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Semester 3: B.Sc., Geology Choice Based Credit System Syllabus 2023-2024
Interpretation of fluvial cycle Landforms developed by running water valley development river capture waterfalls meandering river terraces Lakes their types and deposits Geological work of wind and Underground water
Interpretation of Fluvial Cycle and Related Landforms
Fluvial Cycle
The fluvial cycle refers to the stages of river development over time, influenced by erosion, transportation, and deposition of sediments. It typically includes the processes of rejuvenation, mature, and old age stages. Each stage has distinct characteristics in terms of landform development.
Valley Development
River valleys develop through the processes of erosion and sediment transport. V-shaped valleys are typical in youthful stages, while wider, U-shaped valleys are formed through glacial and meandering processes over time.
River Capture
River capture involves one river stealing the flow of another. This occurs due to headward erosion, developing features such as knickpoints and entrenched meanders. It significantly alters drainage patterns.
Waterfalls
Waterfalls are formed when water cascades over a vertical drop or cliff. They typically occur at the junction of hard and soft rock, leading to erosion of the softer rock, creating a retreating waterfall feature over time.
Meandering Rivers
Meandering rivers are characterized by sinuous curves caused by lateral erosion and deposition processes. The dynamics of the river's flow create point bars and cut banks, leading to various landform features along the river.
River Terraces
River terraces are flat, step-like landforms found on either side of a river, formed by the erosion of the river bed and lateral migration. They represent previous floodplains left as rivers downcut into their beds.
Lakes and Their Types
Lakes can be classified based on their origin: tectonic, volcanic, glacial, and fluvial. Types of lakes include open lakes, closed lakes, and saline lakes, each exhibiting unique depositional characteristics.
Geological Work of Wind
Wind erosion shapes landforms like dunes through processes such as deflation and abrasion. Aeolian environments exhibit features such as yardangs and blowouts, important in understanding sediment transport.
Underground Water
Underground water, or groundwater, plays a crucial role in shaping landforms through processes like dissolution and erosion, leading to karst topography including sinkholes and limestone caves.
Glaciers formation movement types and landforms due to their erosional and transportational activity Topography of ocean floor erosional and depositional features of oceans Coral reefs types theories for the origin of coral reefs Submarine Canyons
Glaciers formation movement types and landforms due to their erosional and transportational activity
Formation of Glaciers
Glaciers form when snow accumulates over many years and compacts into ice. The process involves several steps including snow accumulation, compaction, and recrystallization, leading to the formation of glacial ice.
Movement of Glaciers
Glaciers move through two main processes: internal deformation and sliding at the base. Internal deformation occurs when ice deforms under pressure, while sliding happens when meltwater reduces friction between the glacier and the ground.
Types of Glaciers
Glaciers are categorized into two main types: alpine glaciers, which form in mountainous regions, and continental glaciers, which cover vast areas and flow outwards from a central dome.
Erosional Features of Glaciers
Glacial erosion creates various landforms including U-shaped valleys, fjords, and cirques. Abrasion and plucking are the main processes, where glaciers scrape and lift rock material.
Transportational Activity of Glaciers
Glaciers transport debris through processes known as tilling. Material carried can be sorted as lodgment till, meltout till, or ablation till, which are deposited as moraines.
Landforms Produced by Glacial Activity
Landforms resulting from glacial activity include moraines, drumlins, and kettle lakes. Such features are indicative of past glacial movement and landscape alteration.
Mountains their kinds development and important mountain building movements Processes of weathering types and products Mass Movements
Mountains, their kinds, development, and important mountain building movements, Processes of weathering types and products, Mass Movements
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Mountains can be classified into various types based on their formation processes. The main types are: 1. Fold Mountains: Formed by the collision of tectonic plates, leading to a folding of the Earth's crust. Examples include the Himalayas and the Rockies. 2. Fault-block Mountains: Created through the faulting of the Earth's crust, resulting in blocks of the crust being lifted or tilted. Examples include the Sierra Nevada. 3. Volcano Mountains: Formed by volcanic activity as lava cools and solidifies. Examples include Mount Fuji and Mount St. Helens.
Types of Mountains
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Mountain development is a complex process involving various geological forces and factors. Key stages include: 1. Uplift: The movement of the Earth's crust leads to the uplift of landmasses. 2. Erosion: Weathering and erosion sculpt mountain landscapes, redistributing materials. 3. Ongoing Activity: Mountains continue to evolve due to tectonic activity, erosion, and climatic factors.
