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Geomorphological studies of the Himalayan in brief: Geomorphological Facts

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Pradeepika Kaushik Banasthali University

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Page No. PREFACE i

ACKNOWLEDGEMENTS ii CHAPTER-I AND ITS GEOMORPHOLOGY 1-5

1.1 Geomorphology of Glacier and its Origin 1 1.2 Glacier Movement 3 1.3 TheIceAge 4

CHAPTER-II DISTRIBUTION OF GLACIERS 6-12

2.1 Distribution of Glaciers aroundthe World 6 2.2 Distribution of Glaciers in Indian Himalayan Region 7

CHAPTER-III CLASSIFICATION OF GLACIERS 13-19

3.1 Classification of Glaciers 13 3.2 Glaciers Classification Based On Different Features 16

CHAPTER-IV GLACIERS SURFACE FEATURES 20-29

4.1 20 4.2 Ablationzone 21 4.3 Snout 21 4.4 Other glacier surface features 22

CHAPTER-5 GEOMORPHOLOGICAL GLACIAL LANDFORMS 30-45

5.1 Erosional Processes 31 5.2 Erosional landforms 33 5.3 Depositional landforms 40 5.4 Glacio-Fluvial landforms 42

CONCLUSIONS 46 REFERENCES 47 PREFACE

During the past decades rapid physical and chemical changes have taken place in glaciers of the Himalayan region. Hence, scope of studies of different geomorphological glacier features and landforms ie. erosional and depositional have been erased. The geomorphology of Himalayan glacier is changed due to different physical agent such as temperature, pressure, climatic factor etc. The present project deals with the

“GEOMORPHOLOGICAL STUDIES OF HIMALAYAN GLACIERS”. Work addresses the different climatic and physical factors which have been involved for the formation of different geomorphogical features of glaciers and its formations. Present study would be helpful to deciphering the importance of glaciers and its behaviour in respect of environmental and climate impact within the global context. Although detailed geomorphological studies of the Himalayan glaciers have not been studied due to short duration of time, but I hope that this project work is short summary to understand the basic geomorphological features of the Himalayan glacier region.

i ACKNOWLEDGEMENTS  It is my pleasure to express my deep sense of gratitude and thanks to my external guide, Shri Deepak Srivastava, Consultant (Centre for ) and Dr. D.P. Dhobal (Scientist-D) at Wadia Institute of Himalayan Geology, Dehradun for providing me the necessary infrastructure facilities, his valuable guidance, suggestions, whole hearted co-operation and supervision. I am greatly indebted, Professor Prof. Anil Kumar Gupta, director of Wadia Institute of Himalayan Geology for providing me the possible facilities. I wish to express my deep sense of overwhelming gratitude to Prof. U.C Singh, Head, School of studies in Earth Science, Jiwaji University, Gwalior who inspired me to carry out this project work. His critical suggestions at every step, especially at the completion of this project work, helped me in completing the work effectively. I am greatly thankful to Dr.Manish Mehta Research Associate, their suggestions and guidance at every stage of the work. I am also thankful to Mr.Amit Kumar Walia and Mr. Rakesh Bhambri, research associate for their suggestions at every stage of the dissertation work. I owe my sincere thanks to all Junior Research Fellow Mr.Bhanu Thakur, Mr.Akshay Verma, Mr. Amit Kumar, Mr. Kapil Kesarwani, Miss Harika Munagapati, Mr. Priyeshu Srivastava for their invaluable support & moral help. I specially thanks to my loved one Dr.Santosh K Pandey. I heartly thankful to my work mate Miss Azra Irshad, Laitonjam Hemanjit Singh, Thangjam Rahul Singh for their support, suggestions and help for the preparation of this dissertation work. At last but not the least, I feel highly obliged by my Father Late. Mahesh Chandra Kaushik, and my Mother Late. Lata Kaushik, and my Sisters and Brother who are great source of moral support to me and without their encouragement and blessing, this work would have not taken the present shape.

PRADEEPIKA KAUSHIK

ii Chapter I GLACIER AND ITS GEOMORPHOLOGY

1.1 Geomorphology of Glacier and Its Origin Geomorphology (Greek word) means the “Science of earth landforms” which is formed by different process of different agency i.e.: River, Wind, Glaciers etc. Glaciers are receding and advance in yearly but behind it left some features on earth surfaces. These features are study in geomorphology. Geomorphology is the scientific study of landscapes and the processes that shapes them. The science of geomorphology has two major goals. One is to organizes and systematize the description of landscapes by intellectually acceptable scheme of classification. The other is to recognize in landscape evidence for changes in the processes that are shaping and have shaped them. The scientist who describe the analysis, systematic description, and understanding of landscape and the processes that change them are Geomorphologists. According to Geomorphologist the Glacier “is a consequence of ice age” or it is mass of ice which moves downwards under the impact of gravity and must have different dimension. Glaciers are formed due to accumulation of snow at earth surface. Snow line is a line between permanent and seasonal snow. About 10% of earth surfaces are now covered by glaciers. Glaciers are formed by the long process of dynamic and thermal metamorphism on snow.

