5.2 sedimentary rocks

Formation of Sedimentary Rock

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.

Conglomerates

Sandstone

Shale

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