Sample No.:	LAP 04840
Location:	LaPaz Ice Field
Field No.:	17198
Dimensions (cm):	5.0x3.0x1.75
Weight (g):	50.405
Meteorite Type:	R Chondrite

Macroscopic Description: Kathleen McBride
Rough, black fusion crust with polygonal fractures is present on the exterior surface. The interior is a fine grained crystalline matrix with black and white crystalline inclusions. The meteorite was very hard with no rusting or apparent metal.

Thin Section (,4) Description: Tim McCoy
The section is texturally heterogeneous, containing relict chondrules up to 1 mm, isolated mineral grains of 100-200 microns and microcrystalline areas reaching 1 mm with mafic silicate grain sizes of 5-10 microns. Shock effects are pervasive, particularly in plagioclase. The rock consists of FeO-rich olivine (Fa₃₈) and orthopyroxene (Fs₃₀Wo₁). Plagioclase is An₇Or₃. A brown, strongly pleochroic mineral comprises ~15% of the section. Microprobe analyses suggest hornblende with approximately 48% SiO₂, 3% Na₂O, 6% Al₂O₃, 16.5% MgO, 11% FeO, 10% CaO and < 0.5% TiO₂, MnO and K₂O. Low totals and the strong pleochroism may be due to structurally bound OH, as no Cl was noted in EDS analyses. Opaques include troilite, pentlandite and chromite. The meteorite is an R chondrite of petrologic type 6.

Oxygen isotope analysis laser fluorination: D. Rumble
The analysis of two silicate-rich fractions yielded δ¹⁸Ο=+4.28, δ¹⁷Ο=+4.37, and δ¹⁸Ο=+4.76, δ¹⁷Ο=+5.76, similar to other R-chondrites.

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