Olivine Subject

In the context of the discovery of amines and oxygen-containing organic compounds, the question arises as to whether the presence of atomic carbon in olivine or MgO crystals could have led to the formation of amino acids. Knobel et al. (1984) reported the detection of amino acids in liquid extracts of the reaction mixtures at the 1983 ISSOL conference yields were, however, extremely low, the total yield being 1.5-3.0 x 10-7 g per gram of MgO. These results were the subject of considerable attention in the media. 

Response of Natural Coals to Metamorphism. The Martinsburg slate and its anthraxolite have clearly been subjected to low grade metamorphism. Presuming a low temperature origin such as suggested in the preceding section, at least part of the anthraxolite rank increase must be caused by this metamorphism. In order to evaluate this contribution to rank increase, it is useful to examine known cases of metamorphism of natural coals. MacFarlane (25) studied the thermal effects of intruded olivine basalt sills on Yampa coals (Colorado). He carried out parallel laboratory studies in which unaltered... 

The transformation of olivine to spinel which delineates the onset of the Transition Zone in the Mantle is isochemical. However, in the Lower Mantle the (Mg,Fe)2Si04 stoichiometry appears to be unstable with respect to denser oxide structure-types. One post-spinel transformation that has been the subject of numerous investigations is the spinel to periclase plus perovskite transition... 

The precise nature of the chondrule-form-ing event, the "chondrule factory," is also the subject of some discussion. Some workers favor the formation of chondrules by the direct condensation of the solar nebula gas as a melt. Alternatively, chondrules could be the residues of evaporation. The presence of relict olivine grains in some chondrules (Jones, 1996) argues against a simple condensation model and may imply multiple condensation-evaporation events. 

Deer, W. A., Howie, R. A., and Zussman, J. (1992) An Introduction to the Rock-Forming Minerals, 2nd edition, Longman, London. This book (680-1 pages) contains a wealth of data on the subject. Olivines, garnets, and pyroxenes abound. 

---