Here are some more questions that people can use to sharpen their thinking about the paper by Burchfiel et al. (1992) and Cordilleran tectonics in general. Questions provided by Allan. I'm hoping he will tell us the answers at the end of the quarter!
1. See Figs. 1 & 2 in Burchfiel et al. (1992) that show:
(a) accretionary belt. (b) eastern limit of fold and thrust belt. (c) eastern
limit of Laramide deformation. Characterize each zone and explain what the 87Sri/86Sri
tells us about each.
2. Mid to Late Proterozoic sedimentary units termed aulocogens
occur just on the western edge and at the base of the north-south-trending,
Cordilleran passive miogeoclinal sedimentary margin (see Figs. 2 & 3 in
Burchfiel et al., 1992). What is the general nature of these deposits and what
do they tell us about the evolution of the passive margin and the abrupt western
edge of the North American craton?
3. (a)What does the generalized map of the distribution and
thicknesses (Fig. 4) of the latest Proterozoic and early Cambrian terrigenous
rocks tell us about the evolution of the passive margin of the North American
Cordilleran belt? (b) What is the general tectonic significance of the source
areas for erosion of this terrigenous detritus?
4. (a) Name the Western offshore geologic provinces and their
broad plate tectonic character in Late Proterozoic through Devonian time (see
Figs. 5 & 6)?
(b) What do these offshore units tell us about the evolution of the Cordillieran
accretionary belt?
(c) Contrast the rock units and their tectonic setting on the western and eastern
sides of the Cordillera during Devonian Antler orogeny.
(d) What is the significance of Antler events to the evolution of the Cordillera
of western North America?
5. Discuss with reference to Fig. 7, late Paleozoic events
(a) in the North American craton,
(b) in the miogeocline,
(c) in the western offshore terranes
(d) at the southern boundary of the Cordillera in North America
6. (a) What is the age, character, and distribution of the
Cache Creek terrane (Fig. 7).
(b) What is the tectonic significance of Cache Creek everywhere?
(c) What are the names of Cache Creek terranes in the North Cascades, Blue Mountains,
Klamath Mountains, and Northern Sierras?
7. (a)What are the main tectonic elements of the Sonoma event
and what is its timing?
(b) What are the similarities in the Antler and Sonoma orogenic evenst adjacent
to the miogeocline and along the western margin of the Cordillera?
8. What are the names of McCloud affinity terranes in:
(a) British Columbia?
(b) the Blue Mountains?
(c) the Klamath Mountains?
(d) northern Sierra Nevada?