CHAPTER 13-Glaciers and Glaciation
What is a glacier?
It is a persistent mass of ice moving slowly over land.
What are two essential things a region must-have for a glacier to form?
Cold local climate
Abundant of snow
What is the difference between an alpine glacier and a continental glacier (ice sheet)? (Think size and location)
Continental glaciers cover a large mass of land around the earth poles, whereas alpine glaciers cover small land areas in mountain valleys.
What is basal slip?
It is a process in which a temperate glacier slides on the terrain lubricated by water availability.
What is plastic flow?
Plastic flow refers to a stream of fluids where movement is proportional to the force applied.
Define the following terms
Zone of accumulation
It is the part of the glacier in which there is buildup snow that turns to ice and comes out from as water.
Zone of ablation
It refers to a zone in which ice mass loss is relatively higher than its accumulation.
Equilibrium altitude line (aka snowline)
It is the boundary occurring between snow-covered and a snow-free surface
How does the zone of accumulation, zone of ablation, and snowline relate to each other?
The snowline keeps the ablation zone apart from the higher attitude accumulation zone.
What is the end of a glacier called?
Terminus
What shaped valley do glaciers form?
U-shaped
What shaped valley do rivers form?
V-shaped
Describe the difference between till, drift, and stratified drift?
Drift is a segment of glacial origin. A stratified flow is a sediment laid down and relatively well sorted by glacial meltwater, whereas a till refers to unsorted sediment deposited directly by ice.
What is an erratic?
It is a boulder that has been moved and deposited by a glacier having a lithological difference with the bedrock in which it lies.
Name and define two different types of moraines?
Lateral moraine is a type of moraine deposited on the sides of the glacier in a glaciated land.
Terminal moraine-this refers to the moraine found at the endpoint that the glaciated stream.
What is a drumlin?
It refers to an elongated hill formed through streamlined movements of glacial ice sheets across the till
Define the term glaciation.
It is a state in which the moving ice covers a dry land.
How many glaciations have there been in the last billion years? When did the most recent glaciation begin? When did the most recent glaciation start to end?
Three glaciations
The most recent glaciation started around 12800 years ago.
The glaciation ended around 11550 years ago.
Name and define the three different parts of the Milankovitch cycles?
Eccentricity
It is the measurement of earth shape deviation from being a circle
Axial tilt
It refers to the measurement of axis angles to a perpendicular line on the earth plane of orbit.
Precession
Refers to long nights and long days experience at certain times of the year.