The Precambrian ( / p r i ˈ k æ m b r i . ə n , - ˈ k eɪ m -/ pree- KAM -bree-ən, -KAYM- ; or Pre-Cambrian , sometimes abbreviated pC , or Cryptozoic ) is the earliest part of Earth's history , set before the current Phanerozoic Eon. The Precambrian is so named because it preceded the Cambrian , the first period of the Phanerozoic Eon , which is named after Cambria , the Latinized name for Wales , where rocks from this age were first studied. The Precambrian accounts for 88% of the Earth's geologic time.
45-878: Grand Canyon National Park is a national park of the United States located in northwestern Arizona , the 15th site to have been named as a national park. The park's central feature is the Grand Canyon , a gorge of the Colorado River , which is often considered one of the Wonders of the World . The park, which covers 1,217,262 acres (1,901.972 sq mi; 4,926.08 km) of unincorporated area in Coconino and Mohave counties , received more than 4.7 million recreational visitors in 2023. The Grand Canyon
90-708: A supereon , but this is also an informal term, not defined by the ICS in its chronostratigraphic guide. Eozoic (from eo- "earliest") was a synonym for pre-Cambrian , or more specifically Archean . A specific date for the origin of life has not been determined. Carbon found in 3.8 billion-year-old rocks (Archean Eon) from islands off western Greenland may be of organic origin. Well-preserved microscopic fossils of bacteria older than 3.46 billion years have been found in Western Australia . Probable fossils 100 million years older have been found in
135-735: A possible 2450 Ma red alga from the Kola Peninsula , 1650 Ma carbonaceous biosignatures in north China, the 1600 Ma Rafatazmia , and a possible 1047 Ma Bangiomorpha red alga from the Canadian Arctic. The earliest fossils widely accepted as complex multicellular organisms date from the Ediacaran Period. A very diverse collection of soft-bodied forms is found in a variety of locations worldwide and date to between 635 and 542 Ma. These are referred to as Ediacaran or Vendian biota . Hard-shelled creatures appeared toward
180-424: A shuttle can return hikers to their point of origin. Mather Point, the first view most people reach when entering from the south entrance, is a popular place to begin. Private canyon flyovers are provided by helicopters and small airplanes out of Las Vegas, Phoenix , and Grand Canyon National Park Airport . Due to a crash in the 1990s, scenic flights are no longer allowed to fly within 1,500 feet (460 m) of
225-540: Is Gateway Arch National Park , Missouri , at 192.83 acres (0.7804 km ). The total area protected by national parks is approximately 52.4 million acres (212,000 km ), for an average of 833 thousand acres (3,370 km ) but a median of only 220 thousand acres (890 km ). The national parks set a visitation record in 2021, with more than 92 million visitors. Great Smoky Mountains National Park in North Carolina and Tennessee has been
270-469: Is 7a with an average annual extreme minimum temperature of 3.3 °F (−15.9 °C). There are few roads on the North Rim, but there are some notable vehicle-accessible lookout points, including Point Imperial, Roosevelt Point, and Cape Royal. Mule rides are also available to a variety of places, including several thousand feet down into the canyon. Many visitors to the North Rim choose to make use of
315-565: Is an informal unit of geologic time, subdivided into three eons ( Hadean , Archean , Proterozoic ) of the geologic time scale . It spans from the formation of Earth about 4.6 billion years ago ( Ga ) to the beginning of the Cambrian Period, about 538.8 million years ago ( Ma ), when hard-shelled creatures first appeared in abundance. Relatively little is known about the Precambrian, despite it making up roughly seven-eighths of
360-464: Is higher in elevation than the South Rim, at over 8,000 feet (2,400 m) of elevation. Because it is so much higher than the South Rim, it is closed from December 1 through May 15 each year, due to the enhanced snowfall at elevation. Visitor services are closed or limited in scope after October 15. Driving time from the South Rim to the North Rim is about 4.5 hours, over 220 miles (350 km). On
405-604: Is known to occur during the RNA replication of extant coronaviruses . Evidence of the details of plate motions and other tectonic activity in the Precambrian is difficult to interpret. It is generally believed that small proto-continents existed before 4280 Ma, and that most of the Earth's landmasses collected into a single supercontinent around 1130 Ma. The supercontinent, known as Rodinia , broke up around 750 Ma. A number of glacial periods have been identified going as far back as
450-521: Is thought that the Earth coalesced from material in orbit around the Sun at roughly 4,543 Ma, and may have been struck by another planet called Theia shortly after it formed, splitting off material that formed the Moon (see Giant-impact hypothesis ). A stable crust was apparently in place by 4,433 Ma, since zircon crystals from Western Australia have been dated at 4,404 ± 8 Ma. The term "Precambrian"
495-731: Is used by geologists and paleontologists for general discussions not requiring a more specific eon name. However, both the United States Geological Survey and the International Commission on Stratigraphy regard the term as informal. Because the span of time falling under the Precambrian consists of three eons (the Hadean , the Archean , and the Proterozoic ), it is sometimes described as
