Changes

==Characteristics of NL oils==

==Characteristics of NL oils==

[[file:oiloil-and-oilsource-rock-correlations_fig8-52.png|thumb|{{figure number|2}}From Clayton & Koncz<ref name=ch08r6 />; reprinted with permission from AAPG.]]

[[file:oiloil-and-oilsource-rock-correlations_fig8-52.png|thumb|300px|{{figure number|2}}Isotope data used to support oil–oil and oil–source rock correlations for the NL oils of the Zala basin. From Clayton & Koncz;<ref name=ch08r6 /> reprinted with permission from AAPG.]]

The 21 oils can be grouped into at least three families, corresponding roughly to existing fields: the Nagylengyel (NL), Szentgyörgyvölgy (Szen), and Szilvágy (Szil). This article concerns the characteristics and source of the NL oils, which, on the basis of isotopic and molecular criteria (e.g., lack of oleananes), are distinct from the Szen and Szil families. The NL family, reservoired in Upper Cretaceous and Triassic rocks, is characterized by a low pristane–phytane ratio, significant amounts of at least one C₂₄ tetracyclic terpane, and high concentrations of vanadium and nickel. In general, these characteristics suggest a carbonate-rich source rock. Its age, inferred from the absence of oleanane in the oils, may be older than Late Cretaceous, although oleanane is often absent in carbonates due to lack of terrestrial input.

The 21 oils can be grouped into at least three families, corresponding roughly to existing fields: the Nagylengyel (NL), Szentgyörgyvölgy (Szen), and Szilvágy (Szil). This article concerns the characteristics and source of the NL oils, which, on the basis of isotopic and molecular criteria (e.g., lack of oleananes), are distinct from the Szen and Szil families. The NL family, reservoired in Upper Cretaceous and Triassic rocks, is characterized by a low pristane–phytane ratio, significant amounts of at least one C₂₄ tetracyclic terpane, and high concentrations of vanadium and nickel. In general, these characteristics suggest a carbonate-rich source rock. Its age, inferred from the absence of oleanane in the oils, may be older than Late Cretaceous, although oleanane is often absent in carbonates due to lack of terrestrial input.