Conversion of Snow into Ice Ice is both a mineral and rock, which under the temperature and the earth surface is exceptionally unstable. Wherever water freeze under the lakes, the sea, the atmosphere, and the ground. The resulting kind of ice has distinctive characteristics. And the most distinctive and remarkable kind is glacier ice. The snow has low specific gravity and high porosity. These properties together with irregular shapes of flakes. Snow exchange moisture readily with the adjacent air, at low temperature by sublimation, at higher temperature, near the melting point, by evaporation. As the snow flakes gradually change shape, and cluster of them are converted into nearly spherical grains, settles and become more compact.

1 If this compaction continues, air is forced out from the diminishing intergranular space. When permeability to air becomes zero and converted to ice. These changes are occurring when density has increased about 8.3 normally the density of glacier ice varies, from 0.8 to 0.9.

Fig. 1: Conversion from Snow to Glacier ice

The time required for the conversion of snow into ice varies with the rates of accumulation of snow and with temperature is estimates to range from 1 year to 300 years or even more and the depth at which conversion to ice become complete also varies greatly. If the temperature becomes so high then granular snow become to melt and percolating in downward direction. When the glacial ice is formed then it has various thickness at various location .The average thickness of is around 2 km for large ice sheet with maximum thickness is 4.2 km (Antarctica ice sheet). The aggregate volume of glacier ice in the northern hemisphere was roughly twice that in the southern .This difference arose from the fact that Antarctic ice could not spread far beyond the Antarctic continent .It broke up in the ocean and floated away. As, In the Antarctic ice sheet, it reaches large value more than 150m in some places. In North America and Eurasia, ice sheet is far more ample space for spreading over land areas. The position and extend of the farmer ice sheet are known because the recognizable effect of thick ice spreading over the land have been observed in detailed and carefully mapped. Such effect include scouring and rupture of bedrock, and

2 deposition of non sorted rock particle to form broad layers of glacial drift spread over the surface. Direction of flow of the ice masses is consistently shown by a variety of linear features. Layers of glacial sediments and non glacial sediments in some places containing fossils are widespread on the land.

1.2 Glacier Movement As we know that the glaciers are move yearly .Those which are not moved then we do not called it glaciers. It is called pure ice and its inactive and when the pressure of overlying debris are more on ice field then the movement is start and is called Glaciers. Ice behaves like an easily breaking solid until its thickness exceeds about 50 meters (160 ft). Below that depth the increased pressure causes ice to become plastic and flow. The glacial ice is made up of layers of molecules stacked on top of each other with relatively weak bonds between the layers. When the stress exceeds the inter-layer binding strength, the layers start to slide past each other. Another type of movement is basal gliding. In this process, the whole glacier moves over the terrain on which it sites, lubricated by melt water. As the pressure increases toward the base of the glacier, the melting point of water decreases, and the ice melts. Friction between ice and rock and geothermal heat from the Earth's interior also contribute to thawing. This type of movement is dominant in temperate glaciers. The top 50 meters of the glacier are more rigid. In this section, known as the fracture zone, there are no layers which slide past each other; instead the ice mostly moves as a single unit. Ice in the fracture zones moves over the top of the lower section. When the glacier moves through irregular terrain, cracks form in the fracture zones. These cracks can be up to 50 meters deep, at which point they meet the plastic flow underneath that seals them.

Velocity of Glacier Movement The speed of glacial displacement is partly determined by friction. Friction makes the ice at the bottom of the glacier move slower than the upper portion. In alpine glaciers, friction is also generated at the 's side walls, which slows the edges relative to the center. This has been confirmed by experiments in the 19th century, in

3 which stakes were planted in a line across an alpine glacier, and as time passed, those in the center moved further. Mean speeds vary; some have speeds so slow that trees can establish themselves among the deposited scouring. In other cases they can move as fast as many meters per day, as is the case of , an overflowing glacier in Antarctica which moves 750-800 meters per year (some 2 meters (6 ft) per day), according to studies using satellites. Many glaciers have periods of very rapid advancement called Surges. These glaciers exhibit normal movement until suddenly they accelerate then return to their previous state. During these surges, the glacier may reach velocities up to 1000 times greater than normal.

1.3 The Ice Age

In 4.6 billion year history Earth was experienced to more than 4 major glaciations (i.e. Pleistocene 3 ma, Permian 250-220 ma Ordovician 450 ma, Precambrian (Snowball Earth) 900-650 ma) and several miner glaciations. When the glacier is growing its know as glacial period and the glacier are reduced their volume is intra glacial period. The recent glacier period was Last Glacial Maxima (LGM), when the glacier was covered by 30 % of the Earth surface area. The LGM was started from early quaternary and ended 10000 year before present, in between these periods the Earth was witness for 20 glaciations (Raina and Srivastava 2008).

Fig. 2: Total 30 % of the world area covered by snow during the winter. This figure assumes the maximum concentrati on of Ice was during the past glaciation.

4 Earth seems to have alternated between “Icehouse” and “Greenhouse” episodes the last ice age ,which ended approximately 10,000 year ago 30 % of the Earth land area was covered with glacier .At present glacier cover roughly 10% of the land area.

