Find publications, data and maps managed by the
Yukon Geological Survey

Occurrence Details


Occurrence Number
116B 108
Occurrence Name
Nebulous
Occurrence Type
Hard-rock
Status
Prospect


General Information

Secondary Commodities: uranium, gold
Deposit Type(s): Uranium
Location(s): 64.4650 N, -138.770280 W
NTS Mapsheet(s): 116B07
Location Comments: .5 Kilometres
Hand Samples Available at YGS: No

Capsule

Work History

Discovered during regional airborne radiometric surveying and staked as Nebulous cl 1-9 and 10-15 (YA5089) in two separate claims blocks during Jun/76 by Ukon Joint Venture (Chevron Canada Ltd and Kerr Addison Mines Ltd). The joint venture immediately carried out prospecting, staked Nebulous cl 16-29 (YA5142) in Jul/76 to form a single contiguous claim block and then completed detailed radiometric surveying and geochemical sampling before staking Nebulous cl 30-33 (YA5170) in Aug/76. The joint venture carried hand trenching, channel sampling and additional ground radiometric surveying in 1977 and blast trenching in 1980.
Restaked as Zulu cl 1-49 (YB67828) in Dec/95 by Mar West Resources Ltd.
In Apr/2000, Canadian United Minerals Inc staked Brenner cl 1-8 (YC19910) 3 km to the west-southwest and carried out reconnaissance geochemical sampling and prospecting later in the year; geochemical rock sampling in 2001; and magnetometer surveying and prospecting in 2003.

Capsule Geology

The occurrence is underlain by the mid Cretaceous Mount Brenner Stock of the Tombstone Intrusive suite, which has intruded Jurassic aged argillite and shale. Although shown on published maps as being syenitic in composition, detailed study by Lambert (1966) showed that the stock is actually monzonitic in composition and consists of four major concentric phases with a porphyritic quartz monzonite core. Three showings, named West, Ridge and East, occur over 250 m on the north-northwest flank of Mount Brenner and are collectively refered to as the Nebulous showings.
Mineralization at the Nebulous showings consists of a soft yellow, secondary(?) uranium mineral found coating joints and filling fractures within the host monzonite. It is often associated with a white precipitate, both of which fluoresce moderately to strongly green. A sample across 10 m assayed 0.015% U3O8, of which slightly more than half was contributed by the monzonite and the remainder was due to secondary enrichment.
The Brenner claims were staked to cover a magnetic anomaly near the contact between the Mount Brenner Stock and the intruded sediments. Two silt samples collected downstream of an east-west trending dyke, likely related to the Mount Brenner stock, returned weakly anomalous values for Au, Bi and Cu (peaks of 20 ppb, 6 ppm and 254 ppm, respectively). A grab sample of dyke material taken in 2000 returned 785 ppb Au, 316 ppm As and 36 ppm Bi, while followup sampling in 2001 returned only weakly anomalous values from the same dyke.

References

BREMNER, T.J., 1994. Proposed Tombstone Area Park: Preliminary Review of Mineral Potential. Indian and Northern Affairs Canada, Exploration and Geological Services Division, Open File 1994-2(T), 115 p.

CANADIAN UNITED MINERALS INC, Oct/2001. Assessment Report #094273 by S. Ryan.

CANADIAN UNITED MINERALS INC, Oct/2002. Assessment Report #094353 by S. Ryan.

GEOLOGICAL SURVEY OF CANADA Bulletin 180.

GORDEY, S.P. and MAKEPEACE, A.J., 2003. Yukon Digital Geology, version 2.0, S.P Gordey and A.J. Makepeace (comp.); Geological Survey of Canada, Open File 1749 and Yukon Geological Survey, Open File 2003-9(D).

LAMBERT, M.B., Apr/66. Geology of the Mount Brenner Stock. Unpublished M.Sc. thesis, University of British Columbia.

MINERAL INDUSTRY REPORT 1976, p. 141; 1977, p. 54-55.

UKON JOINT VENTURE, Mar/77. Assessment Report #090184 by A.R. Archer and E.P. Onasick.

UKON JOINT VENTURE, Dec/77. Assessment Report #090271 by Archer, Cathro and Associates.

UKON JOINT VENTURE, Jan/81. Assessment Report #090708 by A.R. Archer and W.D. Eaton.

YUKON EXPLORATION AND GEOLOGY 2003, p. 6.

YUKON GEOLOGY AND EXPLORATION 1979-80, p. 293.

Location Map

Last Updated: Jul 10, 2018

Work History

Year Work Type Comment
2003 Ground Geophysics: Magnetics
2003 Other: Prospecting
2001 Geochemistry: Rock
2000 Geochemistry: Soil Also silt samples.
2000 Other: Prospecting
1980 Trenching: Hand
1977 Geochemistry: Rock
1977 Ground Geophysics: Radiometric Survey
1977 Trenching: Hand
1976 Airborne Geophysics: Radiometric
1976 Geochemistry: Rock
1976 Geochemistry: Silt
1976 Geochemistry: Soil
1976 Geochemistry: Water
1976 Other: Prospecting

Regional Geology - Terrane

Group: Ancestral North America
Affinity: W Laurentia
Name: North America - basinal strata
Realm: Laurentia


Regional Geology - Bedrock

Supergroup:
Group/Suite: Tombstone
Formation:
Member:
Terrane:
Period Max: Cretaceous
Age Max: 94 MA
Period Min: Cretaceous
Age Min: 90 MA
Rock Major: syenite
Rock Minor: monzogranite
Reference: Thompson et al. (1994) - GSC OF 2849
Geological Unit (1M): mKT
Geological Unit (250K): mKyT

Assessment Reports that overlap occurrence

Report Number Year Title Worktypes Holes Drilled Meters Drilled
091432 1982 1982 Geology Report on the Marn 1-180 Claims Bedrock Mapping - Geology, Prospecting - Other
090183 1977 Geochemistry, Geology, and Radiometric Survey on the TING, NOTING, and PROSPECTING Claims Gamma-Ray Spectrometry - Airborne Geophysics, Rock - Geochemistry, Silt - Geochemistry, Soil - Geochemistry, Water - Geochemistry, Bedrock Mapping - Geology, Gamma-ray Spectrometry - Ground Geophysics, Petrographic - Lab Work/Physical Studies, Prospecting - Other
090184 1976 Report on Geochemistry, Geology and Radiometric Survey on the NEBULOUS 1-33 Claims Rock - Geochemistry, Silt - Geochemistry, Soil - Geochemistry, Water - Geochemistry, Gamma-ray Spectrometry - Ground Geophysics, Petrographic - Lab Work/Physical Studies

Related References

Number Title Page(s) Document Type
ARMC005689 Enquiry - Nebulous claims Miscellaneous Company Documents
ARMC006891 Fig. U-TS2 - Geochemistry map - Tombstone area - Ukon joint venture Geochemical Map
ARMC006887 Fig. U-NE1 - Radiometrics, geology and chip sampling map - Mt. Brenner stock - Nebulous claims - Ukon joint venture Geophysical Map
ARMC006890 Fig. U-TS1 - Radiometrics map - Tombstone area - Ukon joint venture Geophysical Map
ARMC016775 Geochemical map - 116B/7 Geochemical Map
ARMC004671 Report on Nebulous property - Ukon joint venture Report
ARMC004672 Re: Reanalysis of samples from the Ukon joint venture - Nebulous property Miscellaneous Company Documents
ARMC016774 Geology map - 116B/7 Geoscience Map (Geological - Bedrock)
Citations

Submit Information to Yukon Geological Survey

Name:

E-mail:

Comment: