Geologic Formations
Geologic formation symbols in white (P2, M2, etc.) are from Hintze, L.H., Williis, G.C.,
Laes, D.Y.M., Sprinkel, D.A., and Brown, K.D., 2000, Digital Geologic Map of Utah: Utah
Geological Survey Map 179DM, 1 CD-ROM. The digital geologic map is a scanned
version of Hintze, L. H., 1980, Geologic Map of Utah: Utah Geological Survey, scale
1:500,000.
From Marjorie Chan, Todd Ehlers, and Erich Petersen, Big Cottonwood field trip,
http://www.mines.utah.edu/~wmgg/Geology/FieldTrips/Big_Cottonwood_Canyon.html, accessed
15 September, 2000.
Data from Hintze, L.H., Williis, G.C., Laes, D.Y.M., Sprinkel, D.A., and Brown, K.D., 2000, Digital Geologic Map of Utah: Utah Geological Survey Map 179DM, 1 CD-ROM.
Faults and Earthquakes
Forest Service and Utah Geological Association sign in parking lot at the mouth of Big Cottonwood Canyon.
http://www.ugs.state.ut.us/fmodel.gif, accessed 15 September 2000
http://www.ugs.state.ut.us/pi-3.jpg, accessed 15 September 2000
Late Proterozoic: 1100 - 544 million years ago
Field Trip Stops: SEAS (2.3 miles from the beginning), and SLATE (2.8 miles).
Slate
Quartzite
SLATE: Beach sands and tidal shales. The shales (metamorphosed to slate) show rythums of the tides. According to
Marjorie A. Chan, 1993, the age of the rocks is in the range of
850 to 1 billion years old.
SEAS: Mud (dessication) cracks in marine
shales.
Paleogeography of the western USA during Late Proterozoic time.
Late Proterozoic: 1100 - 544 million years ago
MFORK, Mineral Fork Stop, 5.8 miles from the mouth of Big Cottonwood Canyon.
Mineral Fork Tillite
(Loose material on the slope)
Gate at the entrance to Mineral Fork Canyon.
Mineral Fork Tillite (black rocks) on the slope of a mine dump.
Glacial moraine deposit, “till”; it will be a “tillite” when it
becomes cemented. Bells Canyon, Salt Lake County, Utah.
Mineral Fork Tillite. The rock is believed by some
to be a glacial deposit approximately 800 million
years old.
Cambrian Period: 570 - 505 million years ago.
Field Trip Stop: CAM, 6.5 miles from the beginning.
Ophir Shale
Tintic
Quartzite
U. of California, Berkeley, Museum of Paleontology
Mississippian Period: 360 - 325 million years ago.
Field Trip Stop: MISSM, 7.2 miles from beginning.
DIORITE
MARBLE
Mississippian Deseret Limestone, metamorphosed into marble when intruded by 72 million year old
Diorite magma.
Limestone
Pleistocene Glaciation of the Wasatch Mountains according
to Wallace Walter Atwood, 1909.
Field Trip Stops: QM (8.2 miles from the mouth of Big Cottonwood Canyon) and RFLAT
(8.9 miles).
http://www.ucmp.berkeley.e
du/quaternary/ple.html
Utah, A Geologic History. Utah Geological
Survey, USDA Forest Service Intermountain
Region.
Pleistocene: 1.6 million years to 11,000 years
ago.
Quaternary Moraine, about 18,000 years ago
Field Trip Stop: QM, 8 miles from mouth of Big Cottonwood Canyon.
Permian Period: 250-290 million years ago.
Field Trip Stop: PPC, 8.5 miles from mouth of Big Cottonwood Canyon.
Park City Formation limestone. This limestone was
deposited on a continental shelf, 200 meters or so below
sea level. The black color, and sulphorous odor, is because
there was no decaying oxygen on the shelf.
Http://vishnu.glg.nau.edu/rcb?Geologic_History_WUS.html
Meeting of the Glaciers, Reynolds Flat
Rflat, 8.5 miles from mouth of Big Cottonwood Canyon
Glacier gravel in moraines
“Meeting of the Glaciers. A small, vigorous glacier coming down Mill D. South Fork (from bottom edge of graphic) met
the larger, sluggish glacier from the main canyon and the two wedged together and stagnated at [Reynolds Flat] ... “
After the Forest Service Sign at Reynolds Flat parking lot.