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58-469: Isle Royale ( / ˈ r ɔɪ əl / , ROY -əl ) is an island of the Great Lakes located in the northwest of Lake Superior and part of the U.S. state of Michigan . The island and the 450 surrounding smaller islands and waters make up Isle Royale National Park . Isle Royale is 45 miles (72 km) long and 9 miles (14 km) wide, with an area of 206.73 square miles (535.4 km), making it

116-487: A N(n,p) C reaction, direct uranium decay (though reported measured ratios of C/U in uranium-bearing ores would imply roughly 1 uranium atom for every two carbon atoms in order to cause the C/ C ratio, measured to be on the order of 10 ), or other unknown secondary sources of C production. The presence of C in the isotopic signature of a sample of carbonaceous material possibly indicates its contamination by biogenic sources or

174-525: A direct comparison of carbon-14 levels in a sample, with tree ring or cave-deposit C levels of a known age, then gives the wood or animal sample age-since-formation. Radiocarbon is also used to detect disturbance in natural ecosystems; for example, in peatland landscapes, radiocarbon can indicate that carbon which was previously stored in organic soils is being released due to land clearance or climate change. Cosmogenic nuclides are also used as proxy data to characterize cosmic particle and solar activity of

232-510: A few scrubby trees, blueberry bushes, and hardy grasses. Occasional marshes exist, which are typically the by-product of beaver activities. There are also several lakes, often with wooded or marshy shores. The climate, especially in lowland areas, is heavily influenced by the cold waters of Lake Superior . The island is well known among ecologists as the site of a long-term study of a predator-prey system , between moose and eastern timber wolves . L. David Mech began this study in 1958 as

290-417: A graduate student at Purdue University. There is a cyclical relationship between the two animals: as the moose increase in population, so do the wolves. Eventually, the wolves kill too many moose and begin to starve and lower their reproductive rates. Historically neither moose nor wolves inhabited Isle Royale. Just prior to becoming a national park the largest mammals on Isle Royale were Canadian Lynx and

348-440: A nuclear reactor) are summarized in the table. Another source of carbon-14 is cluster decay branches from traces of naturally occurring isotopes of radium , though this decay mode has a branching ratio on the order of 10 relative to alpha decay , so radiogenic carbon-14 is extremely rare. The above-ground nuclear tests that occurred in several countries in 1955-1980 (see List of nuclear tests ) dramatically increased

406-403: A slower rate to form CO 2 , radioactive carbon dioxide . The gas mixes rapidly and becomes evenly distributed throughout the atmosphere (the mixing timescale on the order of weeks). Carbon dioxide also dissolves in water and thus permeates the oceans , but at a slower rate. The atmospheric half-life for removal of CO 2 has been estimated at roughly 12 to 16 years in

464-649: Is cosmic ray action on nitrogen in the atmosphere, and it is therefore a cosmogenic nuclide . However, open-air nuclear testing between 1955 and 1980 contributed to this pool. The different isotopes of carbon do not differ appreciably in their chemical properties. This resemblance is used in chemical and biological research, in a technique called carbon labeling : carbon-14 atoms can be used to replace nonradioactive carbon, in order to trace chemical and biochemical reactions involving carbon atoms from any given organic compound. Carbon-14 undergoes beta decay : By emitting an electron and an electron antineutrino , one of

522-490: Is 0.05 mm. Radiocarbon dating is a radiometric dating method that uses C to determine the age of carbonaceous materials up to about 60,000 years old. The technique was developed by Willard Libby and his colleagues in 1949 during his tenure as a professor at the University of Chicago . Libby estimated that the radioactivity of exchangeable C would be about 14 decays per minute (dpm) per gram of carbon, and this

580-447: Is also generated inside nuclear fuels (some due to transmutation of oxygen in the uranium oxide , but most significantly from transmutation of nitrogen-14 impurities), and if the spent fuel is sent to nuclear reprocessing then the C is released, for example as CO 2 during PUREX . After production in the upper atmosphere, the carbon-14 reacts rapidly to form mostly (about 93%) CO ( carbon monoxide ), which subsequently oxidizes at

