Sedimentary rock

Formed from sediments (rock fragments, mineral grains, animal & plant remains) that are pressed or cemented together.

What is sediment?

Small pieces of rock fragments, mineral grains, animal & plant remains or other materials found in earth.

• These sediments are moved by wind, water, ice or gravity.

• Sedimentary rocks represent 7% of the Earth’s crust, but they cover 70% of the Earth’s surface.

• Sedimentary rocks are fossil-carrying rocks.

What turns sediments into solid rock?

• Weathering – Wearing away of rock by water, wind or ice

• Erosion – movement of sediment by water, wind or ice

• Deposition – dropping of sediment and wind or water slows down

Last steps for turning sediments into solid rock…

Compaction - The heavy sediments press down on the layers beneath (pressure)

Cementation - Dissolved minerals flow between the particles and cement them together

Review: 5 Steps to sedimentary rock formation:

• Weathering- wearing away of rock by wind, water or ice

• Erosion- movement of sediment by water, wind or ice

• Deposition- dropping of sediment as wind or water slows down

• Compaction- pushing together of pieces of sediment under pressure

• ***Cementation- “glueing” together of sediment by minerals that dissolve and harden

Sediment does NOT become rock until

cementation occurs.

How can sedimentary layers help us understand the age of fossils?

• As sedimentary rocks are deposited, they form horizontal layers

• Scientists know that the layers on top (and the fossils in the top layer) are YOUNGER than the fossils in lower layers.

3 Types of Sedimentary Rock

1. Clastic (also called Detrial)- made from broken pieces of rock

• Examples: conglomerate →

←breccia

more examples of clastic sedimentary rocks

shale → ( from clay)

← sandstone

(from sand)

3 Types of Sedimentary Rock 2. Organic- forms from the remains of plants or

animals that were buried in sedimentExamples: Coal → (from plants)

– ← limestone

» (from shells, used to make chalk)

3 Types of Sedimentary Rock3. chemical - mineral deposits left

when seas or lakes evaporate

Fossils in sedimentary rock

• Fossils are seldom found in any rock type except sedimentary rock. If

you find a fossil, you can be fairly sure it is sedimentary rock.

Uses of sedimentary rock• Buildings are made of limestone and

sandstone because they are easily cut into blocks or slabs.

• The White House in Washington, DC is built from

sandstone. View this information through the Human Ingenuity Lens.

Notes

• What is sediment?

• How is sedimentary rock formed?

• What are the 5 steps to sedimentary rock formation?

1.2.3.4.5.

• Sediment does not become rock until what process occurs?

What are 3 types of sedimentary rock?

1. ________________ made from________________________

2._________________Made from__________________________

3. ________________Made from__________________________

• In what type of rocks are fossils usually found?

• What are some uses of sedimentary rock?

Review and Preview

• View this video to review igneous and sedimentary rock formation. Also view a preview of metamorphic rock formation.

• Rock_Formation video united streaming.mov