{"id":104743,"date":"2024-06-01T16:03:28","date_gmt":"2024-06-01T10:33:28","guid":{"rendered":"https:\/\/pwonlyias.com\/stage\/?post_type=udaan&#038;p=104743"},"modified":"2024-06-19T13:40:15","modified_gmt":"2024-06-19T08:10:15","slug":"define-exogenic-forces","status":"publish","type":"udaan","link":"https:\/\/pwonlyias.com\/stage\/udaan\/define-exogenic-forces","title":{"rendered":"Exogenic Forces: Definition, Classification &#038; Processes"},"content":{"rendered":"<p><span style=\"font-weight: 400;\">Exogenic forces, also known as external forces or <\/span><b>land-wearing forces<\/b><span style=\"font-weight: 400;\">, are natural processes that shape the Earth&#8217;s surface from the outside. They work over long periods, like thousands or millions of years. These forces include things like <\/span><b>erosion by water<\/b><span style=\"font-weight: 400;\">,<\/span><b> wind<\/b><span style=\"font-weight: 400;\">, and<\/span><b> ice<\/b><span style=\"font-weight: 400;\">, as well as movements of the Earth&#8217;s crust caused by things like <\/span><a href=\"https:\/\/pwonlyias.com\/stage\/ncert-notes\/protection-against-earthquake\/\" target=\"_blank\" rel=\"noopener\"><span style=\"font-weight: 400;\">earthquakes<\/span><\/a> <span style=\"font-weight: 400;\">and volcanic eruptions. They&#8217;re the things that wear down mountains, carve out valleys, and shape the landscape we see around us.<\/span><\/p>\n<h2><span style=\"font-size: 18pt;\"><b>Understanding Exogenic Forces in Geomorphology<\/b><\/span><\/h2>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-104719 alignright\" src=\"https:\/\/pwonlyias.com\/stage\/wp-content\/uploads\/2024\/04\/277-662ccdb40e176.webp\" alt=\"Exogenic Forces\" width=\"557\" height=\"393\" srcset=\"https:\/\/pwonlyias.com\/stage\/wp-content\/uploads\/2024\/04\/277-662ccdb40e176.webp 868w, https:\/\/pwonlyias.com\/stage\/wp-content\/uploads\/2024\/04\/277-662ccdb40e176-300x212.webp 300w, https:\/\/pwonlyias.com\/stage\/wp-content\/uploads\/2024\/04\/277-662ccdb40e176-768x541.webp 768w\" sizes=\"(max-width: 557px) 100vw, 557px\" \/><\/p>\n<ul>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><b>External Forces:<\/b><span style=\"font-weight: 400;\"> They originate at or near the Earth\u2019s surface, are influenced by solar energy and tectonic gradient, and <\/span><b>draw energy<\/b><span style=\"font-weight: 400;\"> from the <\/span><b>atmosphere<\/b><span style=\"font-weight: 400;\">.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><b>Characteristics: <\/b><span style=\"font-weight: 400;\">They are slow and gradual forces and are also known as <\/span><b>denudational<\/b><span style=\"font-weight: 400;\">\/ <\/span><b>destructional\/<\/b> <b>exogenetic processes<\/b><span style=\"font-weight: 400;\">.\u00a0<\/span>\n<ul>\n<li style=\"font-weight: 400;\" aria-level=\"2\"><b>Actions <\/b><span style=\"font-weight: 400;\">of <\/span><b>exogenic forces result<\/b><span style=\"font-weight: 400;\"> in <\/span><b>wearing down (degradation<\/b><span style=\"font-weight: 400;\">) of relief\/ elevations and<\/span><b> filling up (aggradation) <\/b><span style=\"font-weight: 400;\">of basins.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"2\"><b>Rock type and structure<\/b><span style=\"font-weight: 400;\"> significantly affect the intensity of exogenic processes.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"2\"><b>Climatic factors: <\/b><span style=\"font-weight: 400;\">Temperature, precipitation, insolation, wind patterns, etc. affect exogenic processes.<\/span><\/li>\n<\/ul>\n<\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><b>Gradation: <\/b><span style=\"font-weight: 400;\">The phenomenon of wearing down of relief variations through <\/span><a href=\"https:\/\/pwonlyias.com\/stage\/ncert-notes\/discovering-coastal-landforms-how-they-form\/\" target=\"_blank\" rel=\"noopener\"><span style=\"font-weight: 400;\">erosion<\/span><\/a> <span style=\"font-weight: 400;\">is known as <\/span><b>gradation.\u00a0<\/b><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><b>Denudation:<\/b><span style=\"font-weight: 400;\"> All the exogenic geomorphic processes are covered under a general term, <\/span><b>denudation <\/b><span style=\"font-weight: 400;\">(weathering, mass wasting\/movements, erosion, and transportation).\u00a0<\/span><\/li>\n<\/ul>\n<h2><span style=\"font-size: 18pt;\"><b>Weathering<\/b><\/span><\/h2>\n<ul>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><b>Definition: <\/b><span style=\"font-weight: 400;\">Weathering is defined as the <\/span><b>mechanical disintegration<\/b><span style=\"font-weight: 400;\"> and <\/span><b>chemical decomposition<\/b><span style=\"font-weight: 400;\"> of rocks through the actions of various elements of weather and climate. It is an <\/span><b>In-Situ<\/b><span style=\"font-weight: 400;\"> or <\/span><b>Onsite <\/b><span style=\"font-weight: 400;\">process<\/span><span style=\"font-weight: 400;\">.\u00a0<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><b>Factors Influencing Weathering:<\/b><span style=\"font-weight: 400;\"> Geology, weather and climate, topography, and vegetative factors.<\/span><\/li>\n<\/ul>\n<p style=\"text-align: center;\"><span class=\"vc_button\"><a href=\"https:\/\/www.pw.live\/batches\/upsc?utm_source=seo+upsc+batch&#038;utm_medium=seo+upsc&#038;utm_campaign=seo&#038;utm_id=upsc\" target=\"_blank\" rel=\"noopener\">Enroll now for UPSC Online Course<\/a><\/span><\/p>\n<h2><span style=\"font-size: 18pt;\"><b>Classification of Weathering processes<\/b><\/span><\/h2>\n<h3><span style=\"font-size: 16pt;\"><b>Chemical Weathering Processes<\/b><\/span><\/h3>\n<ul>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">It includes <\/span><b>solution, carbonation, hydration, oxidation <\/b><span style=\"font-weight: 400;\">and <\/span><b>reduction<\/b><span style=\"font-weight: 400;\">. Water, air and heat are vital for accelerating chemical reactions.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><b>Solution<\/b><span style=\"font-weight: 400;\">: Dissolution in <\/span><b>water or acid<\/b><span style=\"font-weight: 400;\">. Minerals like <\/span><b>calcium carbonate<\/b><span style=\"font-weight: 400;\"> and <\/span><b>calcium magnesium bicarbonate <\/b><span style=\"font-weight: 400;\">present in <\/span><b>limestone <\/b><span style=\"font-weight: 400;\">are soluble in water containing carbonic acid.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><b>Carbonation<\/b><span style=\"font-weight: 400;\">:<\/span> <span style=\"font-weight: 400;\">Process of<\/span><b> atmospheric carbon dioxide<\/b><span style=\"font-weight: 400;\"> causing <\/span><b>solution weathering;<\/b><span style=\"font-weight: 400;\"> common process helping in breaking down of <\/span><b>felspar <\/b><span style=\"font-weight: 400;\">and <\/span><b>carbonate <\/b><span style=\"font-weight: 400;\">minerals.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><b>Hydration<\/b><span style=\"font-weight: 400;\">: Minerals<\/span><b> take up water<\/b><span style=\"font-weight: 400;\"> and expand which <\/span><b>increases the volume<\/b><span style=\"font-weight: 400;\"> of the material (Calcium sulphate+water= Gypsum).\u00a0<\/span>\n<ul>\n<li style=\"font-weight: 400;\" aria-level=\"2\"><span style=\"font-weight: 400;\">Continued repetition leads to <\/span><b>physical weathering<\/b><span style=\"font-weight: 400;\"> through exfoliation and granular disintegration.\u00a0<\/span><\/li>\n<\/ul>\n<\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><b>Oxidation and Reduction<\/b><span style=\"font-weight: 400;\">: In <\/span><b>oxidation,<\/b><span style=\"font-weight: 400;\"> rock breakdown occurs due to the disturbance caused by <\/span><b>addition of oxygen<\/b><span style=\"font-weight: 400;\">.\u00a0<\/span>\n<ul>\n<li style=\"font-weight: 400;\" aria-level=\"2\"><span style=\"font-weight: 400;\">When oxidized minerals are placed in an environment where<\/span><b> oxygen is absent <\/b><span style=\"font-weight: 400;\">(eg: below water table\/ waterlogged areas) <\/span><b>reduction <\/b><span style=\"font-weight: 400;\">takes place.