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Lewis Cliff 87295
Basic information Name: Lewis Cliff 87295
     This is an OFFICIAL meteorite name.
Abbreviation: LEW 87295
Observed fall: No
Year found: 1987
Country: Antarctica [Collected by US Antarctic Search for Meteorites program (ANSMET)]
Mass:help 20 g
Classification
  history:
Antarctic Meteorite Newsletter:  AMN 14(1)  (1991)  Eucrite
AMN 17(1)  (1994)  Eucrite-pmict
Meteoritical Bulletin:  MB 76  (1994)  Eucrite-pmict
NHM Catalogue:  5th Edition  (2000)  Eucrite-pmict
MetBase:  v. 7.1  (2006)  Eucrite-pmict
Recommended:  Eucrite-pmict    [explanation]

This is 1 of 342 approved meteorites classified as Eucrite-pmict.   [show all]
Search for other: Achondrites, Eucrites, and HED achondrites
Comments: Field number: 4283
Writeuphelp
Writeup from AMN 14(1):

Sample No: LEW87295

Location: Lewis Cliff

Field Number: 4283

Dimensions (cm): 3 x 2.5 x 2

Weight (g): 20.0

Meteorite Type: Eucrite

 

Macroscopic Description: Roberta Score

LEW87295 was found in the Lewis Cliff area emerging from the ice. The field team collected it by sawing a block of ice containing the meteorite. The ice block was sent to the Cold Regions Research and Engineering Lab in Hanover, New Hampshire, where the meteorite was removed. Care was taken to avoid contamination. The ice block remains in New Hampshire while the meteorite specimen resides in Houston.

 

Dull black fusion crust covers approximately 40% of this eucrite. Numerous vugs, typical of Antarctic eucrites, penetrate deep into the interior. Many clasts, polymineralic and monomineralic are present in the medium gray matrix. One notable clast is an easily extractable black clast whose dimensions are 6 x 5 x 4 mm. Some areas of rust are visible.

 

Thin Section (,4) Description: Brian Mason

The section shows clasts of pyroxene and plagioclase up to 1.8 mm long in a comminuted groundmass. Within the section there are individual brecciated clasts, up to 4 mm across. A black clast, 1.5 x 0.7 mm, appears to be a C2 carbonaceous chondrite; it contains chondrule-like aggregates of granular olivine and pyroxene up to 0.3 mm across. A patch of transparent brown glass, 0.6 mm long, is also present. Microprobe analyses show pyroxene compositions ranging fairly continuously from Wo2Fs59 to Wo42Fs24, the range in En content being quite limited; one clast of Mg-rich pyroxene, Wo3Fs20, was analyzed. Plagioclase composition is fairly uniform, averaging An91. One grain of a silica polymorph, probably tridymite, was noted. The brown glass is somewhat variable in composition, but averages (weight percent): SiO2 48, Al2O3 16, FeO 13, MgO 6.2, CaO 12, Na2O 3.6, K2O 0.2, MnO 0.5. The meteorite is a eucrite.

 

Data from:
  MB76
  Table 2
  Line 3858:
Origin or pseudonym:South Lewis Cliff
Mass (g):20
Class:Eu "pm"
Weathering grade:B
Fayalite (mol%):¾
Ferrosilite (mol%):20-59
Catalogs:
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References: Published in Antarctic Meteorite Newsletter 14(1) (1991), JSC, Houston
Published in Meteoritical Bulletin, no. 76, Meteoritics 29, 100-143 (1994)
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Geography:

Antarctica
Coordinates:
     Catalogue of Meteorites:   (84° 17'S, 161° 5'E)
     Recommended::   (84° 21' 51"S, 161° 23' 1"E)
Note: the NHM and MetBase coordinates are 9.6 km apart

Statistics:
     This is 1 of 39173 approved meteorites from Antarctica (plus 5051 unapproved names)
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