Geo Thinking

Glacier and its Types Glacier:    The moving ice mass downslope under the impact of gravity is called Glacier. About 10% of the Earth's surface is now covered by glaciers. About 2-3 million years BP glaciers extended over almost one third of the Earth's lithospheric surface. Glaciers are formed due to accumulation of ice above Snow Line under extreme cold climate. Snow Line is generally defined as a zone between permanent and seasonal snow. In fact snowline denotes that height above which there is permanent snow cover and thus it corresponds to the the level where average temperature is always below freezing point during the warmest month of the year. The snow line is at the lowest height ( 0 m or sea level ) in the Polar region and and increases equatorward where it tends to between 500 to 6000 m. The estimated number of all types of glaciers all over the world ranges between 70,000 and 200,000. The areas of accumulation huge volume of ice are called snow-fields which ...

Fluvial works Erosional work of river :      The word erosion has been derived from the Greek word 'erodere' which means to gnaw. Fluvial erosion is a dynamic process which involves the removal of Geo material from the rocks. The factors controlling the erosional work of river include channel gradient and volume of water, velocity of water, river load etc. The quantity and angularity of erosion tools largely control nature and magnitude of fluvial erosion.        The following relationship may be identified between the rate of fluvial erosion and river load. 1. Erosion becomes minimum in the absence of required amount of river load. 2. Erosion also becomes minimum when the river has maximum load. 3. Erosion becomes minimum when the river carries load according to its transporting capacity.       Besides river load velocity and channel gradient are also important factors which effectively control fluvial er...

Folded Mountains    Folded Mountains are formed due to folding of Crustal Rocks by compressive forces generated by endogenetic forces coming from within the earth. These are the highest and most extensive mountains of the world and found in all the continents. The distributional pattern of folded mountains over the globe denotes the fact that they are generally found along the margins of the continents either in north south direction or East West direction. Rockies, Andes, Himalayas etc. are the examples of folded mountains.    Folded Mountains are classified on various bases as follows.       1. Folded Mountains are divided into two broad categories on the basis of the nature of folds. (a) Simple folded mountains with open folds - Such Mountains are characterized by well developed system of anticlines and synclines where infolds are arranged in wave like pattern. (b) Complex folded mountains represent very complex structure of intensel...

Interior structure of the Earth  : 1. The Crust  :-                            The crust is the outermost layer of the earth. The thickness of the crust is varies under oceanic and continental areas. The thickness of the oceanic crust is around 5 km, where as the thickness of the continental crust is around 30 km. It should be note here that the crust is thicker under mountainous areas. It is around 70 km thicker under the Himalayan region. The average density of the outer and lower crust is 2.8 and 3.0 respectively. The difference of density between the upper and lower crust is because of the pressure of supperincumbent load. The average velocity of P waves in the upper crust is 6.1 km per second while it becomes 6.9 km per second in the lower crust. 2. The mantle :-                            The portion of the interior bey...

Fault : When the The Crustal rocks are displaced due to tensional moment caused by endogenetic forces along a plane the resultant structure is called a fault. Components of a fault : Components of a fault are given below, 1. Fault Plane  is that plane along which the rock blocks are displaced by tensions and compressional forces acting vertically and horizontally to form a fault. 2. Fault dip is the angle between the fault plane and horizontal plane.. 3. Upthrown Side represents the uppermost block of a fault. 4. Downthrown side represent the lower most block of a fault. 5. Hanging wall represents the upper wall of a fault. 6. Foot wall represents the lower wall of a fault. 7. Fault scarp is the steep wall-like slope caused by faulting of the crustal rocks. Types of faults : 1. Normal faults  are formed due to the displacement of both the rocks blocks in opposite directions due to fracture consequent upon greatest stress. 2. Reverse faults are ...

Facts of Interior of the Earth               The earth's radius is 6370 km. No one can reach the centre of the earth and make observation or collect samples of the materials. Under such conditions it is wonder to know how scientist tell us about the earth's interior and the type of materials that exist at such depths. Basically the sources of information about the interior of the earth are two types. These are- 1. Direct Sources, 2. Indirect Sources. The most easily available solid Earth material is surface Rock On The Rocks we get from mining areas. Gold mines in South Africa sdps 3-4 km. Going beyond this depth is not possible as it is very hot at such depths. Besides mining, scientists have taken up a number of projects to explore the conditions in the crystal portions. Scientist world over are working on two major projects such as deep ocean drilling project and integrated Ocean drilling project. The deepest drill at Kola in Arctic Ocea...

Plate tectonics  : The earth's crust is made up of several rigid and a solid plates. The term plate was first used by J. Tuzo Wilson, a Canadian geophysicist in 1965. Plate tectonic means the moment of plates. Classification of plates  : Plates can be classified into two groups, these are- 1. Major plates : a. Indian Plate, b. Pacific plate, c. American plate, d. African plate, e. Eurasian plate, f. Antarctica plate. 2. Minor plates : a, Arabian plate, b. Philippines plate, c. Cocos plate, d. Caribbean plate, e. Nazca plate, f. Scotia plate, g. Carolina plate, h. Juan de puca plate, I. Bismarck plate. Plate Margins : Plate margins or boundaries are most significant because all tectonic activity occur along the plate margins. Plate margins or boundaries are classified into three categories. These are- 1. Constructive or divergent plate boundary : divergent plate boundary in plate tectonic is a linear feature that exist between two plates that are moving away ...