Vitrinite
It is also abundant in kerogens that are derived from the same biogenic precursors as coals, namely land plants and humic peats.Vitrinite forms diagenetically by the thermal alteration of lignin and cellulose in plant cell walls.[2] The study of vitrinite reflectance (or VR) is a key method for identifying the maximum temperature history of sediments in sedimentary basins.More recently, its utility as a tool for the study of sedimentary organic matter metamorphism from kerogens to hydrocarbons has been increasingly exploited.The key attraction of vitrinite reflectance in this context is its sensitivity to temperature ranges that largely correspond to those of hydrocarbon generation (i.e. 60 to 120 °C).