MECHANISMS AND TEXTURES OF BASALT CARBONATION IN THE SUWANEE BASIN, FLORIDA

Climate Change represents a serious threat to habitability on Earth with widespread and rapid changes already observed in the ocean, cryosphere, biosphere and atmosphere (IPCC 2023). In order to reach zero carbon emissions and reduce the impact of climate change the deployment of carbon dioxide removal techniques is nearly unavoidable. Geologic carbon sequestration may prevent CO2 release into the atmosphere by securing it in deep geologic formations where it is unable to contribute to global warming, (USGS 2011) yet many questions remain about the kinetic and thermodynamic factors driving rock carbonation. We therefore present the results of a field-based study of natural analogues for carbon sequestrations in the Suwanee Basin, Florida. Our sample set includes mesozoic basalt flows and diabase sills from Florida's basement which were collected in oil exploration wells and first described in the 1970s and 1980s (Milton 1972; Lloyd 1985; Arthur 1988). Wells of interest were selected from documented examples of carbonated mafic rock as described by Milton (1972). Initial detailed petrography on a basaltic sill from Florida Geological Survey well W-1789 shows two dominant carbonation textures: (1) pervasive carbonation via replacement of clinopyroxene, and (2) carbonate precipitation in veins. Pervasive carbonation is observed near the top of the sill and carbonate precipitation in veins is observed lower in the sill. Future work will involve SEM chemical mapping and stable isotope analysis for a detailed characterization of the source(s) and mechanisms of carbonation in these mafic rocks.