ABSTRACT
Infrared imaging using an array of detectors has been successfully applied to petroleum inclusions in fluorites from the Illinois Fluorite District. The spatial resolution of 7 µm enables spectra to be obtained of organic fractions within single inclusions, including liquid petroleum, heteroatom-rich asphaltenes, wax precipitates and the vapour phase. Chemical mapping, using diagnostic infrared absorbtion bands, delineates the segregation of these organic phases within the inclusions. The development of multiple organic phases in the inclusions is considered to reflect cooling of the petroleum since entrapment from the hydrothermal fluids.