Glacial Chronological of Quaternary Ice Age

It has been postulated on the basis of study of cores of oceans sediments and vast loess deposits during the quaternary ice age .In this ice age more than 20 glacial cycles may have occurred (Table 1).

Table 1: Glacial chronology of the Quaternary period

Total Span Period 0-15 Interglacial 15-65 Glacial worm 65-125 Interglacial 125-180 Glacial rises 180-230 Interglacial 230-300 Glacial minded 300-330 Interglacial 330-470 Glacial guns 470-540 Interglacia l 540-550 Glacial 550-585 Interglacia l 585-600 glacial 600-2MY About20 glacialadvances

2MY- Beginning of Pleistocene

5 Chapter II DITRIBUTION OF GLACIERS

2.1 Distribution of Glaciers around the World

At present, the total area of the world covered by Glaciers is about 14.9 million km2 (i.e. 10% of the world’s land area are covered by ice). Out of this, about 12.5 million km2 of glaciers is recorded for the Antarctic ice sheet and 1.7 million km2 is for the Greenland ice sheet. (Flint, 1971).

Fig. 3: Present distribution of Glaciers in the World (Fig by CFG)

In the Antarctic and the Greenland ice sheet, glacierization is accumulated in the Northern Hemisphere, for the most part on the island of the North Polar Basin and on the highland of the oceanic peripheries example the Atlas and the Scandinavia. Other highland of the middle and low altitude has appreciable ice cover area such as the Alps Karakorum and Himalayan ranges. In the southern hemisphere, glaciers are concentrated on the southern Andres and the Antarctic Peninsula. Thus between the two

6 major landmass, ice covered are discontinuous and no balance. (Hattersley-Smith, 1974; Østrem 1974b)

Table 2: Present day glacier extends. (Flint, 1971)

RegionA rea (km2) Total South Polar Region 1) Antarctic ice sheet 12,535,000 12,588,000 2) Other Antarctic glaciers 50,000 3) Sub Antarctic island 3,000 North Polar Region 1,726,400 1) Greenland ice sheet 76,200 2) Other Greenland glaciers 153,169 3) Canadian Arctic archipelago 12,016 4) Iceland 5) Spits Bergen and 58,658 Nordauslandet 55,658 2,081,616 6) Other Arctic island North American continent 1) Alaska 51,476 76,880 2) Other 25,404 South America cordillera 26,500

European continent Scandinavia 3, 600 1) Alps 1,805 2) Caucasus 61 3) Other 9,276

Asian continent Himalaya 1) K’um Lun chains 3,200 2) Karakorum and Ghujerab- 16,000 Khunjerab ranges 115,021 3) Other 12 African continent Pacific region (including New 1,015 Zealand) Grand Total 14,898,320

2.2 Distribution of Glaciers in Indian Himalayan Region

In India, the glaciers are restricted to the extra-peninsular area i.e. the Himalayas within the latitude 270N - 360N and longitude 720E -960E. Geological Survey of India

7 has revealed the existence of glaciers is to be 9,575, in which the part of Himalayas comprised the territories of and Kashmir, Himachal Pradesh, Uttarakhand, Sikkim and Arunachal Pradesh (Table 3). Total area covers by glaciers within these state is less than 40000km2.

Table 3: Distribution of Glaciers in India (Raina and Srivast ava, 2008)

StateNo. of glaciers Area (km2) % area Jammu & Kashmir 5262 29163 77.84 Himachal 2735 4516 12.05 Uttarakhand 968 2857 7.63 Sikkim 449 706 1.88 Arunachal Pradesh 161 223 0.6 Total 9575 37465 100

The Himalayas forms natural barriers between the southern India peninsula and mainland Asia, extending from Pamir Knot in the west and Arunachal Pradesh in the east with three parallel ranges the Himadri, the Himachal and the Siwalik. It is divided into three river basins namely the Indus, the Ganga and the Brahmaputra (Table 4). The Indus basin has the largest number of glaciers ~7,997, whereas the Ganga basins contain ~1,578 glaciers (Raina and Srivastava, 2008) Table 4: Number and area of glaciers in different sub basins of Himalayas

Indus b asin Ganga ba sin No. Glaciers Ice Glaciers Ice No. Basin of covers area volume Basin cover area volume of glaciers glaciers (km2 ) (km3 ) (km2 ) (km3 )

Ravi 172 193 8.04 Yamuna 52 144 12.20

Chenab 1278 3059 206.30 Bhagirathi 238 755 67.02

Jhelum 133 94 3.30 Alaknanda 407 1229 86.38

Beas 277 579 36.93 Ghaghara 271 729 39.61

Sutlej 926 635 34.95 Tist a 4 49 7 06 39.6 1

8 Brahmaputra 161 223 10.0 Upper Indus 1796 8370 73.58 Shyok 2454 10801 Nubra 204 1536 Gilgit 535 8240 Kishangang 222 163 a Total 7997 33679 363.10 1578 3787 258.98 (Raina and Srivastava, 2008)

The glaciers of high Asia comprises 50% by area of all glaciers out side the Polar region and they are contain nearly 33 times areal cover of the glaciers in the European Alps. The Himalaya, include Tibetan plateau contains one of the largest concentrations of the glaciers and permanent snowfield. About 17% of the Himalaya is permanently covered with glaciers and additional nearly 30-40% area is snow covered (Vohra, 1978). The Himalaya is third largest ice bodies on the earth after outside the polar caps. The Great Himalaya, the highest mountain range in the world, extends along the northern frontiers of Pakistan, India, Nepal, China, Bhutan and Bangladesh broadly classified into Western, Central and Eastern Himalaya (Fig. 3).

