Sedimentary rocks are formed by the accumulation and compaction or cementation of sediments. There are three main types - clastic sedimentary rocks which are composed of rock fragments transported by water, wind or ice; chemical sedimentary rocks which form from minerals precipitating from water; and organic sedimentary rocks which are formed from the remains of organisms. Sedimentary rocks can be further classified based on sediment size and include conglomerates, sandstones, shales, evaporites, and coal. They often exhibit layering, ripples, mud cracks, fossils, and concretions.

1. Formation of Sedimentary
Rock

2. Formation of Sedimentary Rock
• Made up of an accumulation of various types
of sediment.
• Compaction or cementation are two process
that form sedimentary rock.
– Compaction- when all air and water is squeezed
out of sediment
– Cementation- when minerals are left between the
fragments of sediment.

3. 3 Types of Sedimentary Rocks
• Clastic Sedimentary Rock- rock is made up of
rock fragments that have been moved by
water, wind or ice.
• Chemical Sedimentary Rock- forms from
minerals that precipitate from water.
• Organic Sedimentary Rock- forms from the
remains of organisms.

4. Clastic Sedimentary rocks
• Rocks are classified by the sediments size.
• Conglomerates- rocks composed of rounded gravel
size fragments or pebbles.
– Individual pieces are easily seen.
• The sandstone group is made up of sand size grains
that have been cemented together.
• The third group is shale, which consists of clay size
particles the easily flake or break apart.

5. Conglomerates

6. Sandstone

7. Shale

8. Chemical Sedimentary Rocks
• Rocks that form from
minerals that were once
dissolved by water.
• These rocks are called
evaporates.

9. Organic Sedimentary Rock
• Formed out of the remains of living things.
• Coal is a prime example of this.

10. Sedimentary Rock Features
• Easily identifiable
– Layering
– Ripples marks
– Mud
– Cracks
– Fossils
– Concretion