Sedimentary Rock Worksheet Blank.pdf

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Earth Science

Name Per.

Classifying Common Sedimentary Rocks

Sedimentary rocks may be classified into t h r e e groups based on what t h e y a r e made of and how they were formed. I f t h e sediments t h a t make up t h e rocks came mostly from t h e shells or body parts of living things, t h e rocks would be classif ied a s

organic sedimentary rocks.

I f t h e sediments were produced from minerals t h a t were dissolved in water but later came out of solution, t h e rocks would be classif ied as

chemical sedimentary rocks.

When elements come out of solution, t h e elements a r e said to have precipitated and t h e process is called chemical precipitation. Chemical sedimentary rocks a re also called evaporites. I f t h e sediments were formed from particles t h a t were weathered (broken off) from other rocks, t h e rocks are called clastic sedimentary rocks. Clastic sedimentary rocks a r e classif ied on t h e basis of t h e size of t h e sediment particles t h a t t h e rock is made o f .

The chart of sedimentary rocks summarizes t h e characteristics of t h e most important types of sedimentary rocks.

Common Sedimentary Rocks

Sedimentary Rock Type Particle S i z e or Composition Rock Name 1. Organic Sedimentary Rocks

Formed from t h e remains of living things such as plants or animals. Limestone comes from tiny animals in t h e ocean. Coal comes from plants t h a t grew in swamps.

mostly shells of tiny animals Limestone

1. Organic Sedimentary Rocks

Formed from t h e remains of living things such as plants or animals. Limestone comes from tiny animals in t h e ocean. Coal comes from plants t h a t grew in swamps.

mostly plant remains t h a t a r e

millions of years old Coal

(bituminous)

2. Chemical Sedimentary Rocks

Formed when minerals t h a t were dissolved in water come out of solution. Minerals can be

dissolved from rocks into ground water, and then transported somewhere else where they can form a new rock.

Sediment particles a r e too small to be seen without a microscope. The dissolved mineral t h a t comes out of solution determines t h e rock t h a t is made:

Rock type

Sediment particles a r e too small to be seen without a microscope. The dissolved mineral t h a t comes out of solution determines t h e

rock t h a t is made: formed:

Mineral:

-Calcite — • Dolomite — • Halite — • _ Gypsum — •

Limestone Dolomite Rock Salt Gypsum

3. Clastic Sedimentary Rocks

Formed when t h e particles t h a t a r e weathered (broken off) from o t h e r rocks a r e cemented

together to form a new rock.

Particle Size: boulder-sized (greater than 256 mm) cobble-sized (64 to 256 mm) pebble-sized (2 to 64 mm) sand-sized (0.06 to 2 mm) clay-sized (less than 0.06 mm)

| Conglomerates

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Refer to the chart on page 1 to complete the Data Table and answer the questions.

1. Read t h e description and fill in t h e correct Sedimentary Rock type.

DATA TABLE

Description Sedimentary Rock Type Rock Name

a.The sediment particles a r e formed by chemical precipitation and a r e too small to see without a microscope.

b.The sediment particles a r e mixtures of sizes t h a t range between 3.0 mm and 20.0 mm.

c. The sediment particles a r e pieces of shells.

d. The sediment particles a r e sand-sized.

e. The sediment particles a r e mostly p a r t s of plants.

2. a. What sedimentary rock can be formed in two di f f e r e n t ways?

b. Describe t h e two ways t h a t this rock can form

3. What is t h e only sedimentary rock type t h a t can be formed from things t h a t were once alive?

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Name Date Class

Review and Reinforce

Sedimentary Rocks

Understanding Main Ideas

Answer the following question on a separate sheet of paper.

1. In order, list the sequence of processes through which sedimentary rocks form.

Classify each of the following sedimentary rocks by writing clastic, organic, or chemical

in the blank beside it.

2.

3.

4.

5.

sandstone 6.

limestone made 7. from shells

conglomerate 8 .

coal 9.

breccia

limestone made from precipitated calcite

rock salt

shale

Building Vocabulary

Match each term with its definition by writing the letter of the correct definition in the right column on the line beside the term in the left column.

small, solid pieces of material from rocks or living things 10. clastic rock a.

11. sediment b.

c.

12. cementation _d.

13. organic rock

e.

14. compaction

f. 15. chemical rock

16. deposition

g-h. 17. erosion

the process by which running water, wind, or ice carry away bits of broken-up rock

the process in which dissolved minerals crystallize and glue sediment together

sedimentary rock that forms when rock fragments are squeezed together

water solution crystallize

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N a m e Date Class

Enrich

n

Sedimentary Rocks

Coal is one of the most useful rocks on Earth. Read the passage below and study the diagram. Then answer the questions that follow on a separate sheet of paper.

