Cariquima        19°28’S, 68°39’W

Tarapaca, Chile

Find: 2021 Jul 26

Classification: HED achondrite (Howardite)

History: The meteorite was found by Alexandre Corgne and Gaëlle Plissart while trekking

Physical characteristics: A single specimen with glassy fusion crust on all sides and some flow lines. Mass is 280 g. Density is 2.8. Fairly porous and weakly consolidated.

Petrography: (A. Corgne, Universidad Austral de Chile) Polymict breccia of submm/ mm sized basalt and OPX clasts in a fine matrix of related crystalline debris with typical grain size less than 50 µm. Contains aprox. 70 wt% eucrite materials and 30 wt% diogenite materials (based on average Al and Ca contents of the fusion crust). Eucrite components are mostly lithic fragments of basaltic eucrite, with only some clasts of cumulate eucrite. These clasts vary in texture from fine-grained porphyritic to coarsegrained subophitic. One cumulate eucrite clast presents a variolitic texture. The eucrite materials typically contain exsolved ferroan pigeonite and plagioclase, as well as minor and accessory phases such as silica, ilmenite, chromite, troilite, metal, zircon, fayalitic olivine, apatite and merrillite. Diogenite components are essentially orthopyroxene fragments, some with thin chromite veins. Shock evidence include the presence of melt pockets and veins with quenched texture in some pyroxene and silica grains and darkening of pyroxene by small blebs of metal and troilite. One round chondrule-like chromite-plagioclase assemblage was also observed in the studied polished thick section.

Geochemistry: Pyroxene overall Fe/Mn (atomic) 29.8±3.1 (N=77). Diogenitic low-Ca pyroxene Fs_21.7±2.9Wo_2.1±0.7 (N=18), Ca-pyroxene Fs_16.6Wo_38.8 (N=1). Eucritic low-Ca pyroxene Fs_47.5±9.0Wo_5.7±3.2 (N=36), Ca-pyroxene exsolution lamellae Fs_33.7±12.4Wo_34.4±7.6 (N=12). Plagioclase An_87.8±4.8Ab_12.2±4.8 (N=42). Chromite Cr# = 0.77±0.06 (N=8).

Classification: HED achondrite (howardite). No evident weathering.

Specimens: Type specimen at CEREGE (20 g). A polished section at CRPG. A polished thick section and main mass with Corgne (Universidad Austral de Chile).