Natural bitumens in kimberlite pipes and host rocks in the Yakutian diamond province

Natural bitumens are widespread in the sedimentary cover of the Yakutian diamond province. They occur within a broad stratigraphic range and differ in size and character. A number of oil and gas fields have been discovered in the province. Numerous natural bitumen occurrences are found in kimberlite pipes and host rocks. Geochemical characteristics of the samples taken from different sites in and off the body of kimberlite pipe - kimberlite, xenolith, host rocks - display a rather intricate pattern. Their composition can be considered as a result of superposition of two processes: thermal destruction and deasphaltization of oils. The calculated temperatures of host rock heating and the time of cooling of kimberlite pipe suggest weak thermal destruction in both xenoliths and host rocks.