Evaluation of ultramafic deposits in the Eastern United States and Puerto Rico as sources of magnesium for carbon dioxide sequestration

摘要: In this report, the authors evaluate resource potential of extractable magnesium from ultramafic bodies located in Vermont, Pennsylvania-Maryland-District-of-Columbia (PA-MD-DC) region, western North Carolina, and southwestern Puerto Rico. The first three regions occur Appalachian Mountains contain most attractive deposits eastern United States. They were formed during prograde metamorphism serpentinized peridotite fragments originating an ophiolite protolith. rocks consist variably dunite, harzburgite, minor iherzolite generally containing antigorite and/or lizardite as major serpentine phases. Chrysotile contents vary to major, depending on occurrence. Most outer sheath chlorite-talc-tremolite rock. Larger Vermont Carolina a core dunite. Magnesite other carbonates are common accessories. these deposits, MgO ranges 36 48 wt % with relatively pure dunite having highest lowest H{sub 2}O contents. Ultramafic Rico harzburgite thought be emplaced large diapirs or tectonic melanges. nearly pure, low-grade serpentinite which chrysotile primary minerals. Chlorite is ubiquitous trace amounts. accessory. Contents rather uniform at roughly 13 %. Dissolution experiments show that all serpentinites dunite-rich soluble 1:1 mixtures 35% HCl water by volume. suggest slightly more reactive than higher grade, antigorite-bearing Mountains. also dunites least amounts undesirable insoluble silicates. Individual great 7 km{sup 3} although typically they {le}1 3}. contrast, have estimated volume 150 Based few detailed geophysical studies Rico, it evident estimates any deposit would benefit greatly gravity magnetic investigations, corehole drilling. Nevertheless, data States could potentially sequester many years annual CO{sub 2} emissions if favorable geotechnical, engineering, environmental conditions prevail.