Applications of Geomorphology in Mineral Prospecting, Civil Engineering | Geology Optional Notes for UPSC PDF Download

Introduction

• Understanding landforms is crucial for humans, as it directly or indirectly affects their interaction with the earth's surface features. By correctly interpreting landforms, we can gain insights into the geological history, structure, and composition of a region. Applied geomorphology, as defined by D.K.C. Jones, is the process of utilizing geomorphic knowledge to address issues related to land use, resource management, and environmental planning.
• According to R.G. Craig and J.L. Craft, all geomorphological knowledge tends to have practical applications. As our understanding of the earth's processes improves, geomorphologists can use this knowledge to assess resources, plan development projects, identify potential natural hazards, and reduce the impact of natural disasters. In essence, the study of landforms plays a significant role in managing and planning our interactions with the earth's surface.
• Geomorphic knowledge and techniques may be applied in the following areas:
  • Examining the effects of geomorphic and environmental processes on human society and activities, as well as addressing the challenges that result from these impacts;
  • Exploring the alterations in geomorphic and environmental processes caused by human actions and managing the issues that arise from such interactions.
  • Overseeing resource management and tracking changes in the geomorphic system to propose appropriate solutions that ensure sustainable development.

Two Main Lines of Application

The application of geomorphology, according to Charley, Schumn, and Sugden, may be considered along two lines:

Resource evaluation, engineering construction and planning

• In the field of applied geomorphology, various applications can be found, such as resource inventories, environmental management, soil and land evaluation, and producing maps for hydrological, erosional, and stability control. This field also encompasses geomorphic mapping, land system mapping, terrain evaluation, and information retrieval on terrain and other relevant subjects for earth scientists, engineers, and planners.
• Applied geomorphology plays a crucial role in urban planning across diverse geomorphic environments. It aids in the creation of natural hazard maps, morpho-agricultural regionalization, land use planning, and the construction and management of roads. By utilizing applied geomorphology, professionals can better understand and address the challenges posed by various landscapes and environments, ultimately leading to more informed decision-making in urban planning and development.

Human beings as geomorphic agents:

• Applied geomorphology is a field that examines the impact of human activities on the Earth's surface, particularly in terms of intentional or unintentional effects on the various processes and forms that shape the landscape. Throughout history, humans have sought to control and manipulate these natural processes to meet their economic needs.
• For example, people have constructed embankments to prevent river flooding, straightened and redirected river courses, built walls to protect coastal areas from wave erosion, attempted to stabilize sandy areas through planting vegetation, and combated soil erosion through reforestation. These are all examples of intentional human actions that have influenced the geomorphic processes and forms.
• Meanwhile, there are also numerous unintentional consequences of human activities on the Earth's surface. These include deforestation and burning grasslands for agricultural or urban development purposes, land subsidence due to mining activities and groundwater extraction, alteration of the landscape as a result of construction and mining, and increased soil erosion and sedimentation rates due to excessive and unplanned deforestation. Pollution, a significant byproduct of human economic activities, also plays a role in altering geomorphic processes and forms.
• Furthermore, the building of dams can lead to changes in river sediment loads and increased erosion, while construction in high-altitude regions can alter permafrost conditions. In summary, applied geomorphology seeks to understand the complex interplay between human activities and the Earth's surface, with a particular focus on both the intentional and unintentional consequences of these actions on the landscape and its processes.

Specific Applications

1. Geomorphology and Hydrology: Geomorphology plays a crucial role in understanding the movement and distribution of water on Earth's surface. By studying the shape and structure of landscapes, hydrologists can predict and manage water flow, flood risks, and water resource availability.
2. Geomorphology and Mineral Exploration: The study of landforms and the processes that shape them can provide essential clues for locating valuable mineral deposits. Geomorphologists can help identify areas with high potential for mineral resources, reducing the time and cost of exploration.
3. Geomorphology and Engineering Works: Geomorphologic analysis can help engineers design safe and sustainable infrastructure projects by assessing the stability of slopes, the susceptibility of an area to erosion, and the potential impacts of construction on surrounding landscapes.
4. Geomorphology and Military Geology: Geomorphology can provide valuable information for military strategists, such as identifying potential obstacles, determining the optimal placement of defensive structures, and understanding how the terrain may affect troop movement and transportation.
5. Geomorphology and Urbanization: As cities continue to grow and expand, geomorphology can help planners make informed decisions about where to build and how to minimize the impacts of urbanization on the natural environment, such as preserving vital ecosystems and reducing the risk of natural hazards.
6. Geomorphology and Hazard Management: Geomorphologists can help identify areas at risk for natural hazards, such as landslides, earthquakes, and floods, and develop strategies for mitigating these risks by understanding the underlying geological processes at work.
7. Geomorphology and Regional Planning: By analyzing the physical characteristics of a region, geomorphologists can provide valuable insights for regional planners, helping them make informed decisions about land use, resource management, and environmental protection.

In summary, geomorphology has a wide range of applications that can benefit professionals in various fields, from guiding mineral exploration efforts to informing urban planning decisions. By understanding the processes that shape Earth's landscapes, we can make more informed decisions about how to manage and protect our environment.

