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Rocks and Weathering
Term | Definition |
---|---|
uniformitarianism | The geologic principle that the same geologic processes that operate today operated in the past to change the Earth's surface |
erosion | The process by which water, ice, wind or gravity moves weathered particles of rock and soil. |
weathering | The chemical and physical processes that break down rock and other substances |
mechanical weathering | The type of weathering in which rock is physically broken into smaller pieces |
chemical weathering | The process that breaks down rock through chemical changes. |
abrasion | The grinding away of rock by other rock particles carried in water, ice, or wind. |
frost wedging | Process that splits rock when water seeps into cracks, then freezes and expands. |
oxidation | A chemical with oxygen, as when iron oxidizes, forming rust |
permeable | Characteristics of a material that contains connected air spaces, or pores, that water can seep through easily |
soil | The loose, weathered material on Earth's surface in which plants can grow. |
bedrock | Rock that makes up Earth's crust; also the solid rock layer beneath the soil. |
humus | Dark-colored organic material in soil |
fertility | A measure of how well soil supports plant growth |
loam | Rich, fertile soil that is made up of about equal parts of clay, sound, and silt |
pH scale | A range of values used to indicate how acidic or basic a substance is; expresses the concentration of hydrogen ions in a solution |
soil horizon | A layer of soil that differs in color and texture from the layers above or below it |
topsoil | The crumbly, topmost layer of soil made up of clay and other minerals and humus (nutrients and decaying plant and animal matter). |
subsoil | The layer of soil below topsoil that has less plant and animal matter than topsoil and contains mostly clay and other minerals |
decomposer | An organism that gets energy by breaking down wastes and dead organisms, and returns raw materials to the soil and water |
natural resource | Anything naturally occurring in the environment that humans use |
soil conservation | The management of soil that differs in color and texture from the layers above or below it |
crop rotation | The planting of different crops in a field each year to maintain the soil's fertility |
contour plowing | Plowing fields along the curves of a slope to prevent soil loss. |
conservation plowing | Soil conservation method in which weeds and dead stalks from the previous year's crop are plowed into the ground |