User:Tobias1984/Sandbox 7

Primitive enstatite achondrite is a proposed meteorite group, that would be part of the primitive achondrites. It would accompany some meteorites that are currently classified as enstatite chondrites and enstatite achondrites. The group is defined as the residue of the partial melting of an enstatite chondrite. Similar to the primitive achondrites some of the members of this group have signs of partial melting and relic chondrules.

Examples
A number of meteorites have been described as primitive enstatite achondrites. They all share... QUE 94204 and Itqiy are currently classified as enstatite chondrites with petrologic type 7 (EH7).

QUE 94204
Queen Alexandra Range 94204 is a stony meteorite that consists of enstatite (orthoenstatite), plagioclase, meteoric iron (kamacite) and troilite. Accessory minerals include daubréelite and cristobalite. It is coarse grained, has no chondrules, and shows no signs of brecciation. It is currently classified as an enstatite chondrite with petrologic type 7 (EH7).

Petrologic type 7 indicates that the meteorite experienced temperatures close to the melting point within the parent body. Although complete melting can be discounted, some scientists believe that the meteorite experienced partial melting. Some inclusions indicate that two types of melt (or magma) formed: one with a iron-nickel-sulfide composition and one with a plagioclase±pyroxene composition. This episode of partial melting would indicate that QUE 94204 is a primitive enstatite achondrite.

The only other enstatite chondrite with petrologic type 7 is the Itqiy meteorite.

Zakłodzie
Zakłodzie meteorite is a stony-iron meteorite composed of enstatite (Orthoenstatite) (60 %), meteoric iron (20 %), troilite (10 %) and feldspar (10 %). Accessory minerals include alabandite, amphibole, oldhamite, keilite, schreibersite. It is currently classified as an enstatite-rich achondrite that is ungrouped.

The primitive character of Zakłodzie is emphasized by relic chondrules which also occur in many of the meteorites of the primitive achondrites. Another line of evidence is the occurrence of keilite, an iron-magnesium sulfide mineral with the formula (Fe,Mg)S, that is interpreted to form through impact-melting and subsequent fast cooling ( quenching). All of these observations are interpreted as indicators for partial melting, which could happen during a impact event that triggered melting.

NWA 2526
Northwest Africa 2526

NWA 4301
Northwest Africa 4301

Itqiy
Itqiy meteorite

List
The following meteorites are described as products of partial melting: