NCERT Class 11 Physical Geography Chapter 6: Geomorphic Processes | English | CBSE

Описание: Dr. Manishika Jain explains the NCERT Class 11 geography chapter 6.

Exogenetic & endogenetic forces act on earth
Exogenic forces – degradation or aggradation (gradation – variation by erosion) – weathering, mass wasting, deposition & erosion
Endogenic = Diastrophism & volcanism
Variations = opposing action of exogenic & endogenic
Geomorphic Process = Physical action + chemical action + changes in configuration
Geomorphic Agents = Wind, water, ice, waves, curents
Basics:    • Geomorphology - Types & Components of Fold...  
What is must?
Gravity & Gradient
Endogenic Processes: Radioactivity, rotational and tidal friction and primordial heat from the origin of the earth
Diastrophism – move, elevate & build – PVT (Pressure, volume & temperature)
• Orogenic: mountain building - folds
• Epeirogenic: Uplift – continental building
• Earthquake
• Plate tectonics
Volcanism: Movement of magma to earth
Exogenic Forces: gravity, sun & gradient by tectonic forces
Stress = force per unit area (push & pull – deformation)
Shear Stress: Breaks rock & angular displacement
Molecular stress by temperature, crystallization & melting
2 main factors are temperature & precipitation
All exogenic process are denudation (uncover)

KEY: Differences on earth surface though originally related due to crustal evolution continue to exist in some form or other due to differences in type and structure of earth materials, differences in geomorphic processes and rates of operation
Weathering: Mechanical disintegration and chemical decomposition of rocks
• Chemical
• Physical
• Biological: earthworm, rodents – burrow; decaying plants and animals; algal growth; plant roots

Physical Weathering: forces- gravitation, expansion & water pressure
• Unloading & expansion:
• Temperature Change & Expansion:
• Freezing, Thawing & Frost Wedging: Growth of ice in rocks; rapid freezing cause expansion and high pressure
• Salt Weathering: salt expand due to thermal action, hydration and crystallization; NaCl & gypsum crystals in desert heave up

Chemical Weathering:
• Solution: contents are dissolved with water/acid – nitrate, sulphate/potassium; calcium carbonate & NaCl
• Carbonation: reaction of carbonate & bicarbonate breaks down feldspar
• Hydration: Addition of water, rock expands
• Oxidation & Reduction: Reduction in areas of below water table – stagnant water & waterlogged ground with no oxygen (iron on reduction changes to bluish green)

Benefits of Weathering:
• Formation of soil & regolith
• Prepare for erosion & mass movement
• Increase deposits of minerals
• Enrichment: Mining as economically viable

Weathering & Erosion:    • Weathering & Erosion - 3 Types and 6 Agent...  
Mass Movement
Transfer of debris down the slope under gravity
Debris may carry with it air, water or ice
Purely by gravity & no geomorphic agent
Forms of movement: Heave, flow & slide
• Slow Movement: Creep (leaning of poles) & solifluction (slow downslope flowing soil mass)
• Rapid Movement: humid areas – earthflow (water saturated clayey soil at low angle), mudflow (no vegetation with heavy rainfall), avalanche (narrow track on steep slopes – faster than mudflow)
• Landslides: Rapid & perceptible with dry material – discontinuity & steepness in rock, slump (slipping of unit with backward rotation wrt slope)

Gravity & Gradient @3:41
Endogenic Processes @5:07
Diastrophism @5:17
Exogenic Forces @5:21
KEY @7:10
Physical Weathering @8:02
Chemical Weathering @10:16
Benefits of Weathering @12:14
Weathering & Erosion @12:42
Mass Movement @12:47
Slow Movement @13:33
Rapid Movement @14:03
Landslides @14:36
Soil Formation @15:48
Soil Formation Factors @16:09
#Chemical #Weathering #Crystallization #Denudation #Exogenic #Tidal #Radioactivity #Diastrophism #Endogenic #Geomorphic #Manishika #Examrace


Erosion & Deposition: Acquisition and transportation of debris, has continuous changes
Mass Movement:    • Mass Wasting and Landslides - Types, Compo...  
Soil Formation
Pedologist – studies soil
Pedology – science of soil
Soil: dynamic medium- physical, chemical & biological acitivities
Soil-Forming Factors:
• Parent material: passive factor
• Topography: passive factor
• Climate: moisture & temperature (eluviation & illuviation)- active factor
• Biological activity – humus accumulates, nitrogen fixation - rhizobium
• Time

Soil Formation:    • Forming the Soil - Factors, 4 Methods and ...  

For handouts google "NCERT Class 11 Geography Chapter 6 Examrace Youtube Handouts" #examrace #upsc #ugcnet