Arndt, Graham2024-03-162024-03-162024https://hdl.handle.net/1828/16165The atmospheric carbon budget is dominated by the long-term (>1 Myr) carbon cycle and has great implications on Earth’s habitability. One potential source of degassed carbon can be derived from magma-wallrock interactions within the overlying continental plate. This thesis is focused on carbonate interactions with meter-scale dikes within the Jurassic Bonanza arc on Northern Vancouver Island. Two types of samples were investigated: (1) bulk rock samples and (2) micro-slice sampled from a single 25 cm cross-section of dike 79B. Major and trace element chemistry was collected using LA-ICP-MS. We discovered that the dikes show anomalous variations in concentration for Sr, U, MnO2, and Na2O along their profile. One explanation for the enriched Sr concentrations can be explained using binary mixing models which indicate that the dikes assimilated a primitive limestone source with up to 10,000 ppm Sr. Additionally, the reacted boundary melts are enriched in Ca and depleted in silica which increases their capacity to transport sulfur. Data suggests that the dike margins can solubilize three times more sulfur species compared to the dike interior which has important implications on ore metal deposition. Overall, shallow magma-carbonate interactions greatly affect dike geochemistry which leads to enhanced CO2 production and ore mineralization.enBasaltdikeslimestone assimilationgeochemistrycarbon dioxidesulfide saturationPoster