IGNEOUS ORIGINS OF MINERALS IN BERMUDAN CARBONATE ROV SAMPLES

There is still much that is unknown about Bermuda’s volcanic history. Despite their rarity, Bermuda is a potential candidate for having carbonatites due to the abundance of silica-undersaturated volcanic rocks that may originate from carbon-rich metasomatized mantle (Mazza et al., 2019). We studied samples collected from a remotely operated vehicle (ROV) from the Bermuda seamount, and in particular focused on BSM 5-5S for having the most promising characteristics of carbonatites, such as grain texture and lack of fossils in the initial survey of the samples. Textures were observed in thin section under a petrographic microscope, whole rock mineral abundance was determined via a whole powder pattern fitting (WPPF) model using X-ray diffraction (XRD), and mineral compositions were measured via energy-dispersive X-ray spectroscopy (EDS) on a scanning electron microscope (SEM). Aside from the bulk mineral calcite, we found clinopyroxene, biotite, apatite, as well as various iron and titanium oxides, including perovskite. Most non-carbonate minerals were euhedral to subhedral and fractured. Many oxides were found in a glassy matrix with similar chemical compositions to pyroxene. Biotite was often found in elongated strips paired with a larger calcite crystal. The igneous minerals present in the sample are consistent with Bermudan paleosols (Prognon et al., 2011), and volcanic mineral bearing bands within Pleistocene beach deposits from Whale Bone Bay (Eldridge et al., 2023). From the mineral makeup coupled with the textural analysis, we suggest that these samples are sedimentary carbonate rocks. However, paleosols of the area are often partially lithified, while these samples are fully lithified. Further research on comparing Bermudan paleosols with the grains in these samples must be done to determine their origins.