Antarctic Meteorite Newsletter, Volume 22, No. 2 - August 1999
Volume 22, No. 2 - August 1999

Petrographic Descriptions

Sample No.:

QUE 97 168

Location:

Queen Alexandra Range

Dimensions (cm):

3.0x2.5x1.5

Weight (g):

24.75

Meteorite Type:

H3 Chondrite (estimated 3.6)

QUE97168
 
Macroscopic Description: Kathleen McBride
The exterior of this ordinary chondrite is covered completely with smooth, shiny fusion crust, exhibiting numerous oxidation halos. The interior is mostly rust with abundant metal. There are mm-sized chondrules that are stained with rust and appear as small specks. This meteorite is very hard.

Thin Section (,2) Description: Tim McCoy
QUE97168 - Cross-Polarized Light The section exhibits numerous well-defined chondrules (most ~0.5 mm in diameter), metal and troilite. Weak shock effects are present. Polysynthetically twinned pyroxene is abundant. Weathering is pervasive, with extensive staining. Silicates are unequilibrated; olivines range from Fa9-23 and pyroxenes from Fs1-25. The meteorite is probably an H chondrite of subtype ~3.6.



Sample No.:

QUE 97 186

Location:

Queen Alexandra Range

Dimensions (cm):

5.0x2.5x2.5

Weight (g):

72.712

Meteorite Type:

CV3 Chondrite

QUE97186 Thumbnail

Macroscopic Description: Kathleen McBride
The exterior of this carbonaceous chondrite has brown/black shiny fusion crust covering 100% of its surface area. It is fractured and has oxidation halos. The interior has a dark matrix with some rust and metal. Irregularly shaped chondrules are light colored, stained with rust. Other inclusions appear rusty, tan and gray in color.

Thin Section (,2) Description: Tim McCoy
QUE97186 - Cross-Polarized Light The section exhibits large chondrules (up to 3 mm) and CAIs in a dark matrix. Olivines range from Fa1-31, with most Fa1-5, and pyroxenes from Fs1-2. The meteorite is an unequilibrated carbonaceous chondrite, probably a CV3.



Sample No.:

QUE 97 289; 97 348

Location:

Queen Alexandra Range

Dimensions (cm):

4.5x3.0x2.0; 5.0x3.0x2.0

Weight (g):

51.898; 50.749

Meteorite Type:

Aubrite

QUE97289 QUE97348

Macroscopic Description: Kathleen McBride
This aubrite is extremely altered and is very rusty inside and out. It has small thin patches of fusion crust that comprise less than 5% of the surface area. It is very friable and crumbles easily. QUE97348 contains mm-sized inclusions.

Thin Section (,2) Description: Tim McCoy
Skip TS Images que97289 QUE97289 - Cross-Polarized Light QUE97289 - Reflected Light QUE97348 - Reflected Light QUE97348 - Reflected Light
QUE97289 - Cross-Polarized QUE97289 - Reflected QUE97348 - Cross-Polarized
(2.6mm FOV)
QUE97348 - Cross-Polarized
(650µm FOV)

The section consists of mm-sized enstatite grains (Fs0.1), reasonably abundant (10% or more?) feldspar of variable composition (An4-35), Si-bearing metal (1.9 wt.% Si), Ti-bearing troilite, daubreelite, alabandite and schreibersite. The latter phases often occur as rounded enclaves in the enstatite. The meteorite is an unusual aubrite. It is similar in many respects to LEW 88055 (Casanova et al., 1993, LPSC XXIV, 259-260).



Sample No.:

QUE 97 294

Location:

Queen Alexandra Range

Dimensions (cm):

3.0x2.0x1.0

Weight (g):

14.942

Meteorite Type:

H5 Chondrite

QUE97294

Macroscopic Description: Kathleen McBride
QUE97294 - Cross-Polarized Light 100% of this ordinary chondrite’s exterior has rough, black fusion crust with oxidation halos. The interior is a steel gray color with rusty patches and is somewhat flaky. It is very dense with no visible inclusions.

Thin Section (,2) Description: Tim McCoy
This meteorite is a strongly shocked H5 chondrite (Fa20,Fs17) with shock blackening and dispersion of metal and troilite. Olivines exhibit planar fractures and mosaicism.



