A GEOLOGICAL, MICROBIOLOGICAL AND GEOCHEMICAL STUDY OF AGATES FOUND TO HAVE FLUID INCLUSIONS WITHIN THEIR INTERNAL CAVITIES

As part of the Physical Geology course at Delaware County Community College the students can choose an honors option project. This allows the students to gain a deeper understanding of geology though the practice of doing an undergraduate research project. Learning geology by doing geology. This year a group of students choose to combine the sciences of geology, microbiology and geochemistry to investigate the fluids inclusion in Agates.

Agates are rock formations created within cavities which are formed when gases trapped within cooling lava leave behind vesicles. Over time, the vesicles fill with silica-rich groundwater which deposits the dissolved silica in layered quartz deposits. These cavities seal themselves with the silica deposits and can potentially permanently trap some water within the vesicle. The samples obtained for this study came from various regions in Brazil. In tapping this trapped water we can test for microorganisms that may thrive along with investigating into the actual chemical makeup of the fluid. By drilling into the internal cavity of the agate within a sterile environment samples of the trapped water were extracted. In order to detect microorganisms the samples were then cultured onto a growth medium along with a corresponding control sample of pure distilled and sterilized water. Individual colonies were picked and sub-cultured on nutrient agar slants for farther identification. Geochemical analysis of the fluids were done to determine the fluid composition and identify any accessory minerals in the agates.