J. Tuzo Wilson: Father of Transform faults,
Hotspots, and the Wilson Cycle.
The Wilson Cycle
Embryonic Stage – e.g.
Immature Stage - e.g.
Mature Stage - e.g.
Declining Stage - e.g.
Remnant Stage - e.g.
Suture Stage - e.g.
Evolution of a Mature Ocean
Stage: volcanic and
non-marine sediment deposited in rift valleys
Stage:
continued rifting creates new oceanic crust and a long, linear marine seaway.
Cooling and subsidence of the rifted margin allow sediment to be deposited
Stage:
A broad ocean develop sand the continental margin continues to grow as sediment
derived from erosion of the land is deposited
The Ocean is
a “typical” mature ocean.
Q. What type of continental margin fringes
the Atlantic and Gulf coast of the US?
A.
Q. How does the continental margin of Texas
differ from that of Oregon? Why are they different?
A.
The Pacific is an ocean in _______________.
Ocean-Ocean and Ocean-Continent Convergent
Margins. (fig 14.4)
A Remnant Ocean (fig 14.19a)
Q. What is a Suture Zone? (fig 14.19b)
A.
Selected examples of present-day plate
boundaries.
East African Rift System (fig. 13.18)
Active Volcano in the East African Rift
System
The Great Rift Valley of East Africa
(an "embryonic ocean")
Q. What type of faulting would you expect to
occur in the Rift Valleys?
A.
The Red Sea started out like the rift
valleys, but now is an "__________ ocean"
The Atlantic Ocean started out like the Red
Sea, but now is a “__________ ocean”.
Q. Where are most Divergent Plate Boundaries
located? (fig. 13.12)
A.
Q. How and why does the profile across the
Mid Atlantic Ridge differ from that across the East Pacific Rise?
A.
Q. What is an Ophiolite (fig. 13.15) and how
does it form (fig. 13.13)?
A.
Pillow Lavas (fig. 13.16) and Pillow Basalts
(fig. 13.17)
"Black Smokers" and Life at a
Mid-Ocean Vent (fig. 13.D,E)
Q. The Pacific ocean is getting smaller
everyday. How is that possible?
A.
Composite volcanoes along the Pacific "Ring of Fire" (USGS)
Andesitic volcanism is typically associated with oceanic trenches
(e.g. the Japan Trench)
Q. Volcanic Island Arcs form under what tectonic
setting? (fig.14.4A)
A.
Q. Where would you likely find a “passive”
continental margin? (fig. 14.7B)
A.
Q. Where would you find a typical
“Andean-type” continental margin? (fig. 14.4B)
A.
Q. How did the Himalayas form? (fig. 2.23;
14.11)
A.
Q. How (and when) did the Southern
Appalachian Mountains form? (fig. 14.12)
A.
Q. What is the Valley and Ridge Province and
how does it differ from the Basin and Range Province? (fig. 14.13; fig. 14.18)
A.
Q. What California look like during the
Mesozoic? (fig. 14.7B)
A.
Q. What modern physiographic features in
California (see fig. 14.7c) formed from the tectonic features listed below:
Accretionary Wedge ŕ
Forearc Basin ŕ
Magmatic Arc ŕ
What does the Juan de Fuca Ridge have
to do with the Cascade Range?
Origin of the Cascade Mountains
Sometimes the collision is between a large
continent and a smaller arc or fragment of a continent (exotic terrane) –
fig.14.16).
The accretion of such terranes has resulted
in significant widening of the western margin of North America over the past
200 million years (fig. 14.16)
Plate Tectonics in the Western United States
San Andreas Transform Fault System
Dead Sea Fault Zone
Transform faults with a "bend" can
form:
Origin of the Dead Sea