638-910: Is evidence for an unusually high production rate in AD 774–775 , caused by an extreme solar energetic particle event, the strongest such event to have occurred within the last ten millennia. Another "extraordinarily large" C increase (2%) has been associated with a 5480 BC event, which is unlikely to be a solar energetic particle event. Carbon-14 may also be produced by lightning but in amounts negligible, globally, compared to cosmic ray production. Local effects of cloud-ground discharge through sample residues are unclear, but possibly significant. Carbon-14 can also be produced by other neutron reactions, including in particular C (n,γ) C and O (n,α) C with thermal neutrons , and N (n,d) C and O (n, He) C with fast neutrons . The most notable routes for C production by thermal neutron irradiation of targets (e.g., in

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696-406: Is in the oceans. The following inventory of carbon-14 has been given: Many human-made chemicals are derived from fossil fuels (such as petroleum or coal ) in which C is greatly depleted because the age of fossils far exceeds the half-life of C. The relative absence of CO 2 is therefore used to determine the relative contribution (or mixing ratio ) of fossil fuel oxidation to

754-430: Is small compared to the doses from K (0.39 mSv/year) and radon (variable). C can be used as a radioactive tracer in medicine. In the initial variant of the urea breath test , a diagnostic test for Helicobacter pylori , urea labeled with about 37  kBq (1.0  μCi ) C is fed to a patient (i.e. 37,000 decays per second). In the event of a H. pylori infection, the bacterial urease enzyme breaks down

812-524: Is still used as the activity of the modern radiocarbon standard . In 1960, Libby was awarded the Nobel Prize in chemistry for this work. One of the frequent uses of the technique is to date organic remains from archaeological sites. Plants fix atmospheric carbon during photosynthesis; so the level of C in plants and animals when they die, roughly equals the level of C in the atmosphere at that time. However, it thereafter decreases exponentially; so

870-477: Is the Minong Ridge, which has a 13-mile hike from North Lake Desor to Windigo. It passes through quick elevation changes, high plants, and miles upon miles of hiking on ridges overlooking Lake Superior. A number of habitats exist on the island, the primary being boreal forest , similar to neighboring Ontario and Minnesota. Upland areas along some of the ridges are effectively "balds" with exposed bedrock and

928-436: Is the largest lake on the island. It has cold, clear water which is relatively low in nutrients. Siskiwit Lake contains several islands, including Ryan Island, the largest. Source climate data for Isle Royale is lacking, particularly for the winter season, though general summaries of seasonal variations are available and data from nearby areas have been used to derive deductions for purposes of scientific study. For example, see

986-442: Is the least visited national park in the lower 48 states. Recreational activity on Isle Royale includes hiking , backpacking , fishing , boating , canoeing , kayaking , and observing nature. Wheeled vehicles are not permitted on Isle Royale, such as bicycles or canoe portage devices; however, wheelchairs are allowed. There are numerous campgrounds, many of which are only accessible by water. There are two small settlements on

1044-436: Is the preferred method although more recently, accelerator mass spectrometry has become the method of choice; it counts all the carbon-14 atoms in the sample and not just the few that happen to decay during the measurements; it can therefore be used with much smaller samples (as small as individual plant seeds), and gives results much more quickly. The G-M counting efficiency is estimated to be 3%. The half-distance layer in water

1102-477: The Boreal woodland caribou . Archeological evidence indicates both of these species were present on Isle Royale for 3,500 years prior to being removed by direct human actions (hunting, trapping, mining, logging, fires and possibly the introduction of invasive species). The last Boreal woodland caribou documented on Isle Royale was in 1925. Though Canadian Lynx were removed by the 1930s some have periodically crossed

