(photos from the textbook CD)


St. Mary Lake at Wild Goose Island overlook, Glacier National Park, Montana, USA.  This is probably the most stereotypical scenery and most photographed spot in Glacier National Park.  Notice the U-shaped valley, carved by Pleistocene-aged mountain glaciers (valley glaciers/alpine glaciers).  Notice the layered sedimentary rocks in the mountains - part of the Belt Supergroup, a Proterozoic-aged rift valley fill.  The portion of the American Rocky Mountains having layered sedimentary rocks is called the Northern Rocky Mountains Physiographic Province.


Cirque and hanging valley and waterfall in Glacier National Park.  Note the U-shaped valley of the cirque.  Notice the aretes (knife-like ridges at the margins of the cirque).


Grinnell Glacier & diorite sill (above & below) - the Grinnell Glacier terminates in a small lake.  The rock wall behind Grinnell Glacier has sedimentary rocks of the Belt Supergroup intruded by a diorite sill.  The whitish zone above & below the diorite sill is a bleached zone, the result of contact metamorphism.


Cirque and hanging valley.  Note the diorite sill and bleached zone in the distant rock wall to the left of center.


U-shaped valley carved by mountain glaciers (a.k.a. valley glaciers; a.k.a. alpine glaciers) during the Pleistocene Ice Age.



Horn - a pointed, peaky mountain top formed by glacial erosion and the development of multiple cirques.


Mudcracks preserved in reddish, hematite-rich argillite (slightly metamorphosed shale) of the Grinnell Formation (Belt Supergroup, Proterozoic).  Mudcracks form under alternating wet and dry conditions.




(photos from JSJ)


Till - Pleistocene-aged glacial till in roadcut outside Glacier National Park, Montana, USA.  Till consists of poorly-sorted, coarse-grained, poorly-bedded to nonbedded glacial deposits.  With burial and lithification, till deposits become glacial conglomerates, or tillites.


Diorite sill (dark rock at bottom) intruding Belt Supergroup sedimentary rocks at Big Drift roadcut along Going-to-the-Sun Highway.

Light-colored rocks at center & top = bleached zone from contact metamorphism.



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