GEOL 1300 Self Quiz #15
massive natural clams have formed in the gran canyon, causing the colorado river to swell into big lakes, what caused the dams?
lava flows
the "basement rocks" of the grand canyon are igneous and ______________ rocks
metamorphic
what type of unconformity is the "Great Unconformity" in the Grand Canyon?
nonconformity
the grand canyon is in _____________
Arizona
the "great unconformity" of the grand canyon represents at least _________ of missing time
a billion years
how long did it take for the Colorado River to carve out the Grand Canyon
about 6 million years
most of the sedimentary rocks above the grand unconformity were deposited ______________
by marine waters
what rock unit from the grand canyon was deposited in a desert, unlike the most other rocks in the canyon walls
coconino sandstone
T/F: dinosaur fossils are found in the sedimentary rock layer sitting on top of the "great unconformity"
false
the rocks above the great unconformity are ___________ in age, but the rocks below the unconformity are precambrian in age
paleozoic
in the grand canyon, shales tend to form _______________ on the walls of the canyon
sloping surfaces
what sedimentary bed lies immediately on the top of the "great uncomformity"?
tapeats sandstone
who was John Wesley Powell
the first geologist to study the canyon and boat through the canyon
T/F: volcanoes have been erupting on the edges of the Grand Canyon off and on for 2 million years
true