<\/span><b>\u00a0<\/b><\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<h3><span style=\"font-size: 16pt;\"><b>Physical or Mechanical <\/b><b>Weathering Processes<\/b><span style=\"font-weight: 400;\">\u00a0<\/span><\/span><\/h3>\n<ul>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Physical or mechanical weathering refers to a process that relies on applied forces. Most of the processes are caused by thermal expansion and pressure release. These forces could be <\/span><a href=\"https:\/\/pwonlyias.com\/stage\/ncert-notes\/newton-law-of-gravitation\/\"><b>gravitational forces<\/b><\/a><b>, <\/b><span style=\"font-weight: 400;\">\u00a0<\/span><b>expansion forces<\/b><span style=\"font-weight: 400;\">, and <\/span><b>water pressures.<\/b><span style=\"font-weight: 400;\">\u00a0<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><b>Unloading and Expansion: <\/b><span style=\"font-weight: 400;\">In areas of <\/span><b>curved ground surface<\/b><span style=\"font-weight: 400;\">,<\/span><b> arched fractures<\/b><span style=\"font-weight: 400;\"> tend to <\/span><b>produce<\/b><span style=\"font-weight: 400;\"> massive sheets or<\/span><b> exfoliation slabs<\/b><span style=\"font-weight: 400;\"> of rock. Large smooth rounded domes called exfoliation domes are a result of this process.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><b>Temperature Changes and Expansion<\/b><span style=\"font-weight: 400;\">: Most <\/span><b>effective<\/b><span style=\"font-weight: 400;\"> in <\/span><b>dry climates <\/b><span style=\"font-weight: 400;\">and<\/span><b> high elevations <\/b><span style=\"font-weight: 400;\">where <\/span><b>diurnal temperature changes<\/b><span style=\"font-weight: 400;\"> are <\/span><b>drastic.<\/b><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><b>Freezing, Thawing and Frost Wedging<\/b><span style=\"font-weight: 400;\">: Most<\/span><b> effective<\/b><span style=\"font-weight: 400;\"> at<\/span><b> high elevations <\/b><span style=\"font-weight: 400;\">in <\/span><b>mid-latitudes<\/b><span style=\"font-weight: 400;\"> where freezing and melting are often repeated.<\/span>\n<ul>\n<li style=\"font-weight: 400;\" aria-level=\"2\"><b>Freezing <\/b><span style=\"font-weight: 400;\">involves the transformation of water into ice.\u00a0<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"2\"><b>Thawing <\/b><span style=\"font-weight: 400;\">is the process of melting ice back into water, and\u00a0<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"2\"><b>Frost Wedging<\/b><span style=\"font-weight: 400;\"> is the mechanical breakup of rocks caused by repeated freezing and thawing cycles.\u00a0<\/span><\/li>\n<\/ul>\n<\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><b>Salt weathering<\/b><span style=\"font-weight: 400;\">:<\/span><b> Salts<\/b><span style=\"font-weight: 400;\"> in rocks <\/span><b>expand <\/b><span style=\"font-weight: 400;\">due to<\/span><b> thermal action<\/b><span style=\"font-weight: 400;\">, <\/span><b>hydration<\/b><span style=\"font-weight: 400;\"> and <\/span><b>crystallisation<\/b><span style=\"font-weight: 400;\">. Salt crystallisation is the most effective of all salt weathering processes.<\/span><\/li>\n<\/ul>\n<table style=\"width: 100.198%;\">\n<tbody>\n<tr>\n<td style=\"border-style: solid; border-color: #000000; background-color: #e9ebe8; width: 100%;\" scope=\"row\">\n<ul>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><b>Exfoliation<\/b><span style=\"font-weight: 400;\"> occurs<\/span> <span style=\"font-weight: 400;\">when curved sheets of material peel away from rocks due to temperature-induced expansion and contraction.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><b>Exfoliation domes <\/b><span style=\"font-weight: 400;\">are large and smooth rounded domes formed due to unloading and expansion of rocks.