Interpretation of Micro-structures in Carbonaceous Meteorites

Abstract

IN our recent article1, a size distribution histogram of 303 randomly selected type 1 and 2 organized elements was presented and the results were interpreted as possibly indicating a biogenical origin for these elements. Prof. Mueller in his note reiterates his older argument in favour of an abiogenical origin of these structures and suggests that the particles arose through the solidification of fine sprays and were ejected by gases from the interior of the parent body of the meteorite. He refers to his histogram, which, according to him, is practically identical to the one we presented. Several points, however, speak against the acceptability of the identity of the histograms. Since one of us (G. Claus) was a participant at the first International Meeting in Organic Geochemistry in Milan, 1962 (Prof. Mueller2 mentions our presence in his paper, p. 118), naturally we are well aware of Prof. Mueller's results; however, even at that Meeting, during the discussion, it was pointed out that a basic misunderstanding exists over the identification of what Prof. Mueller calls glass particles or olivine crystals and what we call type 1 or 2 organized elements. In his histogram (loc. cit., p. 114), the curve indicated as glass and homologized with the organized elements is clearly not identical with the histogram we presented. Indeed, the organized elements are never ‘transparent globules’, as stated by Mueller, and are definitely not composed of glass. This has been demonstrated by the electron microprobe (Nagy et al.3); most of, and probably all, the type 1 and 2 organized elements are structures which possibly contain limonite. It is possible that Prof. Mueller may have missed this article and, similarly, the subsequent work on the properties of the organized elements, for example, that of Urey4 in which it is stated that after acid treatment of the meteorite an acid-insoluble residue is obtained which is composed primarily of spherical bodies. The large number and size of these bodies show good correlation with the numbers and shapes of organized elements in native meteorite preparations. Mueller does not make any allusion to this finding; furthermore, he does not take into account the work of Nagy et al.5 concerning the ultra-micro ultra-violet absorption spectra derived from single organized elements, which indicate the possible presence of proteinaceous and nucleic acid-like substances in them. Clearly these data definitely contradict his assumption about the glassy nature of the organized elements. It seems that we are dealing with a quite different group of particles from that which Prof. Mueller counted.