It is a term that is mostly used in Geology, Geophysics, and Geodesy or Geography and Earth Science, its first proposal was made in 1889, by C. Dutton who was an American Geologist. Our Earth has different layers and these layers have different properties and this term is one of the phenomena that deals with some of these layers. In this article, we will be talking about this, one of the important phenomena and will learn about what is Isostasy, meaning, Isostasy Geology definition and examples, etc.
Introduction
The Earth can be divided into various layers such as Crust, Mantle, Outer Core and Inner Core based on chemical composition and lithosphere, asthenosphere & mesosphere based on physical properties. The lithospheric crust of the Earth lies on the upper mantle ie. Asthenosphere. The upper mantle is considered dense thus, the crust floats on it rather than simply resting on it. Here, we will discuss one of the phenomena that describe the relationship between the two.
[Image will be Uploaded Soon]
Isostasy Meaning
This term is made up of two Greek words ie. isos which means equal and stasis which means standstill. The crust of the Earth is lighter than the layer it lies on, i.e. on the mantle which is denser and it floats on this mantle sheet. Isostasy is nothing but a phenomenon that keeps a balance between the lithospheric crust and the mantle of the Earth. It is also termed as isostatic equilibrium. It helps in keeping the balance between the forces that leads to upliftment or sinking of the lithospheric crust.
There are some standard definitions are written below which describes Isostasy:
Isostasy Geology Definition
Examples
We have read about the Isostasy which helps in maintaining the equilibrium of the portion whenever the weight is lifted and added there. Let's have a look at the examples:
[Image will be Uploaded Soon]
1. Here, in this diagram the right side is non - static equilibrium whereas the left shows the isostatic equilibrium. The relationship is similar to the left side, the upper mantle is denser thus the upper crust is floating on it. Whenever more weight is added there, then it starts sinking downwards in the mantle whereas it starts uplifting whenever the weight is lifted.
[Image will be Uploaded Soon]
2. Here, the diagram shows the time of the formation of the mountain. On the left side, during its formation when more weight is added, the crust sinks in the mantle and on the right side, when after several years, due to erosion and weathering, the weight is lifted, then the crust starts lifting.
[Image will be Uploaded Soon]
3. Let's see the same isostatic process in glaciation. In Greenland, the more weight of the ice sheets will lead to its sinkage towards the mantle. It will rebound whenever this melts but that will take several years to happen.
[Image will be Uploaded Soon]
4. This diagram shows the period when the ice melts completely and the crust starts lifting upwards. The melting of the ice sheets will take a huge number of years but the way climate change is happening, it can be faster
Conclusion
Thus, to sum up we can say that we have studied one of the major and important phenomena that deal with layers of the crust and the upper mantle and helps in balancing the crust which floats on the mantle. We have covered Isostasy, its meaning, Isostasy Geology definition and its examples with diagrams. This article will help you whenever you will study the layers of the Earth in Geology, Geography or other Earth Sciences etc.
We have learned about Isostasy comprehensively. Let's have a look at some of the related questions:
FAQs on Isostasy
Question 1. Define Isostasy.
Answer. It is a geographical phenomenon that deals with the crust of the Earth and the upper mantle i.e Asthenosphere. The upper mantle layer is considered as much denser that is why the layer of the crust used to float on it and isostatic equilibrium helps in maintaining the balance whenever any weight is added and lifted on the crust which leads to sinkage as well as the upliftment of the crust of the Earth. It maintains a balance of both continental and oceanic crust with respect to its underlying layer.
Question 2. Explain the Process of Isostatic Equilibrium.
Answer. Whenever some weight is added to the crust, it sinks towards the mantle whereas whenever some weight is lifted it tries to go back and move upwards. For example in the formation of the mountain, when more and more weight is being added to the crust, it starts sinking in the mantle. After a number of years, when because of erosion and other weathering activities, the weight is lifted then it starts moving upwards. This process happens on the oceanic surface as well. It also takes a lot of years to happen.
Question 3. What is the Major Benefit of Isostasy?
Answer. The major benefit of Isostasy is that it helps in controlling the different elevations at the lithospheric and oceanic surface with respect to the layer of rocks lying underneath them. It helps in maintaining the equilibrium whenever something adds up and something lifts from these surfaces. The crust sinks when some weight is added and it starts lifting upwards when the weight is lifted and this process is Isostasy.
