Pb-Pb Mu Grid (ores)

This is an interpolated grid of Pb-Pb μ (mu, 238U/204Pb) data from primarily ore-related rocks and minerals. The point data used for the interpolation is from the Pb-Pb dataset held in the Isotopic Atlas as of February 2021. Point data added to the Isotopic Atlas after February 2021 is not represented in this grid. The grid was generated with Esri's ArcMap Spatial Analyst interpolation tool using the Natural Neighbor algorithm and 0.01 degree cell size. Two classifications are provided for this grid; a Jenks natural breaks classification with ten classes (classification 1) as per Champion (2013) http://pid.geoscience.gov.au/dataset/ga/77772, and; the same seven-class interval binning and colour scheme applied to the source point data in the Pb-Pb Isotope Data layer (classification 2).