9 Fig. 3: Distribution of Himalaya glaciers (Figure by Centre for Glaciology, WIHG)

Table 6: Some salient features of Himalayan glaciers (Source, GSI 2009, )

S. No Features Western Himalaya Central Himalaya Eastern Himalaya 1 Source/Basin Indus Ganga Brahmaputra 2 Climate arid to semi arid Semi arid and semi Humid to per- humid humid 3 Latitudes 32-360N 29-320N 27 -300N 4 No. of Glaciers 7462 968 610 5 Ice volume 1042.88km3 213.75km3 49.57km3 6 Snowline 4700-5000m. asl 5100-5300m.asl 5200-5600m. asl 7 Max. Length 74 km 30 km 10.9 km 8 Snout altitude 3490-4100m 3800-4200m 4200-4500m 9 Glacier surface Clean with debris Partially debris Thick debris covered lower part covered covered 10 Av. Discharge 206 km3/yr 488 km3/yr 510 km3/yr

10 Glaciers are some of the most fascinating frozen elements of nature. Glaciers and ice sheets cover approximately 10% of the earth’s surface, out of which 3% are in Asia (IAHS (ICSI)/UNEP/UNESCO 1989). Glaciers, snow, and ice sheets are key components of the earth's hydrologic cycle and climate system that have great spatial and temporal variability. They not only reflect changes in climate; but through changes in the land-surface energy budget, they have a profound impact on global and regional climate. Like climate, variations in the snow and ice cover of the earth occur on local, regional, continental, and global spatial scales, and over seasonal, decade, century and millennia time scales. Measuring changes in extent and mass of glaciers and snow cover, on the appropriate time scale, is a direct way of determining the net effect of current global climate variations. However, because of the great spatial distribution, remote location, rapid variability, and the lack of adequate observations, the relationship between snow and ice and both climatic change and water resources is not well understood.

Glaciers in Indian Himalayan region More than 9 thousand glaciers are occurring in Indian part of Himalaya, due to high and rugged topography it is not possible to studies of all glaciers. Only few numbers of glaciers are studies for different aspect of glaciology.

Jammu and Kashmir Siachen Glacier is the second longest glacier outside of the polar regions and largest in the Himalayas-Karakoram region. (i) Nubra Glacier (ii) Chong KumdanGlacieR (iii) Drang Drung Glacier(iv) Rimo Glacier

Himachal Pradesh

(i) Bara ShigriChandra Glacier(ii) Chandra Nahan Glacier(iii) Bhadal Glacier(iv) Bhaga Glacier(v) The Lady of KeylongMukkila Glacier(vi) SonapaniGora Glacier (vii) Perad Glacier(viii) Parbati and Dudhon Beas Kund Miyar Glacier

11 Sikkim

(i) The Zemu Glacier (ii) Rathong Glacier (iii) Lonak Glacier

Uttarakhand

Goumukh, terminus of the Gangotri glacier (lower right in image, behind prayer flag). The Bhagirathi peaks rise in the background.

(i) Gangotri Glacier (ii) Kalabaland Glacier (iii) Glacier (iv) Milam Glacier (v) Namik Glacier(vi) Panchchuli Glacier (vii) Pindari Glacier (viii) Ralam Glacier (ix) Sona Glacier (x) Kafni Glacier (xi) Sunderdhunga (xii) Jaundhar

12 CHAPTER III CLASSIFICATION OF GLACIERS ______

3.1 Classification of Glaciers Glaciers are generally classified on the basis of: A. Size and Morphology B. Thermal regime, C. Mass balance climate-characteristic, D. Types of nourishment, E. Dynamic behaviour

In other hand, Small glaciers different in form and other characteristic from large ice masses, such as those of Greenland and Antarctic. But on the basis of size, shape, and mode of occurrence, glaciers may be classified as; 1) Continental 2) Alpine 3) Piedmont

1) Continental Glaciers It is extensive ice sheet known as “Continental” because they cover most part of the continent. Extensive ice sheet radiate outward from two centres and move down slope. During Pleistocene ice age extensive ice sheet moved from two centres, these centres are i) Labrador and ii) Keewatin. These both centre covered about ½ area of North America continent. At present the biggest continents glaciers are Antarctic Ice sheet and Greenland Ice sheet, these are describes in below.

(a) Antarctic (Thickness is 4000m, cover an area of 8 million sq.km) Antarctica is a largest ice sheet it cover an area about 8 million sq.km part of continent .It has varies thickness at various point (Fig. 4).

13 Fig. 4 Antarctic Ice Sheet = 90% of world's continental ice sheet volume

(b) Greenland Ice Sheet (Thickness is 3000 m at its central dome) It covers an area about of 1, 30.000km square (Fig. 5). This is about ¾ of the island. Similar ice caps occur in arctic, Canada, Iceland, Norway etc.

