"be as old as 70 million years. However, this study has been criticized by those who support the ""young canyon"" age of around six million years as ""[an] attempt to push the interpretation of their new data to their limits without consideration of the whole range of other geologic data sets."" The canyon is the result of erosion which exposes one of the most complete geologic columns on the planet. The major geologic exposures in the Grand Canyon range in age from the 2-billion-year-old Vishnu Schist at the bottom of the Inner Gorge to the 230-million-year-old Kaibab Limestone on the"
"Granite and other granites, were intruded into the major unit of the Vishnu Schist, the basement paleo unit found in the Inner Gorge region of the Grand Canyon. The neighboring Sierra Ancha range has another occurrence of the Great Unconformity, with a sandstone unit that is an analogue of the Tapeats Sandstone. The Arizona 87 highway section south of Pine is where the north Mazatzal Mountains merge into the western region of the Mogollon Rim, as the Rim continues northwest into the Oak Creek Canyon region. Verde River Sycamore Creek Barnhardt Trail #43 - North East corner just south of"
"the Grand Canyon, in Salt River Canyon, and in mountain ranges throughout the state. Arizona's oldest rocks overall are metamorphosed volcanic rocks, including basalt and rhyolite and related sedimentary rocks, that now constitute the bottom of the Grand Canyon and formed beginning 1.8 billion years ago. The Verde district at Jerome, in Yavapai County also preserves rocks from this period. There, ancient submarine hydrothermal vents precipitated sulfides directly onto an ancient seabed, creating massive copper and zinc ore sulfide deposits. The Mazatzal orogeny occurred from 1.7 to 1.61 billion years ago. During this event, igneous rocks that were more enriched"
"collided with the proto-North American continent. This process of plate tectonics compressed and grafted the marine sediments in the basin onto the mainland and uplifted them out of the sea. Later, these rocks were buried under the surface and pressure-cooked into metamorphic rock. The resulting Granite Gorge Metamorphic Suite, which is part of the Vishnu Basement Rocks, consists of the metasedimentary Vishnu Schist and the metavolcanic Brahma and Rama Schists that were formed 1.75 billion to 1.73 billion years ago. This is the resistant rock now exposed at the bottom of the canyon in the Inner Gorge. As the volcanic"
"Geology of the Grand Canyon area 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"
"the south side of Granite Gorge, on the platform. The Tonto Group units were deposited on an ancient erosion surface (angular unconformity) on the Vishnu Basement Rocks. The Vishnu sequence has a dip of about 45 degrees. As this unconformity represents about 1,000 million years (1.0 billion years) of non–deposition, tectonic activity and erosion on the Vishnu Basement Rocks is called the Great Unconformity. Beyond the Grand Canyon area the Muav occurs in southern Utah, southern Nevada and southern California. In the California occurrence it is known as the Muav Marble. The units of the Tonto Group: Muav Limestone The"
"age of 2.3 billion years. Other geologists found 2.4 billion year old schist and gneiss in the Albion Range Green Creek Complex. Prior to the 1960s, geologists inferred the Vishnu and Farmington Canyon gneiss and schist as Archean in age, but subsequent research indicated an formation between 1.6 and 1.5 billion years ago in the Proterozoic. From 1.75 to 1.65 billion years ago, Utah was impacted by the Matzatzal Orogeny. Thick sequences of sedimentary rocks from the Neoproterozoic, including tillite underlie much of the state. Utah has numerous rocks deposited during the Paleozoic, as multicellular life diversified for the first"
"between 1,253 to 1,104 million years old. It is younger than a layer of volcanic ash in the underlying Bass Formation that has been dated at 1,253 million years. In addition, the Ar/Ar dating of detrital muscovite from the basal, Escalante Creek Member of the overlying Dox Formation indicates that it is younger than 1,140 million years. The overlying Dox Formation is older than the age of the Cardenas Basalt, which is 1,104 million years. Isis Temple-Cheops Pyramid is a small horst, located close to the geographic center of the Grand Canyon. It is bordered on the east by the"
"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. The Grand Canyon Supergroup overlies the Vishnu Basement Rocks, but were never subjected to metamorphism. The units of the Supergroup were faulted and then tilted from 10"
