Question

What do sedimentary rocks look like?

Answer 1

Hint: These types of rocks are also found on Mars. These rocks are important sources of natural resources like fossil fuels, ores, etc.

Complete answer:
Sedimentary rocks are those rocks which are formed by accumulation and deposition of minerals or organic materials of the Earth. This accumulation is then followed by cementation which causes the accumulated materials to solidify and become sedimentary rocks. All these processes which together lead to the formation of sedimentary rocks is collectively known as sedimentation.

The looks of the sedimentary rocks, depends on its contents. When the rock contains Ferrous oxide (which is formed under a low oxygen environment), it appears grey or greenish in color. When the rock contains Ferric oxide (which is formed under higher oxygen circumstances), it appears reddish to brownish in color.

In arid regions where the rock does not come in contact with water and is directly exposed to the air, it gets a light coloration and it looks very light red or even orange in color. This is due to oxidative reaction because of its direct contact with air.

When the rock contains organic matter, is submerged in water, is present in a place with high humidity, or it is exposed to anoxic condition, then the sedimentary rock gets a very dark coloration. It looks dark grey in color or even black, at times.

Note:
- Sedimentary rocks cover almost 73% of the earth’s land surface.
- But they only make up 8% of the total volume of the earth’s crust.
- Sedimentary rocks, when deposited over a large area, are known as sedimentary basin.