Fluorescence measurements can indicate the presence of aromatic compounds in petroleum and its products. Fluorescence of pyrolysis products (bitumen) is an approximate indicator of the petroleum potential of a sediment.
Most of the time, when the gas data suggest a thermogenic origin, fluorescence is measured on the bulk samples taken from each core. A small amount of sample taken from the headspace sample is placed in an aluminum pan, and a few milliliters of trichloroethane are added. The sample stays in the trichloroethane for 15-30 min, and the fluorescence intensity is estimated by the ODP operations manager or organic chemist under an ultraviolet lamp. Strong light yellow fluorescence of the sediment and a white-blue fluorescence of the fluid ("cut fluorescence") may indicate the presence of liquid hydrocarbons (Shipboard Scientific Party, 1995).