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

Abstract

High-resolution mass spectrometry indicates that the isotopic abundance of V-50 Of the Late Cretaceous La Luna petroleum asphaltenes of marine origin (highly enriched with V GT 2000 ppm)fi higher by about 3.5% than that of the inorganic source (VOSO4 X 5H(2)O, Merck). We propose that the difference in the V-50/V-51 values between the La Luna petroleum asphaltenes and the inorganic source can be best ascribed to the biological processing of seawater vanadium. The fact that the V isotopic compositions of petroleum asphaltenes vary over avery narrow range (2.46-2.52) suggests essentially the same (or similar) and fixed biological source of vanadium. (C) 2000 Elsevier Science Inc. All rights reserved.