Meteorite Errachidia 004 – Morocco

The Errachidia 004 meteorite was discovered in 2020 in Morocco, in the Errachidida region. This meteorite is classified as a primitive achondrite from the winonaite group, indicating its ancient origin. The total amount of this meteorite found is approximately 2.64 kg. Winonaites are known for their complex formation history, which dates back to the early stages of the solar system, several billion years ago.

Winonaites are a rare group of primitive achondritic meteorites. These meteorites have a composition similar to chondrites but have undergone partial melting and differentiation, which distinguishes them from classical chondrites. Winonaites contain both silicate minerals (such as forsterite, enstatite, augite, and plagioclase) and metallic components (kamacite and taenite). Winonaites are named after the first specimen discovered in Winona, Arizona, USA.

Composition

Errachidia 004 consists of two main lithologies - one low in metal and the other high in metal. The low metal lithology includes minerals such as forsterite, enstatite, augite and sodic plagioclase. The high-metal lithology contains significant amounts of kamacite, taenite and exhibits a well-developed Widmanstätten pattern.

The low-metal lithology in Errachidia 004 meteorite is characterized by a granoblastic texture where mineral grains have an average size of about 110 µm. Kamacite and troilite are finely dispersed throughout the texture, often as veins or single grains, some of which have been converted to iron oxides. This structure is indicative of a history of mild shock and alteration on the surface of the meteorite during its journey through space.

The high-metal lithology of Errachidia 004 contains up to 80% metal and is characterized by the presence of the Widmanstätten pattern, a structure formed by the slow cooling of the meteorite's metal core in space. The high-metal lithology also contains minerals such as kamacite, taenite, plessite, and the accessory minerals troilite and schreibersite. Silicate inclusions in this lithology include sodic plagioclase, augite and enstatite with an average grain size of 350 µm.

These two distinct lithologies are evidence of the complex geological processes that the meteorite has undergone.