Sulphur isotope variations in diagenetic pyrite from core plug to sub-millimetre scales
Abstract:Sulphur isotope ratio measurements (34S) of diagenetic pyrite are commonly used to identify S sources and mechanisms of sulphide formation in basinal sediments. This study reports such data for a diagenetic pyrite nodule from the Brent Group sandstones of the northern North Sea at three sampling scales: 50 cm (core subsample), 500 m (laser microprobe) and 50 m (ion microprobe). Similar 34S variations are found by the laser and ion microprobe techniques. There is a very wide range in 34S (< -10‰ to > +50‰) within the nodule and isotopically heavy S (34S > +20%) is common at all scales. The nodule 34S distribution does not fit a Rayleigh fractionation pattern. The laser microprobe sampling at 100-500 m scales seems to be adequate to characterize S isotope variations in this material.
Document Type: Research Article
Publication date: March 1, 2000