Acoje (Zambales ophiolite)

Luzon, Zambales ophiolite (Acoje block), Philippines

Magmatic (Ni-Cu-PGE, carbonatites)Cr (EGP)

Type: PGE-rich podiform chromitites in the mantle of an arc ophiolite

Acoje block of the Eocene Zambales ophiolite (37 to 58 Ma), with island-arc character; PGE-rich chromitite layers in tectonised mantle harzburgite. Martin (1991): cumulate chromitites with 187Os/186Os of 1.040 to 1.053.

187Os/188Os isotope ratio, no unit Values of the same system

Standard : Rapport absolu, sans standard de référence

Value	Range	n	Mineral or matrix	Source
0.1259 ± 0.0008	0.1252 / 0.1267	3	chromitite (whole rock) Mean and standard deviation recalculated from 3 analyses, 0.1252 to 0.1267 (GB288A 0.1252; GB227A 0.1257; GB85-5 0.1267). Published 187Os/186Os: GB288A 1.04 ± 0.011 (splits 1.038, 1.041); GB227A 1.0443 ± 0.0073, Os 87.9 ppb; GB85-5 1.053 ± 0.013, Os 17 ppb. GB288A: Os 128.3 ppb (fused split) and 96.4 ppb (leachate).	Martin (1991), Osmium isotopic characteristics of mantle-derived rocks, Geochimica et Cos…

Deposits of the same type

Bayan Obo China
Norilsk-Talnakh Russia
Bushveld, Merensky Reef South Africa
Bushveld, UG2 chromitite South Africa
Bushveld, Platreef South Africa
Sudbury Canada
Voisey's Bay Canada
Rössing Namibia

Cite this page

IsoFind Atlas (2026). Acoje (Zambales ophiolite), isotope signatures. https://www.isofind.tech/isotopes/en/deposits/acoje-ophiolite-de-zambales/ (accessed 2026-10-21).

@misc{isofind2026acojezambalesophioliteisotope,
  title = {Acoje (Zambales ophiolite), isotope signatures},
  author = {{IsoFind Atlas}},
  year = {2026},
  url = {https://www.isofind.tech/isotopes/en/deposits/acoje-ophiolite-de-zambales/},
  note = {Accessed 2026-10-21}
}

Updated : 2026-10-21