Ordinary chondrite, veined (L5)
Fell, July 1889; 20.375 kg.

Baldanza described the location of the find as "Ergheo, Brava, Somaliland".
The port town of Brava is now also known as Barawa (Baraawe).

A single stone fell and was left where it lay for several years. The moderately equilibrated interior is characterized by indistinct chondrules with small metal grains. Widespread wavy extinction is present within mineral grains and interstitial maskelynite is ubiquitous. Olivine (Fa~24) and orthopyroxene (Fs~21) compositions are characteristic of the L-chondrite geochemical group. Mineralogically the meteorite is dominated by silicates [>90 vol%] (primarily olivine and pyroxene) accompanied by minor troilite (~6 vol%), and Fe-Ni (~2 vol%) metal. Accessory chromite and other minor silicates and oxides are also reported. Shock indicators include prominent veining, fractured crystals, irregular aggregates of polyhedral chondrules, maskelynite, and plessite. Not surprisingly, significant weathering is often apparent.

K-Ar and Pb,Th:He gas retention ages of 1.023 Ga & 0.61 Ga, respectively, as well as a cosmic-ray exposure (CRE) age of ~24 Ma have been reported. Helium and Argon release ages often reflecting major collisional events, while the CRE age often reflects the meteoroid's final period before earth-encounter.

The L-group of ordinary chondrites (relatively low in total iron) is the largest group of classified witnessed meteorite falls and account for ~45% of the well-classified meteorite falls. The small L5 petrologic type subgroup accounts for ~ 20% of the group. 82 meteorite falls had been classified exactly as L5 chondrites by early June 2017.

The Ergheo mass was well distributed with masses of ~ 1 kg still held by the United States National Museum (Washington) and the British Natural History Museum (NHM) in London. Consequently, it has been been a minor part of a number of studies. Much of the mineralogical and petrographic work was consolidated in the article by Baldanza & Levi-Donati (1971).

Nota bene: The coordinates provided by both the Catalogue of Meteorites (5/e) and the Meteoritical Bulletin Database (June 2017) would place the fall site in the ocean east of Somalia.

Coordinates are approximate only.

Other Regions, Features and Areas containing this locality

References