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#1732766223115540-686: The Colorado Plateau was uplifted, causing the Colorado River system to develop along its present path. The primary public areas of the park are the South and North Rims, and adjacent areas of the canyon itself. The rest of the park is extremely rugged and remote, although many places are accessible by pack trail and backcountry roads. The South Rim is more accessible than the North Rim and accounts for 90% of park visitation. The park headquarters are at Grand Canyon Village , not far from
585-526: The Earth's history , and what is known has largely been discovered from the 1960s onwards. The Precambrian fossil record is poorer than that of the succeeding Phanerozoic , and fossils from the Precambrian (e.g. stromatolites ) are of limited biostratigraphic use. This is because many Precambrian rocks have been heavily metamorphosed , obscuring their origins, while others have been destroyed by erosion, or remain deeply buried beneath Phanerozoic strata. It
630-534: The Huronian epoch, roughly 2400–2100 Ma. One of the best studied is the Sturtian-Varangian glaciation, around 850–635 Ma, which may have brought glacial conditions all the way to the equator, resulting in a " Snowball Earth ". The atmosphere of the early Earth is not well understood. Most geologists believe it was composed primarily of nitrogen, carbon dioxide, and other relatively inert gases, and
675-482: The oxygen catastrophe . At first, oxygen would have quickly combined with other elements in Earth's crust, primarily iron, removing it from the atmosphere. After the supply of oxidizable surfaces ran out, oxygen would have begun to accumulate in the atmosphere, and the modern high-oxygen atmosphere would have developed. Evidence for this lies in older rocks that contain massive banded iron formations that were laid down as iron oxides. A terminology has evolved covering
720-602: The territories of American Samoa and the U.S. Virgin Islands . The state with the most national parks is California with nine, followed by Alaska with eight, Utah with five, and Colorado with four. The largest national park is Wrangell–St. Elias in Alaska: at over 8 million acres (32,375 km ), it is larger than each of the nine smallest states . The next three largest parks are also in Alaska. The smallest park
765-656: The Colorado River northeast from the Grand Canyon to Lees Ferry , were made part of Grand Canyon National Park. In 1979, UNESCO declared the park a World Heritage Site . The 1987 the National Parks Overflights Act found that "Noise associated with aircraft overflights at the Grand Canyon National Park is causing a significant adverse effect on the natural quiet and experience of the park and current aircraft operations at
810-859: The Grand Canyon Forest Reserve in 1893. Theodore Roosevelt created the Grand Canyon Game Preserve by proclamation on November 28, 1906, and the Grand Canyon National Monument on January 11, 1908. Further Senate bills to establish the site as a national park were introduced and defeated in 1910 and 1911, before the Grand Canyon National Park Act ( Pub. L. 65–277 ) was finally signed by President Woodrow Wilson on February 26, 1919. The National Park Service , established in 1916, assumed administration of
855-537: The Grand Canyon National Park have raised serious concerns regarding public safety, including concerns regarding the safety of park users." In 2010, Grand Canyon National Park was honored with its own coin under the America the Beautiful Quarters program. On February 26, 2019, the Grand Canyon National Park commemorated 100 years since its designation as a national park. The Grand Canyon had been part of
900-608: The National Park Service "to conserve the scenery and the natural and historic objects and wildlife therein, and to provide for the enjoyment of the same in such manner and by such means as will leave them unimpaired for the enjoyment of future generations." Many current national parks had been previously protected as national monuments by the president under the Antiquities Act or as other designations created by Congress before being redesignated by Congress;
945-558: The National Park Service's Intermountain Region until 2018. Today, the Grand Canyon is a part of Region 8, also known as the Lower Colorado Basin. The Grand Canyon, including its extensive system of tributary canyons, is valued for its combination of size, depth, and exposed layers of colorful rocks dating back to Precambrian times. The canyon itself was created by the incision of the Colorado River and its tributaries after
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#1732766223115990-665: The National Park System are considered equal with the same mission, national parks are generally larger and more of a destination, and hunting and extractive activities are prohibited. National monuments , on the other hand, are also frequently protected for their historical or archaeological significance. Eight national parks (including six in Alaska ) are paired with a national preserve , areas with different levels of protection that are administered together but considered separate units and whose areas are not included in
1035-550: The North Rim is the historic Grand Canyon Lodge , managed by Forever Resorts, and a campground near the lodge managed by the national park staff. According to the Köppen climate classification system, Grand Canyon National Park has five climate zones; Cold Semi-Arid ( BSk ), Humid Continental Dry Cool Summer ( Dsb ), Humid Continental Dry Warm Summer ( Dsa ), Warm Summer Mediterranean ( Csb ), and Hot Summer Mediterranean ( Csa ). The plant hardiness zone at Grand Canyon Visitor Center
