Glacial sediment is extremely heterogeneous. It typically displays great lateral and vertical variations in thickness, composition, texture, sedimentary structures, and mode of origin. Glacial sediment can be divided in two general categories: till and stratified sediment.

Till is defined as " a sediment that has been transported and is subsequently deposited by or from glacier ice, with little or no sorting by water". It is material that was released from glacier ice usually by melting and was deposited without significant transportation or sorting due to water or gravity movements.

Several general observations may be given about the occurrence of till

• Deposition of till must postdate erosion or deformation of the underlying substratum; most till was probably deposited late in the glacial cycle; the law of superposition applies to till as well as to other glacial sediment.
• Till is a mixture of anything and everything over which the ice moved, including: bedrock, older till and sediment, weathered material, soil, plant fragments, and animal remains. Till is dominated at any spot by material of local origin; the content of local material generally decreases upward in a till sequence
• Multiple till layers are common in the outer zones of glaciation. However, owing to different mechanisms of till deposition and changing ice movements, separate tills do not always indicate separate glaciations. Periods of glacier withdrawal are shown by buried soil, peat, weathered zones, fossils, permafrost features, etc

(63) Answer:

At the younger stage of a stream different size and shapes of hard rock particles are added to the flow due to rapid mechanical weathering action. These particles have sharp edges at the very beginning of its formation. However, intensive mechanical weathering action at the younger stage of a river causes to remove sharp and irregular edges of such partials mentioned above with the long distance of their travel in the flow path. This is mainly due to the action of mechanical erosion at the early stages of the river flow. Finally, mechanical weathering of the long distance transported particles cause to produce well rounded particles with smooth surfaces.

(62) Answer:

If we take the cross section of the meander, out side of the curve of meandering channel has a high flow velocity than its inner side curve and tend to produce turbulent flow at the outer side of the meander. Therefore at the outer side of the curve experience more erosion. Because the turbulent flow causes to erode the bank including the bottom of the stream, under the conditions of the mechanical weathering. By the way at the inner side of the meandering curve, sediments of the stream flow tend to settle at its bank. Due to such sediment deposits, further decrease of flow velocity will be taken place.

Answer for Q (61):

Type 1 - This diagram shows younger stage of the river flow. Because it tends to form “V” shaped valley with steep sides of its flow path. It is due to erosion of its bed more rapidly than it erodes its bank. Further it has almost straight flow path. It does not consist of deposition of sediments. These all are due to high velocity of river flow under the highest gradient condition than older and younger stages of a river flow.

Type 2 - It indicates older stage of a river flow. According to the diagram the river flows, forming very broad valley with flat plain. The broad flat plain formed mainly due to sedimentation process and erosion of valley walls of the river at its older stage.Additionally at this stage the river carryout large amount of sediments with its flow and it causes to decrease the stream flow velocity at this stage of flow. Further, river has significant meanders and tends to form oxbow lakes on its flow path. This is due to decrease of flow velocity under the lowest gradient conditions of the main river comparatively with other two stages (younger & mature) of the river flow.

According to the above explanation given under the Type 1 and Type 2, it can that the find difference of stream velocities with relate to different ages of stream formation. Therefore type 1 that the stream at younger stage, it has higher average flow velocity than the older age is represented by the type 3.

Answer:

X- 44.5^oN and 73.7^o W

(44) Correct answer: Option (1)

If we are starting to work from the A to B on the given line, we can find following observations.

1. We find the lake in between the contour of 900 feet elevation. Therefore in the cross section, it should be indicated the depression with gentle slope. Because the lake is find within the same elevation contour line.

2. Then elevation is gradually increases from the level of 900 to 1600 feet (height difference = 700 feet). However, the contours are drawn showing the considerable space in between each of them. It gives idea that the slope does not change rapidly on its elevation.

However, the slope from X to B has rapid change of its elevation. There is same elevation different (1600 to 900 feet = 700feet) at that slope, but contours drown more densely within that same elevation deference. It means changing of the elevation is more rapid than other side of the slope (A to X). Therefore in the cross-section this slope is indicated more sharply than the other slope.

(43) Correct answer: Option (2) 250 ft/mi

Steps of the calculation

Slop (gradient) = Vertical distance/Horizontal distance

Also known as rise (vertical distance) and run (Horizontal distance)

Since contour interval is = 100m

Vertical distance = Height of the higher elevation point (C) – Height of the lower elevation point (D)

(Rise)

= 1500 – 1000 = 500m

Horizontal distance = given line represent the distance along the hill slope where it is needed to calculate the slope. According to the scale given, we have to obtain horizontal distance.

Length between C-D is 2 units (use a ruler to find out this length).

According to the scale, 1unit = 1Km. So distance between C-D is = 2Km

Slop = 500feet/2mile = 250ft/mi

(42) Correct answer: (4)

According to the diagram, we can find the contour intervals as 100 feet

The point X is located in the 1600 feet contour line and there is no other contour line within that elevation zone. Therefore height of any point can be varied in the elevation rang between 1600 to 1699 feet. So, the possible highest elevation in this zone will be 1699 feet.

This stream pattern can be identified as Trellis (or some time calls as

Espalier) according to the geological stream pattern categorization. This stream pattern has a network of parallel or sub parallel streams that is resulted due to strong structural events of geology such as tight regional folding. Tight regional folding followed by alteration of hard and weak formations of underline bedrock structure cause to form ridge and valley geomorphology similarly depicted in the diagram number 04. In such geomorphological condition, streams align themselves in the valleys parallel to ridges with minor tributaries coming almost at right angles through weathering of weak structurally control bedrock units

Important points to stress include:

There is another stream network system that named as Rectangular stream pattern which one can observe very similar to Trellis stream pattern. However, it is significant that the rectangular stream pattern tend to develop where the areas common with tectonic faults or bed rock joints. In this pattern, the tributary streams make more shape bends and enter the main stream at high angles than in Trellis stream pattern.

Based on these arguments, the rest of the options are incorrect

Correct Answer: Option 1 – 1.4%

The time scale is depicted in its traditional form with oldest at the bottom and youngest at the top - the present day is at the zero mark. (See figure below).

The age of the earth is four thousand, six hundred million years old (4,600 million = 4.6 billion), Cenozoic era represent the 65 million years through today. It is approximately 1.41% of the estimated age of the earth