Table of Contents

3-5 Sedimentary Rocks

Ms. De Los Rios

Earth’s Structure and Materials – Course 2

Sedimentary Rocks 3-5

How Do Sedimentary Rocks Form?

What Are the Three Major Types of Sedimentary Rocks?

How Are Sedimentary Rocks Formed?

Vocabulary 3.5 Sediment- Small, solid pieces of material that come from rocks or living things.

Weathering- the effects of freezing, thawing, plant roots, acid and other forces on rock that break down the rock into fragments.

Erosion –process by which running water, wind, or ice carry away the fragments of broken-up rock. Deposition- the process by which sediment settles out of the water or wind carrying it.Compaction- the process that presses sediments together

Clastic Rock- a sedimentary rock formed when rock fragments are squeezed together.

Organic Rock- a sedimentary rock formed with the remains of plants and animals are deposited in layers.

Chemical Rock- a sedimentary rock that forms when minerals dissolved in a water solution crystallize.

How Do Sedimentary Rocks Form? Pg. 120

Sediment is small, solid pieces of material that come from rocks or living things.

How do sedimentary rocks form?Sedimentary rocks form when sediment is deposited by water and wind.

Most sedimentary rocks are formed through a sequence of processes:

1. weathering2. erosion3. deposition4. compaction5.cementation

How Sedimentary Rock FormsSedimentary rocks form through a series of processes over millions of years.

Sedimentary Rocks WEDCC

How Do Sedimentary Rocks Form? Pg. 121Rock on Earth’s surface is constantly broken up by weathering—the effects of freezing and thawing, plant roots, acid, and other forces on rock.

After the rock is broken up, the fragments are carried away as a result of erosion—the process by which running water, wind, or ice carry away bits of broken-up rock.

Deposition is the process by which sediment settles out of the water or wind carrying it.

The process that presses sediments together is compaction.

Cementation is the process in which dissolved minerals crystallize and glue particles of sediment together.

What Are The Three Major Types Of Sedimentary Rocks?

Geologists classify sedimentary rocks according to the type of sediments that make up the rock.

The 3 major groups of sedimentary rocks are:

Clastic rocks Chemical rocks

Organic rocks

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Clastic Sedimentary Rocks – pg 122

Clastic Rock •A sedimentary rock formed when rock fragments are squeezed together. •The fragments size vary from clay particles that are too small to see without a microscope to large heavy boulders.

How are Clastic rocks classified? by the size of the rock particles that make them up.

SOME COMMON CLASTIC ROCKS ARE: SHALE -Which forms from tiny particles of clay which water deposits in thin flat layersSANDSTONE-Which forms from sand on beaches, the ocean floor, riverbeds and sand dunes CONGLOMERATE- forms from rock fragments that have rounded edgesBRECCIA- Forms from rock fragments that have sharp edges

Organic Sedimentary Rocks pg. 123

Organic rock •A sedimentary rock that forms where the remains of plants and animals are deposited in layers. •Organic means substances that were once living or that were made by living things.

SOME COMMON ORGANIC ROCKS ARE:COAL -which is made from the remains of swamp plants buried in water. As layers build up, the weight squeezes the decaying plants together. Over millions of years they slowly change into coal.

LIMESTONE- Which forms in the ocean, where coral, clams, and oysters have hard shells or skeletons made of the mineral calcite. When they die, their shells pile up and over millions of years, compaction and cementation change the thick sediment into limestone.

Organic RocksHow do coal and limestone form?

Sedimentary Rocks pg. 123

Chemical Sedimentary Rocks pg. 124Chemical rock forms when minerals dissolved

in a water solution crystallize.

SOME COMMON CHEMICAL ROCKS ARE:LIMESTONE-forms when calcite that is dissolved in lakes, seas, or underground water comes out of a solution and creates crystals.

ROCK SALT- made from the mineral halite which forms by evaporation.

Apply It! Pg. 124These rock “towers” in Mono Lake, California, are made of tufa, a form of limestone. Tufa forms from water solutions that contain dissolved materials. The towers formed under water. They became exposed when the water level in the lake dropped as a result of water needs for the city of Los Angeles.

1. Classify Tufa is a (clastic, organic, chemical) sedimentary rock.

2. Infer What mineral was dissolved in the waters of Mono Lake and later crystallized to form the rock towers?_______________________________________________________3. Challenge When acid comes into contact with calcite, the acid bubbles. How can geologists use acid to confirm that the rock towers are made of limestone?______________________________________________________________________________________________________________

How Are Sedimentary Rocks Used? Pg. 125

People have used sedimentary rocks throughout history for many different purposes, such as tools and

building materials. Guess what Material is the White House made of?

The White House is made out of sandstone!!!

Chert and flint were used to make spearheads and arrowheads.

Sandstone and limestone are used as building materials because they are both soft enough to be cut easily into blocks or slabs.

Limestone and sandstone are used on monuments and buildings.

Limestone is also used to make cement and steel.

Figure 4 Hurricane Monument (Islamorada, FL)

Evaluate the design Do the benefits of constructing monuments out of limestone outweigh the damage acid rain causes them?

Explain._________________________________________________________________________________________________________________________________________________________________________________________________________________