Horace meteorite, Greeley County, Kansas, USAi

Regional Level Types
Horace meteorite	Meteorite Fall Location
Greeley County	County
Kansas	State
USA	Country

Ordinary chondrite, (H5)
Found, 1940; 19.7 kg

After Harvey Nininger had disseminated information about meteorites in Greeley County schools and newspapers two meteorites were reported. The larger stone (9.2 kg) of these stones is now called Horace. Flow lines with unusual associated elongated pits mark this oriented stone. An additional Horace fragment was found later. Equilibrated olivine (Fa19) and pyroxene ('bronzite') accompanied by lesser amounts of Fe-Ni metal and troilite account for most of the meteorite mass. Accessory chromite, copper and spinel are also reported. Olivine X-ray patterns display orientation patterns due to strong shocks.

A reported 2.47 Ga U/He age and 7.0 Ma cosmic ray exposure (CRE) age provide initial chronological markers to constrain the actual timing of events effecting the mineralogical record. The CRE age of Horace is actually a little more complex than the simple 7 Ma age cited above. Ne-22/Ne-21 ratios suggest a two stage history with the preterrestrial meteoroid spending considerable time as a deeply buried aggregate before a latter ejection event created a smaller meteoroid on a collision course with the earth.

The H-group (relatively high in total iron) chondrites are the largest group of ordinary chondrites and represent ~40% of classified meteorites. The H5 petrologic type are the largest H petrologic subgroup. The main mass (~10 kg) was held by the Max Planck Institute for several decades. A smaller mass has also been at The Center for Meteorite Studies at Arizona State University [3.7036 kg in 2016].

What's in a name?

The Horace meteorite was originally labelled "Horace (No. 2)". The first and smaller stone "Horace (No. 1)" was later determined to be a fragment of the Ladder Creek (L6) chondrite, a meteorite which had been recovered earlier. Harvey Nininger was so thorough in his search for meteorites that it sometimes took years or decades to determine that a number of meteoritic stones found in close proximity to each other were in fact fragments of separate (unobserved) falls. Such identification problematics are a common staple of current meteorite recovery deserts in hot and cold deserts, but before Nininger identification problems were more likely to be products of specimen mislabeling.

Other Regions, Features and Areas containing this locality

References