Abstract: Vitrinite-Like Material as an Indicator of Thermal Maturity in Pre-Silurian Rocks

F. Goodarzi

Paleozoic rocks may contain marine-derived vitrinite-like material such as: bitumen, chitinozoan and graptolite. Reflectance of these macerals can be used as indicators of thermal maturity; case examples from Silurian rocks are discussed. Application of bitumen reflectance for maturity in rocks can be complicated if the rock contains both primary and secondary (migrated) varieties. In contrast, the fragments of chitinozoan or graptolite in the same rock are mainly a primary nature. Thermal maturity studies based on graptolite reflectance show that it is a sensitive indicator of regional maturation. Graptolite reflectance depth profiles are also useful for constraining thickness estimates of strata removed at unconformities.

AAPG Search and Discovery Article #90986©1994 AAPG Annual Convention, Denver, Colorado, June 12-15, 1994