Given to the Gold Prospectors Association of America in 2018 this talk illustrates a workflow on how to research, evaluate and put together a resource prospect. it is designed to be from the type of individual who is planning a trip, how do they use the tools available to find and look for rocks and minerals.

1. Geologic History of the
Seminoe Mountains
Researching, Evaluating, and Putting a Resource
Prospect Together
Marron J. Bingle-Davis
Mike A. Bingle-Davis

2. The Seminoe Mts are in central Wyoming on southern flank
of Sweetwater Arch ~40 mi northeast of Rawlins

3. A Little History
• The Seminoe Mts were named for one of Fremont’s guides – Basil
Cimineau Lajeunesse
• In 1871, General Bradley’s troops set out to explore the Seminoe
Mts because of reports of silver-bearing galena
• They found gold instead along the flank of Bradley Peak
• Several gold prospects were staked after this and by 1873 it was
established but Indian attacks drove them away in 1874
• Penn Mining Company bought
much of the area mines in 1885
and started mining
• Iron prospecting started in the
early 1900s but never really took
off
• An estimated 100 million tons
of taconite from the BIFs
1880s

4. • ~1,500 – 2,000 ft high in relief
• Bounded on SW by low-angle thrust fault, bounded
on N by reverse fault
• Precambrian rocks contact Cretaceous or younger rocks

5. Laramide Orogeny
• The Seminoe Mts are one of several uplifts from the
Laramide Orogeny from ~70 to 40 Ma
• Cores are Precambrian rocks that were uplifted almost
vertically; Flanks are younger rocks that are often
steeply dipping
• Mountains are broad and vertical

6. Mountain Mineralogy
• Most outcrops Precambrian;
Fragment of greenstone belt
• Archean amphibolites (>2.7 Ga)
intruded and folded by
granodiorite (>2.6 Ga)
• Divided into three mappable
units:
• Upper – Seminoe Formation
(4,000 ft of metasedimentary
rocks (BIFs))
• Middle – Bradley Peak (1,000 ft of
ultramafic/mafic metavolcanics)
• Lower – Sunday Morning Creek
(11,000 ft of mafic schists)

7. Mineral Deposits
• Copper-silver-gold veins
• Gold placers
• Iron formation
• Nephrite Jade
• Serpentine
• Leopard Rock
• Kimberlite indicator minerals
• Rare Lead and Zinc

8. Where are the Deposits?
• Most trace precious
metals are found with
the BIFs that mostly
come out of the
Seminoe Formation
• BIFs not in the Sunday
Morning Creek and rare
in the Bradley Peak
Penn Mines (1980s)

9. Where are the Deposits?
• Jade is found along the northern flank of
the Seminoes in the Bradley Peak
ultramafics (amphibolite dikes)
• Leopard Rock occurs in the Seminoe Fm
with the best quality near Wood Creek
• Diamond indicator minerals, like pyrope
garnets, are found in alluvium

10. Introduction to Exploration
• From nothing
• Basic research
• Basic Mapping
• Advanced research
• Advanced mapping
• Planning
• Site Determination-evaluation

11. FromNothing
• Topic – Seminoe Mountains
• Extreme basic – Internet
• Greenstone Belt
• Blog on gold in Seminoe Mtns.
• Wikipedia
• Gold anomalies at Bradley Peak
• Low grade iron 100,000,000 tons
• Serpentine, leopard rock, jade,
jasperized banded iron, copper,
zinc and lead

12. Serpentine, leopard rock, jade, jasperized
banded iron, copper, zinc and lead (gold?)

13. Basic Research
• Google (of course)
• Google Scholar
• Wyoming Geological Survey
• US Geological Survey
• Thesis and Dissertations
• Google Earth
• Layers for Google Earth

14. Basic Research
• Search Seminoe
Mtns.
• Click MAPS
• This screen pops
• Each bookmark
is clickable
• Start word
document with
links
• Also LAT/LONG

15. Basic Research
• General search – go through as
much as possible
• Image search – grab maps,
change search specs
• Google maps coordinates
• Build a document / folder of
locations, maps, pictures,
literature

16. Basic Mapping
• Using the database and locations
from your basic research
• Google Earth Pro
• Free, create a project
• Load Public Land Survey System
• Load Wyoming Geologic Map

17. Basic Mapping
• Maps from Google
• Maps from publications
(scanned)
• Ensure they can be
georeferenced
• The will be used to locate in
advanced mapping and rubber
sheeting

18. Advanced Research
• Google Scholar
• Peer reviewed journals
• Open access thesis and
dissertations

19. Advanced Research
• Mindat.org

20. Advanced Mapping
• Add the PLSS layer for reference
• Know Google Earth Shortcuts
• Mapped Nephrite location From
Mindat
• Use Geological Map on Google
Earth, find trends
• BE LEGAL!

21. Advanced Mapping
• N,U, Crosshairs on Image
• Now actual lat/long can be
determined
• As well as structural elements
• Faults
• Hard rock boundaries
• Etc.

22. Advanced Mapping
• Remember to pay attention to
scales
• Also township and ranges
• Image will or may look distorted
real world
• Add points – Penn Gold Mine
locations 1-5
• 5 locations in 4 miles square

23. Advanced Mapping
• PGM #1: 42.151952°,
-107.041416°
• And so on…
• Quick area survey on aerials
• QA/QC
• Road Access

24. Advanced Mapping

25. Advanced Mapping
• Add all lat-long
• Use aerials to survey
• Plan routes
• Bring gear
• Correct vehicle choice
• LEGALITY

26. Site Determination
• Aerial review
• Use historical imagery slider
• Check land ownership
• (Next slide) geologic faults,
• ETC

27. Site Determination
• Geology
• Any areas that may have
potential that were overlooked?

28. Conclusions
• Seminoes rich in geology
• Abundant minerals
• Applicable to many projects
• Gold
• Minerals
• Fossils
• Metal Detecting
• Caving
• Anything you can imagine