Vitrinite reflectance analysis

Vitrinite is a maceral group (a set of organic matter types with similar properties and appearance) derived from the remains of woody material from vascular plants and is composed of the thermally evolved products of lignin and cellulose. Vitrinite is the dominant component of humic coal and is found as a minor component dispersed into sedimentary rocks, especially mudrocks, the primary source rocks for petroleum. Vitrinite reflectance analysis is the microscopical determination of the reflectance of incident light from vitrinite as calibrated to standards of known reflectance. The reflectance of vitrinite increases systematically with increasing thermal maturation during burial and heating of sedimentary rocks, and this property allows vitrinite reflectance analysis to be used as a common geothermometer for source rocks in petroliferous basins. Vitrinite reflectance analysis also is used as a method to determine coal rank.