1160-476: The SS America . The NPS Submerged Resources Center mapped the 10 most famous of the shipwrecks contained within the park , and published Shipwrecks of Isle Royale National Park; The Archeological Survey , which gives an overview of the maritime history of the area. In 1845, an Ojibwe woman named Angelique and her voyageur husband Charlie Mott were left on Isle Royale, as hires for Cyrus Mendenhall and

1218-785: The fourth-largest lake island in the world. In addition, it is the largest natural island in Lake Superior, the second-largest island in the Great Lakes (after Manitoulin Island ), the third-largest in the contiguous United States (after Long Island and Padre Island ), and the 33rd-largest island in the United States . Isle Royale is defined by the United States Census Bureau as Census Tract 9603 of Keweenaw County, Michigan (a county found in

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1276-609: The 1842 Webster–Ashburton Treaty that was signed before the Treaty of La Pointe, the Ojibwas re-affirmed the 1842 Treaty of La Pointe in the 1844 Isle Royale Agreement , with the Grand Portage Band signing the agreement as an addendum to the 1842 treaty. In the mid-1840s, a report by Douglass Houghton , Michigan's first state geologist , set off a copper boom in the state, and the first modern copper mines were opened on

1334-428: The 19th-century mines to fail quickly. Between the miners and commercial loggers, much of the island was deforested during the late 19th century. Once the island became a national park in 1940, logging and other exploitive activities ended, and the forest began to regenerate. The island was once the site of several lake trout and whitefish fisheries, as well as a few resorts. Today, it has no permanent inhabitants;

1392-771: The Great Lakes Too Many Requests If you report this error to the Wikimedia System Administrators, please include the details below. Request from 172.68.168.133 via cp1102 cp1102, Varnish XID 552436249 Upstream caches: cp1102 int Error: 429, Too Many Requests at Thu, 28 Nov 2024 05:38:18 GMT Carbon-14 There are three naturally occurring isotopes of carbon on Earth: carbon-12 ( C), which makes up 99% of all carbon on Earth; carbon-13 ( C), which makes up 1%; and carbon-14 ( C), which occurs in trace amounts, making up about 1-1.5 atoms per 10 atoms of carbon in

1450-533: The Lake Superior Copper Company. They were hired and carried to Isle Royale by Mendenhall's schooner, the " Algonquin ", first to scout for copper. Angelique found a large mass of copper ore, upon which she and her husband were hired to stay and guard until a barge could come to retrieve it, promised in no more than 3 months' time. They were dropped off in July and were left stranded there until

1508-564: The Northern Hemisphere. The transfer between the ocean shallow layer and the large reservoir of bicarbonates in the ocean depths occurs at a limited rate. In 2009 the activity of C was 238 Bq per kg carbon of fresh terrestrial biomatter, close to the values before atmospheric nuclear testing (226 Bq/kg C; 1950). The inventory of carbon-14 in Earth's biosphere is about 300 megacuries (11  E Bq ), of which most

1566-635: The United States by the 1783 treaty with Great Britain , but the British remained in control until after the War of 1812 , and the Ojibwa peoples considered the island to be their territory. The Ojibwas ceded the island to the U.S. in the 1842 Treaty of La Pointe , with the Grand Portage Band unaware that neither they nor Isle Royale were in British territory. With the clarification to the Ojibwas of

1624-634: The above-ground nuclear tests of the 1950s and 1960s. Though the extra C generated by those nuclear tests has not disappeared from the atmosphere, oceans and biosphere, it is diluted due to the Suess effect . Carbon-14 is produced in coolant at boiling water reactors (BWRs) and pressurized water reactors (PWRs). It is typically released into the air in the form of carbon dioxide at BWRs, and methane at PWRs. Best practice for nuclear power plant operator management of carbon-14 includes releasing it at night, when plants are not photosynthesizing . Carbon-14

