Nagy et al. : Environment of Orgueil Meteorite Parent Body 537 



preliminary observation was made that the type of molecular species present in 

 the meteorite hydrocarbon mixture and the molecular weight range of the 

 mixture resembled in many important aspects the hydrocarbons in the products 

 of organisms and in sediments on earth. Studies in progress are to extend the 

 preliminary investigation.^- The purpose of the present study is to determine 

 whether the physical-chemical conditions on the meteorite parent body may 

 have been suitable to sustain a form of life. 



Inorganic Analyses 



Carbonaceous chondrites contain only a small percentage of organic matter, 

 the remainder consists of inorganic minerals. Their history can be determined 

 most clearly only if one has a satisfactory understanding of both their organic 

 and inorganic composition. Most stony meteorites, have been subjected to 

 inorganic analyses. As early as 1878 Nordenskiold'^ noted the pronounced 

 uniformity in the chemical compositions of chondrites. In 1953, Urey and 

 Craig^ reviewed some 350 chemical analyses, selected the reliable ones, and 

 came to the conclusion that chondrites fell into two distinct groups, a high and 

 a low group as far as their total iron content and the oxidation state of their 

 iron was concerned. They suggested that the cause of this phenomenon was 

 related to the genesis of meteorites. The parent asteroids went through a low 

 temperature accumulation process, a high temperature melting and evaporation 

 process, a stage of collision with smaller objects and finally a collision of 2 

 asteroidal sized bodies. These authors, and later Wiik,- observed that the 

 carbonaceous chondrites belonged to the high iron group. Urey and Craig 

 suggested that the material forming the carbonaceous chondrites had been 

 infiltrated on the parent body by water, carbon compounds, and hydrogen 

 sulfide. It is generally agreed that more information is a necessary prereq- 

 uisite to a satisfactory understanding of the genesis of these meteorites. 



Wiik- has shown that there are three types of carbonaceous chondrites. The 

 first type (Orgueil, Ivuna, Tonk) contains approximately 20 per cent water, 

 approximately 22 per cent Si02 and 15 to 18 per cent "FeS." All forms of 

 sulfur, including elementary sulfur, were hypothetically combined with the 

 iron in the "FeS" reported, but x-ray diffraction data on Orgueil does not show 

 any FeS. The second type (Cold Bokkeveld, Murray, Mighei, Staroye 

 Boriskino) contains approximately 13 per cent water, 27.5 per cent Si02 , and 

 9 per cent "FeS." Neither the first nor the second group contains any metalUc 

 iron, nickel, or cobalt. The third type (Lance, Mokoia) contains approximately 

 33 to 34 per cent Si02 , less than 1 per cent water and between 5 and 6 per cent 

 "FeS." Metallic nickel and iron are present in the third group. Edwards,^* 

 using an analytical method developed by Edwards and Urey,^^ found that the 

 sodium and potassium distributions in carbonaceous chondrites agreed with 

 Wiik's classifications. They noted that there was one exception, the Murray 

 meteorite, which gave abnormally low alkali metal values. 



Inorganic analyses of meteorites point out certain important relationships, 

 which can serve to supplement mineralogical data. Structural and synthetic 

 mineralogy, an active field of study during the preceding 15 years, has been 

 repeatedly applied with success to investigations concerned with determining 

 the physical-chemical environment during rock and mineral genesis. The 



