Catalina 621        25.084490°S, 69.911778°W

Antofagasta, Chile

Find: 2019 Nov 09

Classification: Mesosiderite (group A3)

Petrography (E. Jacquet, C. Brillatz, MNHNP): A fresh (<1 vol% weathering phases) recrystallized stone with 54 vol% (point counting with N=504) pyroxene crystals with augite exsolution, up to 1 mm in size (the largest still identifiable as preexisting mineral clasts), anorthitic plagioclase (23 vol%) up to 0.5 mm across (excluding a large 1.5 mm plagioclase grain with pyroxene inclusions) sometimes neighbouring with silica (4 vol%), more or less irregular Fe-Ni (chiefly kamacite) grains up to 1 mm in size (17 vol%), small troilite a few 10s of µm across at most (1 vol%), chromite (1 vol%; especially abundant in one pyroxene area which may have contained olivine (now absent) prior to metamorphism), trace ilmenite, merrillite.

Geochemistry: Mineral composition and geochemistry: plagioclase An_90.5±1.0Ab_9.2±1.0Or_0.3±0.0 (N=3)

Classification: Mesosiderite, group A from plagioclase/pyroxene ratio (see Mittlefehldt et al. 1998), and grade 3 from level of recrystallization (Powe, 1971), with no impact melt evident. Probably paired with Catalina 392 and 399 found nearby (although classified B2, with Catalina 399 having nonetheless 21 vol% plagioclase)