Cape York meteorite


The Cape York meteorite, also known as the Innaanganeq meteorite, is one of the largest known iron meteorites, classified as a medium octahedrite in chemical group IIIAB. In addition to many small fragments, at least eight large fragments with a total mass of 58 tons have been recovered, the largest weighing. The meteorite is named after the location where the largest fragment was found: near Cape York, in Savissivik, Meteorite Island, Greenland.
The date of the meteorite fall is debated, but was probably within the last few thousand years. It was known to local Inuit for centuries, who used it as a source of meteoritic iron for tools. The first foreigner to reach the meteorite was Robert Peary in 1894, with the assistance of Inuit guides. Large pieces are on display at the American Museum of Natural History and the University of Copenhagen Geological Museum.

History

The meteorite fell to Earth after the retreat of glaciers from the area. All fragments recovered were found at the surface, partly buried, some on unstable terrain. The largest fragment was recovered in an area where the landscape consists of "flowing" gravel or clay-like sediments on permafrost, indicating that it had been in place for no more than a few thousand years. Other estimates have put the date of the fall as 10,000 years ago.
The iron masses were known to Inuit as Saviksoah weighing ; the Woman, weighing ; and the Dog, weighing. For centuries, Inuit living near the meteorites used them as a source of metal for tools and harpoons. The Inuit would work the metal using cold forging—that is, by hammering the metal with stones. Excavations of a Norse farm in 1976 located an arrowhead made of iron from the meteorite, dating from the 11th to 14th century AD; its presence is evidence of Norse journeys to northern Greenland.
In 1818, the British First Ross Expedition made contact with Inuit on the northern shore of Melville Bay, who stated they had settled in the area to exploit a nearby source of iron. The Inuit described the location of this iron, but poor weather and sea ice prevented Ross from investigating further. Ross correctly surmised that the large iron rocks described by the Inuit were meteorites, and purchased several tools with blades made of the meteoritic iron.
Between 1818 and 1883, five further expeditions to the area were mounted by Britain, Sweden and Denmark, which all failed to find the source of the iron. Only in 1894 did a Western explorer reach the meteorite: Robert E. Peary, of the US Navy. Peary enlisted the help of a local Inuit guide, who brought him to Saviksoah Island, just off northern Greenland's Cape York. It took Peary three years to arrange and carry out the loading of the heavy iron meteorites onto ships. This process required the building of small, short railroad. Peary sold the pieces for in $40,000 to the American Museum of Natural History in New York City where they are still on display. It is unknown whether the fragments were purchased from the Inuit or stolen.
Today the piece named Ahnighito is open for viewing at the American Museum of Natural History in the Arthur Ross Hall. It is the second-heaviest meteorite to have been relocated. It is so heavy that it was necessary to build its display stand so that the supports reached directly to the bedrock below the museum.
In 1963, a fourth major piece of the Cape York meteorite was discovered by Vagn F. Buchwald on Agpalilik peninsula. The Agpalilik meteorite, also known as the Man, weighs about, and it is currently on display in the Geological Museum of the University of Copenhagen, Denmark. Other smaller pieces have also been found, such as the Savik I meteorite found in 1911 and the Tunorput fragment found in 1984. Surveys of the area with a magnetometer in 2012 and georadar in 2014 found no evidence of further large iron fragments, either buried or on the surface.
The Cape York asteroid has been suggested by the crater discoverers to be a part of the asteroid which created the Hiawatha crater, but which split off prior to impact.

Specimens

Each of the most important fragments of Cape York has its own name :
  1. Ahnighito,, 1884–1897, Meteorite Island, 76°04'N – 64°58'W
  2. Woman,, 1897, Saveruluk, 76°09'N – 64°56'W
  3. Dog,, 1897, Saveruluk, 76°09'N – 64°56'W
  4. Savik I,, 1913, Savequarfik, 76°08'N – 64°36'W
  5. Thule,, summer 1955, Thule, 76°32'N – 67°33'W
  6. Savik II,, 1961, Savequarfik, 76°08'N – 64°36'W
  7. Agpalilik,, 1963, Agpalilik, 76°09'N – 65°10'W
  8. Tunorput,, 1984

    Composition and classification

It is an iron meteorite and belongs to the chemical group IIIAB.
There are abundant elongated troilite nodules. The troilite nodules contain inclusions of chromite, sulfides, phosphates, silica and copper. The rare nitride mineral carlsbergite occurs within the matrix of the metal phase. Graphite was not observed and the nitrogen isotopes are in disequilibrium.