[meteorite-list] Kalkaska
From: G. Nicula <treasurehunter_at_meteoritecentral.com>
Date: Mon Aug 21 08:11:29 2006 Message-ID: <003101c6c516$20f04f10$6401a8c0_at_JOSHUA> Wow! Thanks to all of you for your help. I think I need to be brought up to speed on database material. Besides "Rocks From Space" and a few other amatuer must-haves, what kinds of catalogued data should I have so I don't have to come to the list every time I want to research a meteorite? And of course where can I aquire such things? I live within a few miles of the Kalkaska find and visited the site the other day. I'm in the process of contacting the surrounding land owners, but it seems much has changed in the last 60 years. A very large portion of the immediate area was planted with cornrows of red pine within the last forty years or so. Wish me luck. ----- Original Message ----- From: <bernd.pauli_at_paulinet.de> To: <Meteorite-list_at_meteoritecentral.com> Sent: Monday, August 21, 2006 4:17 AM Subject: [meteorite-list] Kalkaska Hi George and List, "I'm looking for any information regarding the Kalkaska find (Michigan, 1947, medium octahedrite). An image of the main mass or perhaps its location would be helpful. It's a stretch I'm sure, but you never know." Here are some passages from Buchwald with regard to the Kalkaska iron. Maybe this is helpful. Best wishes, Bernd Kalkaska, Michigan, U.S.A. 44? 38' 49" N, 85? 08' 12" W Medium octahedrite, Om. Bandwidth 1.00?0.15 mm. Group IIIA. 7.4% Ni, about 0.1% P, 18.1 ppm Ga, 33.5 ppm Ge, 11 ppm Ir. HISTORY A mass of 9.4 kg (20.7 pounds) was plowed up in 1947 or 1948 by A.R. Sieting, about 10 km south-southwest of Kalkaska, in Kalkaska County. The field had been cultivated for over 30 years, so the sound of the cultivator blades striking metal was quite unexpected. The mass was shown to various peoples and to schools, before it was presented, in 1964, to Michigan State University where it was described with a photo- graph of the exterior and a photomacrograph by Chamberlain (1965) who also gave further details of the find. COLLECTIONS Abrams Planetarium, Michigan State University, East Lansing (main mass), Washington (759 g). DESCRIPTION The irregular mass has the approximate overall dimensions 18 x 15 x 9 cm, and it shows numerous well developed regmaglypts 10-20 mm in size. Locally, deeper holes are carved out, as for instance, 10 mm deep with an aperture of 20 x 15 mm. The mass is covered by a brown oxide crust from terrestrial corrosion, but the fusion crust may still be observed in various places. Etched sections display a medium Widmanst?tten structure of straight, long kamacite lamellae with a width of 1.00?0.15 mm ... the plessite fields are degenerated and contain only little taenite. Schreibersite is not common ... Rhabdites are present in many kamacite lamellae, but they are small, generally less than 2 ? thick. Troilite occurs as angular and lenticular bodies, ... frequently enveloped in 0.5-1 mm swathing kamacite ... The troilite contains daubreelite as 50-200 ? wide bars that are often brecciated together with the troilite itself. Isolated daubr?elite, or possibly brezinaite, grains occur as angular crystals, 10-40 ? in size, in the kamacite. Veinlets of troilite extend into the metallic matrix, ... contain breccias of troilite with minor amounts of daubr?elite that are set in a matrix of terrestrial corrosion products. The breccia-filled fissures mainly follow schreibersite-filled grain boundaries; it appears that the cracks were created at a remote shock event and that shattered debris from the troilite nodules partly filled them up. Open as they were, they became an easy prey for percolating, terrestrial ground water. Kalkaska is a shocked medium octahedrite which appears to be related to Costilla Peak and Boxhole. It is a low-nickel low-phosphorus member of group IIIA. Specimen in the U.S. National Museum in Washington: 759 g slice (no. 3217, 10 x 5 x 2.4 cm) Reference: BUCHWALD V.F. (1975) Handbook of Iron Meteorites, Volume 2 , pp. 707-709. ______________________________________________ Meteorite-list mailing list Meteorite-list_at_meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list Received on Mon 21 Aug 2006 07:37:05 AM PDT |
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