1. Soil Horizon: The layer of soil parallel to the soil surface is known as soil horizon. Depending upon the texture and composition of the soil, it is categorized as O, A, B and C. Horizon O consists of organic matter such as remains of plants. Horizon A contains plants’ roots, fungi, bacteria and chemically stable minerals. Horizon B is the accumulation of soluble minerals. Horizon C contains bed rock, in other words rock fragments.
2. Mechanical Weathering: Mechanical withering occurs as a result of physical processes that break down rocks and minerals into smaller pieces that hold back the properties of the parent material. The physical processes can be activities of organisms, expansion and contraction due to changes in temperature, frost action, and so on.
3. Chemical Weathering: Chemical weathering alters the structure and composition of the parent material. The physical processes can be oxidation, solution or hydrolysis and mostly occur on the surface of the particles. Plants, and organisms made up of algae and fungi are responsible for chemical weathering. The roots of plants release organic acids and remove the ions from soil water to reduce the chemical stability of soil minerals.
4. Spheroidal weathering: Spheroidal weathering is another form of chemical weathering which results in spherical layers of rocks upon weathering. Water penetrates in the intersecting joints of the rocks and alters the shape of the rocks. Firstly, the corners, then the edges, and finally the faces of the rocks erode and result in a spherical shape.
5. Leaching: Leaching is defined as the process of carrying away of soluble particles from the top layer of the soil. This is caused as a result of precipitation in areas of high rainfall and high temperatures. As a result of leaching, soil loses all the valuable nutrients and is left with hydroxides of iron, aluminum and magnesium.
1. Creep: A creep is used to describe a slow and gradual downward movement of a hill or a mountain due to gravity. It is as slow as less than one inch an year. Creep generally forms due to long term exposure of the land under the influence of stress.
2. Landslide: Landslide is a quick and sudden downward movement of the side of a hill or a mountain. It is referred to as mass wasting. It can be due to various factors like gravity, rainfall and earthquake. In mountains, landslides generally occur due to the melting of snow.3. Permafrost: When the ground remains under the freezing point for a consecutive period of two years, it is known as permafrost. It is mostly found in the higher altitudes of Northern Hemisphere where the average annual temperature is 0oC.4. Solifluction: Solifluction is defined as the slow downhill movement of waterlogged soil sediments. It occurs due to the force of gravity. The rate at which soil slides downward is up to a few inches a year. Solifluction frequently occurs in mountain regions during summer when the snow melts on the surface of the soil leaving the soil waterlogged. It produces gentle concave slopes.5. Talus: Talus is a group of rocks that accumulate at the base of a steep cliff due to rapid movement of rocks that fall down the slope of a hill. Rockfalls generally occur from the failure of bedding planes in the bedrock. Chemical weathering, earthquakes and human activities are a few reasons for the formation of talus.
Hydrologic Cycle
Define
1. Stream divide: Stream divide is defined as a ridge or an elevation that separates one stream from another.
2. Stream piracy: Stream piracy is the phenomenon in which a stream diverts its path from its original bed and flows downward in the path of its neighboring stream. Stream piracy generally occurs due to landslides, erosion or tectonic movements.
3. Dendritic drainage: Dendritic drainage is a pattern that looks like the branching of a tree. The water flows into several smaller branches and finally joins at the tribute of the main river.
4. Dissolved load: Dissolved load is referred to the stream of water that carries some kind of material in it, mostly chemical ions which are a result of chemical weathering.
5. Natural levee: Natural levee is formed as a result of seasonal flooding of rivers. It is a deposit of sand that is built up alongside of a river or stream.
6. Suspended load: Suspended load is fine sediment of sand or silt or clay that flows along with the water without coming in contact with the stream bed. It is a result of the erosion of soil due to weathering or hydraulic action.
7. Meander cutoff: Meander is a bend that forms in the watercourse or a river due to the erosion of outer banks of a river. Meander cut off is defined as the connection between the two closest parts of the bend.
8. Ultimate base level: Ultimate base level is defined as the mouth of the river where it meets the sea or ocean. It is the lowest point up to which a river can flow.
Works Cited
Monroe, J., & Wicander, R. (2011). The Changing Earth: Exploring Geology and Evolution. Cengage Learning.
Pipkin, B., Trent, D., Hazlett, R., & Paul, B. (2010). Geology and the Environment. Cengage Learning.
Reynolds, S. J. (2013). Exploring Geology, 3 illustrated. McGraw-Hill Education.
