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World Geography
Chapter 4 Vocabulary
Term | Definition |
---|---|
Core | Earth's center, where pressures and temperatures are very high. |
Mantle | The section of Earth's interior that lies above the outer core and has the most mass. |
Magma | Liquid rock within Earth. |
Plate Tectonics | The theory that Earth's crust is divided into rigid plates that slowly move across the upper mantle. |
Continental Drift | The process by which Earth's plates slowly move across the upper mantle. |
Rift Valleys | Places on Earth's surface surface where the crust stretches until it breaks. |
Abyssal Plains | Areas of the ocean floor where rocks gradually sink because they have no supporting heat below them; the world's flattest and smoothest regions. |
Continental Shelves | Areas where continental surfaces extend under the shallow ocean water around the continents. |
Trench | A deep valley marking a collision of plates, where one plate slides under another. |
Folds | Places where rocks have been compressed into bends by colliding plates. |
Faults | Places where rock masses have been broken apart and are moving away from each other. |
Weathering | The process by which rocks break and decay over time. |
Sediment | Small particles of weathered rock. |
Erosion | Movement of surface material from one location to another by water, wind, and ice. |
Glaciers | Thick masses of ice including great ice sheets and bodies of ice that flow down mountains like slow rivers. |
Plateau | An elevated flatland that rises sharply above nearby land on at least on one side. |
Alluvial Fan | Fan-shaped deposit of mud and gravel often found along the bases of mountains. |
Delta | Accumulation of sediment at the mouth of a river. |
Desalinization | Process of removing salt from ocean water. |
Hydrologic Cycle | Movement of water through the hydrosphere. |
Head Waters | First and smallest streams formed from the runoff of a mountain eventually forming rivers. |
Tributary | Any smaller stream or river that flows into a larger stream or river. |
Watershed | The entire region drained by a river and its tributaries. |
Estuaries | Semi-enclosed bodies of water, seawater, and freshwater formed where a river meets an inlet of the sea. |
Wetlands | Landscapes that are covered with water for at least part of the year. |
Groundwater | Water found below ground. |
Water Table | The groundwater level at which all the cracks and spaces in rock are filled with water. |
Humus | Broken-down plant and animal matter in soil. |
Leaching | Downward movement of minerals and humus in soils. |
Contour Plowing | Plowing fields across a hill, rather than up and down the hill. |
Soil Exhaustion | A condition in which soil has lost nutrients and becomes nearly useless for farming. |
Crop Rotation | The practice of planting different crops in a field in alternating years. |
Irrigation | A process in which water is artificially supplied to the land. |
Soil Salinization | Salt build-up in the soil. |
Deforestation | Destruction or loss of forests. |
Reforestation |