Loro        2°13’07"N, 32°32’56"E

Northern, Uganda

Confirmed fall: 24 Dec 2021

Classification: Ordinary chondrite (L6)

History: Around 10 pm on 24 December 2021, residents in the rural regions of north-central Uganda (Northern Region, Oyam and Apac Districts) were awoken by loud sonic booms. Mr. Dan Opito Odwee who lives SSE of Loro, Uganda, was startled by the sudden booming, which was followed shortly thereafter by a whistling sound and a bang. The following morning he found a melon-sized black stone in a small depression in the garden behind his house. Mr. Odwee arranged for export permits from the Geological Survey and the stone was purchased by Michael Farmer.

Physical characteristics: Single, rounded, fusion-crusted stone with shallow, broad regmaglypts. The interior is uniformly light gray with a few recognizable chondrules and an even distribution of small metal and sulfide grains. One thin shock vein is visible in one slice.

Petrography: (A. Distel, L. Garvie, A. Wittmann, ASU) A 1-inch polished mount displays a coarse-grained matrix with several well-defined chondrules that range up to ~3.4 mm in size. Observed chondrule textures include BO, RP, PO, and PP. Olivine and pyroxene are the major rock-forming minerals. Feldspar grains range in size but many are in the 50 to 100 µm size range. The olivine and pyroxene show intense fracturing, whereas fractures in the feldspar grains are rare. The feldspar grains typically show radial fractures in the host olivine and pyroxene. Troilite, kamacite and taenite are generally anhedral and range in size up to ~820 µm, ~1.3 mm, and ~600 µm, respectively. Troilite is coarsely polycrystalline and lacks shock lamellae. Kamacite is dominantly coarsely crystalline and lacks Neumann bands. Chromite occurs as euhedral grains, as intergrowths in feldspar, and subhedral to anhedral grains in the matrix. Chromite ranges in size up to ~330 µm. Ca-Na-Mg-rich phosphates are anhedral with grains up to ~650 µm and the rarer Cl-rich grains range up to ~260 µm. Areal percentages measured for the opaques are: Troilite 4.3 vol.%, kamacite 1.7 vol.%, taenite 0.9 vol.%, and chromite 0.4 vol.%.

Geochemistry: Olivine, low-Ca pyroxene, and feldspar dominate the sections. Olivine (n=15) - Fa_25.2±0.3, FeO/MnO= 49.6; low Ca-pyroxene (n=14) - Fs_21.0±0.2Wo_1.7±0.2, FeO/MnO=29.5; high Ca-pyroxene (n=3) - Fs_8.2±0.5Wo_44.3±0.5, FeO/MnO=21.3; plagioclase (n=3) - Ab_84.4±0.1An_8.7±0.1; taenite (n=4) - Fe 71.6±0.6 wt%, Ni 27.3±0.8 wt%, Co 0.24±0.06 wt%; kamacite (n=5) - Ni 6.3±0.3 wt%, Co 0.78±0.08 wt%, n=5; and, troilite (n=5) - Fe 63.7±0.3 wt%, S 36.4±0.2 wt%.

Classification: Ordinary chondrite, L6, S3, W0

Specimens: 36.1 g and two polished mounts at ASU.