MINERALOGICAL AND GEOCHEMICAL ANALYSES OF SAND AND SANDSTONE SAMPLES FROM THE MERIDIAN SAND MEMBER, GRENADA COUNTY, MISSISSIPPI; IMPLICATIONS TO INTERPRET PROVENANCE AND PETROLOGY OF THE MERIDIAN SAND

The Meridian Sand represents the lower member of the Middle Eocene Tallahatta Formation, which is found in the Gulf Coast region of the United States. Preliminary research at two sites in Grenada County, Mississippi yielded measured sections with total thicknesses of 7.8 m and 4.7 m. The general lithology of the Meridian Sand Member is mainly very fine to medium, angular to sub-angular, poorly to moderately well sorted sand and sandstone. Ten sand and sandstone samples were collected from the two sites. Ten thin sections were made from these samples, and XRF analyses were performed on 10 sand and sandstone samples to determine major and trace element abundances.

Quartz is the most dominant mineral and composes approximately 95% of all framework grains in each sample. These sand and sandstone samples were classified according to Dott (1964) as quartz sand, sandstone arenite, and quartz sand wacke. Bulk geochemical analysis of sand and sandstone samples show that SiO₂ is the most dominant compound with an average of 55% in all ten samples, while Fe₂O is the less dominant compound with an average of 0.41%. Thin section petrography indicates that the Meridian Member was sourced from a continental block, likely the craton interior, due to the high percentage of quartz to feldspar and lithic fragments. Furthermore, a plot of Th/Sc against Zr/Sc shows enrichment in Zr, which is characteristic of recycled sediment.