Table 2.
Major Gossan Rock Types and Associated Hand Sample–Scale and Microscale Textures
| Major rock type | Hand sample–scale textures | Microscale textures |
|---|---|---|
|
PQB Pyrite and quartz boxwork rock (from the in situ gossan) ∼pH 2.5–3 |
• Pyrite with quartz boxwork in altered rhyolite | • White tabular crystals • Fibrous efflorescent crystals • Cryptic filaments • Coupled oblong spheroids |
| • Pyrite with quartz boxwork and jarosite in altered rhyolite | ||
|
QBG HFO and quartz boxwork gossan rock (from the in situ gossan) ∼pH 5.5–6 |
• Dull luster QBG | • Bumpy HFO filaments • Hexagonal plates • Oblate spheroids • Laminated HFO (hemi)spheres • Smooth spheres • Bladed crystals • Tabular crystals • Knurled surfaces • Hatched surfaces • Agglomerated anhedral crystals |
| • Brightly colored QBG | ||
| • Resinous luster QBG | ||
|
IO Iron-only Gossan rock (from the remobilized iron deposits) ∼pH 5.5–6 |
• Brightly colored laminated HFO | • Smooth HFO filaments • Patterned HFO masses • Laminated HFO masses • Coupled oblong spheroids • Filamentous plexi • Mats of organic filaments • Bundled filament networks |
| • Dull laminated HFO | ||
| • Dendritic HFO masses | ||
| • Coalesced vertical columns | ||
| • Siliceous HFO masses | ||
| • Clast- and HFO filament–bearing masses |