[Mission 2024] STATIC QUIZ, 8 July 2023 – Environment

Solution: b)

Statement 3 is incorrect.

There are four types of plate boundaries:

• Divergent boundaries — where new crust is generated as the plates pull away from each other.
• Convergent boundaries — where crust is destroyed as one plate dives under another.
• Transform boundaries — where crust is neither produced nor destroyed as the plates slide horizontally past each other.
• Plate boundary zones — broad belts in which boundaries are not well defined and the effects of plate interaction are unclear.

Divergent boundaries occur along spreading centers where plates are moving apart and new crust is created by magma pushing up from the mantle. Picture two giant conveyor belts, facing each other but slowly moving in opposite directions as they transport newly formed oceanic crust away from the ridge crest.

Perhaps the best known of the divergent boundaries is the Mid-Atlantic Ridge.

Solution: a)

The key difference between intrusive and extrusive rocks is that the intrusive rocks are formed from magma whereas the extrusive rocks are formed from lava.

Intrusive rocks: With no air to cool the magma, these rocks are formed very slowly. Composition of these rocks reflects presence of large crystals. These crystals interlock to form the rock.

These rocks take a very large amount of time to solidify and they remain buried deep inside the surface of the earth being surrounded by country rocks that have been there already.

Very slow cooling means that these rocks remain coarse-grained.

Some of the perfect examples of intrusive rocks are the diorite, gabbro, and granite.

Much of the core of various mountain ranges around the world is made up of these intrusive rocks.

Extrusive Rocks: Sometimes, molten rocks find a way to come out of the surface of the earth through cracks and openings.

This magma flows in the form of lava and cools down quickly as it comes into contact with air.

Igneous rocks that are formed from the magma that pours out of the surface of the earth are called extrusive rocks.

As these rocks cool down and solidify very quickly, they do not get sufficient time to form large crystals. Thus, they have small crystals and boast a fine texture.

Solution: b)

Quartz and Basalt both can be associated with sedimentary rocks, even though Quartz may occur in felsic igneous rocks or granite.

Bulk of the valuable minerals in India are products of pre-Palaeozoic age spanning from nearly 540-250 million years ago. Hadean age refers to the one right after formation of earth.

These minerals are mostly associated with metamorphic and igneous rocks of the peninsular India, and not sedimentary rocks.

Solution: a)

Block Mountains are created when large areas are broken and displaced vertically. The uplifted blocks are termed as horsts and the lowered blocks are called graben. The Rhine valley and the Vosges mountain in Europe are examples of such mountain systems. Vindhyan and Satpura ranges with Narmada rift valley is another example.

Volcanic mountains are formed due to volcanic activity. Mt.Kilimanjaro in Africa and Mt.Fujiyama in Japan are examples of such mountains.

Solution: a)

Pir Panjal is the further South of Zanskar and Karakoram.