About This Item

Share This Item

The AAPG/Datapages Combined Publications Database

AAPG Bulletin


Volume: 69 (1985)

Issue: 2. (February)

First Page: 243

Last Page: 243

Title: Uses of Vitrinite Reflectance in Determining Thermal History in Sedimentary Basins: ABSTRACT

Author(s): John R. Castano

Article Type: Meeting abstract


Vitrinite reflectance (VR), adapted from coal petrology, came into routine use in the petroleum industry in the late 1960s. Initially, the principal goal was to help establish the VR limits for oil and gas generation. Subsequently, VR has become accepted as the most useful measure of burial history and paleotemperature, largely because VR affords the most practical means of measuring the progression of organic metamorphism. VR is used to correlate other measures of thermal history such as chemical maturity parameters, Rock-Eval tmax, and burial-history reconstruction. VR can aid in identifying unconformities, geopressured sections, and thermally altered zones. Combined with good temperature data, the determination of VR equivalents from temperature and burial t me are used to evaluate the relationship of depth to log VR obtained directly. The time and temperature required for maturation in Tertiary basins stresses the interplay of both factors in the maturation process. Reflectance has been employed in deciphering the burial history and tectonic evolution of many areas, including structurally complex regions as the Alps and the Wyoming Overthrust belt.

Interpretational problems that arise include: (1) VR can be altered by the absorption of hydrogen-rich materials, oxidation, and natural coking; (2) the presence of reworked and caved organic matter produces multiple reflectance populations; and (3) vitrinite is sometimes difficult to distinguish from solid hydrocarbons and some inerts if the particle size is small. Most of these problems are resolved at the microscope. Interpretation is improved significantly by analyzing a series of samples rather than an isolated sample.

End_of_Article - Last_Page 243------------

Copyright 1997 American Association of Petroleum Geologists