\u00a0<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><b>Exfoliation tor <\/b><span style=\"font-weight: 400;\">is smooth surfaced and rounded small to big size boulders, formed due to temperature changes and expansion in rocks.<\/span><\/li>\n<\/ul>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h3><span style=\"font-size: 16pt;\"><b>Biological Weathering<\/b><\/span><\/h3>\n<ul>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">It involves <\/span><b>organisms <\/b><span style=\"font-weight: 400;\">and includes:\u00a0<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><b>Organism Growth: <\/b><span style=\"font-weight: 400;\">It involves <\/span><span style=\"font-weight: 400;\">burrowing and wedging activities by creatures like earthworms, termites, and rodents that expose fresh surfaces.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><b>Organic Matter Decay:<\/b> <span style=\"font-weight: 400;\">Decomposing plant and animal matter generates humic, carbonic, and other acids, promoting the decay and solubility of certain elements.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><b>Root Pressure:<\/b> <span style=\"font-weight: 400;\">mechanically breaking apart earth materials.<\/span><\/li>\n<\/ul>\n<h2><span style=\"font-size: 18pt;\"><b>Erosion And Deposition<\/b><\/span><\/h2>\n<ul>\n<li><b>Erosion: <\/b><span style=\"font-weight: 400;\">This involves the acquisition and transportation of rock debris by various geomorphic agents (running water, groundwater, glaciers, wind, and waves). Abrasion by rock debris carried by these geomorphic agents also aids greatly in erosion.<\/span>\n<ul>\n<li><span style=\"font-weight: 400;\">Though<\/span><b> weathering aids erosion, <\/b><span style=\"font-weight: 400;\">it is<\/span><b> not a precondition<\/b><span style=\"font-weight: 400;\"> for erosion to take place. <\/span><a href=\"https:\/\/pwonlyias.com\/stage\/ncert-notes\/basic-soil-formation\/\" target=\"_blank\" rel=\"noopener\"><b>Weathering<\/b><\/a><b>, mass-wasting and erosion <\/b><span style=\"font-weight: 400;\">are <\/span><b>degradational processes.<\/b><\/li>\n<\/ul>\n<\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><b>Deposition: <\/b><span style=\"font-weight: 400;\">It<\/span> <span style=\"font-weight: 400;\">is a consequence of erosion; and occurs in the reverse order of particle size, with coarser materials depositing first.\u00a0<\/span>\n<ul>\n<li style=\"font-weight: 400;\" aria-level=\"2\"><b>Agents of Deposition<\/b><span style=\"font-weight: 400;\">: running water, glaciers, wind, waves, and groundwater.<\/span><\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<table style=\"width: 100.208%;\">\n<tbody>\n<tr>\n<td style=\"width: 664.175%; border-style: solid; border-color: #000000; background-color: #ff5e00; text-align: center;\" colspan=\"2\"><strong><span style=\"color: #ffffff;\">Must Read<\/span><\/strong><\/td>\n<\/tr>\n<tr>\n<td style=\"width: 49.91%; text-align: center; border-style: solid; border-color: #000000; background-color: #e9ebe8;\"><a href=\"https:\/\/pwonlyias.com\/stage\/current-affairs\/\"><span style=\"font-weight: 400;\">Current Affairs<\/span><\/a><\/td>\n<td style=\"width: 614.265%; text-align: center; border-style: solid; border-color: #000000; background-color: #e9ebe8;\"><a href=\"https:\/\/pwonlyias.com\/stage\/editorial-analysis\/\"><span style=\"font-weight: 400;\">Editorial Analysis<\/span><\/a><\/td>\n<\/tr>\n<tr>\n<td style=\"width: 49.91%; text-align: center; border-style: solid; border-color: #000000; background-color: #e9ebe8;\"><a href=\"https:\/\/pwonlyias.com\/stage\/upsc-notes\"><span style=\"font-weight: 400;\">Upsc Notes\u00a0<\/span><\/a><\/td>\n<td style=\"width: 614.265%; text-align: center; border-style: solid; border-color: #000000; background-color: #e9ebe8;\"><a href=\"https:\/\/pwonlyias.com\/stage\/blogs\/\"><span style=\"font-weight: 400;\">Upsc Blogs\u00a0<\/span><\/a><\/td>\n<\/tr>\n<tr>\n<td style=\"width: 49.91%; text-align: center; border-style: solid; border-color: #000000; background-color: #e9ebe8;\"><a