Willamette Meteorite

Willamette

Willamette Meteorite at the American Museum of Natural History
Type Iron
Structural classification Medium Octahedrite
Group IIIAn
Composition 7.62% Ni, 18.6ppm Ga, 37.3ppm Ge, 4.7ppm Ir
Country United States
Region Oregon
Coordinates 45°22′N 122°35′W / 45.367°N 122.583°W / 45.367; -122.583Coordinates: 45°22′N 122°35′W / 45.367°N 122.583°W / 45.367; -122.583[1]
Observed fall No
Found date 1902
TKW 14,150 kilograms (15.60 short tons)[2]

The Willamette Meteorite, officially named Willamette,[3] is an iron-nickel meteorite discovered in the U.S. state of Oregon. It is the largest meteorite found in North America and the sixth largest in the world.[4][5] There was no impact crater at the discovery site; researchers believe the meteorite landed in what is now Canada or Montana, and was transported as a glacial erratic to the Willamette Valley during the Missoula Floods at the end of the last Ice Age (~13,000 years ago).[6] It was long held sacred by indigenous peoples of the Willamette Valley, including the federally recognized Confederated Tribes of the Grand Ronde Community of Oregon (CTGRC). The indigenous peoples referred to this stone with the name Tomonowos (the visitor from the sky).

The meteorite is currently on display at the American Museum of Natural History in New York, which acquired it in 1906.[5] Having been seen by an estimated 40 million people over the years, and given its striking appearance, it is among the most famous meteorites known.[7][8][9] In 2005, the Confederated Tribes of the Grand Ronde Community of Oregon sued to have the meteorite returned to their control but they were unsuccessful.[8]

Physical characteristics and formation

Close-up of the meteorite

The Willamette Meteorite weighs about 32,000 pounds (15,000 kg). It is classified as a type III iron meteorite, being composed of over 91% iron and 7.62% nickel, with traces of cobalt and phosphorus. The approximate dimensions of the meteorite are 10 feet (3 m) tall by 6.5 feet (2 m) wide by 4.25 feet (1.3 m) deep. Most iron meteorites like Willamette have originated from the differentiated core of planetesimals or asteroids that collided with another object. Willamette has a recrystallized structure with only traces of a medium Widmanstätten pattern; it is the result of a significant impact-heating event on the parent body.[5][10] The Willamette Meteorite contains higher concentrations of various metals that are quite rare in Earth's crust. For example, Iridium, one of the least abundant elements in Earth's crust, is found in the Willamette Meteorite at a concentration of 4.7 ppm, thousands of times more than its crustal abundance.[11]

Emplacement and erosion

Glacial Lake Columbia (west) and Glacial Lake Missoula (east, in blue) were south of Cordilleran Ice Sheet. The areas inundated in the Columbia and Missoula floods are shown in red. The meteorite was rafted by the floods embedded inside an ice block.

The lack of an impact crater at the discovery site was only explained after the 1920's, with the new understanding about the Missoula Floods, one of the largest floods documented, caused by the collapse of an ice barrier during the last deglaciation. The meteorite presumably landed on an ice cap in what is now Montana or western Canada, and was transported as a glacial erratic (dragged by the glacier ice) to the vicinity of an ice barrier that formed across the Clark Fork River. This barrier had ponded a huge amount of water at the Lake Missoula right at the time when the meteorite reached the area and the ice barrier became unstable and breached. The resulting flood involved up to 10 million cubic meters per second of water discharge, with large blocks of ice rafting down the Columbia River and the Willamette Valley at the end of the last Ice Age (~13,000 years ago).[6] Some of these ice rafts included boulders (named erratics by geologist) like the Willamette meteorite, which eventually sunk in the flood waters and settled where it was found by humans.

The deep crevasses of the meteorite resulted from both its high-speed atmospheric entry and subsequent terrestrialization, i.e., weathering. Exposed to the elements for thousands of years, rainwater interacted with the mineral troilite, resulting in a form of sulfuric acid which slowly dissolved portions of the meteorite. This resulted (over a very long period) in the development of the hollows that are visible today.

