Hutchison Icefield 18034 (HUT 18034)        81°28.64683’S, 26°17.66250’W

Antarctica, Antarctica

Find: 2019 Jan 20

Classification: Enstatite achondrite (Aubrite)

History: The meteorite was recovered as part of the Lost Meteorites of Antarctica project, which was funded in the UK by the Leverhulme Trust and supported by the British Antarctic Survey and the University of Manchester. These samples were collected as part of the project’s first field season in austral summer December 2018 - January 2019 by a two person field party consisting of Katherine Joy and Julie Baum. Found on firn. Altitude 1152 m.

Physical characteristics: Mass: 0.81 g. Pieces: 1. Dimensions: 2 × 2 × 1 cm. An irregular, white-grayish part-stone with visible white grains (enstatite) and 40% black fusion crust. Several orange-brownish stained areas sometimes with silvery metallic grains are visible.

Petrography (J. L. MacArthur, K. H. Joy, R. Jones): The section consists of predominantly enstatite grains up to 3 cm in size in a brecciated matrix dominated by enstatite. Additional minerals include diopside (~8%), some containing abundant enstatite exsolution lamellae, ~4% feldspar, ~3% forsterite and occasional grains of Ti-bearing troilite, daubreelite and schreibersite.

Geochemistry: Mineral compositions and geochemistry (J. L. MacArthur, K. H. Joy, R. Jones): All analyses by EPMA. Olivine: forsterite Fo_100±0 (N=7). Pyroxene: En_98.9±0.4Fs_0.0±0.0Wo _1.1±0.4 (N=10) and En_55.9±1.2Fs _0.1±0.1Wo _44.0±1.2 (N=6). Plagioclase An_5.0±4.6Ab_92.0±3.8Or _3.0±0.9 (N=5). Oxygen Isotopes (J. Malley, R. Greenwood and R. Findlay, OU): One fragment was analyzed for oxygen isotopes by laser fluorination at OU. An ~18 mg homogenized sample yielded the following results (per mil deviation from VSMOW): δ¹⁷O=2.414, δ¹⁸O=4.531, Δ¹⁷O=0.058. Δ¹⁷O values are calculated using a slope of 0.52. The oxygen isotope analysis of the fragment plots close to the terrestrial fractionation line and is only slightly displaced from the aubrite analyses of Newton et al. (2000) and Barrat et al. (2016).

Classification: Aubrite

Specimens: 0.672 g type specimen (main mass) held at NHM .