Correlations between petrographic and geometrical properties of ophiolitic aggregates from Greece

The study investigated the influence of petrographic characteristics on the geometrical properties of ultrabasic and basic ophiolitic aggregates from Greece. Quantitative petrographic analysis indicates that the studied lithologies display various percentages of secondary mineral phases. Statistical analyses indicate that the geometrical characteristics of ultrabasic rocks tend to improve as the micropetrographic index Irep, the degree of serpentinisation, the ratio of soft to hard minerals and the ratio of secondary to primary minerals decrease. The aggregate particles of the basic lithotypes tend to be more elongated and flaky when the ratio of soft to hard minerals increases. The higher flakiness and elongation index values of the ultrabasic samples are attributed to the high percentage of serpentine, the local preferred orientation of the olivine grains and the existence of oriented transgranular microcracks.