What do the terms flow and basal slip mean?

What is the difference between plastic flow and basal slip?

Plastic flow involves movement within the ice, whereas basal slip involves the entire ice mass slipping along the ground. Plastic flow occurs in the deeper parts of the ice mass, whereas basal slip occurs at the base of the glacier only.

What is a basal flow?

The basal part is a hyperconcentrated flow with a laminar regime and the upper part is a more dilute flow in which turbulence progressively develops. It corresponds to the coarse-grained turbidite depositional sequence of Nardin et al. (1979).

What is basal slip in geography?

Basal slippage (or sliding) is the act of a glacier sliding over the bed due to meltwater under the ice acting as a lubricant.

What does glacier flow mean?

In simple terms, for a glacier to maintain a state of equilibrium, glacier flow is required to balance inputs and outputs to the system. Glacier motion facilitates the transfer of ice from the accumulation zone (where mass gain is dominant) to the ablation zone (where mass loss is dominant).

What causes basal slip?

basal slip: when a thin layer of water builds up at the ice-rock interface and the reduction in friction enables the ice to slide forward. enhanced basal creep: ice squeezes up against a large (>1m wide) bedrock obstacle the increase in pressure causes the ice to plastically deform around the feature.

Are drumlins layered?

Drumlins may comprise layers of clay, silt, sand, gravel and boulders in various proportions; perhaps indicating that material was repeatedly added to a core, which may be of rock or glacial till. Alternatively, drumlins may be residual, with the landforms resulting from erosion of material between the landforms.

What does a drumlin look like?

Whilst there are many variations in shape, the “classic” drumlin is a smooth, streamlined hill that resembles an egg half buried along its long-axis. They tend to exist as fields or swarms of landforms rather than as isolated individuals, with a typical swarm comprising tens to thousands of drumlins.

What are sunken drumlins?

Drumlins are elongated, teardrop-shaped hills of rock, sand, and gravel that form from the movement of glaciers, according to the National Snow and Ice Center. They are typically oblong, two or three times longer than they are wide.

How can you tell a drumlin?

Drumlins are generally found in broad lowland regions, with their long axes roughly parallel to the path of glacial flow. Although they come in a variety of shapes, the glacier side is always high and steep, while the lee side is smooth and tapers gently in the direction of ice movement.

What can drumlins help determine?

Glacial geologists frequently use these swarms of drumlins in palaeo-ice sheet reconstruction, because they can be directly related to the direction of former ice flow. They can therefore be used to reconstruct the dynamic behaviour of former ice sheets (Livingstone et al., 2010; Livingstone et al., 2012).

Are drumlins stratified?

Drumlins may be composed of layers of till (sediment deposited by a glacier), frequently clay-rich, in which the pebbles are oriented subparallel to drumlin elongation and the direction of ice flow, although many drumlins have cores of stratified sand, boulders or bedrock.

What is the difference between drumlins and eskers?

As nouns the difference between drumlin and esker



is that drumlin is (geography) an elongated hill or ridge of glacial drift while esker is a long, narrow, sinuous ridge created by deposits from a stream running beneath a glacier.

What is the difference between a kame and an esker?

Quote from video:These are the formation of Kames a came is deposited mound of sediment left in the path of a retreating glacier firstly rock falls onto the valley on top of the glacier.

What is drumlin esker and kame?

Drumlins: elongated egg-shaped hills. Kames: dumpling shaped hills. Eskers: long sinuous hills, snake shaped. Follow this answer to receive notifications. answered Apr 14, 2020 at 1:37.

What is a kame in geology?

kame, moundlike hill of poorly sorted drift, mostly sand and gravel, deposited at or near the terminus of a glacier. A kame may be produced either as a delta of a meltwater stream or as an accumulation of debris let down onto the ground surface by the melting glacier.

What is kettle in geology?

Kettles form when a block of stagnant ice (a serac) detaches from the glacier. Eventually, it becomes wholly or partially buried in sediment and slowly melts, leaving behind a pit. In many cases, water begins fills the depression and forms a pond or lake—a kettle.

What do kames look like?

Kame terraces are frequently found along the side of a glacial valley and are stratified deposits of meltwater streams flowing between the ice and the adjacent valley side. These kame terraces tend to look like long, flat benches, with many pits on the surface made by kettles.

What is a hanging valley in geology?

Definition: Glaciers form U-shaped valleys through erosion. Hanging Valleys are found high up on the sides of larger U-shaped valleys. Hanging valleys begin as corries, but over time, more and more erosion creates an elongated corrie or a small U-shaped valley.

What is a glacier horn?

Horns are pointed peaks that are bounded on at least three sides by glaciers. They typically have flat faces that give them a somewhat pyramidal shape and sharp, distinct edges.

Why do hanging valleys form waterfalls?

The rivers formed due to melting of the glaciers flow through these glacial valleys. The water pouring in from the tributary glacial valleys into the main valley jumps downwards due to difference in elevation, thus creating waterfalls.

Is Yosemite a hanging valley?

Examples Of Hanging Valleys



Some hanging valleys in the region are Bridal Veil Falls, Ribbon Falls, and the Yosemite Falls. The latter has a vertical drop of 2,425 feet, the highest in the state and among the highest in the country.

What is a V-shaped valley?

BSL Geography Glossary – V-shaped Valley – definition



A V-valley is formed by erosion from a river or stream over time. It is called a V-valley as the shape of the valley is the same as the letter “V”.

What do you mean by U-shaped valley?

Definition: U-shaped valleys form through glacial erosion. Glaciation develops in established v-shaped river valleys where the ice erodes the surrounding rocks to create a “U” shaped valley with a flat bottom and steep sides. Glacier movement is driven by gravity.

What is a flat floored valley?

Flat-Floored Valley



These valleys, like V-shaped valleys, are formed by streams, but they are no longer in their youthful stage and are instead considered mature. With these streams, as the slope of a stream’s channel becomes smooth, and begins to exit the steep V or U-shaped valley, the valley floor gets wider.

What is the difference between U and V-shaped valleys?

Glacial erosion causes the formation of U-shaped valleys, whereas V-shaped valleys are the result of carving by the rivers through their course. U-shaped valley walls are straighter than V-shaped valleys due to the non-bending glacier’s movement. Glaciers do not get influenced easily by rock hardness as are rivers.