Commodities
PrimaryCopper, Gold, Silver
Commodity typeM
Deposit
Model78: Porphyry Cu-Au
Deposit sizeN
Ore controlChalcopyrite Is More Commonly Disseminated Than Veinlet Controlled
Materials
Ore mineralsChalcopyrite
GangueAnhydrite
Other materialsMagnetite, Pyrite
Geology
Host rockFelsic Volcanic Rock,Basalt
Associated rockTonalite
StructurePluton Is In Elongate Cluster Of Stocks Aligned Perpendicular To The Regional Grain Of The Island. Fractures Striking N.18 W. And N.2 E. In The Helecho Porphyry Match Mineralized Fractures In The Tanama Deposit. The N.30 E.-Striking Fractures Match The Trend Of The Elongate Cluster Of Stocks Of Which Helecho And Tanama Are A Part., Veins And Mineralized Fractures Show Difference In Orientation Between The Porphyry And Metavolcanic Country Rocks. N.30 E.-Striking Fractures Predominate In The Volcanic Rocks But Are Rare In The Porphyry.
Tectonic settingGold-Rich Porphyry System In Low-Potassium Island Arc Environment
AlterationChalcopyrite Associated With Magnetite In Feldspar-Stable-Alteration Assemblages, And With Pyrite In The Feldspar-Destructive-Alteration Zone
Economic & production
Development statusOccurrence
Discovery year1958
Identification
Deposit ID10085468
MRDS IDW701059
RegionCR
Data scoreB
Coordinates18.24455, -66.79947
References
COX, DENNIS P., AND BRIGGS, REGINALD P., 1973, METALLOGENIC MAP OF PUERTO RICO: U.S. GEOLOGICAL SURVEY, MISCELLANEOUS GEOLOGIC INVESTIGATIONS MAP I-721, ACCOMPANIED BY EXPLANATORY PAMPHLET, 6 P.COX, DENNIS P., 1985, GEOLOGY OF THE TANAMA AND HELECHO PORPHYRY COPPER DEPOSITS AND VICINITY, PUERTO RICO: U.S. GEOLOGICAL SURVEY PROF. PAPER 1327, 59 P.BARABAS, A. H., AND QUINN, E. J., 1980, ALTERATION, MINERALIZATION, AND FLUID INCLUSIONS IN THE HELECHO PORPHYRY COPPER PROSPECT, WEST CENTRAL PUERTO RICO [ABST.]: 9TH CARIBBEAN GEOL. CONF. SANTO DOMINGO TRANS., P. 2-3.