Glacial – Glacial Landforms

-
  • Masses of ice moving as sheets over the land.
  • Linear flows down the slopes of mountains in broad trough-like valleys. Move basically because of the force of gravity.
  • Erosion by glaciers is tremendous because of friction caused by sheer weight of the ice.
  • Glaciers can cause significant damage to even unweathered rocks and can reduce high mountains into low hills and plains.
  • River Bhagirathi is basically fed by meltwaters from under the snout (Gaumukh) of the Gangotri glacier. Alkapuri glacier feeds waters to Alakananda river.
  • Rivers Alkananda and Bhagirathi join to make river Ganga near Deoprayag.
Erosional Landforms
Cirque
  • Found at the heads of glacial valleys.
  • The accumulated ice cuts these cirques while moving down the mountain tops.
  • Deep, long and wide troughs or basins with very steep concave to vertically dropping high walls at its head as well as sides.
  • Lake of water can be seen quite often within the cirques after the glacier disappears. Such lakes are called cirque or tarn lakes.
Horns and Serrated Ridges
  • Three or more radiating glaciers cut headward until their cirques meet, high, sharp pointed and steep sided peaks called horns form.
Glacial Valleys/Troughs
  • Glaciated valleys are trough-like and U shaped with broad floors and relatively smooth, and steep sides. contain littered debris or debris shaped as moraines with swampy appearance.
  • Elevation on one or both sides of the main glacial valley.
  • Very deep glacial troughs filled with sea water and making up shorelines (in high latitudes) are called fjords /fiords 
Depositional Landforms
  • Unassorted coarse and fine debris dropped by the melting glaciers is called glacial till.
  • Some amount of rock debris small enough to be carried by such melt water streams is washed down and deposited - outwash deposits.
  • Rock fragments in outwash deposits are somewhat rounded at their edges.
Moraines
  • Terminal moraines - long ridges of debris deposited at the end (toe) of the glaciers.
  • Lateral moraines - form along the sides parallel to the glacial valleys.
  • Ground moraines - deposits varying greatly in thickness and in surface topography.
  • Medial moraine - moraine in the centre of the glacial valley flanked by lateral moraines.
Eskers
  • Glaciers melt in summer, streams flow.
  • Very coarse materials like boulders and blocks along with some minor fractions of rock debris carried into this stream settle in the valley of ice beneath the glacier and after the ice melts can be found as a sinuous ridge called esker.
 Outwash Plains
  • Foot of the glacial mountains or beyond the limits of continental ice sheets are covered with glacio-fluvial deposits.
  • Outwash plains of gravel, silt, sand and clay.
Drumlins
  • Smooth oval shaped ridge like feature of glacial till with some masses of gravel and sand.
  • Parallel to the direction of ice movement up to 1 km length & 30m height.
  • Stoss End - drumlins facing the glacier.
  • Tail End - blunter and steeper than the other end.

Comments

Post a Comment

Popular posts from this blog

Indian Painting - Pre History

-
Image
    History and Evolution of Painting in India - An Overview India has a long tradition of artistic excellence and painting is one of the major mediums that has been used to express it. There is several evidence suggesting that painting flourished in India since ancient times. Archaeologists have found wall paintings in parts of India, which suggest that even the early historic man in India was engaged in activities of art and leisure The history of painting can be traced through the ancient and medieval period where the books were illustrated with paintings Then came the miniature style that dominated the Mughal and Rajput courts. With the coming of the Europeans, the art of painting and engraving took a western turn. Modern painters experimented with styles, colours and designs. Many Indian painters have gained worldwide recognition and are winning prizes and accolades for their vision. Principles of Painting The history of paintings can be known from primitive rock paintings of Bhim
Read more

Classification of Indian Paintings

-
Image
    Classification of Indian Paintings Indian Paintings have been broadly classified into two. Mural Paintings Miniature Paintings Mural Paintings The work on the walls or a solid structure are referred to as Murals. These have existed in India since ancient times and can be dated between 10th century BC and 10th century AD. The evidence of such paintings can be found at several locations in India. The beauty and the exquisiteness of mural paintings can be seen in places like Ajanta, Armamalai Cave, Ravan Chhaya Rock Shelter, Bagh Caves, Sittanavasal Caves and Kailash Temple in Ellora. Most of the mural paintings are either in natural caves or in rock cut chambers. The paintings follow a theme, the most common being Hindu, Buddhist and Jain. Mural paintings were also made to adorn any mundane premise. For e.g. Ancient theatre room in Jogimara Caves. Ajanta Cave Paintings One of the oldest surviving murals of Indian sub-continent, Ajanta caves were carved between 2nd century BC to 5th c
Read more

Solar system

-
Image
Galaxy Gravitational bound system of star, stellar remnants, interstellar gas, dust, and dark matter. Ex: Milky way. A galaxy is a huge system of billions of stars. Our solar system is a part of the milky way galaxy. Our Milky way galaxy was named “Akash ganga”. There are millions of galaxies that make the Universe. Distance galaxy: GN-z11 (March 2016) Hubble classification Eliptical (E) Spiral (S): Andromeda & Sombrero (unbarred) Lenticular Celestial bodies: Sun, Moon. Two types: Emit light (Star), Don’t Emit Light (Planets) North Star – Pole Star – Indicates north Direction Constellations (Group of star) – 88 Official Ursa Major – Big Dipper Tail – Alioth – Brightest in Ursa Major Saptarishi Mandal Polaris – Brightest in Ursa Minor The Sun Made up of extremely hot gases. The sun is about 150 million km away from the earth. 30 times greater than Earth. Black hole – It absorb light but does not emit due to high gravitational force. Corona – Outer surface of the sun (About 6000 k) S
Read more