SedimentaryRocks

Inside Earth Chapter 5.3Pages 154-158

Weathering

• Weathering: break down rocks on the surface into sediments– Sediments : pieces of material that come

from rocks or living things.

Weathering

Mechanical (pg 213)

Chemical (pg 215)

• Freezing & thawing• Growth of plants• Animal actions• Abrasion -

sediments wear down exposed rock

• Water (solution)• Oxygen (rust)• Carbon Dioxide• Acid Rain -

pollutants in the air make water vapor acidic.

Erosion

• Running water or wind carries away loose sediments.

Which is a form of Chemical weathering?

1 •Abrasion

2 •Plants

3 •Freezing & Thawing

4 •Oxygen

Deposition

• When sediments are “dropped off” by the water or wind carrying it.

Compaction

• Pressing rocks together due to gravity and the weight of overlying layers.– Layers build up

over time– As layers form on

top, press down and compact layers below

– Creates visible layers

Cementation

• When dissolved minerals crystallize and glue sediment together.• Occurs during compaction• Dissolved minerals fill in the spaces

between sediments.

When sediment is carried away by wind or water.

1 •Compaction

2 •Erosion

3 •Deposition

4 •Weathering

When layers of sediment are pressed together by gravity.

1 •Compaction

2 •Cementation

3 •Deposition

4 •Weathering

Sedimentary rocks are formed by…

1 •Human interactions

2 •Cooling of molten material

3 •Physical and chemical processes

4 •Metamorphism

• Sedimentary rock from rock fragments that are squeezed together.

Clastic Rocks

Shale Sandstone Conglomerate• (Breccia)

Clastic Rocks

Shale• Common rock that

forms from clay• Thin, flat layers that

split easily• Smooth

Clastic Rocks

Sandstone

• Forms from sand that is compacted and cemented

• Mostly made of quartz

• Somewhat porous

Clastic Rocks

Conglomerate / Breccia

• Mixture of grain sizes• Conglomerate has

more rounded grains• Breccia has sharp-

edged grains

Which process forms Sedimentary rock after it is deposited?

1 •Mechanical Weathering

2 •Erosion

3 •Compaction

4 •Chemical Weathering

• The remains of plants and animals deposited in thick layers.

Organic Rocks

Coal

• From plants buried in swamps

• Compacted over millions of years

Limestone• From shells of aquatic

animals (Calcite)• Some shells are

compacted, some dissolve

• Dissolved calcite cements it together.

Chemical Rocks

• Forms when dissolved minerals crystallize.

Rock Salt

• Forms from evaporation.

• Made of halite.

Gypsum

• Forms from evaporation.

Limestone

• Forms from dissolved calcite.

Which of these is an Organic rock?

1 •Shale

2 •Sandstone

3 •Conglomerate

4 •Limestone

Which of these is a Chemical rock?

1 •Shale

2 •Sandstone

3 •Conglomerate

4 •Limestone

Uses of Sed. Rocks

• Sandstone and Limestone are commonly used as building material• Easily cut into slabs• Limestone is used in cement.

Which of these does NOT describe how Sedimentary rocks are

classified?

1 •What it’s made of

2 •Size of grains

3 •If it was compacted

4 •If it crystallized