Capão do Leão        31º46’3"S, 52º26’55"W

Rio Grande do Sul, Brazil

Find, possible fall: 2019

Classification: Ordinary chondrite (L5)

History: (José M. Monzon, Rodrigo Guerra) On the night of April 10, 1999, a driver from the Federal University of Pelotas, Altamir Manuel Gonçalves, was fishing on the banks of Arroio Padre Doutor, near the Capão do Leão city, in the state of Rio Grande do Sul/Brazil. According to his report, at that moment there was a flash in the sky and he felt a strong gust of wind, followed by the noise of something cutting through the air. Altamir collected some samples, which were not meteorites and from the photos published in some news, they appeared to be slag. Following this bolide history, in 2019, José Maria Monzon, and his son Camilo I. Monzon, decided to do a fieldwork in the region during October and November, during which they found five samples, totaling about 210 g.

Physical characteristics: Weathered stones, totaling 210 g, partially covered with dark-brown fusion crusted.

Petrography: (M. E. Zucolotto, MN/UFRJ) Two polished thin sections were exhamined under OM and EPMA, showing discernible chondrules and chondrules fragments. Chondrule types include BO, RP, PO, POP and GOP. One chondrule is fully enveloped by a wide troilite rim. Chondrule sizes range from 0.3 to 1.5 mm with average diameter of 0.78 mm. Clinoenstatite grains are present in PP chondrules. Plagioclase occur as small grains, few larger than 50 µm in size. Many metal grains show dark plessite etch, most of them have tetrataenite rim. Neuman lines in kamacite are present. Troilite is polycrystalline. Olivine and pyroxene show weak mosaicism, planar fractures and undulatory extinction, suggesting shock stage S3/4. Less than 20% of Few Fe-Ni metal present oxidation and no evidence of weathering in silicate minerals indicating weathering grade W1.

Geochemistry: (A. Tosi, IGEO/UFRJ) Electron microprobe: olivine Fa_{26.1 ± 0.9} (n=13); low Ca pyroxene Fs_20.5±1.1Wo_0.98±0.5 (n=9); plagioclase Ab_80.4±1.75An_10.2±0.60Or_9.42±2.0 (n=8). Kamacite Ni=6.79±0.23 wt. %, Co=0.835±0.16 wt. % (n=7).

Classification: L5 brecciated ordinary chondrite. Weathering (W1) and moderated shocked (S3/4)

Specimens: MNRJ 21.5 g and Finder 188.5 g type specimen