SAMPLE SUITABILITY ASSESSMENT AND PREPARATION FOR GEOCHRONOLOGICAL AND GEOCHEMICAL ANALYSIS

Determining sample suitability and appropriate preparation methods are the two fundamental steps in retrieving meaningful analytical data. For any given analysis, these stages require careful attention to avoid potential contamination or loss of precious material. In this study, three sets of samples with individual analytical goals were examined, and an overview of sample preparation and future steps for these projects are presented.

A sphalerite-galena ore from a Pb-Zn (Au-Ag) mineralization (Bergama, Turkey) was examined aiming to determine the timing of mineralization. The sampled ore occurred as a vein within a porphyritic andesite host, and the available portion of the vein includes the contact wall and the sphalerite ore. The sample was carefully crushed, and individual euhedral sphalerite crystals were separated. Pieces of the vein wall and the sphalerite crystals were mounted for LA-ICPMS analysis for their geochemical characteristics. Additional grains were separated for determining Rb-Sr concentrations with solution ICPMS analysis and Sr isotopic ratios with TIMS analysis. The completion of these analyses will yield further insights into the characteristics and the timing of the mineralization.

The second set of samples examined were basaltic pebbles separated from a conglomerate layer of the Black Warrior Basin stratigraphic succession obtained from the Hendrix drill core. Samples were crushed and handpicked, removing all matrix material. Several grains were mounted for characterization with an electron microprobe, and the remaining will be analyzed with solution ICPMS for determining trace-element compositions. These results will provide further information on the provenance of these pebbles.

The goal of the last project was attempting to date pillow basalts from the Izmir-Ankara-Erzincan Mélange (Corum, Turkey). Previous attempts to separate zircons from the samples were not successful. Considering the abundance of pyroxene in the samples, the method for dating was switched to pyroxene Sm-Nd dating (with TIMS). Yet, the separated pyroxenes were either hydrothermally altered or still in aggregates at the smallest size picking was possible. The limitations experienced in this project emphasized the need for further developments in current capabilities of geochronology methods.