Fig. 5 Greenland Ice Sheet = 10% of world's continental ice sheet volume

2) Alpine Glaciers The body of ice moving down slope under the impact of gravity through the valley bordered by rock valley walls in the mountains its called “mountain glaciers” or alpine glaciers (Fig. 6). The length of these glaciers ranges from few kilometres to more than 100 km.They are located generally above snow line as they are ablated while descending down the snow line.

14 Fig. 6: Alpine glacier of Indian Himalaya region

2) Piedmont Glaciers The glaciers formed due to coalescence of several mountain or valley glaciers at the foothill zone are called Piedmont glaciers (Fig. 7).

Fig. 7: Piedmont glaciers Such glaciers are found in only colder areas and not in the tropical and temperate region because they melt when they reach the foothill zone.

15 3.2 Glaciers Classification Based On Different Features (A) On the basis of Surface feature The classification for the Himalaya region Based on the Surface characters of the glaciers (i) Debris free or Clean glacier (ii) Debris covered or Dark glacier

(i) Clean glacier: The term clean glacier that for whatever the reason is practically devoid of any debris cover over the entire glacier surface including the zone.

Fig. 8: of Dokriani Glacier, Bhagirathi Basin

(ii) Dark glaciers: Dark glaciers as the name suggest has been used for the normal Himalaya glaciers that covered by a thick mantle of debris and in the ablation zones.

16 Fig 9: Ablation zone and snout of Chorabari Glacier, Alaknanda river basin

(B) On the basis of temperature of the ice forming the glacier (i) Cold glacier (ii) Temperate glacier

(i) Cold glacier: Its terminology used for the glaciers that are presumably cold enough, so that the ice forming the glacier exhibits a temperature gradient that is well below the pressure melting point. This term is restricted to the glaciers that exist in polar region.

Fig 10: Ice shelve of Antarctica Ice sheet

17 (ii) Temperate glacier: The term used to denote the glaciers that occur in the Himalayas and Alps. Ice forming such glaciers is supposed to be stable at what is termed as the pressure melting point temperature and hence small change can produce melting and slippage.

Fig 11: Ablation zone of Hamta Glacier, Chandra River basin Himachal Pradesh. Behind the glacier snow clad Suderson peak

(C) Another important classification is based on the geomorphic factor i.e. Location, size, and shape etc.

(i) Niche glacier: It’s also called ‘baby glacier’. It is term used for small remnant glaciers that can be seen occupying hollow and troughs in the higher reaches of the mountain. These also could have been the part of the accumulation of a glacier that had not developed into a proper valley.

18 Fig 12: A Niche glacier

(ii) Hanging glacier The term Hanging glacier is used to identify small glaciers that may entirely comprise only the accumulation zone, and occupy hollow and trough that are perched steeply along the walls.In the past when the size of the main valley glacier was mu ch larger, then these glacier could have been feeding into it and be in contact with it as tributaries glacier.

Fig. 13: Hanging Glacier

19 CHAPTER IV GLACIAL SURFACE FEATURES ______

The snow surface of the accumulation area of a mountain glacier display the same snow dune and Sastrugi features found on ice sheet, especially in winter, but normally these features are neither as large nor as well developed. Where appreciable melting of the snow occurs, several additional features may be produced. During periods of clear, sunny weather, sun cups (cup-shaped hollows usually between 5 and 50 centimeters [2 and 20 inches] in depth) may develop. On very high-altitude, low- latitude snow and firn fields these may grow into spectacular narrow blades of ice, up to several meters high. But some most important and chief features are: 1) Accumulation zone 2) Equilibrium line area 3) Ablation zone 4) Snout

4.1 Accumulation zone: Accumulation is the addition of ice or snow to the glacier surface by snowfall, hail, rainfall that freezes. Hence, the zone over the glacial surface where the accumulation takes place relative to the previous year surfaces.

4.2.1 Equilibrium line area This line theoretically separates the accumulation zone from the ablation zone over the glacier surfaces. The position of the line is governed by the mass balance of the glacier. Positive balance brings down the position of this line on the glacier surface and the negative balance leads to the recession of the line on the glacier surface.

20 Fig 14: Accumulation and Ablation zone with Equilibrium line

4.2 Ablation zone Ablation is the loss of ice from the glacier by melting, evaporation, calving, deflation etc. The zone over the glacier surfaces within which the loss of ice takes place, as compared to the previous year surfaces .its called ablation zone. In ablation zone here highly dirty and rubble covered and show supra with moraines.

4.3 Snout “It is terminus of the glacier”. It’s a part of ablation zone .snout front in the Himalayas exhibit varying shapes and characters, depending upon the size of the glaciers, nature of the valley, slope of the valley, mass balance of the glacier. It’s of three type i.e. 1) Lope shaped 2) Narrow front 3) Expanded foot

21 Fig 15: Snout of Gangotri glacier

4.4 Other glacier surface feature (i) Ice caves: A cave formed in or under a glacier, typically by running water. Steam or highheat flow can also form glaci er caves. Also called Ice Cave

Fig 16: A Ice cave

22 (ii) A single large or series of sub-parallel crevasses that develop at the head of a glacier. The location where ice pulls away from the bedrock wall of the against which it accumulated. In winter, the fills with snow. In spring or summer, it reopens. (Originally a German term)

Bergschrun

EL

Fig 17: A Bergshrund Glacier

(iii) Foliation The layering or banding that develops in a glacier during the process of transformation of snow to glacier ice. Individual layers, called foliation, are visible because of differences in crystal or grain size, alternation of clear ice and bubbly ice, or because of entrained sediment.

