Question

distinguish between intrusive igneous rock and extrusive rock ?

Answer 1

Hey dear
here is ur answer

The most clear answer is that extrusive rocks form from material ejected from volcanoes or spreading ridges, e.g. rocks made from lava, tuff, pyroclastic flows, etc. whereas intrusive rocks are formed from molten rock in situ underground (often relatively deep), e.g. granite, gabbro, peridotite, dolerite, etc.

Extrusive rocks cool quickly, which means they only have time to form very small crystals (basalt), or none at all (obsidian, pumice).

If you find basalt with large crystals, those are crystals that formed over time in a magma chamber, sill or dike.

Intrusive rocks take a lot longer to cool, permitting the growth of larger crystals. Sometimes these crystals can be massive, as seen in the pegmatites of Norway.

Deep, very slow-cooking magma chambers tend to produce granites and gabbros. (Granites are a huge family of rocks that I don't want to go into here!).

The pathways taken by magma as it moves from magma chamber toward the surface are called dikes. (If these change direction and go horizontal they are called sills). Rocks formed by magma cooled in these environments have smaller crystals than granite or gabbro but (usually) much larger than basalts.

I’ll finish by saying that extruded igneous rocks usually last much longer in the destructive environment at the earth’s surface, because they formed there! The larger minerals of intruded rocks, once exposed to the elements (weather), tend to break down relatively quickly.

Hope it helps u
Have a great day

Answer 2

Answer:

Extrusive or volcanic rocks:

These rocks are formed when magma breaks through the crust and reaches the surface of the earth (where it is called lava). It cools rapidly and solidifies to form rocks. The common rocks formed in this manner are basalt and obsidian.

Instrusive or plutonic rocks:

These rocks are formed when magma fails to break through the crust and cools slowly under the crust  forming rocks. Because of slow cooling it solidifies into rocks with large grains of crystals. The common eg of rocks formed in this manner are granite and dolerite.

I Hope this will help uh ! :)