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 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.
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.
Chemical Sedimentary Rocks• Rocks that form from minerals that were once dissolved by water.• These rocks are called evaporates.
Organic Sedimentary Rock• Formed out of the remains of living things.• Coal is a prime example of this.
Sedimentary Rock Features• Easily identifiable – Layering – Ripples marks – Mud – Cracks – Fossils – Concretion