Modern history

The Willamette Meteorite was discovered in the Willamette Valley of Oregon near the modern city of West Linn. Although already known and sacred to Native Americans, its "discovery" was made by settler Ellis Hughes in 1902. At that time the land was owned by the Oregon Iron and Steel Company. Hughes recognized the meteorite's significance, and in an attempt to claim ownership, secretly moved it to his own land. This involved 90 days of hard work to cover the 3/4 mile (1200 m) distance. The move was discovered, and after a lawsuit, the Oregon Supreme Court held that Oregon Iron and Steel Company was the legal owner. Oregon Iron Co. v. Hughes, 47 Or 313, 82 P 572 (1905).[12]

In 1905 the meteorite was purchased by Mrs. William E. Dodge for $26,000 (around $680,000 in 2011). After being displayed at the Lewis and Clark Centennial Exposition, it was donated to the American Museum of Natural History in New York City where it has since been on display.[13]

The meteorite was venerated by the Clackamas tribe inhabiting the area where it was found. The Confederated Tribes of the Grand Ronde Community of Oregon, a confederation of Native American tribes, used the meteorite, which they call Tomanowos, in ceremonies and demanded that it be returned and filed a NAGPRA action (Native American Graves Protection and Repatriation Act) against the American Museum of Natural History in 1999. In response, the Museum filed a federal lawsuit seeking a declaratory judgment against the Grand Ronde in 2000. An agreement with the Museum was reached later that year in which the meteorite would remain at the museum with tribal members being able to conduct a private ceremony around the meteorite once a year, and that ownership will be transferred to Grand Ronde should the museum cease to have the meteorite on display.[14]

In response to a student's request in 2007, Representative John Lim introduced a resolution that would demand that the museum return the meteorite to Oregon. The tribes said they were not consulted, they did not support the resolution, and were content with the current arrangement with the museum.[15]

The 28-pound (13 kg) crown section of the meteorite that had been traded to the Macovich Collection for a Martian meteorite in 1997, was planned to be auctioned in October 2007, which led to claims by the Grand Ronde of insensitivity.[16][17][18] Bidders dropped out when an editorial in the Portland Oregonian newspaper asserted the Grand Ronde would file a lawsuit against the new owner, but the Grand Ronde disavowed the editorial and said they had no such intent, and that they couldn't stop the sale. While the newspaper printed an apology, the specimen was withdrawn.[19][20][21] A lawsuit was filed against the newspaper in Oregon Circuit Court and failed.[22]

A 4.5-ounce (130 g), 7.5-inch (19 cm) piece of the meteorite, also with a Macovich Collection provenance, was purchased in a 2006 auction and is on display at the Evergreen Aviation & Space Museum in McMinnville, Oregon.[23][24]

Mass

A historical marker in the Willamette area of West Linn, Oregon. The plaque reads: "In 1902 Ellis Hughes discovered the 15 1⁄2 ton Willamette Meteorite, the largest ever found in the United States, about 2 miles N.W. of this place. Marker erected August 4, 1962 by West Linn Fair Board."

There is some confusion about the actual mass of the Willamette meteorite due difference between metric tons and short tons, often both referred simply as tons. The result is that several sources report different weights ranging from 15,500 kilograms (34,200 lb)[25] to 12,700 kilograms (28,000 lb).[26] The official American Museum of Natural History website also reports both "15.5 tons"[27] and "14 tons".[28][29] However 15,500 kg is likely 15.5 short tons converted as metric tons and 12,700 kg is likely 14 metric tons converted as short tons. Moreover in 1906 the American Museum of Natural History itself stated that the weight of the Willamette meteorite was at least 31,200 pounds, or about 15.6 tons.[2] After these considerations it is reasonable to guess that the real weight of the meteorite is about 14,150 kilograms (31,200 lb).