Geomorphology and Hydrology

• Water sources for human consumption can be derived from various sources such as streams, lakes, rivers on the Earth's surface, or groundwater. Different geological zones offer diverse conditions for both surface and groundwater availability.
• Limestone terrains have varying water-yielding capacities depending on the rock type. Permeability in limestones can be primary or secondary. Primary permeability depends on the existence of initial interconnected voids in the calcareous sediments from which the rock was formed. Secondary permeability arises from earth movements like faulting, folding, and warping, as well as solution or corrosion mechanisms.
• This secondary permeability is greatly influenced by a region's topography, being most significant beneath and adjacent to topographic lows or valleys. In karst terrain, much of the groundwater is confined to solution channels.
• In the early stages of karst evolution, conditions are not very different from those in other landscapes with similar relief. However, as the cycle progresses, a large portion of water is diverted to solutionally opened passageways, reducing surface water availability. The primary source of water in such regions then becomes karst springs. These springs can provide water to meet moderate demands, but the water quality may be affected by pollutants and bacteria.
• To determine the sources of spring water in cases of pollution, the swallow holes and sinkholes that feed water to the underground drainage systems emerging as springs must be located. This can be achieved by introducing a coloring material, like fluorescein, into the water entering nearby swallow holes (or sinkholes) and testing the various spring waters to identify their source. A knowledge of the region's structural geology is helpful in this context, as groundwater tends to move down rather than up the regional dip.
• The ease of obtaining water in a limestone region depends on the area's geomorphology. If the limestones have adequate permeability and are capped by a sandstone layer, large-yield wells may be easily obtained. Additionally, the water would be naturally filtered as it passes through the sandstone beds.
• However, if the limestone is dense and compact with low mass permeability, groundwater movement will primarily occur through secondary openings. In such circumstances, the water yield may be low, or even if sufficient, subject to contamination. Karst plains lack a filtering cover, and sinkholes, swallow holes, or karst valleys within an area of clastic rocks should raise concerns about the purity of nearby spring water.
• Groundwater potential in glaciated regions can be determined based on the area's geomorphic history, characteristics of glacial deposits, and landforms. Outwash plains, valley trains, and intertill gravels are likely to yield large volumes of water. Most tills are poor water sources due to the clay content, but they contain local strata of sand and gravel that may hold and supply enough water for domestic needs.
• Buried preglacial and interglacial valleys could be good sources of groundwater. Their presence (or absence) can be detected by studying the preglacial topography and geomorphic history of the area. Buried valleys are located by constructing bedrock topography maps of glaciated areas.

Geomorphology and Mineral Exploration

Mineral deposits are often associated with specific geological structures, and the landscape characteristics of certain areas can indicate the presence of these structures. There are several types of minerals and ore bodies that can be identified by their surface expressions or through the study of geomorphology.

• Surface Expression of Ore Bodies: Some ore bodies, such as lead-zinc lodes or quartz veins, have visible surface expressions in the form of topographic forms, outcrops, gossans, or structural features like faults, fractures, and breccia zones. These can help in identifying the presence of mineral deposits in the area.
• Weathering Residues: Minerals like iron ore, clay, caliche, bauxite, and some manganese and nickel ores are formed as weathering residues of present or ancient geomorphic cycles. These minerals are typically found on pleneplain or near-pleneplain surfaces, which are remnants of Tertiary erosional surfaces.
• Placer Deposits: Placer deposits are mixtures of heavy metals formed through chemical weathering or erosion of metallic formations. These deposits are formed due to specific geomorphic processes and can be found in particular topographical positions. Examples of minerals found in placer deposits include gold, tin, platinum, and diamonds.
• Oil Exploration: Many oil fields have been discovered due to their distinct topographic expression. Oil is usually trapped in rocks under structural or stratigraphic traps, with porous and permeable rocks like sandstone and limestone being ideal locations for oil deposits. Techniques such as drainage analysis using aerial photography can help identify areas with geological structures favorable for oil accumulation.

In summary, the study of geomorphology can be highly beneficial in mineral exploration. Knowledge of the bedrock geology, geophysical surveying, test drilling, and aerial-photograph interpretation are essential components in the search for mineral deposits. A thorough understanding of the geomorphic history of a region can significantly aid in the discovery of valuable mineral resources.

Geomorphology and Engineering Works

Engineering projects typically involve evaluating various geologic factors, with terrain characteristics being among the most common. Geomorphology, the study of landforms and their processes, plays a vital role in several engineering fields, including road construction, dam site selection, airstrip construction, locating sand and gravel pits, military geology, urbanization, hazard management, and regional planning.

