Nobleborough meteorite (Nobleboro), Nobleboro, Lincoln Co., Maine, USA

Eucrite, polymict
Fell, 7 Aug 1823, 2.3 kg

On a late August afternoon the second recorded fall of a meteorite in the United States arrived in the new state of Maine. One A. Dinsmore thought he heard musket fire and saw a small whitish cloud spiraling earthward which made a noise "like a whirlwind stirring leaves." Something struck the ground nearby, startling a flock of sheep. Mr. Dinsmore dug down half a foot and found 5 or 6 pounds of a sulphrous-smelling material. In August 2014 Nobleborough is one of only 35 eucrites and like most eucrites is compositionally dominated by pyroxenes (mostly pigeonite) accompanied by lesser amounts of plagioclase of mixed anorthite and bytownite composition. It is somewhat distinguished from other eucrites by a somewhat wider range in pyroxene composition than most eucrites (both ferroaugite & ferrohedenbergite are present) - hence the 'polymict' designation. A few additional silicates (olivine, tridymite) and opaques (chromite, ilmenite) have been reported in recent decades.

Less than 100 grams of the original mass is still preserved. Much of the mass was consumed by 19th century chemical analyses. Recent reports about Nobleborough meteorite are thus quite sparse. A 1997 analysis reported concurrent cosmic ray exposure ages of ~4.8 million years - somewhat less than most such ages within the HED (Howardite-Eucrite-Diogenite) clan.

Mineral List

14 entries listed. 8 valid minerals.

References

External Links