Minerals The substances that make up rocks and Earth’s surface

Sedimentary Process Physical & Chemical process of weathering and erosion Breaking of rocks into smaller pieces sediment Sediment = loose particulate material (clay, sand, gravel, etc.)

What are the main agents of weathering & erosion? Wind Moving water Gravity Glaciers Text p 135 figure 6.2

Sediment Deposited in low areas Largest grains sink to the bottom and the smallest grains at the top resulting in layers As more sediment is deposited the bottom layers are subject to increasing pressure & temperature causing Lithification

strata (layers) Sedimentary Rock

Lithification Lithify Greek word lithos which means stone Physical & Chemical process that transforms sediments into sedimentary rocks – Compaction – Cementation Sediments harden into rock

Sedimentary Rock Most formed under water but also in deserts/dunes Cemented together by SiO2, CaCO3 or FeO

Classification of Sedimentary Rocks How rock was formed Clastic: From pieces of other rocks Chemical: Precipitating out of a solution Biochemical: From remains of plants & animals

Clastic Greek work klastos meaning broken Most common sedimentary rock Sandstone, shale Further classified by size of particles – Coarse grain – Medium grained – Fine Grain Text p 142 Table 6.1

Chemical & Biochemical Chemical Forms in arid regions mostly called evaporites (example Great Salt Lake in Utah) Limestone, rock salt Biochemical Organic, common in shallow waters Coal, limestone

Common types of sedimentary rocks Shales Mudstones Sandstones Limestones Evaporites (such as salt beds)

Shales are the most common sedimentary rock type being made up of fine particles

Sandstones are made up of sand-sized grains most common is quartz

Limestone is a light whitish-gray

Identifying Sedimentary Rock Some show ripple marks or mud cracks

Desert Salt Flat

Ancient shallow water environment

Why do you think most fossils are found in sedimentary rock?

Homework Read text p &

ANY QUESTIONS?