Describe and explain at least two lines of evidence that Alfred Wegener used to support his theory of continental drift and why was his theory rejected for so long?
1. Identical rocks. Same type, same age, found on both sides of the Atlantic Ocean. 2. Ancient fossils. Same species, same age, but on continents that are now widely separated. It had been rejected because no one could figure out what force had propelled
Describe the fundamental differences among divergent, convergent and transform plate boundaries.
Convergent plate boundary=two plates are moving toward each other; forms volcanoes. Divergent plate boundary=two plates are moving away from each other; results in seafloor spreading. Transform Plate Boundaries=two plates slide past one another; forms und
Briefly describe the differences among the P waves, S waves and surface waves of an earthquake.
P waves: travel through fluids, and solids, fastest seismic waves, rely on compression strength. S waves: depend on the shear strength of the material, think of the ripples that occur as you flick a slinky. Surface waves: similar to ocean waves, only occu
Why do areas far away from the epicenter sometimes experience greater damage during an earthquake than areas closer to the epicenter?
The epicentre of an earthquake is the point on the Earth's surface directly above the point within the Earth where the earthquake actually occurred (focus). From this point on the surface the waves of the earthquake radiate outward like the ripples in a p
Distinguish between weathering, mass wasting, and erosion.
Weathering: If a particle is loosened, chemically or mechanically, but stays put. Erosion: Once the particle starts moving. Mass wasting: is simply movement down slope due to gravity.
What are the general differences between mechanical weathering and chemical weathering.
Chemical weathering: chemical change in the minerals within a rock. Mechanical weathering: physically breaking rocks into fragments.
What roles do rock openings play in weathering?
Openings in rocks allow for the wind and weather to get inside and erode the surface. In areas where the temperatures get below freezing, water gets inside a crack of a rock and when it freezes it expands until the rock cracks, eventually the rock splits
What factors influence the erosional effectiveness of a stream?
Rainfall=more rain more erosion. Slope=the steeper the slope the faster the water will flow. Geology=if the bedrock is a soft silt it will erode faster than granite.
What are some of the negative consequences of using artificial levees for flood control along a major river?
Artificial levees can lead to an elevation of the natural river bed over time. need constant maintenance. if the lev�es are breached, it is even more difficult to pump the water out because the lev�e then serves as a barrier stopping the water from return
How does the underground structure of the bedrock influence the dissolution process?
Bedrock, made of carbonate is more susceptible to being dissolved because the rock is more easily broken down.
How can groundwater pumping by people lead to sinkhole formation?
Pumping out groundwater removes water from an aquifer reducing the volume of sand and gravel this leaves underground holes which lead to sinkholes.
Why is there a scarcity of surface streams in karst areas?
A karst region has an absence of surface water flow mainly because rainfall and surface waters disappear into a drainage system produced in karst areas.
Briefly explain the eruption sequence of a typical geyser.
Groundwater seeps into the geyser's reservoirs where it is heated by magma to its boiling point. Deeper water turns into steam, forcing a mixed jet of water and steam through the geyser's surface vent.
Describe at least two conditions in deserts that tend to increase the likelihood of fluvial erosion whenever it does rain.
River's are continually picking up and dropping solid particles of rock and soil from its bed throughout its length. When a river flow is fast (during flash floods), more particles are picked up than dropped equally throughout the length of the bed. A mov
Why are playas so flat and level?
The surface of the playa used to be the bottom of a lake. Sediments settled at the bottom, and after the water sank into the water table, salt was left over. This inundation of water coupled with wind erosion does the rest.
What are some effects of wind on desert landforms?
Winds move sediment across the desert changing the direction of a sand dunes face. Wind loaded down with sand-sized particles weathers down the surface of rocks. Wind carrying silt deflates an area by leaving behind pebbles and larger sediments.
What causes glaciers to grow larger or become smaller?
Glaciers grow and shrink in response to changing climate. Glaciers form when snow remains in the same area year-round, is compacted than turns into ice. The weight of the ice then causes the glacier to flow downhill from its point of origin. Global warmin
Why is it difficult to know if the Pleistocene glaciations are over or if we are currently just in an interglacial period?
Because not enough time has past to collect data, the last Ice Age occurred 11,000 years ago. Some scientists believe that an increase in global temperature, as we are now experiencing, could be a sign of an impending ice age and increase the amount of ic
What will likely happen to a down current beach when a major river flowing into the ocean is dammed? Why?
Dams well inland from coastal systems can directly affect the coastal zone by blocking sediment supply to beaches causing enhanced down current erosion.
How do groins and jetties typically affect the beaches around them?
Jetties and groins are structures designed to control sand movement. For example, if an ocean current is running from right to left, and a jetty protrudes straight out, the sand will be deposited to the right of the jetty, eroding away the left hand side.