GEOLOGY, SULFUR ISOTOPES AND THE ORIGIN OF THE HEATH STEELE ORE DEPOSITS, NEWCASTLE, N.B., CANADA
The Heath Steele mine is located 35 miles northwest of Newcastle, New Brunswick, Canada. Middle Ordovician Tetagouche Group rocks, consisting of siliceous and basic volcanic rocks, and fine-grained quartz sericite schists and porphyry, have been folded into a steeply plunging recumbent anticline. The ore deposits of zinc, lead, and copper are associated with minor folding and/or sheared dilatent zones at or near the contact between porphyry and fine-grained senicitic schist. Mineralogically the sulfide bodies consist of early, euhedral arsenopyrite, magnetite, and pyrite, followed by interstitial pyrrhotite, sphalerite, chalcopyrite and galena. Minor minerals are ternantite-tetrahedrite, bismuthinite, marcasite, hematite, and some graphite. Supergene minerals consist of chalcocite, covellite, and marcasite with a little native silver. Little hypogene replacement has taken place between the minerals, which show a "porphyritic" texture. Sulfur isotope ratios were determined for over 150 sulfide and sulfate specimens from five of the seven ore bodies, and from granite, acid and basic volcanics, porphyry, and sediments. The results indicate that there is no detectable fractionation either during hypogene mineralization or supergene enrichment. The spread (21.82 to 22.02) covered by the ratios is narrow, and suggestive of a well homogenized source of mineral solutions. The enrichment of S/sup 34/ in the ore sulfides and the presence of graphite, evident from mineralographic studies and mass spectrometric analysis, suggests reduction of original sulfates (known to be enriched in S/sup 34/) by organic carbon at temperatures in excess of 500 deg C. A calculation based on the isotopic exchange reaction between sulfide and sulfate under equilibrium conditions and the spread of the ratios indicates a temperature of 700 to 800 deg C for the source. Finally the ratios determined for sulfides in a gneissic granite close to Heath Steele have the same ratio as the ore. These factors are considered to be diagnostic of a magmatic hydrothermal origin for the orp deposits. It is believed that an original source bed has been buried until suitable temperatures were reached to cause granitization, reduction of sulfates, and mobilization of the resulting sulfides to form ore deposits at favorable loci. (auth)
- Research Organization:
- Yale Univ., New Haven
- Sponsoring Organization:
- USDOE
- NSA Number:
- NSA-14-016893
- OSTI ID:
- 4152304
- Journal Information:
- Economic Geology and the Bulletin of the Society of Economic Geologists (U.S.), Vol. Vol: 55; Other Information: Orig. Receipt Date: 31-DEC-60
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
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Related Subjects
ACIDITY
CANADA
CARBON
COPPER
DEPOSITS
DISTRIBUTION
ENRICHMENT
GEOLOGY
GRANITES
GRAPHITE
IGNEOUS ROCKS
ISOTOPIC EXCHANGE
LEAD
MASS SPECTROMETERS
MINERALIZATION
MINERALS
ORES
ORGANIC COMPOUNDS
QUARTZ
REDUCTION
ROCKS
SCHISTS
SILICON COMPOUNDS
SILVER
SOLUTIONS
SULFATES
SULFIDES
SULFUR 34
SULFUR ISOTOPES
VOLCANICS
ZINC