CARBONACEOUS CHONDRITES AND THE ORIGIN OF LIFE

Organic matter in carbonaceous chondrites can be separated into three fractions. The first component, the fraction that is insoluble in chlo roform and methanol, has a part which is of interstellar origin(1). Th e other two fractions (chloroform-soluble hydrocarbons and methanol-so luble polar organics) are hypothesized to have been synthesized on a p lanetoid body (2). We propose that the polar organics, i.e., amino aci ds, were synthesized close to its surface by the radiolysis of hydroca rbons and ammonium carbonate in a liquid water environment. Some hydro carbons may have been synthesized by a Fischer-Tropsch mechanism (3) i n the interior of the body. Ferrous ion acted as a protection against back reactions. The simultaneous synthesis of iron-rich clays with the polar organics may be indicative of events related to the origin of l ife on Earth.