Sample No.:

GRA 98 005

Location:

Graves Nunataks

Dimensions (cm):

8.0x5.5x2.5

Weight (g):

202.85

Meteorite Type:

C2 Chondrite

QUE98005 Thumbnail

Macroscopic Description: Kathleen McBride
The exterior of this carbonaceous chondrite is dull and black with white evaporites along the edges. The top face has a large yellowish brown inclusion. The meteorite appears to have no fusion crust. The interior is brown, very weathered and crumbles easily. Evaporite deposits are present on the interior surface.

Thin Section (,6) Description: Tim McCoy
GRA98005 - Cross-Polarized Light The section consists of a few small chondrules (up to 0.5 mm), mineral grains and CAIs set in a black matrix; rare metal and sulfide grains are present. Olivine compositions are Fa0-4, orthopyroxene is Fs1-2. The matrix consists dominantly of an Fe-rich serpentine. The meteorite is a C2 chondrite.



Sample No.:

GRA 98006

Location:

Graves Nunataks

Dimensions (cm):

6.5x6.0x2.5

Weight (g):

163.70

Meteorite Type:

Eucrite

GRA98006 Thumbnail

Macroscopic Description: Kathleen McBride
40% of the exterior of this achondrite is covered by thin, shiny black fusion crust. Exposed interior is medium gray in color with white and tan inclusions. The interior is a gray matrix with tan and white clasts, 1 to 4 mm in diameter. This meteorite is coherent and moderately hard.

Thin Section (,6) Description: Tim McCoy
GRA98006 - Cross-Polarized Light The section consists dominantly of a mixture of mm-sized orthopyroxene (Fs60Wo3), with lamellae of augite (Fs30Wo42), and plagioclase (An90Or0.5). The Fe/Mn ratio of the pyroxene is ~30. The meteorite is brecciated and severely shocked. The meteorite is a eucrite.



Sample No.:

GRA 98 033

Location:

Graves Nunataks

Dimensions (cm):

6.0x4.0x3.0

Weight (g):

123.20

Meteorite Type:

Eucrite

GRA98033 Thumbnail

Macroscopic Description: Kathleen McBride
80% of the surface of this achondrite is covered with black fusion crust with shiny patches. There are several large (0.5-2.0 cm) "vugs" where sample material has weathered or has been plucked. The interior has a sugary texture, with a grayish green matrix. Black grains and some clasts are interspersed throughout the matrix. Pure white inclusions, rusty halos and streaks are visible. Several white clasts with matrix material incorporated into the clast are present.

Thin Section (,6) Description: Tim McCoy
GRA98033 - Cross-Polarized Light The section consists dominantly of a mixture of mm-sized orthopyroxene (Fs64Wo2), with lamellae of augite (Fs28Wo44), and plagioclase (An88Or0.5). The Fe/Mn ratio of the pyroxene is ~30. The meteorite is a brecciated eucrite.



Sample No.: GRA 98098
Location: Graves Nunataks
Dimensions (cm):   10.0x6.8x5.5
Weight (g): 779.2
Meteorite Type: Eucrite
    GRA98098,0 Thumbnail GRA98098,0 & ,1 Thumbnail     All Images

Macroscopic Description: Katlheen McBride
The exterior of this meteorite is coarse grained and crystalline with white linear, criss-crossing veins of sugary textured material. The matrix consists of reddish-brown crystals, milky white feldspar crystals, some euhedral and gray translucent crystals. Some thin black patches of shiny fusion crust are present (about 10%). The interior is similar to the exterior except the interior veins are more yellowish in color.

Thin Section (,18) Description: Tim McCoy
Skip TS Images GRA98098
GRA98098,16 - Cross-Polarized Light - Silica Grain GRA98098,18 - Cross-Polarized Light - Normal Part GRA98098,18 - Cross-Polarized Light - White Vein GRA980988,18 - Cross-Polarized Light - Fusion Crust
,16 - Silica Grain ,18 - Normal Part ,18 - White "vein" ,18 - Fusion Crust

The section consists dominantly of a mixture of mm-sized orthopyroxene (Fs59Wo5), with 1-5 micron lamellae of augite (Fs35Wo33), and plagioclase (An89Or0.5). The Fe/Mn ratio of the pyroxene is ~31. A sub-equal mixture of plagioclase and SiO2 with minor pyroxene dominates the white veins seen in hand sample. The dominant opaques are Fe, Ti-and Fe,Ti,Cr,Al-oxides with minor iron sulfide and rare iron metal. The meteorite is a eucrite.

Oxygen Isotope Analysis: Robert Clayton
The oxygen isotope analysis of GRA98098 is d 18O=+3.3; d 17O=+1.4. This is a typical HED composition.