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Stony-meteorites


 

Enstatit, Rumuruti and other Chondrites

 

 

Enstatite Chondrites (E-Chondrites)

Rumuruti Chondrites (R-Chondrites)

Other Chondrites (K, F, B-Chondrites)

Kakangari Chondrites (K-Chondrites)

Forsterite Chondrites (F-Chondrites)

"Bencubbinites" (B-Chondrites)

 

 

 

Enstatite Chondrites

Enstatite Chondrites, often also shortly E-Chondrites, are a rare group of Chondrites that differ in many ways the Ordinary Carbonaceous Chondrites. So they must have emerged in a very oxigen sparse environment, because almost all iron in these meteorites appears in reduced metallic form. Also their pyroxen share contains no iron and appears only in form of the magnesium rich Enstatites, a fact that gave them their name. Petrologically the E-Chondrites encompass all classes of 3 to 7, whereby the classes 3 and 6 are represented quite often. As the Ordinary Chondrites, the E-Chondrites are often subdivided also according to their content of iron into lower groups, so that many of them were classified as EH- or EL-Chondrites. Nevertheless all Enstatite Chondrites might come from one and the same mother body. Many researchers suppose that this has to be searched for in close vicinity to the sun, perhaps in the area of the orbit of Merkury because the origin of the E-Chondrites requires an especially oxygen poor, reducing environment. Other researchers assume an origin in the internal area of the Asteroids Belt, and only future researches will bring news about the actual origin of the E-Chondrites to us.

 

Rumuruti Chondrites

Rumuruti or R-Chondrites were named after the fall at Rumuruti, Kenya, and are in many regards the opposite to the E-Chondrites. However they are similarly rare, but the iron contained in them is almost completely oxidised or exists in form of different iron-sulfides. Also the olivine content in the R-Chondrites is astonishingly iron rich and lends them their dark, often reddish appearance. In comparison with the Ordinary Chondrites in the R-Chondrites relatively few chondrules are found. Petrologically, degrees from 3 to 6 were found, whereby comparatively many R-Chondrites are so-called breccias of different degrees, what suggests an eventful past of the mother body with numerous impacts. In many Rumuruti Chondrites also inclusions of carbon material is found, which is a further indication for the history of the Rumuruti mother-body full of impacts.

 

Other Chondrites

Next to the better known groups, there are still some other Chondrites classes, of which respectively only a couple of representatives were described. These groups are rather "hypothetical", what means, that they are not completely acknowledged by the modern meteorite science as independent classes. Nevertheless they shall be mentioned here:

 

Kakangari Chondrites

Kakangari Chondrites, also shortly named K-Chondrites, carry their name after the fall at Kakangari. Petrologically, the meteorites of this group found till now correspond to class 3. Their oxidising degree lies between that of Ordinary-and Enstatite Chondrites, and their unique isotopical signature suggest that they come from one mother body.

 

Forsterite Chondrites

The Forsterite or F-Chondrites are only known as inclusions in other meteorites and were described by certain lithologies of the Aubrite of Cumberland Falls, USA. Mineralogically, obviously they consist primarily of the olivine end-link Forsterite, what makes them to an unique group. But until now no complete meteorites of this group were found on Earth, and therefore this class is to be considered as hypothetical.

 

Bencubbinites

The Bencubbinites, sometimes also named B-Chondrites, consist just of a handful of members and were named after the fall at Bencubbin. They contain next to carbon material a lot of iron what made many researchers incorporate them into the category of the Stony-Iron-meteorites. Chemically they are very close to the Carbonaceous Chondrites of the CR-clans and the CH-Chondrites so that it can be assumed, that they crystalized at least in a similar area of the presolar primeval nebula. But it is also possible that they represent samples of different regions of one and the same mother body - possibly it is 2 Pallas, the second largest asteroid in our solarsystem!

 

Carbonaceous Chondrites
Ordinary Chondrites

Achondrites