X-RAY ANALYSIS OF EOCENE OCALA LIMESTONE, HAILE QUARRIES, NEWBERRY, FLORIDA. COMPARISON AND INSIGHTS INTO THE MINEROLOGY AND GEOCHEMISTRY OF MARINE CARBONATE UNIT

Upper (N=3) and lower (N=2) Ocala Limestone were collected from Haile quarries. These samples were analyzed using powdered X-ray diffraction (PXRD) and portable X-ray fluorescence (pXRF). PXRD and pXRF were conducted to better understand the minerology and geochemistry of these limestones and to compare them to Ocala Limestone north of Lake Okeechobee. PXRD of all Haile quarry samples are calcite. Haile quarry samples have: Ca from 30.59-38.33 wt. %; Mg from 2.53-3.22 wt. %; Fe from 0.01- 0.07 wt. %; Sr from 220-273 ppm; Ni from 20-28 ppm; and, Zr from 6-10 ppm. Mg of the upper and lower Ocala Limestone do not differ from each other. Iron is higher in the lower Ocala Limestone member. We wanted to compare the Ocala Limestone in northern Florida to occurrences north of Lake Okeechobee. Using the pXRF, 1,494 analyses of the Ocala Limestone were done north of Lake Okeechobee. North of Lake Okeechobee the Ocala Limestone averages: Ca 42.58 wt. %; Mg 3.79 wt. %; Fe 0.04 wt. %; Sr 1238 ppm; and, Ni 26 ppm. Zr was below detection limit for the samples north of Lake Okeechobee.

Our lower member Ocala Limestone samples from Haile quarry are not dolomitic. PXRD data, Ca, Mg, and Fe values suggest they are iron-rich limestones. The Ca, Zr, and low Sr suggests the Ocala Limestones form Haile quarry formed in a shelf environment. The Haile quarry samples have lower Ca, Mg, and Sr than the samples from north of Lake Okeechobee. Fe and Ni are similar. However, Zr was undetected in all 1,494 analyses north of Lake Okeechobee. The higher Ca, Mg, and Sr, as well as Zr not being analyzed, suggests the Ocala Limestone north of Lake Okeechobee formed farther from the margin in a more open-marine setting.