Journal of Petroleum Geology, Vol.6, No.1, pp.5-38, 1983

©Copyright 2000 Scientific Press, Ltd.

GEOLOGIC TIME AS A PARAMETER IN ORGANIC METAMORPHISM AND VITRINITE REFLECTANCE AS AN ABSOLUTE PALEOGEOTHERMOMETER

Leigh C. Price*

*US Dept. of the Interior, Geological Survey, Box 25046 M.S. 940, Denver Federal Center, Denver Co. 80225, USA.

Abstract

Substantial published and unpublished data contradict accepted laws of organic metamorphism. Significant amounts of C15+ hydrocarbons and kerogen with significant generation potential exist in sediments which have been buried at high temperatures for long periods of geologic time. Graphite formation and greenschist metamorphism do not occur at model-predicted burial times and temperatures. Maturation levels for sediments with long (up to 240 million years) burial times are much lower than expected, and conversely, higher than expected for sediments with short (2 million years) burial times. The threshold of intense petroleum generation is not detectable in Plio-Miocene sediments at minimum temperatures of 160 °C.