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 sediment Examples: Coal → (from plants) – ← limestone » ( from shells, used to make chalk)
3 Types of Sedimentary Rock 3. 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
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