1682-593: The amount of C in tooth enamel , or the carbon-14 concentration in the lens of the eye. In 2019, Scientific American reported that carbon-14 from nuclear testing has been found in animals from one of the most inaccessible regions on Earth, the Mariana Trench in the Pacific Ocean. The concentration of C in atmospheric CO 2 , reported as the C/ C ratio with respect to a standard, has (since about 2022) declined to levels similar to those prior to

1740-425: The amount of C in the atmosphere and subsequently the biosphere; after the tests ended, the atmospheric concentration of the isotope began to decrease, as radioactive CO 2 was fixed into plant and animal tissue, and dissolved in the oceans. One side-effect of the change in atmospheric C is that this has enabled some options (e.g. bomb-pulse dating ) for determining the birth year of an individual, in particular,

1798-422: The atmosphere. C and C are both stable; C is unstable, with half-life 5700 ± 30 years. Carbon-14 has a specific activity of 62.4 mCi/mmol (2.31 GBq/mmol), or 164.9 GBq/g. Carbon-14 decays into nitrogen-14 ( N ) through beta decay . A gram of carbon containing 1 atom of carbon-14 per 10 atoms, emits ~0.2 beta (β) particles per second. The primary natural source of carbon-14 on Earth

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1856-421: The date of death or fixation can be estimated. The initial C level for the calculation can either be estimated, or else directly compared with known year-by-year data from tree-ring data ( dendrochronology ) up to 10,000 years ago (using overlapping data from live and dead trees in a given area), or else from cave deposits ( speleothems ), back to about 45,000 years before present. A calculation or (more accurately)

1914-554: The decay of radioactive material in surrounding geologic strata. In connection with building the Borexino solar neutrino observatory, petroleum feedstock (for synthesizing the primary scintillant) was obtained with low C content. In the Borexino Counting Test Facility, a C/ C ratio of 1.94×10 was determined; probable reactions responsible for varied levels of C in different petroleum reservoirs , and

1972-674: The distant past. Carbon-14 is produced in the upper troposphere and the stratosphere by thermal neutrons absorbed by nitrogen atoms. When cosmic rays enter the atmosphere, they undergo various transformations, including the production of neutrons . The resulting neutrons (n) participate in the following n-p reaction (p is proton ): The highest rate of carbon-14 production takes place at altitudes of 9 to 15 kilometres (30,000 to 49,000 ft) and at high geomagnetic latitudes . The rate of C production can be modeled, yielding values of 16,400 or 18,800 atoms of C per second per square meter of Earth's surface, which agrees with

2030-421: The following Spring. They were left with minimal provisions, which consisted of a half-barrel of flour, six pounds of butter, and some beans. A supply boat was promised to arrive after the first few weeks, but it was never sent out. Angelique and her husband were left to survive in the wilderness with limited supplies, on an island with scarce resources. They lost their canoe in a fall storm, and their fishing net

2088-561: The global carbon budget that can be used to backtrack, but attempts to measure the production time directly in situ were not very successful. Production rates vary because of changes to the cosmic ray flux caused by the heliospheric modulation (solar wind and solar magnetic field), and, of great significance, due to variations in the Earth's magnetic field . Changes in the carbon cycle however can make such effects difficult to isolate and quantify. Occasional spikes may occur; for example, there

2146-438: The hiking trails are quite challenging, with steep grades. "The most popular, best marked and longest single route ...is the 40-mile Greenstone Ridge Trail that extends down the island's backbone." The trail leads to the peak of Mount Desor, at 1,394 feet (425 m), the highest point on the island, and passes through northwoods wilderness, and by inland glacial lakes, swamps, bogs and scenic shorelines. The most difficult trail

2204-447: The ice bridge from neighboring Ontario , Canada, the most recent being an individual sighting in 1980. Though Lynx are no longer present on the island, their primary prey, snowshoe hares , remain. Before the appearance of wolves, coyotes were also a predator on the island. Coyotes appeared around 1905 and disappeared shortly after wolves arrived in the 1950s. Four wolves were brought from Minnesota in 2018, after some debate as to whether

