FIG. 3. Backscattered electron images from H₂O-bearing melting experiments in the FeS-PbS-ZnS system. A. and B. Experiment JW02-56 at 865°C. The addition of H₂O depresses the melting temperature in the FeS-PbS-ZnS system and produces patches of quenched melt with large vesicles, partially rimmed with galena. Much of the troilite and sphalerite has been recrystallized to textures similar to those in Figure 2C. Intergranular fluid pores are present throughout the capsule, confirming that the experiments were fluid saturated. C. Detail from (B), showing typical quench textures and small blobs of Pb-rich material within the quenched melt. D. Experiment JW02-50 at 875°C. This experiment contained two distinct types of quench textures. In the lower right corner of the sample there is a pocket of regular quench, whereas the rest of the sample consists of a coarse skeletal intergrowth of galena, sphalerite, and troilite.