-elevation summit located in the Western Grand Canyon, in Coconino County of northern Arizona, Southwestern United States. It is situated ~1.5 miles due east of Mount Huethawali, about 1.0 miles southeast of the Grand Scenic Divide, and 1.0 mi west of Havasupai Point.
The Fossil Mountain prominence is a massif-remainder cliff of Kaibab Limestone, and stands above a tableland of the South Rim, a forested plateau of Kaibab Limestone.