23 Fig 18: Foliation on glacier surface

(iv) Ogives An arcuate, convex, down-glacier-pointing band or undulation that forms on the surface of a glacier at the base of an icefall. Two types of ogives occur (a) Wave ogives, which are undulations of varying height and (b) Band ogives, which are alternating light- and dark-colour bands.

Fig 19: Ogives surface features on glacier surface

24 (v) Crevasses: The pressure is lower near the surface of a glacier making the ice more brittle, where crevasses are likely to form. These cracks form due to velocity differences in the glacial movement. As a glacier moves in different directions and with different speeds, it causes shear stress on the ice to where two sections will break apart.

(a) Transverse crevasses are those which are formed right angle to the movement of glacier.

Fig 20: Transverse crevasses on glacier surface

(b) Longitudinal crevasses Form partially parallel to the flow where there is lateral expansion of the glacier. Crevasses will also form around the edges of a glacier from the reduction of speed caused by on the valley walls friction.

25 Fig 21: Longitudinal crevasses on glacier surface

(vi) Glacial Sole Those stream which are formed by the melting of glacier carry enormous quantity of suspended as well as heavy sediments which get deposit at the base of glacier .Which we called it Glacier sole.

Fig 22: glacial sole

26 (vii) Rock table A rock that is balanced on a pedestal of ice, and elevated above the surface of a glacier. The rock protects the pedestal of ice from melting by insulating it from the sun.

Fig 23: A rock table (viii) Sink hole In accumulation zone of a glacier, a large rock boulder, due to conduction of heat, help in the melting of the underlying glacier ice at faster rates than the surrounding ice this give rise a large depression capped by a boulder. This is called sink hole.

Fig 24: sole hole on glacial surface

27 (ix) Dirt cones A cone or mound of debris-covered ice, with a thick enough sediment cover to protect the ice from melting.

Fig 25: Dirt cone surface features

(x) A narrow, tubular chute or crevasse through which water enters into glacier fro m the surface. Occasionally, the lower end of a Moulin may be exposed in the face of a glacier or at the edge of a stagnant block of ice.

Fig 26: Moulin surface features

28 (xi) Iceberg A block of ice that has broken or calved from the face of a glacier and is floating in a body of marine of fresh water. Alaskan icebergs rarely exceed 500 feet in maximum dimension.

Fig 27: Iceberg

(xii) Supra-glacial Lake Etc. Glacier in the Himalaya generally shows the presence of large water bodies over the glacier surface within the ablation zone .these are varying in size.

Fig 28: Supraglacial Lake

29 CHAPTER V GEOMORPHOLOGICAL GLACIAL LANDFORMS

Glaciers are not landforms. The action of glaciers, however, creates landforms. It is a process known as Glaciation. Glacial ice is an active agent of erosion, which is the gradual wearing away of Earth surfaces through the action of wind and water. Glaciers move, and as they do, they scour the landscape, "carving" out landforms. They also deposit rocky material they have picked up, creating even more features. The work of present-day glaciers, however, is slow and confined to certain areas of the planet. Less obvious but far more reaching has been the work of Ice Age glaciers. Many of the distinctive features of the northern landscapes of North America and Europe were formed by glaciers that once covered almost one-third of the planet's land surface. Glacial processes cover all such activities of the glacier ice that have an impact on the bedrock or the valley walls directly or indirectly. Deposition and accumulation of the glac ier ice, on ground, means storage of water in solid state .This not only affect the ground temperature but also initiated geomorphic processes that have a major impact on the landscape. One of the earliest known landforms that aroused the interest of the human mind and led to the postulation of glacial theory i.e. Erratic Boulder/ Boulder Erratic and other geomorphologic landforms are come into reckoning much latter.

1) Erratic boulder The term erratic is applied to a large isolated boulder perched at such a place where the river water could not have possibly carried it, and it is postulated that these could have been carried to the present location only by a glacier. So a glacial process is thus not only related to the direct action of the glacier ice but related.

The resultan t glacier landforms, from whichever, process these might have resulted, can be classified as those formed by 1) Erosion i.e.; Degradation 2) Deposition i.e.; Aggradation

30 Fig 29: Erratic Boulder

5.1 Erosional Process Erosional landforms are formed by the Erosional work of glacier by some Climatic, Temperature and some Pressure factors.

In erosion some processes are taken place these are 1) Abrasion This is where the bedrock underlying the glacier is eroded by debris embedded in the base and sides of the glacier. As the glacier moves over the bedrock, this material scrapes away at the rock like sandpaper wearing it away. As it does so it leaves behind scratches and grooves in the rock, known as striations.

