The next quarterly MINSA talk will be by Professor Jan Kramers, of the University of Johannesburg:
Hypatia and the mineralogy of interstellar space
Date: 27 March 2018
Venue: Department of Geology, Reading Room, University of Johannesburg
RSVP by 20 March. Please submit number of persons attending and vehicle registration
The diamond-bearing stone named “Hypatia”, found in 1996 in the desert in southwest Egypt by geologist Aly Barakat, was shown to be of extraterrestrial origin. Neon isotopes indicate that it is a fragment of a bolide at least several metres in diameter. Its carbon-dominated chemical composition is unlike that of any known type of meteorite. Petrographic work carried out at UJ by Dr Georgy Belyanin reveals that the carbonaceous matrix can contain up to several % iron and sulphur, and hosts sub-micron grains of iron sulphide. Diamond also occurs as sub-micron grains and was produced by shock. Exotic minerals, occurring as rare inclusions, are moissanite (silicon carbide), a nickel-phosphide compound of a composition never observed before, and metallic aluminium, iron, zinc and silver. These exotic minerals are thought to be pre-solar. No silicates or oxides have as yet been found in the matrix.
Raman spectroscopic analysis shows the presence of disordered carbon as polyaromatic hydrocarbons (PAH’s) that have not been subject to metamorphism. Likewise, the non-annealed nature of the nickel phosphide compound shows that the material was never heated for any length of time. It is concluded that the stone comes from the outermost solar system.
A comparison with minerals and hydrocarbons observed by spectroscopy in interstellar space, and found in interplanetary dust particles and dust collected in space from comets, shows that PAH’s are expected, but the absence of silicates in Hypatia is highly anomalous. It is concluded that the solar nebula originated from a heterogeneous interstellar cloud.
Brief biography of Professor Jan Kramers
Jan Kramers is a Hollander who studied Geology and Physics in Bern, Switzerland and became an isotope geochemist during Postdocs at the BPI Geophysics at Wits (mentored by Hugh Allsopp) and at Leeds University during the 1970’s. He spent the 1980’s at the University of Zimbabwe, and became a professor of Geochemistry and head of the isotope geology unit at the university of Bern in 1991. In 2009 he took early retirement from there and moved back to South Africa where he was awarded post-retirement employment at the University of Johannesburg. He has an A rating from the NRF. He is married and has two daughters and four grandchildren.