Replicas

A replica of the meteorite is in Eugene, Oregon, outside the University of Oregon Museum of Natural and Cultural History on the University of Oregon campus.[13] Another replica stands near the Willamette Methodist Church in West Linn, Oregon.[30]

See also

References

  1. ↑ Willamette meteorite, West Linn, Clackamas Co., Oregon, USA. Retrieved on October 30, 2008.
  2. 1 2 The American Museum Journal, American Museum of Natural History, 1906.
  3. ↑ Meteoritical Bulletin Database: Willamette. The Meteoritical Society. Retrieved on August 16, 2008.
  4. ↑ O. Richard Norton. Rocks from Space. USA, Mountain Press, 1994.
  5. 1 2 3 "Cullman Hall of the Universe: The Willamette Meteorite". American Museum of Natural History. Retrieved 2007-11-02.
  6. 1 2 Pugh, R. N.; Allen J.E. (1986). "Origin of the Willamette Meteorite". Abstracts and Program for the 49th Annual Meeting of the Meteoritical Society 600: 208. Bibcode:1986LPICo.600E.208P.
  7. ↑ "The Willamette Meteorite". Houston Chronicle. October 26, 2007.
  8. 1 2 Weiser, Benjamin (February 29, 2000). "Museum Sues to Keep Meteorite Sought by Indian Group". The New York Times.
  9. ↑ Science Channel's "Top Ten Meteorites". Retrieved on November 29th, 2010.
  10. ↑ ^ Vagn F. Buchwald: Handbook of Iron Meteorites, University of California Press 1975.
  11. ↑ Scott, E. R. D.; Wasson, J. T.; Buchwald, V. F. (1973). "The chemical classification of iron meteorites—VII. A reinvestigation of irons with Ge concentrations between 25 and 80 ppm". Geochimica et Cosmochimica Acta 37 (8): 1957–1983. Bibcode:1973GeCoA..37.1957S. doi:10.1016/0016-7037(73)90151-8.
  12. ↑ Preston, Douglas. Strange Journey: Further Travels of The Willamette Meteorite. Meteor Treasures. Retrieved on October 31, 2007.
  13. 1 2 Geology Tour. University of Oregon: Museum of Natural History. Retrieved on October 31, 2007.
  14. ↑ Sullivan, John (June 23, 2000). "Pact Leaves Meteorite With Museum". The New York Times.
  15. ↑ Walsh, Edward (March 26, 2007). "Oregon's Pet Rock". Retrieved 2010-10-23.
  16. ↑ Chang, Kenneth (February 14, 2002). "Uproar Over a Sliced, and Revered, Meteorite". New York Times.
  17. ↑ "Tribe: Sale of space rock 'insensitive'". CNN. 2007-09-14. Archived from the original on September 14, 2007. Retrieved September 15, 2007.
  18. ↑ "Cow-killing meteorite sells for $1,554". CNN. 2007-10-29. Archived from the original on October 30, 2007. Retrieved October 31, 2007.
  19. ↑ Saturday, October 20, 2007 / Portland Oregonian - Apology/Retraction on the Editorial Page
  20. ↑ Chan, Sewell (September 14, 2007). "Tribe Alarmed by Auction of a Meteorite Fragment". The New York Times. Retrieved November 28, 2010.
  21. ↑ Tims, Dana (Oct 22, 2007). "For sale: 30 pounds of controversy". The Oregonian. Retrieved April 18, 2014.
  22. ↑ Darryl Pitt v. Advance Publications, et al., Oregon Circuit Court, 0810-14798 (2008)
  23. ↑ "Willamette Meteorite to Return to Oregon as Part of Evergreen Aviation Museum's Collection". Salem-News.com. 2006-04-14. Retrieved 2008-06-06.
  24. ↑ Tims, Dana (2008-06-06). "Space history stands tall in museum". The Oregonian. Retrieved 2008-06-06.
  25. ↑ Meteoritical Bulletin Database: Willamette
  26. ↑ Harry Y. McSween. Meteorites and Their Parent Planets. Cambridge University Press, 1999.
  27. ↑ Planets Zone, Rose Center for Earth and Space. American Museum of Natural History. Retrieved on August 16, 2008.
  28. ↑ Arthur Ross Hall of Meteorites. American Museum of Natural History. Retrieved on August 16, 2008.
  29. ↑ AMNH Special Collections: Astronomy slides. American Museum of Natural History. Retrieved on August 16, 2008.
  30. ↑ The Willamette Meteorite, Information Sources and Links. Clackamas County Oregon History and Genealogy. Retrieved on August 16, 2008.

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