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Geology Unit
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Question | Answer |
---|---|
Layers of soil | 1.Organic layer 2.Topsoil 3.Subsoil 4.Regolith and Bedrock |
Organic Layer | sometimes called "litter layer" decomposing organic matter= leaf litter, plant parts,small animals/parts, animal feces |
Topsoil | the most decomposed organic matter called 'humus' rich in nutrients dark color seeds germinate here lots of organisms: worms, ants, other ground insects |
Subsoil | chunks of rocks, and sediments composed of iron, clay, alluminum only a little organic matter lighter color |
Regolith and Bedrock | regolith= top parts:composed of broken rock bedrock= solid rock under regolith little or no organic matter some tree roots get into regolith but not bedrock |
Formation of Soil Timeline | 1.solid rock 2.broken down by weathering 3.transported and broken smaller by erosion 4.becomes particles called sediment 5.add organic matter 6.add water 7.add air 8.becomes rich, fertile soil |
2 types of weathering | mechanical,chemical |
mechanical weathering | ice wedging: water freezes in cracks and expands |
chemical weathering | raindrops absorb carbon dioxide which forms a weak acid and dissolves rock overtime |
two causes of erosion | rivers: flow downhill and carry sediments which erode river banks landslides: rocks and soil are quickly pulled downhill |
know the layers/spheres of the earth | 1.crust 2.mantle 3.outer core 4.inner core 5.hydrosphere- water 6.atmosphere- air 7.lithosphere- land 8.biosphere- living things |
crust | made up of plates oceanic and continental crust |
mantle | thick made up of molten lava/magma |
outer core | mostly made of iron very hot |
inner core | mostly made of iron the hottest layer |