EVALUATING THE MAXIMUM PALEOTEMPERATURE OF SEDIMENTARY ROCKS

Abstract

Determining the maximum temperature to which sedimentary rocks were exposed is of great importance, especially in petroleum geology, and also is one of the most difficult of tasks in that science. A simple method of evaluating the maximum paleotemperature, based on the equation for coalification of natural organic matter should therefore be of interest. This equation is a quantitative formulation of a theory which postulates that the coalification of organic matter is a radiochemical process. The effect of ionizing radiation from radioactive elements (primarily uranium) that are present in buried organic matter is a factor that can influence the transformation of that matter to a degree quite comparable with the effect of the ambient temperature T. We illustrate the reliability of the method by a sample determination of the maximum paleotemperature of deeply buried Jurassic deposits (the Tyumen Formation, Urengoy Rayon) of Western Siberia.