SHOCK-INDUCED BLACK VEINS AND ORGANIC-COMPOUNDS IN ORDINARY CHONDRITES

A detailed study of Barbotan (H5) and Charsonville (H6), and a partial study of AA Pervomaisky (L6) indicates that shock-induced black veins differ from the host part of chondrites by the following peculiarities: (1) smaller quantities of Na and quite possible Fe, Ni, Co, and in some cases Ir; (2) the presence of a major portion of glass and melted structures of troilite-metal mixture; (3) different composition of metal, troilite, Ca-poor pyroxene, feldspar, and some grains of olivine; and (4) the presence of organic compounds. Organic matter in H-chondrites is identical and corresponds to paraffins and in L-chondrite to aliphatic hydrocarbons and carbonyl and N-containing compounds. Their presence in black veins may be related to two possible sources: (1) contamination or, (2) cosmic origin. The character of distribution and disposition of organic compounds in the close pores of veins and their chemical interrelation with chemical group of chondrites allows speculation about a cosmic origin of organic matter related to shock metamorphism.