Organic-chemical clues to the theory of impacts as a cause of mass extinctions

The reasons for the mass extinctions, which occur from time to time in Earth's history-as, e.g., the dinosaur extinction at the Cretaceous/Tertiary boundary 65 myr ago - are still not satisfactorily cleared up. A possible reason might be the impact of one or several comets of several kilometers in diameter. In this paper the astrophysical background of this hypothesis and organic-chemical processes during an impact will be discussed.Quantitative estimations are given, which show that the amount of organic substances brought to the Earth may be of the same order of magnitude as the normal biological production of organic material.Investigations are proposed to examine the organic-chemical composition of profiles of the Cretaceous/Tertiary boundary and other boundaries, at which mass extinction had occurred, in order to find anomalies as consequences of impacts.