"side. Temperatures on the North Rim are generally lower than those on the South Rim because of the greater elevation (averaging above sea level). Heavy rains are common on both rims during the summer months. Access to the North Rim via the primary route leading to the canyon (State Route 67) is limited during the winter season due to road closures. The Grand Canyon is part of the Colorado River basin which has developed over the past 70 million years, in part based on apatite (U-Th)/He thermochronometry showing that Grand Canyon reached a depth near to the modern depth by"
"Pine, on Arizona State Route 87, at the northeast region of the Mazatzal Wilderness, north terminus of the Mazatzal Mountains, the route traverses the contact between two important geologic units. The horizontally laid Tapeats Sandstone, (common areal extent in Grand Canyon), was deposited on Precambrian granite, the Zoroaster Granite. The time between the erosion of the lower unit and deposition of the horizontal sandstone above, is about 1 billion years-(1,000 million years), and is named the Great Unconformity. Besides its occurrence in the Grand Canyon, it is also found west, in the Las Vegas Valley, at Frenchman Mountain. The Zoroaster"
"that extended from at least present-day Lake Superior to Glacier National Park in Montana to the Grand Canyon and the Uinta Mountains. The resulting Grand Canyon Supergroup of sedimentary units is composed of nine varied geologic formations that were laid down from 1.2 billion and 740 million years ago in this sea. Good exposures of the supergroup can be seen in eastern Grand Canyon in the Inner Gorge and from Desert View, Lipan Point and Moran point. The oldest section of the supergroup is the Unkar Group. It accumulated in a variety of fluvial, deltaic, tidal, nearshore marine, and offshore"
"up the Rocky Mountains to the north and east and tremendous, earth-stretching tension created the Basin and Range province to the west and south. Sub ranges of the Southern Rocky Mountains are scattered throughout the Colorado Plateau. The Precambrian and Paleozoic history of the Colorado Plateau is best revealed near its southern end where the Grand Canyon has exposed rocks with ages that span almost 2 billion years. The oldest rocks at river level are igneous and metamorphic and have been lumped together as Vishnu Basement Rocks; the oldest ages recorded by these rocks fall in the range 1950 to"
"Grand Canyon Caverns The Grand Canyon Caverns ( or , ), located just a few miles east of Peach Springs, Arizona, lie below ground level. They are among the largest dry caverns in the United States. Dry caverns compose only 3% of caverns in the world. Because of the lack of water, stalagmites and stalactites are rare in the caverns. During the Mississippian Period, 345 million years ago, the southwestern United States was covered by ocean. Skeletons of sea life settling to the depths, created a mud with a high percentage of calcium. This eventually hardened into the limestone bedrock"
"remainder of the Early Paleoproterozoic granites, granitic pegmatites, aplites, and granodiorites – are parts of either younger plutons or dike swarms, that have intruded the Granite Gorge Metamorphic Suite, either contemporaneously with, or after they were metamorphosed. The Granite Gorge Metamorphic Suite consists of lithologic units, the Brahma, Rama, and Vishnu schists, that have been mapped within the Upper, Middle, and Lower Granite Gorges of the Grand Canyon. The Vishnu Schist consists of quartz-mica schist, pelitic schist, and meta-arenites. They exhibit relict sedimentary structures and textures that demonstrate that they are metamorphosed submarine sedimentary rocks. The Brahma Schist consists of"
"The Apache Group near the bottom of the Grand Canyon, includes fluvial shale and sandstone, as well as limestone from a shallow sea, exposed in the Salt River Canyon. The limestone contains stromatolite remains, mounds of blue-green algae. The Apache Group was intruded with basalt and diabase between 1.05 and 1.14 billion years ago. The Mescal Limestone metamorphosed, forming asbestos and superheated diabase magma ""baked"" the limestone to marble. The 1.07 billion year old limestone, shale, quartzite, sandstone and basalt of the Unkar Group is also found in the Grand Canyon. The Mesoproterozoic formations in the Grand Canyon are overlain"
"Group. This disconformity is sharp and locally truncates cross-bedding and channels exhibited by sandstones in the underlying Hakatai Shale. Within the Shinumo Quartzite, a basal lag composed of a layer of conglomerate, which contains basement clasts up to across, lies on the eroded surface that forms this disconformity. This basal conglomerate contains quartzite clasts that lack any known equivalents in the Grand Canyon region. As documented by the dating of detrital zircons, this disconformity is estimated to represent a period of about 75 million years. The age and exhumation history of the underlying Vishnu Basement Rocks constrain the age of"
