Transcript PowerPoint Presentation - NAU jan.ucc.nau.edu web server

For your sketch here, look at this stream valley. Sketch how
it changes course. If you see any other streams that do the
same, note them.
B
A
Part I. Alone or with 1-2 others, sketch this outcrop and describe what
is going on. What is the approximate dip at A and at B? What stress
regime likely caused this set of relations?
Part II. Below is a list of topics we
can cover next week. Please list
your three highest choices.
• Mass movements (debris flows,
landslides, etc.)
• Streams and rivers (surface water!)
• Hydrology (groundwater)
• Glaciers
• Deserts and wind
MOUNTAIN BUILDING,
or,
why the earth’s surface has such
variable relief
Same maps, different views
Where is the continental
crust thickest? Where is
it thinnest? How does
this relate to plate
tectonics?
So, how much of a material floats in another
material depends on their relative densities
Draw a slice through the earth, with N to the left and S to the right, from Flagstaff
to Tucson, showing how elevation changes from north to south. Tucson is at
about 800 m (2500’) elevation, and we are at about 2000 m (7000’). Beneath
the above-ground topographic profile, draw the likely topography of the crustal
root under Arizona. The root does not change elevations rapidly.
Very flat topography over a few hundred km
(scale below sea level exaggerated 5 X)
The point is, how does the crustal thickness
change, and how thick is the crust under 2-kmhigh Flagstaff?
Scale below sea level again vertically exaggerated (above
sea level too, though not as much). If the crust below
Flagstaff (2100 m) is 40 km thick, how thick might the
crust below K2 and Everest be?
How much more can the crust thicken below the
Himalaya, if at all?