St. Mary's County meteorite, St. Mary's County, Maryland, USAi

Regional Level Types
St. Mary's County meteorite	Meteorite Fall Location
St. Mary's County	County
Maryland	State
USA	Country

Ordinary chondrite, unequilibrated (LL3.3)
Fall, 20 June 1919; 24.3 g

A bright fireball, accompanied by lingering smoke, and thunderous detonations appeared in the afternoon, and at least one stone was seen to fall. A single stone of perhaps 500 g was recovered and kept as a family curio, but only 24 g was preserved. A larger portion of the meteorite may have fallen into Chesapeake Bay. The small piece preserved is, however, of great interest as it is one of the few witnessed falls of an unequilibrated LL chondrite (very low total iron) to be recovered. Olivine compositions are particularly variable (Fa0.2-77, ave Fa14). Variable pyroxenes are mostly clinopyroxenes. Much of the plagioclase has been converted to glass, but both anorthitic and albitic grains are found. Sulfides include both troilite and pentlandite. A number of additional minor phases have also been identified. A spinel-rich inclusion is mentioned as well.

Witnessed falls of 14 unequilibrated LL chondrites are listed at the Meteoritical Society's 'Meteoritical Bulletin Database' (as of August 2015). However, only 4 of those are listed as even more primitive (less metamorphosed) than St. Mary's County. Two of the even more primitive falls are the Semarkona (LL3.0) and the Bishunpur (LL3.15) meteorites.

Other Regions, Features and Areas containing this locality

References