Lake Mead sedimentary Mn
Three Kids / Boulder City wad in tuff
Metals on this play: mn, pb, cu, ag, au
Calibration
Three Kids mine, Las Vegas district, Clark County, NV. Hunt, McKelvey & Wiese USGS Bull. 936-L; McKelvey USGS Bull. 948-D; Longwell et al. 1965 NBMG Bull. 62.
The trap
Host. Tuffaceous sandstone and siltstone of the Muddy Creek Formation (Pliocene) against River Mountains volcanics. Wad (Mn oxide) in beds, pockets, and faulted grabens.
Trap. Sedimentary / hydrothermal wad in playa-tuff beds. Three Kids paid. Boulder City deposit is huge and lean (USGS ~15 Mt at 3–4% Mn). Fannie Ryan is a small cousin. Not a limestone CRD.
What a hit looks like. Black wad beds in tuffaceous sandstone — bacon-rind banding in pit walls. High Mn on XRF. Accessory Pb-Cu-Ag-Au at Three Kids is a byproduct, not a gold vein. This is not Combined Metals limestone and not a Keyhole quartz vein.
Wrong mountain
Do not hunt horn silver or Techatticup gold with a manganese checklist. Three Kids paid Mn for two wars. The Boulder City deposit is the lean cousin east of town — city/federal ground, not a gold strike. If you are standing on granite at Keyhole, you are in Play I.
- Quartz-calcite epithermal vein — Play I. Keyhole / Techatticup is gold, not wad.
- Combined Metals limestone / jasperoid — Play E. Caselton is not Three Kids.
- Sandstone + wood — Plays A–D.
- No Muddy Creek / tuffaceous wad bed, no Mn oxide.
- Three Kids pits and mill are a cleanup / redevelopment site — access-killed. Mapped so you see the calibration, not so you walk a Superfund pit.
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.