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Pressure Dependence Of Polycrystalline Magnesite And Dolomite, Cole Blasko

Williams Honors College, Honors Research Projects

Intermediate depth (170-400 km) deep focus earthquakes are observed in subducting slabs, but unlike shallow (50-170 km) and deep (400-660 km) deep focus earthquakes, the mechanism(s) responsible for them are not clear. Two common alteration products observed in peridotites, magnesite and dolomite, are stable along the pressure-temperature path of a subducting slab. Low pressure experiments indicate that these minerals are weaker than olivine, but there are no data about the pressure dependence of the strength of magnesite or dolomite. Magnesite and dolomite cylinders (1mm by 1mm) were deformed in stacked series to 25-30% strain using the deformation-DIA (DDIA) at Argonne …