TUBBS HILL Bradley Thompson Daniel Twigg Makayla Jones

INTRO • On June 1 st, 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 4 th 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 S 5 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/trails-main • 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, Geo. Notes, G-25: Parks and Rec- http: //parksandrecreation. idaho. gov/find-an-activity • Postcard- http: //www. epodunk. com/cgi-bin/create. Postcard. php? c • ard. Num=3293038 • Miscellaneous info http: //www. cdaid. org/files/Parks/parks/Tubbs%20 Hill/Tubbs. Brochuresmaller. pdf