"highly metamorphosed igneous rocks and shale, from basalt, mud and clay laid from volcanic eruptions, and the granite is the result of magma intrusions into the Vishnu schist. An extensive cross section of sedimentary rocks laid down on top of it through the ages is visible as well. The basement rocks of the continental crust tend to be much older than the oceanic crust. The oceanic crust can be from 0-250 million years in age, and is usually thinner (10 miles or so) and composed of basaltic rocks. Continental crust is older because continental crust is light and thick enough"
"these basaltic sills and dikes range in age from 1,050 to 1,140 Ma. Quite unlike, the Grand Canyon asbestos deposits, the asbestos deposits of the Sierra Ancha-Salt River Canyon region have been extremely productive. 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 and associated strata of the Unkar Group"
"1680 million years. An erosion surface on the ""Vishnu Basement Rocks"" is covered by sedimentary rocks and basalt flows, and these rocks formed in the interval from about 1250 to 750 million years ago: in turn, they were uplifted and split into a range of fault-block mountains. Erosion greatly reduced this mountain range prior to the encroachment of a seaway along the passive western edge of the continent in the early Paleozoic. At the canyon rim is the Kaibab Formation, limestone deposited in the late Paleozoic (Permian) about 270 million years ago. A extension of the Ancestral Rocky Mountains called"
"the Coconino Plateau, an area riddled with numerous cavernous veins that run for miles in all directions. Grand Canyon Caverns The Grand Canyon Caverns ( or , ), located just a few miles east of Peach Springs, Arizona, lie below ground level. They are among the largest dry caverns in the United States. Dry caverns compose only 3% of caverns in the world. Because of the lack of water, stalagmites and stalactites are rare in the caverns. During the Mississippian Period, 345 million years ago, the southwestern United States was covered by ocean. Skeletons of sea life settling to the"
"surface that forms this disconformity. This basal conglomerate contains quartzite clasts that lack any known equivalents in the Grand Canyon region. As documented by the dating of detrital zircons, this disconformity is estimated to represent a period of about 75 million years. The contact between the Tapeats Sandstone and Hatakai Shale and the rest of the folded and faulted Unkar Group is a prominent angular unconformity, which is part of the Great Unconformity. The differential erosion of the Unkar Group left resistant beds of the Cardenas Basalt and Shinumo Quartzite as topographic highs, ancient monadnocks, that are now buried by"
"Plateau, (Cape Royal at Walhalla Plateau). The Colorado River immediately turns due-west here to soon enter the Granite Gorge region (East Inner Gorge), which is made up of the Vishnu Basement Rocks. 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 km (120 mi) 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."
"Grand Canyon The Grand Canyon (Hopi: ""Ongtupqa""; , Navajo: ""Tsékooh Hatsoh"", Spanish: ""Gran Cañón"") is a steep-sided canyon carved by the Colorado River in Arizona, United States. The Grand Canyon is long, up to wide and attains a depth of over a mile (). The canyon and adjacent rim are contained within Grand Canyon National Park, the Kaibab National Forest, Grand Canyon-Parashant National Monument, the Hualapai Indian Reservation, the Havasupai Indian Reservation and the Navajo Nation. President Theodore Roosevelt was a major proponent of preservation of the Grand Canyon area, and visited it on numerous occasions to hunt and enjoy"
"along the south side of the Ochoco Mountains. All three exposures, consisting mainly of tuffaceous sediments and pyroclastic rock rich in silica, lie unconformably between the older rocks of the Clarno Formation below and Columbia River basalts above. The strata, which vary in age from 39 million years to 18 million years, were formed mainly from ashfalls from volcanoes due to a series of calderas now linked to the Yellowstone hotspot. Some of the major layers within the group exposed in the Picture Gorge district are the Big Basin Formation and Bridge Creek Beds (35 to 32 million years), the"
