Explain the formation of thousands of islands in Indonesian and Philippines archipelagos. [150 Words] [10 Marks] [2014]

 

Index-

1. Explanation of question
2. The information need to understand about the convective current
3. Formation of the conversion and the divergent boundary.
4. And in the last connecting the question with convergent boundary of oceanic oceanic convergence
5. Answer writing structure
6. Answer

 

UNDERSTANDING QUESTION-

When the word (terminology)  "explain" used in any given question its simply means that the answer is demanding "indepth" information, riding up on the knowledge, to produce answer.

Same is the demand in this question where actually the basic information has been asked about the formation of archipelagos in respect of Indonesian Philippines.

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EXPLANATION-

     Now, it is a typically "physical World geography question" where we need to explain the formation of group of volcanic Island which are connected through oceanic oceanic plate conversion.

As, we know-

1. if you go through the earth internal structure formation we came to know the two primary layers one is lithosphere and second is asthenosphere.
2. The depth of lithosphere on average is 100 KM which is combination of both -
3. continental crust and 
4. oceanic crust along with the solid upper portion of mental.
5. In the next layer we have the semi- molten layer known as "asthenosphere", in which, the temperature start from 900, and, goes to about 3800 °C (degree centigrade) which means the temperature gradient is about 2900 degree centigrade.

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We also know -

       

1. Inside the earth internal structure 
2. there is a gradual increase in temperature which draw the reference that 
3. the lower or the bottom layer of asthenosphere maintain high temperature in compare to upper layer.
4. If we follow the energy principle it flows from high temperature to low temperature 
5. that means, now, the energy will flow from the bottom of asthenosphere to the a upper surface with material, and, that is how we have the formation of rising limb of convection current.

The moment material gets up -

1. to upper portion it create a space at bottom and the surrounding, comparative low temperature material, with higher density, get subsided and fills up the space, and, 
2. that's how the combination of rising limb and falling limb lead to the formation of convective cell.
3. If, we know this then we also know on the rising limb we have the divergent boundary and 
4. on the falling limb we have the convergence boundary.

So-

1. basically this question is about the converging boundary in respect of Oceanic-Oceanic conversion 
2. which lead to the 02 out product 
3. one is formation of TRENCH, and, 
4. second melting of "LITHOSPHERIC PLATE" through the subduction 
5. lead to the formation of "MAGMA" and 
6. following volcanic eruption 
7. which results in formation of volcanic group of island, which are well connected, known as archipelagos.

And that's how we connect this question to this explanation.

 

ANSWER STRUCTURE

1. Introduction
2. Convergent diagram
3. Explanation
4. Conclusion

 

ANSWER-

Earth internal structure suggest with gradual increase in temperature and density up to Centre resulted in the formation of convective cells in asthenosphere over which the rising limb lead to the formation of the subduction and result in Oceanic-Oceanic plate convergence.

   

In oceanic-oceanic convergence we have to 02 out products one is the formation of the trench and second volcanic archipelagos, which are the well connected group of islands, formed out of volcanic eruptions.

In respect of phippines archipelagos we have convergence of Philippines and Pacific Ocean plate, where as, in respect of Indonesian archipelagos convergence of Philippines plate and Sunda oceanic plate, and, that is how we have formation of Philippines and Indonesian archipelagos respectively.

Volcanoes are "construction unit" of earth continental crust, which is evident from the fact that in the coming future all the four major island of Japan would be connecting together to form a large landmass.

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