Mountain Development
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Several significant mountain building movements are notable for their impact on Earth's topography. 1. Alpine Orogeny: Resulted in the formation of the Alps and Himalayas from continental collision. 2. Appalachian Orogeny: Formed the Appalachian Mountains through a series of geological events. 3. Basin and Range Province: Characterized by alternating mountain ranges and valleys due to crustal extension.
Mountain Building Movements
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Weathering is the breaking down of rocks through natural processes. There are two main types: 1. Physical Weathering: Involves the mechanical breakdown of rocks without changing their chemical composition. Examples include freeze-thaw cycles and thermal expansion. 2. Chemical Weathering: Involves the alteration of the mineral composition of rocks through chemical reactions, often involving water and acids.
Processes of Weathering
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Weathering produces various materials and features: 1. Soil Formation: Weathered rock contributes to soil, which is essential for plant life. 2. Sediments: Broken down rocks form sediments that can be transported by water, wind, or ice. 3. Weathering Residues: Altered mineral mixtures such as clays and oxides are products of weathering.
Types and Products of Weathering
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Mass movements refer to the downslope movement of soil and rock due to gravity. Types include: 1. Landslides: Sudden and fast movement of rock and soil materials. 2. Slumps: Involve the rotational movement of materials along a curved surface. 3. Creep: Slow, gradual movement of soil and debris downslope. Factors influencing mass movements include slope angle, water content, and vegetation cover.
Mass Movements
Earthquakes types seismographs intensity and Magnitude scales Richter Mercalli Tsunami Global Distribution Volcanoes structure types products Global Distribution
Earthquakes and Volcanoes
Types of Earthquakes
Earthquakes are classified into tectonic, volcanic, collapse, and explosion types based on their origin.
Seismographs
Seismographs are instruments that measure and record the motion of the ground during an earthquake.
Intensity and Magnitude Scales
Intensity measures the effects of an earthquake, while magnitude measures the energy released. Various scales like Richter and Moment Magnitude are used.
Richter Scale
Developed by Charles F. Richter, this scale quantifies the size of earthquakes in numerical form and is logarithmic.
Mercalli Scale
This scale measures the intensity of shaking and damage from an earthquake, based on human observations.
Tsunamis
Tsunamis are large ocean waves caused by underwater earthquakes or volcanic eruptions, posing significant risks to coastal regions.
Global Distribution of Earthquakes
Most earthquakes occur along tectonic plate boundaries, notably the Pacific Ring of Fire.
Structure of Volcanoes
Volcanoes consist of a magma chamber, vents, craters, and can be shield, stratovolcanoes, or cinder cones.
Types of Volcanoes
Volcanoes are classified as active, dormant, or extinct based on their eruptive history.
Products of Volcanic Activity
Volcanic eruptions produce lava, ash, pumice, and gases, impacting the environment and climate.
Global Distribution of Volcanoes
Volcanoes are primarily located along plate boundaries, especially in the Pacific Ring of Fire.
Continental drift Wegner Concept various evidences Plate tectonics concept plate characteristics larger and smaller plates types of plate boundaries causes and mechanism of plate motions
Continental Drift and Plate Tectonics
Continental Drift
Proposed by Alfred Wegener in the early 20th century. Suggests that continents were once a single landmass called Pangaea. Over time, continents drifted apart to their current positions.
Wegener's Concept
Wegener used various pieces of evidence to support his theory including fossil distribution, geological similarities, and paleoclimatic evidence. He faced criticism mainly due to the lack of a mechanism for drift.
Various Evidences
Key evidence includes similar rock formations on different continents, fossilized plants and animals found in disparate locations, and glacial deposits in now-tropical regions.
Plate Tectonics Concept
Developed in the mid-20th century, it builds on Wegener's ideas and explains the movement of large plates on the Earth's surface. It incorporates the theory of seafloor spreading.
Plate Characteristics
Plates vary in size and thickness. Major plates are continental and oceanic types. Characteristics include rigidity, but they float on the semi-fluid asthenosphere.
Larger and Smaller Plates
Major plates include the Pacific, North American, Eurasian, African, South American, Antarctic, and Indo-Australian plates. Smaller plates include the Nazca and Cocos plates.
Types of Plate Boundaries
Three main types are divergent, convergent, and transform boundaries. Divergent boundaries occur where plates move apart. Convergent boundaries occur where plates collide. Transform boundaries slide past each other.
Causes of Plate Motions
Caused by convection currents in the mantle, gravity, and the interactions at plate boundaries. The mantle's heat drives the movement of tectonic plates.
Mechanism of Plate Motions
Involves the movement of tectonic plates due to mantle convection, slab pull, and ridge push. These processes facilitate the dynamic nature of Earth's crust.