1080-654: The North Rim to the South Rim. Overall, some 30 miles of the South Rim are accessible by road. Grand Canyon Village is the primary visitor services area in the park. It is a full-service community, including lodging, fuel, food, souvenirs, a hospital, churches, and access to trails and guided walks and talks. Several lodging facilities are available along the South Rim. Hotels and other lodging include El Tovar , Bright Angel Lodge , Kachina Lodge, Thunderbird Lodge, and Maswik Lodge , all of which are located in Grand Canyon Village, and Phantom Ranch , located on
1125-558: The South Entrance to the park, near one of the most popular viewpoints. Most visitors to the park come to the South Rim, arriving on Arizona State Route 64 . The highway enters the park through the South Entrance, near Tusayan, Arizona , and heads eastward, leaving the park through the East Entrance. Interstate 40 provides access to the area from the south. From the north, U.S. Route 89 connects Utah , Colorado , and
1170-615: The canyon floor. There is also an RV Park named Trailer Village. All of these facilities are managed by Xanterra Parks & Resorts , while the Yavapai Lodge (also in the village area) is managed by Delaware North . The North Rim area of the park is located on the Kaibab Plateau and Walhalla Plateau, directly across the Grand Canyon from the principal visitor areas on the South Rim. The North Rim's principal visitor areas are centered around Bright Angel Point. The North Rim
1215-401: The current scheme based upon numerical ages. Such a system could rely on events in the stratigraphic record and be demarcated by GSSPs . The Precambrian could be divided into five "natural" eons, characterized as follows: The movement of Earth's plates has caused the formation and break-up of continents over time, including occasional formation of a supercontinent containing most or all of
1260-453: The early years of the Earth's existence, as radiometric dating has allowed absolute dates to be assigned to specific formations and features. The Precambrian is divided into three eons: the Hadean (4567.3–4031 Ma), Archean (4031-2500 Ma) and Proterozoic (2500-538.8 Ma). See Timetable of the Precambrian . It has been proposed that the Precambrian should be divided into eons and eras that reflect stages of planetary evolution, rather than
1305-760: The end of that time span, marking the beginning of the Phanerozoic Eon. By the middle of the following Cambrian Period, a very diverse fauna is recorded in the Burgess Shale , including some which may represent stem groups of modern taxa. The increase in diversity of lifeforms during the early Cambrian is called the Cambrian explosion of life. While land seems to have been devoid of plants and animals, cyanobacteria and other microbes formed prokaryotic mats that covered terrestrial areas. Tracks from an animal with leg-like appendages have been found in what
1350-552: The figures below. The 431 units of the National Park System can be broadly referred to as national parks, but most have other formal designations. A bill creating the first national park, Yellowstone , was signed into law by President Ulysses S. Grant in 1872, followed by Mackinac National Park in 1875 (decommissioned in 1895), and then Rock Creek Park (later merged into National Capital Parks ), Sequoia and Yosemite in 1890. The Organic Act of 1916 created
1395-541: The landmass. The earliest known supercontinent was Vaalbara . It formed from proto-continents and was a supercontinent 3.636 billion years ago. Vaalbara broke up c. 2.845–2.803 Ga ago. The supercontinent Kenorland was formed c. 2.72 Ga ago and then broke sometime after 2.45–2.1 Ga into the proto-continent cratons called Laurentia , Baltica , Yilgarn craton and Kalahari . The supercontinent Columbia , or Nuna, formed 2.1–1.8 billion years ago and broke up about 1.3–1.2 billion years ago. The supercontinent Rodinia
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1440-594: The most-visited park since 1944, and had almost 13 million visitors in 2022. In contrast, only about 9,500 people visited the remote Gates of the Arctic National Park and Preserve in Alaska in 2022. Download coordinates as: The following table includes the 30 states and two territories that have national parks. Exclusive parks refer to parks entirely within one state or territory. Shared parks refer to parks in multiple states. Territories are set in italics . Precambrian The Precambrian
1485-472: The newest national park is New River Gorge , previously a National River, and the most recent entirely new park is National Park of American Samoa . A few former national parks are no longer designated as such , or have been disbanded. Fourteen national parks are designated UNESCO World Heritage Sites (WHS), and 21 national parks are named UNESCO Biosphere Reserves (BR), with eight national parks in both programs. Thirty states have national parks, as do
1530-433: The park on the North Rim. Access is via unpaved roads off Route 389 west of Fredonia, Arizona . The roads lead through Grand Canyon–Parashant National Monument and to the overlook. A variety of activities at the South Rim cater to park visitors. A driving tour (35 miles (56 km)) along the South Rim is split into two segments. The western drive to Hermit's Point is eight miles (13 km) with several overlooks along
