Taurus prospect (incl. East Taurus prospect; West Taurus prospect), Southeast Fairbanks Census Area, Alaska, USAi

Regional Level Types
Taurus prospect (incl. East Taurus prospect; West Taurus prospect)	Prospect
Southeast Fairbanks Census Area	Census Area
Alaska	State
USA	Country

See also the Pushbush prospect (TC024) and the ASARCO prospect (TC001).
Location: The Taurus prospect is located in section 28, T. 22 N., R. 21 E., of the Copper River Meridian. Access to the property is by air, and there are two gravel airstrips on the property. Alternatively, a rough land route is available for heavy equipment via a winter trail (Leriche, 1995, p. 451). This is locality 5 of Eberlein and others (1977). Bluff prospect (TC005) claims lie directly to the west, and the center of Bluff prospect (TC005) prospecting activity lies to the southwest. The location is accurate to within 1 mile.
Geology: The Taurus property is usually separated into two main zones: West Taurus and East Taurus. The property is underlain in part by a metamorphic basement complex of possible Late Precambrian or early Paleozoic age that consists of biotite gneiss, augen gneiss, biotite schist, and quartzite (Foster, 1970). Early Tertiary felsic rocks intrude the metamorphic rocks. Secondary biotite within the intrusion at the Taurus prospect has been dated by K-Ar techniques to be approximately 57 +/- 2 Ma (Nokleberg and others, 1995). Two major faults have been identified on the property. The Tourmaline fault strikes northeasterly and appears to have left-lateral movement with a possible displacement of up to 6.5 km. The McCord Creek fault trends easterly across the claims. Porphyry intrusions, which host mineralization at the East and West Taurus zones, are located near the McCord Creek fault, suggesting that it controlled their emplacement. Many northeast trending linears have been interpreted using satellite images and topographic maps (Leriche, 1995, p. 452). The Taurus porphyry copper-type mineralization appears to be related to a group of widespread, small bodies of early Tertiary, quartz monzonite porphyry, quartz latite, feldspar-quartz porphyry, intrusive breccia, quartz porphyry and dacite porphyry. Intrusive breccia crops out along the southern border of an altered Upper Cretaceous granodioritic pluton on the eastern side of the property. Quartz monzonite porphyry occurs along the southern contacts of the altered granodiorite and of intrusive breccia in the central part of the property (Leriche, 1995, p. 452). The alteration at the East Taurus zone consists of an upper leached cap underlain by supergene and hypogene zones. The leached cap varies from 40 to 50 meters in depth, and shows pervasive argillic alteration due to groundwater leaching. Other alteration types in the leached cap consist of pervasive silicification, quartz-sericite, and quartz-magnetite alteration. Supergene and hypogene zones are accompanied by phyllic, silicic, propylitic, and potassic alteration (Leriche, 1995, p. 453). Mineralization in the leached cap at East Taurus consists of minor remnant pyrite, chalcopyrite, and molybdenite in quartz stockworks and silicified zones. The supergene zone varies in thickness from 30 meters to 53 meters. Mineralization in it consists of chalcocite, covellite, pyrite, chalcopyrite, and molybdenite. Chalcocite appears in fractures and within quartz veinlets. In the lower hypogene zone, mineralization is pyrite, chalcopyrite, and molybdenite as disseminations along fractures and in the center of quartz veinlets (Leriche, 1995, p. 453). Mineralization in the West Taurus area consists of pyrite and subordinate chalcopyrite, covellite, chalcocite, malachite, and azurite. Molybdenite is found in quartz-filled fractures in the sericitically altered, quartz latite unit. Chalcopyrite and molybdenite are found as fracture fillings in close proximity to the Tourmaline and McCord Creek faults (Leriche, 1995, p. 454). The majority of drilling conducted on the property has been done in the East Taurus zone. In 1993, Noranda calculated preliminary reserves of 23 million tons grading 0.3% Cu and 0.039% Mo. Drill samples collected in the 1970's were not assayed for gold, but later analyses of part of the core reveals some elevated values in gold (Leriche, 1995, p. 455). Resource Associates of Alaska re-staked the Taurus and Bluff (TC005) prospects in 1987 and did some soil geochemistry. They dropped both properties two years later. They probably analyzed for gold and may not have found enough to continue holding the property.
Workings: Taurus prospect was staked in 1970 by International Minerals and Chemical Corporation during a reconnaissance geochemical survey. During the 1970's, geologic mapping, soil sampling, magnetometer and IP surveys, and 3060 meters of diamond and rotary drilling were done. In recent years, an airborne magnetic, electromagnetic, and resistivity survey, as well as 404 meters of reverse circulation drilling have been done (Leriche, 1995, p. 451). In 1987, Resource Associates of Alaska staked the Taurus and Bluff (TC005) prospects, but dropped both 2 years later. Noranda staked Taurus in 1993.
Age: Secondary biotite within the intrusion at the Taurus prospect has been dated by K-Ar techniques as approximately 57 +/- 2 Ma (Nokleberg and others, 1995).
Alteration: Hypogene alteration associated with mineralization includes argillic, potassic, phyllic, silicic, and propylitic alteration of varying intensities. A supergene leached cap, approximately 50 meters thick, exhibits strong argillic alteration over the East and West Taurus zones (Leriche, 1995).
Reserves: In 1993, Noranda indicated that the East Taurus zone contains a 23 million ton reserve grading 0.3% Cu and 0.039% Mo (Leriche, 1995).

Commodities (Major) - Cu, Mo
Development Status: None
Deposit Model: Porphyry Cu-Mo deposit (Cox and Singer, 1986; model 21a)

References

Other Databases

Link to USGS - Alaska:	TC027

Other Regions, Features and Areas containing this locality