Origin of limestone fluorescence

Fluorescence is commonly used in the oil field for the detection of crude o il and in environmental applications for the detection of refined oils. Spu rious fluorescence from minerals can interfere with desired detection, Here , we characterize the fluorescence from lime-stones in order to understand the origin of limestone fluorescence, in particular to compare and contrast it with of her naturally occurring fluorescence, The fluorescence spectra, intensities, and lifetimes of six limestones, ranging in origin and therma l maturity, have been investigated with excitation wavelengths ranging from the ultraviolet through the visible and into the near-infrared. These lime stones exhibit fluorescence spectra that are shown to be quite similar to t hose of crude oils, bitumens, and kerogens. This work strongly supports the conclusion that the fluorescence of limestones is organic in origin. There fore, differentiation of limestone fluorescence from fluorescence of other organics must be accomplished by using known systematic trends of the fluor escence of naturally oo occurring organics.