Statistical analysis of garnet compositions and lithostratigraphic correlation: Brent Group sandstones of the Oseberg Field, northern North Sea

Authors:

• Karl Stattegger,
• A.C. Morton

Abstract

The data set consists of the compositions of 1550 garnet grains from three wells, as determined by electron microprobe analysis. The statistical techniques used include summary statistics, exploratory data analysis, analysis of correlation structure and of subcompositions, discriminant analysis and fuzzy clustering. General univariate statistics provide the characteristic properties of the data distribution pattern. Almandine is the prevailing component, followed by pyrope, grossular and spessartine. There is an overall increase in almandine with time: the Etive-Oseberg interval is characterized by high pyrope contents: the Ness Formation has high grossular and spessartine contents and depletion of pyrope: and the Tarbert Formation is depleted in grossular. Therefore multivariate end-member modelling of garnet compositions has provided objective criteria for classifying and differentiating samples. -from Authors