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21 Cards in this Set
- Front
- Back
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Soil |
A mixture of weathered rock, mineral fragments, decayed organic material, air and water |
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Bedrock |
The parent material of soil |
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Humus |
The organic material found in the topsoil. Made of decayed plant and animal matter. |
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Litter |
Organic material that falls on the surface of the topsoil, such as leaves and twigs. |
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Leaching |
Water seeping through the soil horizons, transporting minerals from the A horizon. |
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Soil horizons |
The layers of soil in a mature soil profile. |
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Topsoil |
The top layer of soil. Another name for the A horizon. Darkest layer, most organic matter (humus). |
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Subsoil |
The middle layer of soil. Another name for the B horizon. Less organic matter (humus) than the A horizon. |
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Substratum |
The bottom layer of soil. Another name for the C horizon. Mostly weathered rock. |
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Fossils |
Remains or traces of an organism that lived long ago. |
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Mold |
A type of fossils that is made from the imprint made by an organism |
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Cast |
A fossil copy of the organism made from the mold |
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Trace |
Fossils that show the existence of an organism, such as tracks, trails, burrows, nests, eggs, and coprolite. |
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Body |
A fossil created when an organism, or part of an organism, is preserved in amber, tar, ice, or ash. |
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Index fossil |
Species that lived only a short time. These fossils are used to determine the age of rock layers. |
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Relative dating |
Any method of determining whether an event or object is older or younger than other events or objects. |
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Superposition |
younger rocks lie above older rocks, if the layers have not been disturbed |
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Geologic Time Scale |
The division of earth's history based on major events |
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Epoch |
the smallest division of time on the geologic time scale |
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Era |
A division of the geologic time scale based on appearance of life. The paleozoic, mesozoic, and cenozoic. |
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Eon |
The largest division on the geologic time scale. The precambrian is the largest. |
