The vanadium isotopic constitution of petroleum asphaltenes: La Luna Formation (Venezuela)

摘要

High resolution mass spectrometry indicates that the isotopic abundance of ~50 va- nadium (V) of the Late Cretaceous La Luna petroleum asphaltenes and related source kerogen of marine origin (both highly enriched with V>2000 ppm) is higher by about 3.5/100 than that of an inorganic vanadium source (VOSO_4·5H_2O, Merck). It is proposed that the difference in the ~50V/~51V values between the LaLuna source kerogen/the associ- ated petroleum asphaltenes and the inorganic source can be best ascribed to the biologi- cal processing of seawater V. The fact that the isotopic compositions of V vary over a very narrow range (2.46-2.5) suggest an essentially same (or similar) and fixed biolog- ical source of V.