The physical breakdown and chemical alteration of rocks and minerals at or near Earth s surface.

Transcription

1 The physical breakdown and chemical alteration of rocks and minerals at or near Earth s surface. The material that is chemically and mechanically weathered to yield sediment and soil. Regolith consisting of weathered materials, water, air, and humus that can support vegetation. The removal of weathered materials from their source area by running water, wind, glaciers, and waves. Weathering that occurs at different rates on rocks, thereby yielding an uneven surface. Disaggregation of rocks by physical processes that yields smaller pieces that retain the composition of the parent material. The disaggregation of rocks by repeated freezing and thawing of water in cracks and crevasses. Accumulation of coarse, angular rock fragments at the base of a slope. A mechanical weathering process in which rocks that formed under pressure expand on being exposed at the surface. A large, rounded dome of rock resulting when concentric layers of rock are stripped from the surface of a rock mass.

2 A type of mechanical weathering in which the volume of rocks changes in response to heating and cooling. A mechanical weathering process in which salt crystals growing in cracks and pores disaggregate rocks. The decomposition of rocks by chemical alteration of parent material. A reaction in which the ions of a substance become dissociated in a liquid and the solid substance dissolves. The reaction of oxygen with other atoms to form oxides or, if water is present, hydroxides. The chemical reaction between hydrogen (H+) ions and hydroxyl (OH ) ions of water and a mineral s ions. A type of chemical weathering in which corners and sharp edges of rocks weather more rapidly than flat surfaces, thus yielding spherical shapes. The layer of unconsolidated rock and mineral fragments and soil that covers most of the land surface. A distinct soil layer that differs from other soil layers in texture, structure, composition, and color. Soil formed in humid regions with an organic rich A horizon and aluminumrich clays and iron oxides in horizon B.

3 Soil characteristic of arid and semiarid regions with a thin A horizon and a calcium carbonate rich B horizon. A red soil, rich in iron or aluminum, or both, resulting from intense chemical weathering in the tropics. Any process leading to a loss of soil productivity; may involve erosion, chemical pollution, or compaction. Loose aggregate of solids derived by weathering from preexisting rocks, or solids precipitated from solution by inorganic chemical processes or extracted from solution by organisms. Any rock composed of sediment, such as limestone and sandstone. Any site such as a floodplain or beach where physical, biologic, and chemical processes yield a distinctive kind of sedimentary deposit. The process of converting sediment into sedimentary rock by compaction and cementation. Reduction in the volume of a sedimentary deposit that results from its own weight and the weight of any additional sediment deposited on top of it. The process whereby minerals crystallize in the pore spaces of sediment and bind the loose particles together. Sedimentary rock made up of the solid particles (detritus) of preexisting rocks.

4 Sedimentary rock made up of minerals that were dissolved during chemical weathering and later precipitated from seawater, more rarely lake water, or extracted from solution by organisms. Any sedimentary rock produced by the chemical activities of organisms. Any rock, such as limestone and dolostone, made up mostly of carbonate minerals. Any sedimentary rock, such as rock salt, formed by inorganic chemical precipitation of minerals from evaporating water. Any aspect of a sedimentary rock unit that makes it recognizably different from adjacent sedimentary rocks of the same or approximately the same age. The invasion of a coastal area or a continent by the sea, resulting from a rise in sea level or subsidence of the land. The withdrawal of the sea from a continent or coastal area, resulting in the emergence of the land as sea level falls or the land rises with respect to sea level. Any feature in sedimentary rock that formed at or shortly after the time of deposition, such as cross bedding, animal burrows, and mud cracks. Refers to layering in sedimentary rocks. An individual layer of rock, especially sediment or sedimentary rock.

5 A type of bedding in which layers are deposited at an angle to the surface on which they accumulate, as in sand dunes. Sedimentary layer in which a single bed shows a decrease in grain size from bottom to top. Wavelike (undulating) structure produced in granular sediment, especially sand, by unidirectional wind and water currents or by oscillating wave currents. A crack in clay rich sediment that forms in response to drying and shrinkage. The remains or traces of once living organisms.