The Formation of Coal

Coal is an organic sedimentary rock. One of its properties is that it burns. Coal provides energy for industries and for the production of electricity.

Much of the country's best coal is found in Pennsylvania, Ohio, West Virginia, Kentucky, Tennessee,

and Alabama. The formation of this large coalfield began about 300 million years ago during a time geologists call the Carboniferous Period. During that period, vast tropical swamp forests covered much

of North America. When these ancient trees died, they fell into the swamp water, which was low in oxygen. Instead of rotting—as they would in an oxygen-rich environment—the dead vegetation piled

up. The sequence of pictures below tells the rest of the story of how this plant matter became coal.

1 .What is coal?

2. When did the coal deposits of the eastern United States begin to

form? What were environmental conditions like at that time?

3. What is peat?

4. What process caused the peat to become coal?

5. A type of coal called anthracite is classified by geologists as a

metamorphic rock. It is much harder than sedimentary coal. Describe

how you think anthracite forms.

Dead plant matter built up on the bottom o f a vast swamp during the Carboniferous Period.

Layers o f sediment were deposited. T h e weight of the sediment compacted the plant matter into a substance called peat.

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Name: Date:

Life Science Period:

Classifying Sedimentary Rocks

Rocks derived from pre-existing rocks through the process of erosion, followed by compaction, or chemical precipitation, are called sedimentary rocks. Sedimentary rocks are grouped into three categories: clastic, chemical and organic.

Clastic sedimentary rocks are formed by mechanical weathering. Weathering produces gravel, sand and silt, which are then cemented together by natural cements such a s silica, iron oxides and various carbonates to form clastic sedimentary rocks.

In the process of weathering, rocks or parts of rocks may be dissolved. As the solution cools or evaporates, the solid portion is deposited as precipitate. Rocks formed in this way are referred to a s chemical sedimentary rocks.

Rocks which are formed from the compaction of plant remains are termed organic

sedimentary rocks.

In this activity, you will identify and examine the characteristics of sedimentary rocks.

Clastic sedimentary rocks may exhibit the sediment that comprises them. Chemical

sedimentary rocks have a more homogeneous composition, and it may be much more difficult (or impossible) to distinguish the individual sediment. Only one of the samples is classified as organic sedimentary rock - can you figure out which one it is?

Procedures:

Using the descriptions for each rock in the five groups, identify the names of each one, placing the number in the correct column, and identify it a s clastic, chemical or organic.

GROUP A

Rock

Number

Description

Name

Clastic, chemical

or organic?

Contains solid

hydrocarbons and plant

remains. Petroleum-like

products can be distilled from this rock.

Oil shale

A sandstone composed of quartz grains cemented together by silica.

Quartz sandstone

A limestone composed of

spherical concretions,

each build up layer upon

layer around some

nucleus.

Oolitic limestone

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GROUP 3

Rock

Number

Description

Name

Clastic, chemical or

organic?

Known as "soft coal". It is a lightweight, soft black rock made of compacted fossil plant material.

Bituminous coal

Essentially sand-sized

particles cemented

together by calcite, silica or iron oxides.

Sandstone

A fine-grained, light to

medium gray colored rock

consisting mostly of

calcium carbonate.

Limestone

GROUP C

Rock

Number

Description

Name

Clastic, chemical

or organic?

A gray sediment in which the constituent particles are predominantly of clay size. Has a layered appearance.

Shale

Composed of calcium

carbonate deposited

between layers of other sedimentary rocks.

Rock g y p s u m

Composed of

reconsolidated gravel and

sand particles. Particles

("clasts") are well rounded

from erosional transport

prior to deposition and

compaction.

Conglo merate

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GROUP D

Rock

Number

Description

Name

Clastic, chemical or

organic?

Composed of rose quartz and pink feldspar particles with smaller amounts of mica. It is derived from

the disintegration of

granitic and other igneous rocks.

Arkrose

Crystalline in appearance with granular aggregates

of sodium chloride

deposited from

evaporating sea waters.

Rock salt

A light-colored limestone

formed from cemented

fossil shell fragments

deposited in swamp-like

areas. It has a

recognizable coarse,

shelly texture.

Fossil limestone

GROUP E

Rock

Number

Description

Name

Clastic, chemical

or organic?

Composed of sand grains

cemented together. The

bands of cement are

different colors.

B a n d e d sandstone

Composed of calcium

carbonate deposited from

solution in waters of

springs, lakes or from percolating ground water. Exposure to the water makes the minerals look rusted.

Calcareous tufa

A fine-grained light brown rock composed largely of

calcium carbonate

deposited between layers of other sedimentary rock.

Dolomite

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