Northwest Africa 15245 (NWA 15245)

(Northwest Africa)

Purchased: Jan 2021

Classification: Ordinary chondrite (H3)

History: A 46.3 g piece of the meteorite was sent to Cascadia by John Shea in June, 2013, who purchased the sample on April 8, 2013 from Matt Morgan of Mile High Meteorites, who in turn purchased the sample at the Tucson Gem and Mineral Show in February 2011 from an anonymous Moroccan vendor as part of a lot of unclassified meteorites. On January 19, 2021, Martin Goff emailed Cascadia that he had recently acquired a box of NWA chondrites that came from US collector John/Johannes Shea, including CML 0747.

Physical characteristics: Physical Characteristics: The exterior of the stone is covered by a dark brown weathering rind. Cut faces are a reddish-brown slightly lighter that the exterior, with visible flecks of reflective oxide minerals and red-brown fractures.

Petrography: (M. Hutson, A. Ruzicka, Cascadia): Abundant well-defined chondrules are visible in thin section, many containing low-Calcium clinopyroxene. However, the thin section is cross-cut by numerous veins filled with weathering products, causing interchondrule material to be opaque in transmitted light, causing chondrules to stand out. There is 60-65% replacement of metal and sulfide. BSE images show extensive cross-cutting of chondrules and interchondrule regions by weathering veins. BSE imaging also shows numerous chondrules with zoned olivine grains, magnesian olivine and pyroxene grains, and glassy crystallite-containing mesostases.

Geochemistry: Olivine: Fa_18.4±7.3, N=52; low-Ca pyroxene: Fs_15.2±5.4Wo_1.0±0.4, N=31.

Classification: Ordinary chondrite (H3) based on mineral chemistry and texture.

Specimens: Cascadia holds 43.5 g in two pieces, as well as a polished thin section; MGoff holds the main mass.