Introduction to Soil Science and Geology
Soil Formation and Characteristics
Factors Involved in Soil Formation
Climate, organisms, the overall water balance, time, bedrock, slope, and orientation are all crucial factors in soil formation.
Soil from a Pedological Viewpoint
Soil is a surface layer formed naturally, harboring living material and developing on vegetative cover. It consists of mineral and organic fractions.
Soil Structure
Soil is structured in horizons from the surface to the bedrock. These horizons, differing in composition, structure, and properties, are distinguishable by their color and texture.
Key Features of Soil Horizon “B”
Horizon “B” accumulates mineral elements from the upper horizon. It’s characterized by a higher clay content, lighter color due to the absence of humus, and the presence of iron oxides.
Soil as an Interface
Soil acts as an interface within the Earth system, where the atmosphere, biosphere, hydrosphere, and lithosphere converge.
What is a Soil Horizon?
A soil horizon is a layer within the soil profile, extending from the surface to the bedrock. Each horizon possesses distinct composition, structure, and properties. The complete set of horizons is referred to as the soil profile.
River Systems and Processes
River Load, Capacity, and Competence
- Load: The actual amount of sediment carried by a river at a given time and location. Types include bed load, suspended load, and dissolved load.
- Capacity: The theoretical maximum amount of sediment a river can transport, determined by its volume, velocity, and flow regime.
- Competence: The maximum size of sediment a river can transport as bed load.
Equilibrium Profile of a River
A river achieves an equilibrium profile when it attains a longitudinal shape that minimizes energy expenditure. In this state, the river primarily carries water. Few rivers naturally exist in this condition.
Estuary vs. Delta
An estuary is an open-coast river mouth where river-borne sediments are dispersed by littoral currents. A delta, conversely, forms from sediment accumulation at the river mouth.
Mining and Environmental Impact
Advantages and Disadvantages of Open-Pit Mining
Open-pit mining offers cost advantages over underground methods. However, it carries significant environmental consequences, impacting landscapes and requiring vast land areas.
Formation of River Terraces
River terraces, resembling stair-like formations, result from vertical erosion followed by periods of stability. Fluctuations in river flow, often linked to glacial cycles, contribute to their development.
Energy Resources and Geology
Reservoir Rock Characteristics for Oil Accumulation
Reservoir rocks, such as sandstone and limestone, must possess interconnected pores to facilitate fluid flow. These rocks are crucial for hydrocarbon storage.
Wave Formation and Coastal Impact
Waves, generated by wind friction on the ocean surface, induce circular motion in water particles. They act as erosive agents, shaping coastal morphology through corrosion and abrasion.
Delta Formation
Delta formation begins with underwater sedimentation. As sediments accumulate and reach the surface, a subaerial delta develops, transitioning from a lobate to a triangular shape, filling in basins with sediment.
Major Pollutants from Coal-Fired Power Plants
Coal combustion releases significant amounts of sulfur dioxide (SO2), contributing to acid rain. Dust and leachate further contaminate air, surface water, and groundwater.
Mineral Resources and Management
Mineral Resources vs. Mineral Reserves
Mineral Resources encompass all usable rocks, minerals, metals, and hydrocarbons present in the Earth’s crust. Mineral Reserves, however, represent the economically viable portion of these resources, extractable with current technology.
Remediation of Soil Erosion
Forestry Measures: Afforestation, bush improvement, and silvicultural treatments.
Agricultural Measures: Terracing, conservation tillage, contour plowing, restoring soil fertility, and crop abandonment.
Hydrotechnical Works: Construction of drains and gullies to prevent backflow.
Nuclear Reactions
Nuclear Fission vs. Nuclear Fusion
Nuclear Fission: A heavy nucleus splits into smaller, heavier nuclei, releasing energy and neutrons. This process is initiated by neutron bombardment.
Nuclear Fusion: Two light nuclei combine to form a heavier nucleus, releasing energy and often a free neutron. This process requires overcoming a significant energy barrier.