2262-509: The introduction was an unnatural intervention. Other common mammals are red foxes , beavers , and red squirrels . Some foxes are quite used to human contact, and can be seen prowling the campgrounds at dawn, looking for stray scraps left by unwary campers. For its part, the wolf is an elusive species which avoids human interaction. Few documented cases of direct wolf/human contact exist. Ermine have been periodically sighted around docks. Other mammals that can be seen include mink (along

2320-598: The island is Mount Desor at 1,394 feet (425 m), or about 800 feet (240 m) above lake level. Isle Royale is within about 15 miles (24 km) from the shore of the Canadian province of Ontario and adjacently, the state of Minnesota (near the city of Thunder Bay ), and is 56 miles (90 km) from the Michigan shore, on the Keweenaw Peninsula , itself part of Upper Peninsula. There are no roads on

2378-507: The island proper: Rock Harbor, which has a resort, a marina, and basic amenities, and Windigo, a smaller facility on the far western end of the island. Both Rock Harbor and Windigo have paid showers and provisions available. A typical National Park Service campground consists of a few shelters (cabin-like structures with one wall of mosquito -proof screen ), individual tent sites with picnic table, and group camping sites. There are one or more pit toilets at each facility. Campgrounds along

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2436-659: The island, and wheeled vehicles or devices, other than wheelchairs, are not permitted. Rock Harbor has wheeled carts available to move personal belongings from the Rock Harbor marina to the cabins and hotel. Also, the National Park Service employs tractors and utility terrain vehicles to move items around the developed areas at Windigo, Rock Harbor, and Mott Island. Topsoil tends to be thin, which favors trees that have horizontal root patterns such as balsam fir , white spruce , and black spruce . Siskiwit Lake

2494-417: The island. Evidence of the earlier mining efforts was everywhere, in the form of many stone hammers, some copper artifacts, and places where copper had been partially worked out of the rock but left in place. The ancient pits and trenches led to the discovery of many of the copper deposits that were mined in the 19th century. The remoteness of the island, combined with the small veins of copper, caused most of

2552-578: The lower C levels in methane, have been discussed by Bonvicini et al. Since many sources of human food are ultimately derived from terrestrial plants, the relative concentration of C in human bodies is nearly identical to the relative concentration in the atmosphere. The rates of disintegration of potassium-40 ( K) and C in the normal adult body are comparable (a few thousand decays per second). The beta decays from external (environmental) radiocarbon contribute about 0.01  mSv /year (1 mrem/year) to each person's dose of ionizing radiation . This

2610-458: The maximum distance traveled is estimated to be 22 cm in air and 0.27 mm in body tissue. The fraction of the radiation transmitted through the dead skin layer is estimated to be 0.11. Small amounts of carbon-14 are not easily detected by typical Geiger–Müller (G-M) detectors ; it is estimated that G-M detectors will not normally detect contamination of less than about 100,000 decays per minute (0.05 μCi). Liquid scintillation counting

2668-572: The monthly temperature and precipitation table on the Isle Royale National Park page. The island is composed largely of ridges, running roughly southwest-to-northeast. The main ridge, Greenstone Ridge, is over 1,000 feet (300 m) in many places. Greenstone belts are exposed, with rounded stones of chlorastrolite , also known as greenstone, near and in the lake. According to the National Park Service ,

2726-471: The nearby Keweenaw Peninsula . The region is scarred by ancient mine pits and trenches up to 20 meters deep. Carbon-14 testing of wood remains found in sockets of copper artifacts indicates that they are at least 6500 years old. In Prehistoric Copper Mining in the Lake Superior Region , published in 1961, Drier and Du Temple estimated that over 750,000 tons of copper had been mined from

2784-425: The neutrons in carbon-14 decays to a proton and the carbon-14 ( half-life of 5700 ± 30 years ) decays into the stable (non-radioactive) isotope nitrogen-14 . As usual with beta decay, almost all the decay energy is carried away by the beta particle and the neutrino. The emitted beta particles have a maximum energy of about 156 keV, while their weighted mean energy is 49 keV. These are relatively low energies;

