Presentation on theme: "What is a sedimentary rock? Sedimentary rocks are formed from broken bits of other rocks. The sediments are pressed and cemented together. They can also."— Presentation transcript:
What is a sedimentary rock? Sedimentary rocks are formed from broken bits of other rocks. The sediments are pressed and cemented together. They can also be formed from minerals in solution.
Where can I find sedimentary rocks? Sedimentary rocks are often found in river or stream beds. The weight of the water and the chemicals in the water press the sediment together. Eventually the sediments will cement into a rock.
What are sediments? Sediments are loose materials such as bits of rock, mineral grains, or bits of other things like shells that have been or will be moved around by erosion.
What is erosion? Erosion is the moving of weathered materials from one area to another.
What is weathering? Weathering is the breaking down of rocks by mechanical means such as wind, rain, hail, snow, sleet or human activity. The rocks can also be broken down by chemical means.
What is compaction? Compaction is the process by which the weight of sediments and or water above put pressure on the sediments causing them to stick together to form rocks.
What is cementation? Cementation is the process where water soaks into the soil and rocks, picking up dissolved minerals as it moves through the rocks and soil. The dissolved minerals get deposited in the sediments causing the sediments to cement together.
Sedimentary Rocks: Sedimentary rocks often form layers with the oldest layer on the bottom. There are three types of sedimentary rocks: DetritalChemicalOrganic
Detrital Sedimentary Rocks: Detrital means to “wear away.” Detrital sedimentary rocks formed from fragments of other rocks, which have been compressed and cemented together over time.
Chemical Sedimentary Rocks: Chemical sedimentary rocks formed when dissolved minerals came out of the dissolved solution forming a rock.. They are not made of sediments of preexisting rocks. The dissolved minerals themselves become the rock.
Organic Sedimentary Rocks: Organic sedimentary rocks formed from the remains of once- living organisms. The most common is fossil rich limestone. Another organic sedimentary rock is coal. Coal forms when piece of dead plants are buried under other sediments in a swamp.
Examples of Sedimentary Rocks Include: Conglomerate Sandstone Shale Limestone
How are Metamorphic Rocks formed? Metamorphic rocks are formed from igneous, sedimentary and even other metamorphic rocks.
How are Metamorphic Rocks formed? They can be formed when heat and pressure are exerted on the rocks. Also they can be formed from the presence of very hot watery fluids in close proximity to the rocks that are being changed.
Heat and Pressure: Rocks are exposed to great pressure from the rocks above them. Rocks also experience pressure from shifting plates.
Heat and Pressure: Temperature also plays a factor because as we go deeper into the Earth’s crust the temperatures increase. Metamorphic rocks do NOT melt but are exposed to enough heat and pressure to rearrange the molecules and atoms causing the rocks to change into different types of rocks.
Heat and Pressure: Depending on the amount of heat and pressure one kind of rock can turn into several different types.
Heat and Pressure: An intrusion of magma into an area can cause the surrounding rocks to change into metamorphic rocks. The intense heat and pressure the rocks experience from the intrusion and the pressure from the rocks above can cause changes to metamorphic rock.
Two Types of Metamorphic Rock Foliated Rocks: In foliated rocks, the minerals line up and flatten into parallel lines, such as in slate. Non-foliated rocks: In these rocks, layering does not occur. The mineral grains grow and rearranged but do not line up to form parallel lines, such as in marble.
Examples of Metamorphic Rocks. Marble Quartzite Slate Gneiss Anthracite
Examples of Metamorphic Rocks: Gneiss from granite Marble – from limestone Quartzite from sandstone Slate from shale
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