Consider the following statements 1 Intrusive igneous rocks have larger crystal grains than extrusiv...........

Geography Earth Geology

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Consider the following statements:

1. Intrusive igneous rocks have larger crystal grains than extrusive igneous rocks.

2. Igneous rocks are always crystalline.

3. Igneous rocks are main source of fossils.

Which of the above statements are incorrect?

1 only

2&3 only

All of the above

None of the above

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Explanation:

Crystal formation depends on the rate of cooling of the rock. Since intrusive rock cools slowly, their crystals are well developed and have larger grains. Extrusive rocks are suddenly cooled hence they have smaller crystal grains.Igneous rocks can be both crystalline and amorphous.Fossils are not found in igneous rocks, hot lava burns all the organic content that comes in its way. Fossils are most commonly found in sedimentary rocks. If these sedimentary rocks are metamorphosised then sometimes they are found in metamorphic rocks too.