The Mayo Belwa meteorite: a new enstatite achondrite fall

Abstract

Summary Mayo Belwa, a highly shocked enstatite achondrite, fell during the evening of 3 August 1974 in the Adamawa District, NE. Nigeria (8° 58' N., 12° 05' E.). The stone weighed 4·85 kg and was deposited in the Geological Survey of Nigeria and loaned for study to the British Museum (Natural History). It is composed principally of enstatite (0·02 FeO%), with some olivine (Fo 100 ), diopside, feldspar (An 9 Ab 88 Or 3 ), and minor Fe-Ni metal and the sulphides oldhamite, daubréelite, ferroan alabandine, and troilite. The kamacite contains between 0·15% and 1·2% Si and the troilite contains 1·1% Ti. The meteorite possesses vuggy cavities, which contain fluor-amphibole needles projecting from their walls, suggesting the presence at some time of a volatile-rich phase. The titanium-rich troilite, the nearly ironfree enstatite and the Mg/Si ratio are typical of the E-achondrites.