What is Isostasy? Meaning and Definition.

A wide variety of landforms such as mountains, dissected plsteaus, flat plains, low lying Ocean basins, etc. exists on the earth surface. These landforms differ from each other in respect of their size, height, extent, etc., and yet all of them exist in a state of isostatic balance according to a definite law. There must be some unseen force behind creating such balance. It is known as isostasy.

Isostasy :

The word 'isostasy' has been derived from the Greek word 'iso-stasious' which means 'equal position'. In other words the gravitational adjustment of Earth's crust is isostasy, a state of balance. The term isostasy was first used by the famous American geophysicist C.E. Dutton According to him the doctrine of isostasy implies a position or condition of mechanical equilibrium under the control of of natural laws between the high mountain parts and low lying basins and oceanic parts over the rotating Earth.

Various concepts of Isostasy :

All scholars believe in the doctrine of Isolation. However, their presentation and explanation is different.

1. Pratt's Concept : According to Pratt, inverse relation exists between height and density. Therefore, all the landforms above the level of compensation have different densities, but below it equal density exists.

To prove his point, he made an experiment. He took some blocks of iron, lead, antimony and zinc of different sizes and densities but equal weight and put them into a basin filled with mercury. The level at which they sink equally is called the 'line of compensation'.

Airy's Concept : Airy was a British astronomer. On the basis of the principles of flotation he formulated another hypothesis which appears to be more authentic. He said that The Rocks of different land masses of the earth have the same density.

To prove his point, Airy made an experiment. Two blocks of iron of the same density but different height and put them in Mercury field basin. This blocks sink to different depths according to their size. The highest block was found to sink to the greatest depth.

Comments

What is Plate Tectonic? Types of plate tectonics // Plate Margins or boundaries.

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 ...

What is fault? What are different types of faults ?? Geo thinking

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 ...

What is geomorphology // Nature and scope of geomorphology

DEFINATION: The term geomorphology has been derived from three Greek words that is 'ge' 'Morphe' and 'logos' where Ge means earth, morphe means form and logos means study. Thus geomorphology may be defined as the science or the study of various forms of Earth surface. It is the systematic and organised description and analysis of the landforms of the earth. The word landform has wide connotation and includes not merely the micro features of the land but also the major relief features such as continents, ocean basins, mountains, Plains etc. SCOPE AND NATURE: The subject matter of geomorphology may be organised on the basis 1. Dimension and scale of relief feature 2. Processes that shape the landforms, and 3. Approaches to the geomorphic study. On the basis of dimension and scale, features of the earth are classified into three categories- a. Relief features of the first order: Relief features of the first order include Contin...

Geo Thinking

Search This Blog