Towards a methodology for modelling asbestiform chrysotile in alpine serpentinites

CO2 mineral carbonation has the potential to permanently store Gt of CO2 by reacting feedstock to produce building materials amongst other stable materials. Serpentinite is a leading candidate as a feedstock, however some serpentinite contain asbestiform chrysotile in hazardous concentrations. A novel methodology for quantitatively mapping asbestiform chrysotile concentrations near to or below the 0.1% volume threshold for hazardous material was investigated in the Great Serpentinite Belt (GSB). The approach relied on probabilistically determining sampling locations, measuring the areal composition of outcrop lithologies and additional auxiliary variables, before applying Isometric Log Ratio (ILR) and Gaussian Transforms to the data for cokriging interpolation and conditional simulations to estimate the percentage of the mapping area containing <0.1% volume asbestiform chrysotile. The resulting dataset is uniquely detailed and placed in a section of the GSB generally unstudied in regards to asbestiform chrysotile. The mapping efforts were able to produce a map of the distribution of asbestiform chrysotile to a upper 95% CI <0.1% volume, finding that the entire section of the serpentinite belt is broadly usable as feedstock, the model produced however does not predict accurately outside of the mapping area, requiring significantly more measurements.