Geology Quiz 4: Chapters 7-8 Flashcards
Define volcanism
the eruption of molten rock (magma) onto the surface of the earth
Define escarpment
a steep slope or long cliff that occurs from erosion or faulting and separates two relatively level areas of differing elevations
How was Grand Canyon formed?
At the end of Noah’s flood it appears that a great volume of water was trapped, held in place by the Kaibab Upwarp. Ice Age rains filled the lake to overflowing and as it burst through its mountain “dam,” the huge volume of lake waters carved the canyon.
What causes the geysers in Yellowstone Park?
The soil and rock is thin, allowing very hot material to be near the surface. As rain and run-off water trickle down into the earth they get heated, bubbling up in places as hot springs. In some places the underground water is rapped and when heated to an excessive degree, it bursts out in a geyser.
How did Niagara Falls form?
The level of water in Lake Erie is somewhat higher than the elevation of nearby Lake Ontario. A river draining the waters of Lake Erie into Lake Ontario runs over the Niagara escarpment, resulting in a spectacular set of falls. Erosion takes place as the water roars over the falls, and the escarpment naturally receds toward Lake Erie.
Why are the Appalachian and Rocky Mountains so different?
Both mountain chains are the result of layers of sediments deposited by Noah’s flood. The Appalachians buckled up in the early stages of the flood and were subjected to massive erosion by the continuing flood waters. The Rocky Mountains buckled up late in the flood, extending up above the flood waters as the waters drained off. Thus the erosion to which they were subjected was much less intense.
How long does it take to form petrified wood?
Petrified wood can form, under laboratory conditions, in a very short period of time. The speed of petrification is related to the pressures which inject the hot silica-rich waters into the wood.
How are stalacites and stalagmites formed?
When water saturated with calcium carbonate enters an open space such as a cave, it cools off or evaporates, leaving the calcium carbonate behind. Stalactites (holding “tightly” to the ceiling) and stalagmites (which are usually larger and thus more “mighty” than stalactites) are formed as this calcium carbonate precipitates out of the water.
How is coal formed?
Coal can be formed in a laboratory by heating organic material away from oxygen but in the presence of volcanic clay. Under such conditions, coal can be formed in a matter of hours. One wonders if the abundant forest growing before the flood would not have formed huge log mats floating on the flood ocean. As these decayed and were buried by hot sediments in the presence of volcanic clay, they might have rapidly turned to coal.
How is natural gas formed?
Natural gas, mostly methane, is given off in the coalification process. The largest quantities of it, however, are found in deep rocks not associated with decomposition of organic material. Evidently, some natural gas is from both organic and inorganic sources.
How is oil formed?
Many theories have been promoted as to the specific origin of oil. The best seems to be that it is the remains of algae once floating in the ocean but buried in ocean sediments. Oil is not the remains of dinosaurs as has sometimes been claimed.
Are dinosaur fossils the most abundant type of fossil?
No - they are rare. Most fossils are of sea creatures, fish, and insects. Only relatively few fossils are of land animals, specifically dinosaurs.
