168.9g Diogenite HED Achondrite Meteorite from Asteroid 4 Vesta I NWA 16081
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- $ 1,350.00
The HED meteorites are so named for the three types of meteorites that comprise the group; Howardite, Eucrite and Diogenite. The Eucrite and Diogenite are meteorites with distinct chemistries, while the Howardite is a mix of the eucritic and diogenitic material. The HEDs are differentiated achondritic meteorites, thought to originate from the large differentiated asteroid 4 Vesta. Vesta is one of the only asteroids visible with the naked eye and low powered telescopes.
The Vesta parent body origin for the HED clan of meteorites is considered to have been conclusively established for many years. However, the late Dr. John Wasson, a planetary science researcher from UCLA had long held that the HED meteorite clan originated from another unknown Vesta-like asteroid that was blown apart long ago. This is because we also find a class of iron meteorites with nearly identical oxygen isotopes as the HED clan. This along with other research lead Dr. Wasson to conclude the HED clan of meteorites come from another differentiated V-type asteroid that was in a cataclysmic collision liberating part or all of its metal core along with the HED meteorites.
However, this hypothesis does not necessarily rule out the possibility that a "reaccreted" Vesta and the smaller V-type asteroids collectively known as Vestoids along with the HED meteorites and the isotopically paired irons were all once part of a much larger dwarf planet prior to a massive collision with another large body. While most researchers consider the case mostly closed on this debate, the paradox of isotopically paired core metal raised by Dr. Wasson's hypothesis has not been resolved. This leaves some to speculate that perhaps we still have more to learn about this fascinating clan of achondrite meteorites and even Vesta itself. Diogenite have distinct mineralogies, the Howardite is a breccia of the Eucrite and Diogenite.
| Northwest Africa 16081 | |||||||||||||||||||||||||||||
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| Basic information |
Name: Northwest Africa 16081 This is an OFFICIAL meteorite name. Abbreviation: NWA 16081 Observed fall: No Year found: 2023 Country: Niger Mass: 419 g |
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| Classification history: |
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| Comments: | Approved 21 Aug 2023 | ||||||||||||||||||||||||||||
| Writeup |
Writeup from MB 112:
Northwest Africa 16081 (NWA 16081) Niger Purchased: January 2023 Classification: HED achondrite (Diogenite) History: Purchased by J. Eisler from a meteorite dealer in Mauritania who purchased it from the finder in Niger. Physical characteristics: Two stones of approximate equal size and one slightly smaller stone, each partially covered in black fusion crust with exposed areas showing a light colored interior with a slight green hue. Petrography: (D. Dickens, CCMS and R. G. Mayne, TCU) This meteorite is composed predominately of orthopyroxene with subhedral grains of up to 1mm. Most orthopyroxene grains show some exsolution. Minor and accesory phases include plageoclase, Ti-chromite, and silica. Geochemistry: (D. Dickens, CCMS and R. G. Mayne, TCU) low-Ca pyroxene: Fs24.0±0.5Wo2.2±1.2 range Fs23.9-24.5Wo1.2-4.7, FeO/MnO=28±2, ( n=8); calcic plagioclase: An82.6±0.2 range An82.4-82.7, (n=2). Classification: HED achondrite (Diogenite) Specimens: 20 g including probe mount at TCU; remainder with Mr. J. Eisler. |
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| Data from: MB112 Table 0 Line 0: |
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| Institutions and collections |
TCU: Oscar E. Monnig Collection, Department of Geology, Texas Christian University, Ft. Worth, TX 76129, United States; Website (institutional address; updated 24 Feb 2012) TM: Geoscience Museum, Transvaal Museum, P. O. Box 413, Pretoria 0001, South Africa (institutional address; updated 3 Mar 2011) |
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