1575-496: The park. The creation of the park was an early success of the conservation movement . Its national park status may have helped thwart proposals to dam the Colorado River within its boundaries. (Later, the Glen Canyon Dam would be built upriver.) A second Grand Canyon National Monument to the west was proclaimed in 1932. In 1975, that monument and Marble Canyon National Monument, which was established in 1969 and followed
1620-906: The region. Its goals include: Source: Source: [REDACTED] Media related to Grand Canyon at Wikimedia Commons (image gallery) List of national parks of the United States The United States has 63 national parks , which are congressionally designated protected areas operated by the National Park Service , an agency of the Department of the Interior . National parks are designated for their natural beauty, unique geological features, diverse ecosystems, and recreational opportunities, typically "because of some outstanding scenic feature or natural phenomena." While legislatively all units of
1665-425: The rim within the Grand Canyon National Park. Flights within the canyon are still available outside of park boundaries. The Grand Canyon Association (GCA) is the National Park Service's official nonprofit partner. It raises private funds to benefit Grand Canyon National Park by operating retail shops and visitor centers within the park, and providing educational opportunities about the natural and cultural history of
1710-526: The same area. However, there is evidence that life could have evolved over 4.280 billion years ago. There is a fairly solid record of bacterial life throughout the remainder (Proterozoic Eon) of the Precambrian. Complex multicellular organisms may have appeared as early as 2100 Ma. However, the interpretation of ancient fossils is problematic, and "... some definitions of multicellularity encompass everything from simple bacterial colonies to badgers." Other possible early complex multicellular organisms include
1755-741: The variety of hiking trails including the Widforss Trail , Uncle Jim's Trail, the Transept Trail, and the North Kaibab Trail . The North Kaibab Trail can be followed all the way down to the Colorado River, connecting across the river to the South Kaibab Trail and the Bright Angel Trail , which continue up to the South Rim of the Grand Canyon. The Toroweap Overlook is located in the western part of
1800-781: The way, including Mohave Point, Hopi Point, and the Powell Memorial. From March to December, access to Hermit's Rest is restricted to the free shuttle provided by the Park Service. The eastern portion to Desert View is 25 miles (40 km), and is open to private vehicles year round. Walking tours include the Rim Trail, which runs west from the Pipe Creek viewpoint for about eight miles (13 km) of paved road, followed by seven miles (11 km) unpaved to Hermit's Rest. Hikes can begin almost anywhere along this trail, and
1845-415: The wide world ... Let this great wonder of nature remain as it now is. Do nothing to mar its grandeur, sublimity and loveliness. You cannot improve on it. But you can keep it for your children, your children's children, and all who come after you, as the one great sight which every American should see. Despite Roosevelt's enthusiasm and strong interest in preserving land for public use, the Grand Canyon
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1890-455: Was designated a World Heritage Site by UNESCO in 1979. The park celebrated its 100th anniversary on February 26, 2019. The Grand Canyon became well known to Americans in the 1880s after railroads were built and pioneers developed infrastructure and early tourism. In 1903, President Theodore Roosevelt visited the site and said, The Grand Canyon fills me with awe. It is beyond comparison—beyond description; absolutely unparalleled throughout
1935-482: Was lacking in free oxygen . There is, however, evidence that an oxygen-rich atmosphere existed since the early Archean. At present, it is still believed that molecular oxygen was not a significant fraction of Earth's atmosphere until after photosynthetic life forms evolved and began to produce it in large quantities as a byproduct of their metabolism . This radical shift from a chemically inert to an oxidizing atmosphere caused an ecological crisis , sometimes called
1980-852: Was mud 551 million years ago. The RNA world hypothesis asserts that RNA evolved before coded proteins and DNA genomes. During the Hadean Eon (4,567–4,031 Ma) abundant geothermal microenvironments were present that may have had the potential to support the synthesis and replication of RNA and thus possibly the evolution of a primitive life form. It was shown that porous rock systems comprising heated air-water interfaces could allow ribozyme - catalyzed RNA replication of sense and antisense strands that could be followed by strand-dissociation, thus enabling combined synthesis, release and folding of active ribozymes. This primitive RNA replicative system also may have been able to undergo template strand switching during replication ( genetic recombination ) as
2025-467: Was not immediately designated as a national park. The first bill to establish Grand Canyon National Park was introduced in 1882 by then-Senator Benjamin Harrison , which would have established Grand Canyon as the third national park in the United States, after Yellowstone and Mackinac . Harrison unsuccessfully reintroduced his bill in 1883 and 1886; after his election to the presidency, he established
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