An investigation of the structure of abelsonites from the Uinta Basin of Utah

Abelsonite has been obtained from five widely separated cores in the Green River Formation of Utah. Each occurrence was in fractures or bedding plane partings of lean oil shales. High resolution mass spectra show that the abelsonite samples are vitually identical from core to core and consist largely of the nickel complex of a C-31 porphyrin of DPEP type. ¹H-NMR spectra of some of the samples have been recorded and are compared with spectra of several model nickel porphyrin complexes. From these spectra it is deduced that abelsonite is largely the nickel complex of a nor-DPEP. Abelsonite is believed to differ from nickel DPEP in having a methyl substituent in place of an ethyl substituent at either carbon 3 or 8. Abelsonite is shown not to have a hydrogen substituent on any pyrrolic carbon. A chlorophyll origin of abelsonite is thus indicated. Abelsonite appears to have been introduced into the fractures and bedding planes of the rocks in which it is found subsequent to their lithification, as porphyrins different from abelsonite were extracted from shales associated with abelsonite.