Mesosiderites

The mesosiderites are named for the Greek words mesos for "middle" or "half", and sideros for "iron", meaning "half iron". In fact, they are typical stony-iron meteorites, consisting of approximately equal portions of nickel-iron metal and silicates. Excluding all probable pairings, the mesosiderite group comprises about 50 distinct members, while seven members represent witnessed falls.
Texturally, mesosiderites are a complex mixture of a nickel-iron metal portion and a heavily brecciated silicate portion, consisting of mostly pyroxene and plagioclase. Strangely, the silicates are obviously evolved igneous rocks, representing the crust of an achondritic parent body. They are quite similar to eucrites, diogenites, and other members of the HED group, even plotting on the same oxygen isotope fractionation line. However, the metal in mesosiderites is similar to group IIIAB irons, obviously representing the core of a distinct, differentiated asteroid, genetically unrelated to the precursor of the eucritic and diogenitic portion. This suggests a complex formation history for the mesosiderites and their parent body. One theory has them formed by the collision of two differentiated asteroids, allowing the still liquid core of one asteroid to mix with the solidified crust of the other. This scenario includes the collisional disruption and gravitational reassembly of at least one of the asteroids - the one that later became the parent body of the mesosiderites. It is still heavily debated whether the HED parent body, 4 Vesta, actually represents one of these asteroids.
Based on textural and mineralogical differences, the mesosiderites have been divided into four distinct groups that were further divided into subgroups. These groups are designated 1A, 1B, 2A, 2B, 2C, 3A, 3B, 4A, and 4B. However, there seems to be no scientific consensus about this classification scheme, as it has been differently interpreted by different researchers. To avoid any confusion, we won't elaborate on this matter. Famous members of the mesosiderite group are the witnessed falls of Estherville, Iowa, USA, in 1879, and Lowicz, Poland, in 1935. Another renowned member is Vaca Muerta, a find from Chile. Several hundred individuals of this well-preserved mesosiderite have been recovered from its strewn field in the Atacama Desert, making it the most common mesosiderite in private and public collections. >> top...

NWA 4747 Northwest Africa 4747 TKW : 1200 gr from Morocco Found: 2001- Mesosiderite
				NWA 4747 512 gr the main mass !!! superb specimen Price on request
NWA 4747-01 Superb full slice 40.95 gr SOLD
				NWA 4747-02 Superb full slice 30.65 gr Price on request