Geology Reference
In-Depth Information
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Figure 22.16
Zion National Park, Utah Large cross beds of the
Jurassic Navajo Sandstone exposed in Zion National Park, Utah.
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Figure 22.17
Morrison Formation, Dinosaur National
Monument, Utah
a
Panoramic view of the Jurassic Morrison Formation as seen from
the visitor center at Dinosaur National Monument, near Vernal, Utah.
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Figure 22.18
Mesozoic Terranes Some of the accreted
lithospheric blocks, called terranes, that form the western margin
of the North American craton. The dark brown blocks probably
originated as terranes and were accreted to North America. The light
green blocks are possibly displaced parts of North America. The
North American craton is shown in dark green. See Figure 22.1b for
position of Wrangellian terranes during the Jurassic.
the term now applies to large, low-grade copper deposits
disseminated in a variety of rocks. These porphyry copper
deposits are an excellent example of the relationship between
convergent plate boundaries and the distribution, concentra-
tion, and exploitation of valuable metallic ores. Magma gen-
erated by partial melting of a subducting plate rises toward
the surface, and as it cools, it precipitates and concentrates
b
North wall of the visitor center showing dinosaur bones in bas
relief, just as they were deposited 140 million years ago.
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