FIG. 4.

Mineral textures in QBG rocks. Panel (a) is a transmitted light photomicrograph; panel (b) is the same thin section in reflected light. These panels show the interface of goethite (g) oxidizing from pyrite (py) within negative pseudomorphs defined by quartz (qz), and void space (V). Panels (c–f) are environmental scanning electron microscopy (ESEM) mosaic SE images. (c) Smooth spheres overlay bumpy HFO filaments and knurled surfaces. (d) Hexagonal plates overlay tabular crystals. (e) Large tabular crystals are directly attached to the surface of the quartz boxwork. (f) Tabular crystal interiors are exposed and reveal a recessive material with irregular surfaces and substantial pitting that was eroded back from the exposed crystal surface. Smaller smooth hemispheres overlay tabular crystals. (Color graphics available at www.liebertonline.com/ast)