Grady (1937) meteorite, Curry County, New Mexico, USAi

Regional Level Types
Grady (1937) meteorite	Meteorite Fall Location
Curry County	County
New Mexico	State
USA	Country

Unequilibrated ordinary chondrite, xenolithic (H3.7,br)
Found, 1937; 9.3 kg

A weathered and shocked meteoritic stone was recovered. Inspections reveal distinct chondrules and chondrule fragments within a largely unequilibrated, graphitized, and xenolithic matrix Compositionally, bulk iron contents (Fe 26.23 wt%), nearly equilibrated olivine (Fa15) and variable low Ca-clinopyroxene are characteristic of H3.7 chondrites. Mineralogically the meteorite consists primarily of olivine and pyroxene accompanied by minor troilite and Fe-Ni metal. Accessory chromite, ilmenite, and other minor phases are also reported. Graphite, often aggregated, is found as cliftonite, in metal, and associated with troilite. Minute (nanoscale) pre-solar diamonds, graphite, and SiC have been identified among the disparate phases present in the matrix. Shock indicators include undulating extinction in the (sometimes) fractured olivine grains, Neumann bands in kamacite, veins, and various xenoliths. Extensive weathering is also evident. In addition to pervasive limonite strings and stains, a significant portion of the original kamacite and ilmenite have been weathered into magnetite. A cosmic ray exposure (CRE) age of 6.5 Ma is suggestive of, perhaps, shared collisional histories with other H chondrites with similar CREs.

The H (relatively high in total iron) chondrites are, marginally, the largest group of recovered ordinary chondrites, representing roughly 40% of recognized and properly classified meteorites. However, the H3 (or, unequilibrated) chondrites account for less than 10% of the recovered H-group meteorites. Moderately large specimens are at the Center for Meteorite Studies at Arizona State University [1892.53 g in 2016] and the United States National Museum in Washington [667.4 g in early 2017].

What's in a name? Grady (1937) is but one of 3 ordinary chondrites found relatively near each other in Curry County, largely due to the efforts of Harvey H. Nininger and Glenn Huss. The others are Grady (1933), an L3-6 chondrite, and Grady (c), an H4 chondrite found in 1970. Other meteorites — Clovis (no. 1), Clovis (no. 1), Melrose (a), and Melrose (b) — have also been recovered from slightly more distant locations in the county.

Other Regions, Features and Areas containing this locality

References