Tubbs Hill Group

Report
TUBBS HILL
Bradley Thompson
Daniel Twigg
Makayla Jones
INTRO
• On June 1st, 2014 our group from
Geology 210 travelled to Coeur
d’Alene, Idaho where we walked
along the trails and examined the
geologic makeup of Tubbs Hill.
Figure 1: A view of Corbin Point, the southwestern most point
of Tubbs Hill. Visible in the background is the Coeur d’Alene
Resort.
WHERE?
• Go eastbound
on I-90
• Take exit 13 for
4th street
• Keep right at
the fork and
follow signs for
City Center
• The trailhead is
just to the east
of the resort
Our Site was along the trail on the west side
Figure 2: Tubbs Hill on Google maps
HISTORY
• Coeur d'Alene was originally a military
post in the late 1870’s
• Meant to ensure safety of settlers
heading west
• It became a settlement, then a lumber
town during the 1890’s to 1920’s, and
now a tourist city
Figure 3: A post card depicting Coeur d'Alene in the early 1900’s
(Above) Figure 4: A family in front of Tubbs Hill in 1890
(Left) Figure 5: The same area present day
RECREATION
• Tubbs Hill and Coeur d'Alene offer a variety of activities, including:
• Swimming, boating, camping, rock climbing, fishing, horseback riding
• ATV areas, disc golf, the Museum of North Idaho and plentiful hiking
• The beautiful Lake Coeur d'Alene Resort is open all year around
Figure 6: Lake Coeur d'Alene Resort
TOUR
Figure 7: A view of the
trail
TOUR
• Figure 8: A view of the
East side of Tubbs hill
TOUR
(Below) Figure 9: Corbin's Point
(Right) Figure 10: Trails and the exposed bedrock
FREE BIRD!
I could
make that
jump
TOUR
Left to right
Figure 11: Benji
is 20% mountain
goat 10% Yoda
Figure 12: Benji
enjoying the
wind in his hair
PRIEST RIVER CORE COMPLEX
Tubbs Hill is a metamorphic wonderland!
The hill contains metamorphosed sedimentary rocks, as
well as many mylonites, which is indicative of a
metamorphic core complex.
It is located at the western most edge of the Priest River
Core Complex
Figure 13: A map of the Priest River Core Complex
METAMORPHIC CORE COMPLEX
The complex formed due to the
rising of deeper crust rocks that
shed overlying rock layers.
The younger rocks get slightly
metamorphosed and the underlying
rocks get highly lineated due to
shearing, that is called the shear
zone.
Tubbs Hill is in this shear zone of the
Priest River core complex. Age
dates show that the complex was
formed in roughly Eocene time
(Reid, et al., 1993).
Figure 14: A simplified version of a
metamorphic core complex, with Tubbs Hill
approximated in the red circle
SAMPLES FROM TUBB’S
Figure 15: Mica schist found on
site. An example of most of the
bed rock of the hill.
Figure 16: Granite gneiss. Another
common bedrock found on Tubbs
Hill.
SAMPLES FROM TUBB’S
(Left)
Figure 17: This is an example of a
metamorphic rock from the
shear zone of the crystalline core
complex. It is lineated from
metamorphism right to left, but
then it has been sheared up and
down.
(Right)
Figure 18: Similar to figure S5 this
too has a higher mafic grade.
Seen in the bottom right side,
there is more biotite found in
some areas of the hill.
CONCLUSION
We learned a lot and had a blast on our trip to Tubbs Hill.
With all the wonderful geology, gorgeous views of
Lake Coeur d'Alene and a great hiking area;
maybe north Idaho isn’t completely awful after all.
THE DOCTORS
Makayla
Bradley
Dan and Benji
REFERENCES
• Museum of North Idaho- http://www.museumni.org/index.html
• Recreation source- http://www.cdaid.org/767/departments/parks/trailsmain
• Reid, R.R., Wavra, C, Fleck, R., Geist, D., and Knowles, C., 1993, Walking Field
Trip in the Tubbs Hill Mylonites, Coeur d'Alene, Idaho: Idaho Geological
Survey, GeoNotes, G-25:
Parks and Rec- http://parksandrecreation.idaho.gov/find-an-activity
• Postcard- http://www.epodunk.com/cgi-bin/createPostcard.php?c
• ardNum=3293038
• Miscellaneous info http://www.cdaid.org/files/Parks/parks/Tubbs%20Hill/TubbsBrochuresmaller.p
df

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