Geology seminar series: Petrogenesis of pounamu and associated rocks
Mike Palin and Candace Martin, Department of Geology
From a geological perspective, pounamu is a metamorphic rock, the most abundant variety of which is composed of nearly monomineralic tremolite. We discuss its origin in light of geologic occurrence, reassessed Rb-Sr isotope data, and calculated fluid-mineral equilibria. We conclude that tremolite replaced serpentinite along flow paths of schist-equilibrated aqueous fluid. The model implies that diopside- and talc-rich rocks may form in a similar manner during up- and down-temperature flow respectively.