• Road Construction: Determining the best highway routes depends on the topographic features of the area. Understanding the geologic structure, lithological and stratigraphic characteristics, strength of surface deposits, and geomorphic history of the area is crucial in road engineering. Different terrains, such as karst plains, glacial terrains, and areas with considerable relief, present unique engineering challenges. Modern highway construction also requires knowledge of soil profiles and their relationships to varying topographic conditions and types of parent material.
• Dam Site Selection: Selecting appropriate dam sites involves synthesizing knowledge of geomorphology, lithology, and geologic structure of terrains. Good reservoir sites must meet several geologic conditions, including a watertight basin of adequate size, a narrow outlet with a suitable foundation, an adequate spillway, availability of construction materials, and assurance of a long reservoir life. Understanding the subsurface topography is essential for constructing a dam that will not leak or become structurally compromised.
• Airstrip Construction: Constructing airstrips requires engineering skill and knowledge of landscape characteristics. Ideal airstrip sites have a flat surface with resistant materials, a nearly level slope, and good visibility. Geomorphological knowledge can be used to create a morphological map of the region where the airstrip will be built.
• Locating Sand and Gravel Pits: Sand and gravel have numerous engineering, commercial, and industrial uses. Selecting suitable sites for sand and gravel pits involves evaluating geologic factors such as variation in grade sizes, lithologic composition, degree of weathering, amount of overburden, and continuity of deposits. Geomorphological knowledge helps identify the type of deposit and its potential for development.
• Military Geology: Geomorphology plays a crucial role in military operations, as terrain appreciation and analysis are essential for proper planning. Geomorphologists can provide valuable insights into terrain conditions, influencing the interpretation of topographic maps and aerial photographs.
• Urbanization: Urban geomorphology, the study of landforms in relation to urban development and management, has become a distinct branch of geomorphology. An urban geomorphologist can help in the planning and development process by providing detailed information on topography, soils, hydrology, lithology, and terrain characteristics.
• Hazard Management: Geomorphology is also crucial in identifying, predicting, and managing natural and man-made hazards. Geomorphic knowledge can be used to monitor seismic events, volcanic eruptions, floods, landslides, avalanches, and other hazards, as well as to assess their potential impacts and develop management strategies.
• Regional Planning: Applied geomorphology also plays a role in regional planning, as balanced economic growth requires an understanding of each region's resources, both natural and human. Detailed information on topography, soils, hydrology, lithology, and terrain characteristics can help regional planners devise development projects best suited for the region.

Other Applications
Besides the areas mentioned above, applied geomorphology is also useful in fields such as soil mapping, beach engineering, soil erosion control, and land classification. It can also help control the adverse effects of human activities on geomorphic forms and processes, leading to the development of anthropogeomorphology as a separate branch.

Techniques of Applied geomorphology

Applied geomorphology focuses on the relationship between human activities and geomorphological processes. Some key aspects of applied geomorphology include mapping landforms that affect or are modified by human activity, interpreting aerial photographs and remote sensing images, monitoring environmental changes, assessing the causes of unsustainable changes, and proposing solutions to hazards resulting from these changes.

• Aerial photographs and satellite images have made the preparation and interpretation of specialized maps more accurate and efficient. These images are useful for evaluating landforms and land use in relation to urban development plans, major construction projects, and more. Satellite images also play a vital role in studying global and country-level climatic phenomena, mineral prospecting, preparing land use inventories, and forecasting agricultural outputs.
• Remote sensing involves collecting information about objects from a distance without direct contact, using sensors and cameras to measure the spectral behavior of the objects under study. The most common remote sensing techniques involve sensing electromagnetic radiation emitted by terrestrial objects. Each object has a unique scattering property, or signature, based on its molecular composition. Knowledge of these signatures is crucial for interpreting satellite images.
• Remote sensing is essential for the sustainable management of natural resources such as soil, forests, crops, and oceans, as well as urban and town planning. Resource planners rely on remote sensing for up-to-date information on resource conditions and extent. Since these resources are dynamic and replenishable, ground-based monitoring systems often cannot keep up with their changes. Satellite-based surveys, on the other hand, can provide more frequent and consistent data.
• Geographical Information Systems (GIS) technology is often used in conjunction with remote sensing techniques. GIS are spatial data-handling programs used to collect, store, and retrieve spatial data from the real world, containing only the data that researchers consider relevant.

Remote sensing surveys offer several advantages over ground surveys, including:

• A broader view, covering large areas at once.
• A permanent record of ground conditions that can be verified later.
• Faster data interpretation compared to ground surveys.
• Access to thermal and microwave regions not visible to the naked eye.
• Lower costs and less infrastructure required compared to ground surveys.
• More cost-effective for repeated surveys.
• Versatility, as the same data can be used for various purposes, such as soil, groundwater, or crop surveys.
• Unaffected by weather conditions or other obstacles that hinder ground surveys.

In summary, applied geomorphology is a vital field, utilizing aerial photographs, satellite images, and remote sensing techniques to study the relationship between human activities and geomorphological processes. This information is essential for sustainable resource management and urban planning.

Conclusion

Applied geomorphology plays a critical role in various aspects of human interaction with the Earth's surface, from resource management and urban planning to hazard mitigation and infrastructure development. By understanding landforms and the processes that shape them, professionals in diverse fields can make more informed decisions, leading to sustainable development and better management of natural resources. The use of aerial photographs, satellite images, and remote sensing techniques has greatly enhanced the efficiency and accuracy of applied geomorphology, making it an indispensable tool for addressing the challenges posed by our ever-changing planet.