| Basis for focus area |
Polygon for focus area is Notch Peak mining district from Krahulec (2018b). Scheelite deposits have been found around the periphery of the Notch Peak intrusive, which is approximately 1-1/2 miles north of Notch Peak, a prominent limestone landmark. The surface area of the intrusive is roughly 3 by 6 miles and the intrusive rock is quartz monzonite. Surrounding rocks are gently dipping limestones of the Upper Cambrian Notch Peak and the Orr and Weeks formations. Several small lenses of scheelite have been found in tactite zones near the contact of the quartz monzonite and the limestone. |
| Identified resources |
Indicated resources and historical production of tungsten. |
| Production |
The Notch Peak district is the fourth largest W producer in Utah at just over 100,000 lbs of WO3 (Krahulec, 2018b). |
| Status |
Past mining and exploration. |
| Estimated resources |
Inferred 320,000 metric tons of ore at 0.275% WO3. |
| Geologic maps |
Hintze and Davis (2002a), scale 1:100,000. |
| Geophysical data |
Inadequate aeromagnetic and aeroradiometric coverage. |
| Favorable rocks and structures |
The Notch Peak district is centered on the large (7.4 sq mi) Jurassic (~163 Ma) Notch Peak quartz monzonite stock/laccolith. The stock is light gray, coarsely crystalline, porphyritic, and ranges from diopside monzonite to biotite granite. Late, small aplitic and fine-grained granophyric dikes and sills intrude the stock and adjacent Middle and Upper Cambrian carbonate strata. |
| Deposits |
New Klondike mine, Brown Queen mine (MRDS dep_id: 10087001). |
| Evidence from mineral occurrences |
MRDS; UMOS (Utah Geological Survey, 2021). |
| Geochemical evidence |
Rock samples run as high as >1% W, 5000 ppm Cu, 2000 ppm Mo, and 700 ppm Sn (Krahulec, 2018b). |
| Geophysical evidence |
Unknown. |
| Evidence from other sources |
Krahulec (2018b). |
| Comments |
This area of Utah is underexplored using modern techniques, particularly for covered intrusives. Blind Jurassic intrusions are intersected as shallow as 300 ft undercover (for example, Thompson Knolls). Jurassic intrusives rarely have large tonnage deposits but are associated with critical mineral suites, such as W at Notch Peak. |
| Cover thickness and description |
Exposed at the surface. |
| Authors |
Jane M. Hammarstrom. |
| New data needs |
Regional aeromagnetics and aeroradiometrics survey; mapping. |
| Geologic mapping and modeling needs |
1:24,000 scale mapping. |
| Geophysical survey and modeling needs |
High-resolution, Rank 1 aeromagnetic and radiometric surveys. |
| Digital elevation data needs |
Lidar inadequate. |
