Nossa Senhora do Livramento        15°59’S, 56°18’W

Mato Grosso, Brazil

Find: 2016 Aug

Classification: Iron meteorite (IIIAB)

History: Found by a prospector, Valmir P. Scarabeli, while he was searching for gold with a metal detector. The finder sent samples to Andre Moutinho who performed preliminary tests that confirmed the sample’s meteoritic origin. Samples were then provided to Dr. Zucolotto for a complete analysis and classification.

Physical characteristics: A weathered mass weighing 1120 g and measuring about 110 × 80 × 30 mm. The examined section was highly corroded with a thick oxide crust, the corrosion penetrating deeply to the very center of the meteorite, particularly along grain boundaries.

Petrography: (M.E. Zucolotto, MNRJ/UFRJ) The meteorite is a medium octahedrite containing kamacite, taenite and few plessite fields. Kamacite bandwidth is 0.90±0.15 mm. Kamacite shows Neumann bands with microhardness of HV 205±15. Plessite fields include degenerated comb and net plessite with dark taenite wedges. Also present in some grains are decorated Neumann bands and numerous micrometer-sized gamma precipitates on the kamacite. A small troilite-daubreelite (0.5 × 1.0 mm) nodule was observed with iron sulfide eutectic and small subangular daubreelite grains.

Geochemistry: (J.T. Wasson, UCLA): INAA data, Ni = 74.6, Co = 5.00 (both mg/g), Cr=58, Cu = 204, Ga = 20.7, As = 4.86, W=1.34, Re=1481, Ir =12.8, Pt=18.1 Au = 0.654 (all μg/g). (A. Tosi, IGEO/UFRJ): kamacite 7.24 % Ni, 0.48 % Co, taenite and tetrataenite.

Classification: Iron, IIIAB. The meteorite plots in the IIIAB field and differs in composition from all Brazilian Irons.

Specimens: Main mass with Rodrigo Guerra, 70 g MNRJ, 90 g Andre Luiz R Moutinho, 62 g Carlos Augusto Di Pietro.