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 whick Earth |
rift valleys | places on Earth's surface where the crust stretches until it breaks |
abyssal plains | Areas of the ocean floor where rocks gradually sink beacuse they have no supporting heat below them : the world's flattest and smoothest regions. |
continental shelves | areas where continentals 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 breaks and dacay over time |
sediment | smaller particles of weatherered 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 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 |
hydrolic cycle | movement of water through the hydrosphere |
headwaters | first and smallest streams formed from the runoff of a mountain , eventually forming rivers |
tributary | any smalller stream or river that flows into a larger stream or river |
watershed | the entire region drained by a river and its tributaries |
drainage basin | a 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 is 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 buildup in the soil |
deforestation | destruction or loss of forests |
reforestation | the replanting of a forest |
acid rain | polluted rain than can damage trees and kill fish in lakes |
aqueducts | artificial channels for transporting water |
aquifers | rock layers where groundwater is plentiful |
fossil water | groundwater that is not replenished by rain |
ore | mineral-bearing rock |
fossil fuels | energy resources - formed from the remains of ancient plants and animals - includind coal , natural gas , and petroleum |
petrochemicals | certain products made from oil |
hydroelectric power | electricity produced by moving water |
geothermal energy | Heat of Earth's interior |