Exam 3 part 4 Flashcards
Besides sewage, what are 4 other types of ground water contamination?
1) Highway salt
2) Fertilizers
3) Pesticides
4) Chemical and industry materials
Is ground water acidic?
It is mildly acidic due to carbon acid that it gets from decaying plants and rainwater that dissolved carbon dioxide in the air
What is hard water?
water with a lot of calcium bicarbonate
What happens when carbonic acid reacts with the calcite of limestone in the ground?
It will create calcium bicarbonate
How are most caverns created?
After the water table has been lowered enough for these caves to appear, acidic ground water dissolves soluble rock at or just below the zone of saturation
Where do caverns form?
In the aeration zone
What are drip stones?
They are tavertine, calciate deposited as dripping water evaporates
What are dripstones called collectively?
they are called speleothems
What are stalactites?
They are the drip like stones that hang from the ceiling of a cavern
What are stalagmites?
They are tavertine that forms on the floor
Over time what do stalactites and stalagmites do?
they will form a column
what is karst topography?
Landscapes that have been shaped mainly by dissolving power of groundwater
What are 3 common features of karst topography?
1) Irregular terrain
2) Sinkholes
3) Striking lack of surface drainage (streams)
karst topography doesn’t seem to have streams, why?
They are underground
What are the two basic cycles of glaciers?
1) Rock cycle
2) Hydrologic cycle
What is a glacier?
A thick mass of ice that orginates on land from the accumulaction compaction and recrystallization of snow
Why don’t we have glaciers if we do have snow and it does get cold?
Because the cold and the snow need to be perennial
What are the two major types of ice glaciers?
Alpine (Valley) glaciers and Continental (Ice sheet) glaciers
What is an Alpine/Valley glacier?
It is a glacier that forms in mountainous areas, they flow downwards a valley from an accumulation center at its head
What is a Ice sheet/continental glacier?
It’s a glacier that is much larger than an alpine/valley glacier, they flow in all directions from one or more snow accumulation centers
What are two major ice sheets in the world?
Greenland and Antarctica
Both deltas and alluvial fans reflect deposition due to a drop in stream velocity, true or false?
True
A descending mass moving as a viscous turbulant fluid is?
A flow
A streams _____ is the key to its ability to erode, transport, and deposit material?
Velocity
The driving force for mass wasting is?
Gravity
How much of the world’s water is held in glaciers?
Slightly more than 2% of the world’s water is tied up in the glaciers
If all of the ice melted how much would the sea level rise?
60-70 meters would rise
Where do glaciers form?
They form in areas where there is more snow in the winter than what melts during the summer
What are the three steps to the formation of glacial ice?
1) Air infiltrates the snow (Making porosity)
2) Snow flakes become smaller, thicker and more sphere like (Firn)
3) Air is forced out
What is firn?
It is snow that has recrystalized into a much denser mass of smaller grains, which is firn
At what point does firn become glacial?
Once the thickness of the ice and snow exceeds 50 meters it fuses into a solid mass of interlocking crystals
How can you tell how old a glacial mass is?
Once the firn becomes interlocking ice crystals, gas gets trapped in the process and buried over time, this can determine the age of the ice mass
How is glacier movement referred to? and how many types are there?
As a flow.
1) Plastic flow (Movement within the ice itself, plastic like, below zone of fracture)
2) Basal slip (Ice moves along rock. Thought to be how most glacial ice moves
What is the zone of fracture?
It’s the top half of the glacial ice. The top 50 meters, where it’s brittle and is carried along the bottom half which has a more plastic like nature.
How quickly do glaciers move?
It depends, they could move so slowly that roots in trees can form and others could move several meters a year.
What are surges?
When a glacial ice structure has an extremely rapid movement.
What is the zone of accumulation?
It’s where the area of the glacier forms, where the snow falls.
What is the zone of wastage?
The area where there is a net loss to the glacier due to
1) Melting
2) Calving (The breaking off of large pieces of ice)
Where does most calving occur?
Where the glacier has reached the sea
What is the glacial budget?
The balance or lack of balance, between accumulation at the upper end of the glacier and the loss at the lower end.
If there is more accumulation than there is loss, what happens?
the front (Accumulation end) will advance forward.
What is ablation?
The loss of the glacier
What are the two ways that glaciers can erode land?
1) Plucking (Lifting of rocks)
2) Abrasion (Rocks within the ice act like sandpaper to smooth and polish the surface below
What are eratics?
A rock or piece of sediment that ends up where they couldn’t have possibly originate (Because of glaciers)
What is rock flour and glacial striations?
Rock flour is produced by glacial abrasion (Pulverized rock) and glacial striations are grooves in bedrock
What are the 3 different types of landforms created by glacial erosion?
1) Glacial trough (V shape going into a U after water freezes to ice then unfreezes)
2) Truncated spurs (Triangular cliffs)
3) Hanging valleys (Frozen water falls)
What is glacial drift?
Refers to all sediment of glacial origin
What are 2 types of glacial drift?
1) till: Material that is unsorted and deposited directly by the ice
2) Statified drift: Sediment laid down by glacial melt water
What is a lateral moraine and what is a medial moraine?
a lateral moraine is when the ridges of till are parallel to the sides of the valley, a medial moraines form when the lateral moraines merge
What is a ground moraine?
Ground moraines are till-covered areas with irregular topography and no ridges, often forming gently rolling hills or plains.
What are drumlins?
They are made of till, smooth parallel hills, steep side faces the direction which the ice advanced, occurs in clusters
What are outwash plains?
made by stratified drift and are deposited by melted water leaving a glacier at the edge of moraines
