Conquista meteorite, Mateira farm, Conquista, Minas Gerais, Brazili

Regional Level Types
Conquista meteorite	Meteorite Fall Location
Mateira farm	Farm
Conquista	Municipality
Minas Gerais	State
Brazil	Country

Ordinary chondrite, (H4; S1)
Fall, December 1965; 20.35 kg

Before sunrise a meteorite fall was accompanied by loud noise and material weighing 20.5 kg was soon recovered. The meteorite apparently came from the south and had excavated a 1.5 m diameter, 1 m deep pit. Many fragments were said to have been distributed around the impact pit, but only a single moderately large specimen was preserved. Distinct round and elongated chondrules (up to 1.9 mm in apparent diameter) with various textures are present (including prominent porphyritic, barred, and radial types [BO, PO, RP]) and other microcrystalline and or/partly glassy structures. The matrix of the meteorite consists of chondrules and highly variable-sized mineral fragments (mostly olivine and pyroxene). Olivine is nearly equilibrated (Fa17.2,av.), but low-Ca pyroxene is more variable with minor excursions around the mean Fs15.4Or2 composition. Pyroxenes include low-Ca orthopyroxene and twinned-clinopyroxenes as well as small amounts of both pigeonite and diopsidic clinopyroxene. Glassy material, often silica- and alkali-rich, is found in both chondrules and matrix. Plessitic Fe-Ni metal, troilite, and accessory chromite are also present. Bulk iron contents (~26 wt%Fe), olivine and low Ca-pyroxene composition (mildly variable), the presence of twinned-clinopyroxene, and chondrule textures are all consistent with classification as an H4 chondrite. Shock levels are low (S1).Some terrestrial weathering is apparent with hydrous iron oxides frequently found around metal rims. An unusually short cosmic ray exposure age of ~2.8 Ma has been reported for Conquista.

The H (relatively high in total iron) chondrites are the second largest geochemical group of ordinary chondrites and represent ~40% of classified witnessed falls with the H4 petrologic type representing less than 20 % of the H chondrite group. Conquista is the 12th most massive of 62 meteorite falls currently classified exactly as an H4 chondrite (as of May 2016). The main mass has been at the Museu de História Natural, Belo Horizonte for several decades.

Other Regions, Features and Areas containing this locality

References