Dunas de la Soledad        28°02.51’N, 114°01.83’W

Baja California, Mexico

Find: 2015

Classification: Ordinary chondrite (LL5)

History: The rock was found in 2015 by Mr. Manuel Melesio Macklish in an area covered with sand dunes called Dunas de la Soledad (also known as Dunas de Don Miguelito), near the pueblo of Guerrero Negro, at the western part of the Baja California and Baja California Sur state border. According to the finder, that has a collection of rocks, the fragment was found during one of his walks as he observed half of the rock protruded from the ground. When lifted, the meteorite felt very heavy, so he decided to bring it to his house. The fragment was recognized as a meteorite in 2020 after Mr. Macklish posted a picture of it in a social network group.

Physical characteristics: The only fragment recovered was covered in about 70% of a dark-reddish fusion crust with different ° of oxidation and a few penetrating fractures with iron oxides, so fracturing is moderate. The fusion crust is mainly smooth with only two sides showing well-developed regmaglypts, while the exposed inner parts are light to dark brown colored and have several rust colored spots of oxidized metal flakes. The buried surface is yellowish-white, and in this area, the fusion crust eroded. It shows some isolated droplets of hygroscopic salts. The pores in the cut surface are empty. The fragment was cut to remove two small slices and, after the cut, measured about 10 × 9 × 8 cm. Together, the main mass and the slices weighed 2524 g.

Petrography: (D. Sheikh, Cascadia; K. Cervantes, CU; G. Gonçalves, USP) Specimen is an ordinary chondrite containing secondary recrystallized feldspar (Av. ~40 µm), kamacite, taenite, chromite, Fe-oxides, merrillite, and troilite. The chondrule size range is 700 to 3500 µm, average size is 1700 µm (N=28). The volume of Fe-Ni alloys grains is ~3 vol% of the rock, almost 40 % of these Fe-Ni grains are covered by iron oxides, while the troilite grains oxidation is not evident; this is consistent with weathering grade W2. Almost 50 % of the olivine grains show mosaicism and planar fractures, consistent with a shock grade S4.

Geochemistry: (D. Sheikh, Cascadia) Olivine (Fa_27.1±0.5, range Fa_26.4-28.6, n=22), Low-Ca Pyroxene (Fs_22.8±0.5Wo_1.6±0.2, range Fs_22.1-24.4Wo_0.9-2.1, n=25).

Classification: Ordinary chondrite (LL5) based on silicate mineral geochemistry and size of secondary recrystallized plagioclase feldspar.

Specimens: Finder: ~2400 g (main mass); CU: 98 g, two polished sections and two thin sections; USP: 18.45 g and one thin section, Cascadia: one thin section.