31 Fig 30: Striation Features on glacier surface

Rates of abrasion are greatest where: 1) The rock debris is more resistant than the bedrock it is abrading; 2) There is a plentiful supply of debris at the base of the glacier 3) The glacier is travelling at a greater velocity across the bedrock 4) The ice is thick, enabling the embedded debris to exert greater pressure on the bedrock below.

Crushing and Fractures: Where these grooves are discontinuous but regular in occurrence they are known as chatter marks. The depth of the striations will be dependent on factors such as resistance of the bedrock, as well as the fragments that are undertaking the erosion.

Fig 31: Chatter marks on glacier surface

32 2) Polished Where fine material is embedded in the base of the glacier it will act to 'polish' and smooth the bedrock below . Indeed as abrasion takes place, rock material is ground down to produce a very fine 'rock flour'. The characteristic blue-green colour of glacial lakes and streams (opposite) is due to the high concentrations of this rock flour in suspension.

3) The process of plucking (also known as quarrying), results in the removal of much larger fragments of bedrock than that undertaken by abrasion.

Fig 32: Plucking of a boulder from the parents rock

Rates of plucking are greatest where 1) The bedrock is well jointed 2) The water is present during freezing 3) The ice is thick creating greater frictional drag as the ice move over the bed.

5.2 Erosional Landforms 1) U-shaped valley

33 The cross section of glacial valley or glacial trough of mountain glaciers is u- shaped valley which is characterised by steep valley walls with concave slope and broad and flate valley floor.

Fig 33: U-Shaped valley

2) V-shaped valley valley with a narrow bottom and a cross section shaped like the letter 'V'. Valleys of this shape are almost always cut by stream erosion.

Fig 34: V- Shaped valley

34 3) Cirque A cirque (French for "circus") or corrie (from Scottish Gaelic coire meaning a "") is an amphitheatre-like valley head, formed at the head of a valley glacier by erosion. It’s formed primarily by plucking and freeze-thaw weathering.

Fig 35: A Cirque

4) Col, Aerete, Horn A high plateau or a mountain range after being eroded rather incompletely by glaciers mainly through the processes of cirque recession remains ‘as remnants between the steep, concave, glaciated form’. The cap formed due to cutting of headwalls because of intersection of two steep –sided is call ed Col. The mountain divide its sharpened due to recession of cirque on its both side, such sharpened peak resembling saw-teeth are called Aeretes. A pyramidal and triangular faceted peak formed due to recession and intersection of three or more cirque is called Horn.

35 Fig 36: systematic diagram of Col, Aeretes, and Horn 5) A rock basin is formed at the floor of cirque basin due to erosion consequent upon greater thickness of ice mass and its enormous pressure.

Fig 37: Tarn glacial surface features

5) Nunataks The higher peak and mounds surrounded by ice from all side are called Nunataks. They look like scattered small island .That’s why it’s called glacial island.

36 Fig 38: Nunataks 7) A peculiar landform having vertical eroded steep side up glacial side and tail like appearance with lower height down glacial side is called ‘crag and tail’. Such landforms developed over old volcanic and basaltic plug which project above the ground surface as resistant knots.

Fig 39: Crag and Tail

37 8) Roches mountonness Roches moutonnees are streamlined asymmetrical hillock, mounds or hills having one side smoothly moulded with gentle slope and steepened and craggy lee side. This term first used by “De saussure in 1804”.

Fig 40: Roches Mountonness

9) Glacial stairways These are also known as giant stairways or cyclopean stairs, are very picturesque and bewildering glaciated landforms. The length of each stair ranges from a few meter to several kilometre .each stair is separated from the other by vertical cliff measuring 30 to 300 m.

Fig. 41: Glacial stairways

10) Paternoster lakes Smaller depressions are formed at the base of cliff by plucking. These depression on are filled by melt water and become lake which we called paternoster

38 lakes. These lakes are appearing as beaded lakes because they are associated with almost step or stair.

Fig. 42: Paternoster Lakes

11) Glacial grooves Small scale streamlined depression are called glacial grooves. Individual grooves may be measure 12 km in length, 100m in width, and 30m in depth.

Fig. 43: Glacial gro oves

12) Fiords These are glacial troughs which have been occupied by the sea. Fiords are the arm of the sea which have occupied u-shaped glaciated valley .Fiords are characterized by steep side walls and several hanging valley.

39 Fig 44: Fiords

5.3 Depositional Landforms Depositional landforms formed due to setting down of glacial drift and formed different depositional landforms.

1) Moraines Moraines are like depositional features of glacial tills. They are long but narrow ridge with height more than 30m. Moraines are generally divided into 4 main categories on the basis of location aspect of glacial deposit.

(i) Terminal Are also known as end moraines are formed due to deposition of glacial till across the moving ice sheet at the snout of the glaciers after ablation of ice. These are Horse-Shoe shaped or crecentric ridge having concave slope facing glacial valley. These are 100 of kilometre in length and more than 100 m in height.

40 Fig 45: Systematic diagram of different types of Moraines landforms

(ii) Lateral moraine: These are long, narrow, and steep side ridge parallel ridge of till on either side of a glacier. They are formed due to deposition of sediment along the margin of a glacier when it contract in size due to melting of ice .These are several 100 meter in height.

