1. The document discusses skarn zoning patterns and controlling factors based on a webinar presented by Zhaoshan Chang from Colorado School of Mines. 2. Skarns typically show zoning based on the transfer of heat and mass away from intrusions, with endoskarns nearest intrusions containing garnet and pyroxene that change in ratio and composition farther out. 3. Important controlling factors on skarn formation and metal zoning include the redox state, composition, and degree of fractionation of the causative magma as well as the composition, permeability and depth of the wall rocks.