Red-bed Cu-Ag
Bleached arkose / wood-replacement Cu-Ag
Metals on this play: cu, ag, pb, v
Calibration
Nacimiento–Coyote, NM (Agua Zarca); Scholle, NM (Abo/Yeso).
The trap
Host. Bleached arkose or sandstone (Agua Zarca Chinle; Abo/Yeso Permian) against red beds.
Trap. Redox front. Copper sulfides replace wood and fill pores at the bleach boundary. Silver rides copper.
What a hit looks like. Gray-white bleached sandstone against red, malachite/chalcocite on logs, sooty chalcocite. USGS model 30b.1 red-bed Cu.
Wrong mountain
This is copper first. Silver Reef is the halide cousin, not the same bed. Do not walk a Pioche limestone with a red-bed checklist.
- Porphyry stockwork or skarn — wrong family.
- No redox front, no bleach, no wood.
- Limestone CRD — Play E.
How to use the score
The score orders the day. It is a walk sort. It is not an assay, a mining claim, or permission to enter. Killed ground stays on the map so the boundary is visible. Private land, tribal land, and park interiors stay off the walk.