Fig. 5

Cross-plots of petrographic parameters, with selected parameters plotted against optical porosity, IGV, grain-to-grain coatings and grain-to-IGV coatings. Linear lines of best fit indicate correlations and the corresponding R². Correlations on porosity, quartz cement and ECR would improve if the Cornberg Sandstones preserving early carbonate cements would not be considered. ECR Effective contact ratio, IGV intergranular volume, GTG grain-to-grain, GTI grain-to-IGV