(iii) Medial moraine These are formed due to deposition of glacial sediment along the internal margin of two glaciers at their confluence.

(iv) Ground moraine These are formed when glacial till are deposited at the floor of glacial valley. The sediment are not sorted because coarse and fine till are deposited together.

(v) The swarm of rounded hummocks resulting from the deposition of glacial till are called .They look like an inverted boat or spoon.

41 . Fig 46: Drumlin

5.4 Glacio-Fluvial Landforms The snout of the glacier starts melting due to increase in temperature when it descends below snow line. Melt water escapes through numerous but small and temporary stream .These stream carry sediments for longer distance and deposit form in various form .These sediments still carry some ice ,thus the deposition of sediments after the ablation is called Glacio-Fluvial Deposits.

Fig 47: systematic diagram of Glacio-Fluvial landforms

1) These are long narrow and sinuous of sand and gravels and are situated in the middle of ground moraines. The side of are steep .these are vary in height

42 and width ranging from few meter of ten of meters and extend for kilometres in length parallel to the direction in which ice moves.

Fig 48: Eskers

2) Kames are small hills or irregular mounds of bedded sands and grave ls which are deposited by melt water near or at the edge of the retreating ice sheets. If small alluvial cones are deposited on the land are called cone kames and if small alluvial deltas are deposited in the lakes are called delta kames .These are characterized by steep side slopes.

Fig 49: kames and kames terraces

43 3) Kames terraces Narrow flat topped terrace like ridge formed along the trough between the glacier and the valley side are called kames terraces.

4) Moulin kames or perforation kames The mounds formed in the hollow and perforation in decaying ice are called Moulin kames or perforation kames

Fig. 50: Moulin features on glacial surface

5) Kettles and Hummock Kettles are depression in the .kettles are formed due to melting of large block of ice .Large kettles are dotted with numerous low mounds which are called hummocks.

Fig 51: kettle and hummock

44 6) Sandar or Outwash plain The melt water caused due to ablation of glacier at its snout descends through the terminal moraines and spread like sheet water. This spreading water erodes the terminal moraines and deposit the eroded sediment in front of the terminal moraines and thus form a plain called ‘outwash plain’.

Fig. 52: Outwash plain

These are characterized by well sorted sediments. These are also called “Sandar”.These are characterized by multi thread channel which are called ‘Braids’

45 CONCLUSIONS ______

Geomorphologic study of Himalayan glacier is very complex, because so many changes are occur at glacier surfac e during the dynamic and thermal processes. So there is minor and major changes are formed at glacier surface. Which are unable to recognize without the help of Geomorphological studies. As we know that the glacier are formed after a long time processes of conversion from snow to compact ice. So glacial geomorphology has advanced more gradually about it is not immune to the old outrageous hypothesis, because glacier bed are extremely difficult and dangerous to access. Glacial geomorphologers are concern the process es by which glacier shape landscape and analysis the resulting glaciated landforms. The information about the deformation of ice and the flow of glacier at various temperatures, with or without associated water is necessary prerequisite to understand by glacial geomorphology. As the glacial related geomorphologic work of melt water and wind extend many kilometres beyond a glacier margin, the direct work of glacier ice ends at an abrupt, although shifting boundary. Geomorphologic study of glaciers impo rtant in x Knowing the past history of ancient glaciers that it may be present or not. x Identifications of Glaciers landforms. i.e; Erosional and Depositional. x Study of Sediment formation and deposition in glaciers. x Identification the interrelation between boulder and fine sediment to Glaciers movement. Some important geomorphological tools which are used in the study of Glaciers landforms and features: Geomorphological Mapping Lichens Dating Technique. All glaciated landforms are relict even if they were exposed only by the previous year retreat of a glacial terminus. A problem of glacial geomorphology is that most of the process work beneath ice and are exceptionally difficult to observe. Glaciated terrain is not a landscape until it’s exposed by the disappearance of the glacier.

46 REFERENCES ______

Srivastava D. and Raina V.K. (2008): Glacier Atlas of India. Geological Society of India, Banglore, 1-22. Srivastava D. and Raina V.K. (2008): Glacier Atlas of India. Geological Society of India, Banglore, 23-50. Flint R. F. (1971) Glacial and Quaternary Geology, John Wiley and sons ,New York 892. Flint R. F. (1964) Glacial and Quaternary Geology; Glacier of today 892. Blooms Arthur L. (1991) Geomorphology; A Systematic Analysis of Late Cenozoic Landforms, Prentice Hall, New Jersey 07458,3-4. Evans David J. A. Glacial Geomorphology, Critical Concept in Geography, Routledge, New York 1 Volume IV. Easterbroo Don J. K. (1969) Principal of geomorphology; McGraw-Hill, New York 175. Anderson, D. (2004). Glacial and Periglacial Environments. Hodder Arnold, London.

http://en.wikipedia.org/wiki/Glacier

http://library.thinkquest.org/3876/iceage.html  

http://en.wikipedia.org/wiki/List_of_glaciers_of_India  

http://www.uwgb.edu/dutchs/EarthSC202Notes/glacial.htm  

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