2842-467: The north sides of the ridges tend to be steeper than the south sides. Coastal areas were once submerged beneath prehistoric lake waters, and contain many tumbled boulders and other large rocks. The island was a common hunting ground for native people from nearby Minnesota and Ontario. A canoe voyage of thirteen miles is necessary to reach the island's west end from the mainland. In prehistoric times, large quantities of copper were mined on Isle Royale and

2900-409: The region. However, David Johnson and Susan Martin contend that their estimate was based on exaggerated and inaccurate assumptions. In 1670, a Jesuit missionary named Dablon published an account of "an island called Menong , celebrated for its copper." Menong , or Minong , was the native term for the island, and is the basis for the name of the Minong Ridge on the island. Isle Royale was given to

2958-433: The shore have a boat dock and overnight boaters are a common sight at some campgrounds. Waterfront locations also attract canoeists and kayakers . No wells are available, thus all water is usually filtered or thoroughly boiled to prevent infection by parasites and bacteria . The island offers approximately 170 miles (270 km) of hiking trails for everything from day hikes to a two-week circumnavigation hike. Some of

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3016-599: The small communities of Scandinavian fishermen were removed by the United States National Park Service (NPS) after the island became a national park in the 1940s. About 12 families have lifetime leases for their cabins and claim Isle Royale as their heritage, and several descendant fishermen fish the Isle Royale waters commercially. The western tip of the island is home to several shipwrecks that are very popular with scuba divers, including

3074-447: The state's Upper Peninsula ). As of the 2000 census there was no permanent population on Isle Royale. After the island was made a national park, some existing residents were allowed to stay, and a few leases are still in effect. In 1875, Isle Royale was set off from Keweenaw County , as a separate county, Isle Royale County . In 1897, the county was dissolved, and the island was reincorporated into Keweenaw County. The highest point on

3132-579: The strands, and creating snares with it, by which she caught rabbits on rare occasions. In the Spring of 1846, the Algonquin returned, and brought Angelique back to her mother. She died in 1874, in Sault Ste. Marie, Ontario. The full events were chronicled in a footnote as told by Angelique in the first printing of a book called The Honorable Peter White by Ralph D. Williams in 1907; Angelique's story

3190-458: The total carbon dioxide in a given region of Earth's atmosphere . Dating a specific sample of fossilized carbonaceous material is more complicated. Such deposits often contain trace amounts of C. These amounts can vary significantly between samples, ranging up to 1% of the ratio found in living organisms (an apparent age of about 40,000 years). This may indicate contamination by small amounts of bacteria, underground sources of radiation causing

3248-607: The various lake shores) and muskrats (occasionally at beaver ponds). Several species of bat also exist on the island. Reptiles include the eastern garter snake , painted turtle , and northern redbelly snake . Six species of frogs and three species of salamander also live on the island. The island is accessible by private boat, seaplane, three private commercial ferries, and a National Park Service ferry. Scheduled ferry service generally runs May through September: 48°0′N 88°55′W  /  48.000°N 88.917°W  / 48.000; -88.917 Islands of

3306-426: Was destroyed. By January 1846, Charlie went mad with hunger and even threatened to murder and eat Angelique. He returned to himself, loving and soft, but was weakening greatly, and eventually succumbed to his starvation, dying. Angelique was forced to leave the body in the cabin and created a brush shelter for herself to live in. She survived by eating poplar bark, bitter berries, and by pulling out her own hair, plaiting

3364-481: Was pulled from the subsequent printing, thus making it the only written record that survives. Humans haven't normally settled year-round on Isle Royale. For about three thousand years, Native Americans used the land for copper and fish. These Native Americans usually limited their visiting to the island in the summer. Americans in the nineteenth century did the same thing. The island and the 450 surrounding smaller islands and waters make up Isle Royale National Park . It

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