Keweenaw native silver district
Michigan (Keweenaw Peninsula, Lake Superior), United States
Other hydrothermalCu (Ag accessoire)
- Type
- Native copper and silver in amygdaloidal basalts (Mesoproterozoic)
A historic district of native copper and silver in Keweenawan basalts (Mesoproterozoic rift, 1.1 Ga). Mineralisation fills amygdules and fractures. Production was mainly copper, with native silver as a by-product or as grains and veinlets.
δ109Ag in ‰ (per mil) Values of the same system
Standard : NIST SRM 978a
| Value | Range | n | Mineral or matrix | Source |
|---|---|---|---|---|
| −0.4 / 0.4 ‰ | native silver only Typical hypogene signature. The deposit type differs (native copper and silver of basaltic origin), but the signature stays within the same range. | Arribas et al. 2020, The Isotopic Composition of Silver in Ore Minerals |
Deposits of the same type
- Cobalt district Canada
- Black Hills tin belt (South Dakota) United States
- Terlingua United States
- McDermitt United States
- California Coast Ranges (Hg district) United States
- Huancavelica Peru
- Profunda mine (León district) Spain
- Gibla (Seville district) Spain
Cite this page
IsoFind Atlas (2026). Keweenaw native silver district, isotope signatures. https://www.isofind.tech/isotopes/en/deposits/district-a-argent-natif-du-keweenaw/ (accessed 2026-10-06).
@misc{isofind2026keweenawnativesilverdistricti,
title = {Keweenaw native silver district, isotope signatures},
author = {{IsoFind Atlas}},
year = {2026},
url = {https://www.isofind.tech/isotopes/en/deposits/district-a-argent-natif-du-keweenaw/},
note = {Accessed 2026-10-06}
}Updated : 2026-10-06