Socorro        -8.1255556, -40.5172222

Pernambuco, Brazil

Find: 2019

Classification: Martian meteorite (Shergottite)

History: Found outside of Socorro, Pernambuco, Brazil, by a farmer cutting brush in 2019. He kept it as a strange rock unlike any others with thoughts that it could be a meteorite. After the nearby Santa Filomena meteorite fall in August 2020, the finder realized it was a meteorite and sent it to a relative in Miami, Florida. It was purchased by Michael Farmer soon after. Subsequently the entire main mass was sold to an anonymous meteorite collector. Finder wishes to remain anonymous.

Physical characteristics: Single stone, 4474 g, doubly oriented, flow-lined fusion crust. The interior of the stone is exposed on one side where the main flight-oriented nose has apparently been broken off at some time in the past, perhaps during Earth impact. Some weather-staining is present as orange-brown streaks on the fusion crust and the broken surface. A freshly chipped-off deposit sample reveals shiny maskelynite patches that are visible to the naked eye. A section oriented approximately orthogonal to the fusion crust layer was imaged using BSE, showing it to be highly vesicular with average apparent thickness ~250 μm.

Petrography: (C. Agee, UNM) The two major phases in this meteorite are clinopyroxene and maskelynite. Ubiquitous minor phases are merrillite/apatite, titanomagnetite, ilmenite and silica. The clinopyroxene has a modal abundance of approximately 60%, with significant core to rim zoning observed in backscattered electron images indicating an igneous crystallization trend with Mg-rich sub-calcic augite cores, mantled by intermediate pigeonite, and rimmed with ferropigeonite. Clinopyroxene average grain size is approximately 500-1000 μm. Maskelynite has modal abundance of approximately 30%, most grains are subophitic with maximum length ~1 mm. Merrillite laths are up to 1 mm in length. There are numerous domains of fine-grained intergrowths or quench crystals presumably formed during a shock event.

Geochemistry: (C. Agee, UNM) Clinopyroxene Fs_57.3±21.4Wo_19.5±7.5, core to rim range Fs_29.0Wo_30.6 (sub-calcic augite) – Fs_83.5Wo_11.7 (ferropigeonite), Fe/Mn=36±5, n=34; maskelynite An_47.0±7.7Ab_50.8±6.0Or_2.2±1.8, n=11; fusion crust (20 μm defocused electron beam) SiO₂=47.5±0.7, TiO₂=0.96±0.04, Al₂O₃=11.9±0.3, MgO=4.1±0.1, FeO=18.9±0.3, MnO=0.44±0.03, CaO=9.8±0.1, Na₂O=2.3±0.1 (all wt%), titanomagnetite FeO=52.8±1.2, Fe₂O₃=19.2±1.4, TiO₂=24.2±1.1, Al₂O₃=1.9±0.6±0.4, (all wt%), n=3; Oxygen isotopes (K. Ziegler, UNM): 5 acid-washed fragments analyzed by laser fluorination gave δ¹⁸O= 4.914, 5.357, 4.665, 4.879, 5.073; δ¹⁷O= 2.834, 3.077, 2.730, 2.836, 2.951; Δ¹⁷O= 0.239, 0.249, 0.267, 0.260, 0.272 (linearized, per mil, TFL slope=0.528).

Classification: Evolved martian basalt, clinopyroxene compositional zoning trends are similar to QUE 94201.

Specimens: 20.2 g including a probe mount on deposit at UNM, anonymous holds the main mass.