| "To understand what sedimentary rocks are made of, the processes that lead to their formation must be understood!" |
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| "I'm willing to go there, Lulu! |
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| "Good man, Lou! The recipe for sedimentary rocks is: - Weather a pre-existing rock to make sediment.
- Transport and deposit the sediment.*
- Turn the sediment into rock (lithify the sediment).
Each of these steps plays a part in determining the composition of the sedimentary rock! Let's learn about or review each of the steps!" *Actually, in a small number of cases, step 2 is omitted. The weathered materials stays where it is and turns into rock. |
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TRANSPORT AND DEPOSITION OF SEDIMENT |
Once it is produced by weathering, sediment may be transported from its place of origin. - Sediment may gradually or rapidly work its way downslope due to the pull of gravity.
- Sediment may be picked up and carried by 'agents of transport': streams, wind, flowing ice, tides, waves, or living organisms.
- When the ground becomes level or agents of transport lose their energy, the sediment comes to rest (is deposited).
- Transport and deposition may occur repeatedly until the sediment comes to its 'final' resting place, where it is turned into rock.
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REVIEW SOME OF THE WAYS IN WHICH SEDIMENT MAY BE TRANSPORTED AND DEPOSITED |
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BY FLOWING ICE AND MELTWATER |
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BY LANDSLIDES |
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BY FLOWING WATER |
EXAMINE WHAT HAPPENS TO SEDIMENT DURING TRANSPORT |
| THE EVOLUTION OF SEDIMENT |
List three ways in which the sediment changed during transport.
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TRANSPORT AND DEPOSITION OF DISSOLVED MINERAL MATTER |
| THE FATE OF DISSOLVED MINERAL MATTER |
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LITHIFICATION OF SEDIMENT |
Once sediment comes to rest, it may be turned into rock. Lithification is most likely if a great thickness of sediment accumulates. The sediment grains that are buried are protected from being picked up and moved some more, and so have a chance to become attached to one another. As you have learned, the attachment is accomplished by cementation or by grains growing until they interlock. |
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REVIEW SOME OF THE WAYS IN WHICH SEDIMENT GRAINS MAY BECOME ATTACHED TO ONE ANOTHER |
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BY INTERLOCKING GRAINS |
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BY CEMENTATION |
Sediment accumulates and and has the chance to turn into rock in diverse locations on land and the floors of lakes and oceans. These locations will be described |
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| "So, Lou, what do you think?! Can sedimentary rocks be identified as such on the basis of the minerals they contain?! I'll provide some help in the form of some questions!" |
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| "As always, you're a great help! OK, serve me up the questions!! |
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Here are six questions that will help you decide if the mineralogy of a rock can provide clues as to whether it is sedimentary in origin. A distinction will be made between sediment that is 'fragmental' (composed of broken pieces of rock) and sediment that is 'precipitated' (composed of material precipitated from solution).
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To check your answers and get additional hints and information, click on the link. |