Morenci
Greenlee County, Clifton-Morenci district (Arizona), United States
PorphyriesCu (Mo)
- Type
- Porphyry copper with supergene enrichment
The largest of the three, porphyry bodies of tens of km², protore at 0.25 to 0.8 % Cu, minor skarn; samples from the Garfield pit, with no published Cu grade. Laramide porphyry copper with minor potassic and extensive quartz-sericite alteration, controlled by stockwork fracturing; supergene enrichment active since about 10 Ma, oxidation still under way at surface. Table 3 of Mathur et al. (2010): chalcocite 2.0 ‰ (after Mathur et al., 2009), hematite and goethite -0.9 ‰, chalcopyrite 0.5 ‰. Indicative coordinates: general position of the mine, not published by Mathur et al. (2010), to within 5 km.
δ65Cu in ‰ (per mil) Values of the same system
Standard : NIST SRM 976
| Value | Range | n | Mineral or matrix | Source |
|---|---|---|---|---|
| 0.6 ± 1.4 ‰ | −1.7 / 3.6 ‰ | 14 | leach-cap minerals (iron oxides and sulfates) Mean and standard deviation recalculated from 14 analyses, -1.7 to +3.6 (Garfield, 55 ft (hm) -1.7; Garfield, 90 ft (hm) -0.4; Garfield, 668 ft (jr) +1.6; Garfield, 674 ft (cc-hm) -1.1; Garfield, 199.5 ft (hm) -0.6; Garfield, 852 ft (hm) +0.7; Garfield, 900 ft (hm) +1.8; Garfield, 842 ft (cup-hm) +1.5; Garfield, 942 ft (hm) +0.1; Garfield, 942 ft (hm) +0.8; Garfield, 942 ft (cc-hm) +3.6; Garfield, 669 ft (hm) +0.1; Garfield, 669 ft (cup-hm) +1.2; Garfield, 678 ft (jr-hm) +1.0). Drill hole and depth in feet, XRD-identified minerals in brackets. XRD abbreviations: an antlerite, bor bornite, cc chalcocite, chr chrysocolla, cpy chalcopyrite, cu native copper, cup cuprite, cv covellite, goe goethite, hm (or hem) hematite, jr jarosite, mal malachite, mgn magnetite, py pyrite, qtz quartz, tc tenorite; amorphous: amorphous phase. | Mathur et al. (2010), Patterns in the copper isotope composition of minerals in porphyry … |
| 2.2 ± 1.7 ‰ | 0.3 / 5.2 ‰ | 11 | supergene enrichment zone minerals Mean and standard deviation recalculated from 11 analyses, +0.3 to +5.2 (Garfield, 968 ft (cc-py) +3.1; Garfield, 986 ft (cup) +2.1; Garfield, 1127 ft (cc) +0.4; Garfield, 1515 ft (cpy-py-cc) +1.7; Garfield, 1523 ft (cc-cpy-py) +0.3; Garfield, 1648 ft (cc-cpy-py) +0.4; Garfield, 960 ft (cup) +5.2; Garfield, 976 ft (cup) +3.4; Garfield, 976 ft (cc-hm) +0.8; Garfield, 1267 ft (cc-py) +4.2; Garfield, 1664 ft (cc-cpy-py) +2.6). Drill hole and depth in feet, XRD-identified minerals in brackets. XRD abbreviations: an antlerite, bor bornite, cc chalcocite, chr chrysocolla, cpy chalcopyrite, cu native copper, cup cuprite, cv covellite, goe goethite, hm (or hem) hematite, jr jarosite, mal malachite, mgn magnetite, py pyrite, qtz quartz, tc tenorite; amorphous: amorphous phase. | Mathur et al. (2010), Patterns in the copper isotope composition of minerals in porphyry … |
| 1.1 ± 2.2 ‰ | −0.9 / 7.2 ‰ | 10 | hypogene ore (chalcopyrite and pyrite) Mean and standard deviation recalculated from 10 analyses, -0.9 to +7.2 (Garfield, 766.5 ft (py) +7.2; Garfield, 1062 ft (cpy-py) +0.3; Garfield, 1079 ft (cpy-py) +1.2; Garfield, 1093 ft (cpy-py) +0.7; Garfield, 1168 ft (cpy-py) +0.1; Garfield, 1217 ft (cpy-py) +0.3; Garfield, 1391 ft (cpy-py) -0.9; Garfield, 1749 ft (cv-py) 0.0; Garfield, 1267 ft (cpy-py) +1.5; Garfield, 1664 ft (py-cpy) +0.4). Drill hole and depth in feet, XRD-identified minerals in brackets. XRD abbreviations: an antlerite, bor bornite, cc chalcocite, chr chrysocolla, cpy chalcopyrite, cu native copper, cup cuprite, cv covellite, goe goethite, hm (or hem) hematite, jr jarosite, mal malachite, mgn magnetite, py pyrite, qtz quartz, tc tenorite; amorphous: amorphous phase. | Mathur et al. (2010), Patterns in the copper isotope composition of minerals in porphyry … |
Deposits of the same type
- Ray United States
- Silver Bell United States
- Climax United States
- Henderson United States
- Bingham Canyon United States
- Bingham Canyon United States
- Battle Mountain district (Copper Basin, Elder Creek) United States
- Granisle Canada
Cite this page
IsoFind Atlas (2026). Morenci, isotope signatures. https://www.isofind.tech/isotopes/en/deposits/morenci/ (accessed 2026-10-22).
@misc{isofind2026morenciisotopesignatures,
title = {Morenci, isotope signatures},
author = {{IsoFind Atlas}},
year = {2026},
url = {https://www.isofind.tech/isotopes/en/deposits/morenci/},
note = {Accessed 2026-10-22}
}Updated : 2026-10-22