href=\"https:\/\/pwonlyias.com\/stage\/ncert-notes\/\"><span style=\"font-weight: 400;\">NCERT Notes<\/span><\/a><span style=\"font-weight: 400;\">\u00a0<\/span><\/td>\n<td style=\"width: 614.265%; text-align: center; border-style: solid; border-color: #000000; background-color: #e9ebe8;\"><a href=\"https:\/\/pwonlyias.com\/stage\/mains-answer-writing\/\"><span style=\"font-weight: 400;\">Free Main Answer Writing<\/span><\/a><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h2><span style=\"font-size: 18pt;\"><b>Conclusion<\/b><\/span><\/h2>\n<p><span style=\"font-weight: 400;\">Exogenic forces, covering<\/span><b> weathering, erosion, and deposition processes<\/b><span style=\"font-weight: 400;\">, play a vital role in shaping Earth&#8217;s surface over long periods. Through <\/span><b>chemical, physical, and biological actions,<\/b><span style=\"font-weight: 400;\"> these forces gradually wear down and reshape landscapes, contributing to the dynamic evolution of the Earth&#8217;s topography.\u00a0<\/span><\/p>\n<table style=\"width: 100.101%;\">\n<tbody>\n<tr style=\"height: 30px;\">\n<td style=\"width: 154.947%; border-style: solid; border-color: #000000; background-color: #ff5e00; text-align: center; height: 30px;\" colspan=\"2\"><span style=\"color: #ffffff;\"><b>Related Articles\u00a0<\/b><\/span><\/td>\n<\/tr>\n<tr style=\"height: 30px;\">\n<td style=\"width: 50.3913%; text-align: center; border-style: solid; border-color: #000000; background-color: #e9ebe8; height: 30px;\"><a href=\"https:\/\/pwonlyias.com\/stage\/ncert-notes\/discovering-coastal-landforms-how-they-form\/\" target=\"_blank\" rel=\"noopener\"><span style=\"font-weight: 400;\">Coastal Landforms: Coastal Erosion, Desert Formation<\/span><\/a><\/td>\n<td style=\"width: 104.556%; text-align: center; border-style: solid; border-color: #000000; background-color: #e9ebe8; height: 30px;\"><a href=\"https:\/\/pwonlyias.com\/stage\/ncert-notes\/newton-law-of-gravitation\/\" target=\"_blank\" rel=\"noopener\"><span style=\"font-weight: 400;\">Gravitation: Newton\u2019s Laws &#038; Universal Movement of Celestial Bodies<\/span><\/a><\/td>\n<\/tr>\n<tr style=\"height: 30px;\">\n<td style=\"width: 50.3913%; text-align: center; border-style: solid; border-color: #000000; background-color: #e9ebe8; height: 30px;\"><a href=\"https:\/\/pwonlyias.com\/stage\/ncert-notes\/basic-soil-formation\/\" target=\"_blank\" rel=\"noopener\"><span style=\"font-weight: 400;\">Soil Formation: Key Factors, Climate, Evolution<\/span><\/a><\/td>\n<td style=\"width: 104.556%; text-align: center; border-style: solid; border-color: #000000; background-color: #e9ebe8; height: 30px;\"><a href=\"https:\/\/pwonlyias.com\/stage\/ncert-notes\/protection-against-earthquake\/\" target=\"_blank\" rel=\"noopener\"><span style=\"font-weight: 400;\">Earthquakes: Causes, Impact, and Mitigation Strategies in India<\/span><\/a><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>\u00a0<\/p>\n","protected":false},"author":11,"featured_media":0,"parent":0,"comment_status":"open","ping_status":"closed","template":"","udaan-chapter":[5420],"udaan-subject":[5415],"acf":[],"_links":{"self":[{"href":"https:\/\/pwonlyias.com\/stage\/wp-json\/wp\/v2\/udaan\/104743"}],"collection":[{"href":"https:\/\/pwonlyias.com\/stage\/wp-json\/wp\/v2\/udaan"}],"about":[{"href":"https:\/\/pwonlyias.com\/stage\/wp-json\/wp\/v2\/types\/udaan"}],"author":[{"embeddable":true,"href":"https:\/\/pwonlyias.com\/stage\/wp-json\/wp\/v2\/users\/11"}],"replies":[{"embeddable":true,"href":"https:\/\/pwonlyias.com\/stage\/wp-json\/wp\/v2\/comments?post=104743"}],"wp:attachment":[{"href":"https:\/\/pwonlyias.com\/stage\/wp-json\/wp\/v2\/media?parent=104743"}],"wp:term":[{"taxonomy":"udaan-chapter","embeddable":true,"href":"https:\/\/pwonlyias.com\/stage\/wp-json\/wp\/v2\/udaan-chapter?post=104743"},{"taxonomy":"udaan-subject","embeddable":true,"href":"https:\/\/pwonlyias.com\/stage\/wp-json\/wp\/v2\/udaan-subject?post=104743"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}