"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. It is about thick and composed, in ascending order, of the Bass Formation, Hakatai Shale, Shinumo Quartzite, Dox Formation, and Cardenas Basalt. It accumulated approximately between 1250 and 1104 Ma (1,104 million years ago, 1.1 billion). In ascending order, the Unkar Group is overlain by the Nankoweap Formation, about thick; the Chuar Group, about thick; and the Sixtymile Formation, about thick. The Nankoweap and Sixtymile formations together with the Chuar"
"Glen Canyon Group The Glen Canyon Group is a geologic group of formations that is spread across the U.S. states of Nevada, Utah, northern Arizona, north west New Mexico and western Colorado. It is sometimes called the Glen Canyon Sandstone in Colorado and Utah. There are four formations within the group. From oldest to youngest, these are the Wingate Sandstone, Moenave Formation, Kayenta Formation, and Navajo Sandstone. Part of the Colorado Plateau and the Basin and Range, this group of formations was laid down during the Late Triassic and Early Jurassic, with the Triassic-Jurassic boundary within the Wingate Sandstone. The"
"20 Ma. A recent study examining caves near Grand Canyon places their origins beginning about 17 million years ago. Previous estimates had placed the age of the canyon at 5–6 million years. The study, which was published in the journal ""Science"" in 2008, used uranium-lead dating to analyze calcite deposits found on the walls of nine caves throughout the canyon. There is a substantial amount of controversy because this research suggests such a substantial departure from prior widely supported scientific consensus. In December 2012, a study published in the journal ""Science"" claimed new tests had suggested the Grand Canyon could"
"of erosion, the Great Unconformity, of 1,000 million years (1.0 billion). Besides the ""erosion unconformity"", the Unkar Group of the basement rocks are also at an ""angular unconformity"", being an 8-member sequence tilted at 45 degrees. The horizontal Tonto Platform has hiking trails that cross it from the South Rim to North Rim, Grand Canyon for instance. The extensive Tonto Trail lies on parts of the Tapeats Sandstone, and the platform on the south side of Granite Gorge. The units of the Tonto Group: Examples of the ""deposition unconformity"" of time (550-800 million yrs), the Great Unconformity. The Tapeats approximately"
"1860 during the Little Ice Age. All of the geological processes, above, have left a complex set of rocks exposed at the surface. For example, in the Rockies of Colorado, there is extensive granite and gneiss dating back to the Ancestral Rockies. In the central Canadian Rockies, the main ranges are composed of the Precambrian mudstones, while the front ranges are composed of the Paleozoic limestones and dolomites. Volcanic rock from the Cenozoic (66 million–1.8 million years ago) occurs in the San Juan Mountains and in other areas. Millennia of severe erosion in the Wyoming Basin transformed intermountain basins into"
"as 2 billion years. The of the river that flow through the Grand Canyon are largely encompassed by Grand Canyon National Park and are known for their difficult whitewater, separated by pools that reach up to in depth. At the lower end of Grand Canyon, the Colorado widens into Lake Mead, the largest reservoir in the continental United States, formed by Hoover Dam on the border of Arizona and Nevada. Situated southeast of metropolitan Las Vegas, the dam is an integral component for management of the Colorado River, controlling floods and storing water for farms and cities in the lower"
"Cenozoic-aged rocks that are 100 million years younger. In fact the youngest formation seen in the Zion area is the oldest exposed formation in Bryce Canyon – the Dakota Sandstone. There are, however, shared rock units between all three, creating a super-sequence of formations that geologists call the Grand Staircase. Bryce Canyon's formations are the youngest known units in the Grand Staircase. Younger rock units, if they ever existed, have been removed by erosion. These layers have undergone 5000 to 10,000 feet (1500 to 3000 m) of uplift starting about 66 million years ago with the Laramide orogeny which has"
"a partial rifting of the continent. The collision expanded the continent from the Wyoming–Colorado border into Mexico and almost doubled the crust's thickness in the Grand Canyon region. Part of this thickening created the high ancestral Mazatzal Mountains. Subsequent erosion lasting 300 million years stripped much of the exposed sediments and the mountains away. This reduced the very high mountains to small hills a few tens to hundreds of feet (tens of meters) high. Geologist John Wesley Powell called this major gap in the geologic record, which is also seen in other parts of the world, the Great Unconformity. Other"