Iron, IAB complex, Mundrabilla duo
30° 47′ S., 127° 33′ E. Initially, three small masses known as the Premier Downs masses were found between 1911 and 1918 in Western Australia. Other small specimens were subsequently found and given the names Loongana Station and Loongana Station West. In March of 1966, two larger masses of about 6 and 16 tons were found by geologists R. Wison and A. Cooney and described under the name Mundrabilla. This name was also given to the previously discovered masses without consideration to their former description under the name Premier Downs. The two larger masses, recovered only 180 m apart on the Nullarbor Plain just north of the Transcontinental Railway, can be matched up along similar sharp faces. In 1979, two more large masses weighing approximately one ton each were found by A. Carlisle about 20 km east of the 1966 location. In addition, over 500 small, knuckle-shaped specimens were found distributed along an east–west line of several miles, having a cumulative weight of over 24 tons.
Diagram credit: Worsham et al., GCA, vol. 188, p. 269 (2016)
‘Literally, "iron-loving" element that tends to be concentrated in Fe-Ni metal rather than in silicate; these are Fe, Co, Ni, Mo, Re, Au, and PGE. These elements are relatively common in undifferentiated meteorites, and, in differentiated asteroids and planets, are found in the metal-rich cores and, consequently, extremely rare on systematics of IAB complex iron meteorites: New insights into the formation of an enigmatic group’
(https://doi.org/10.1016/j.gca.2016.05.019) In contrast to the time of Element that readily forms cations and has metallic bonds; sometimes said to be similar to a cation in a cloud of electrons. The metals are one of the three groups of elements as distinguished by their ionization and bonding properties, along with the metalloids and nonmetals. A diagonal line drawn Click on Term to Read More segregation and In the context of planetary formation, the core is the central region of a large differentiated asteroid, planet or moon and made up of denser materials than the surrounding mantle and crust. For example, the cores of the Earth, the terrestrial planets and differentiated asteroids are rich in metallic iron-nickel. Click on Term to Read More formation on the IAB parent body at ~5 m.y. after The Sun and set of objects orbiting around it including planets and their moons and rings, asteroids, comets, and meteoroids. formation, the separation of metal in Mundrabilla occurred ~8 m.y. later. At this time radiogenic heating had diminished and only impact-heating could plausibly explain large-scale melting events. The photo above shows a typical ‘zoomorphic’ individual weighing 150 g consisting of three or four precursor taenite crystals. This mass was shaped by both selective Gradual removal of the successive surface layers of a material through various processes. • The gradual removal and loss of meteoritic material by heating and vaporization as the meteoroid experiences frictional melting during its passage through the atmosphere. The resulting plasma ablates the meteor and, in cases where a meteor Click on Term to Read More of troilite during atmospheric entry and terrestrial weathering processes. The photo below shows the cut surface of a large mass of Mundrabilla.
Photo courtesy of S. Vasiliev
See the ‘Meteorite Men’ episode Mundrabilla, Australia 21 December 2010, originally broadcast on the Science Channel and now available on YouTube.