World Geography Part 2 – Basic Concepts (Geomorphology – 2)

In this article we have shared some more important terms to understand the basic concept of geomorphology.

To understand the Movement of Earth

  • Endogenetic forces – the forces coming from within the earth are called as Endogenetic forces which cause two types of movement in the earth viz (i) Horizontal movement and (ii) vertical movement
  • Exogenetic forces – it applies to the processes which occur at or near the earth’s surface.
  • Folds – Wave – like bands are formed in the crustal rocks due to the tangential compressive force resulting from m horizontal movement caused by the Endogenetic force originating deep within the earth. Such bands are called folds.
  • Faults – A fault is a fracture in the crustal rocks wherein the rocks are displaced along a plane called the fault plane.
  • Plate tectonics – the study of the whole mechanism of evolution, nature and motion of plates, deformation within plates and interaction of plate margin with each other is collectively called as plate tectonics.
  • Volcano – A landform at the end of a conduit or pipe which rises from the below the crust and vents to the surface. Magma rises and collects in a magma chamber deep below, resulting in eruptions that are effusive or explosive forming the mountain/plateau landform.

To understand mountain building

  • Mountain – A general term for any land mass that stands above its surrounding. In the stricter geological sense, a mountain belt is a highly deformed part of the earth’s crust that has been injected with igneous intrusion and the deeper part of which have been metamorphosed. The topography of Young Mountain is high, but erosion can reduce Old Mountain to flat low land.
  • Geosyncline – A subsiding part of the lithosphere in which thousands of metres of sediment accumulate.

To understanding Weathering and Mass movement

  • Weathering – the process of disintegration and decomposition of rocks in situ, it’s a static process.
  • Mass Movement (mass wasting) – Disintegrated and fragmented rock materials due to the mechanism of weathering process (mechanical, chemical, biotic and biochemical).
  • Landslide – a general term for relatively rapid types of mass movement such as debris flows, debris slides, rockslide, and slumps.
  • Slump –It involves intermittent sliding of rock fragments, rock blocks or soil downslope along a curve plane caused by rotational movement and displaced blocks (whether rocks blocks or soil blocks) cover a very short distance.
  • Rockslide – its most significant of all types of slides wherein large rock blocks slide down the hillslope.
  • Creep – very slow and imperceptible movement of materials (colluvium) is called creep.

To understand erosion

  • Erosion – the processes that loosen sediment and move it from one place to another on earth’s surface. Agents of erosion include running water, ice, wind, sea waves, underground water, and gravity.
  • Denudation – A general term that refers to all processes that cause degradation of the landscape weathering, mass movement, erosion, and transport.

To understand drainage systems

  • Drainage – An integrated system of tributaries and trunk stream, which collect and funnel surface water to the sea, a lake, or some other body of water.
  • Stream – long, narrow body of flowing water occupying a stream channel and moving to lower levels under the force of gravity.
  • Drainage pattern – the drainage pattern means the ‘form’ (geometrical forms) of the drainage system and the spatial arrangements of streams in a particular locality or regions.

To understand fluvial landforms

  • Fluvial – Pertaining to river or rivers
  • Fluvial landforms – the landforms either carved out (due to erosion) or built up (due to deposition) by running water.
  • Surface runoff – The rainwater reaching the earth’s surface becomes surface runoff when it spreads laterally on the ground surface.
  • Solution or corrosion – It involves the dissolution of soluble materials through the process of disintegration and decomposition of carbonate rocks.
  • The river meanders – It refers to the bands of longitudinal courses of the rivers.
  • Oxbow lakes – The lakes formed due to impounding of water in the abandoned meander loops are called oxbow or horseshoe lakes.
  • Peneplains – It represents featureless plain having undulating surface and remnants of convexo-concave residual hills.
  • Delta – the depositional feature of almost triangular shape at the mouth of river debouching either in a lake or a sea is called delta.

To understand karst landforms

  • Regolith – The blanket of soil and loose rock fragment overlying the bedrock
  • Groundwater – The water present in the pore spaces of regolith and bedrocks (those rocks which have not been weathered and eroded) below the ground surface.
  • Aquifers – A permeable stratum or zone below the earth’s surface through groundwater moves.
  • Ponores – The vertical pipe-like chasms or passages that connect the caves and the swallow holes are called ponores.

To understand coastal landforms

  • Swell – The regular pattern of smoothly rounded waves that characterize the surface of the ocean during fair weather.
  • Wavelength – The straight horizontal distance between two successive crests or through.
  • Swash or uprush – The turbulent water, known as swash or uprush rushes shoreward with great velocity and force.
  • Plungeline – The distance from the shore where the waves break is called plunge line, where the depth of seawater and the wave height is approximately equal.
  • Surf – The turbulent forward moving swash or breaker.
  • Hydraulic action – It refers to the impact of moving water on coastal rocks.
  • Cliffs – Steep rocky coast rising almost vertically above seawater is called sea cliff, which is very precipitous, with overhanging crest.
  • Wave cut platform – Rock – cut flat surface in front of cliffs they are also known as shore platform, which is slightly concave upward.
  • Beaches – Temporary or short-lived deposits of marine sediment consisting of sands, shingles, cobbles etc. On the seashore.
  • Bars – The ridges, embankments or mounds of sand formed by sedimentation through sea waves parallel to the shoreline.
  • Barriers – The larger forms of bars.

 To understand arid and semiarid landforms

  • Ergs – The deserts having mobile sands, Arabic word erg means shifting sands
  • Attrition – It involves mechanical tear and wear of the particle suffered by themselves, while they are being transported by wind through the processes of saltation, and surface creep
  • Saltation – It involves the movement of sand and gravels through the mechanisms bouncing, jumping and hopping by turbulent air flow.
  • Mushroom rocks – The rocks having the broad upper part and narrow base resembling an umbrella or mushroom.
  • Inselbergs – These are very controversial landforms, this is a German word, was used by Passarge in 1904 to indicate sharply rising residual hill above the flat surfaces in South Africa.
  • Zeugen – Rock masses of tabular form resembling a capped inkpot standing on the softer rock, pedestal shale, mudstone etc.
  • Yardangs – These are steep-sided deeply undercut overhanging rock ridges separated from one another by long groups of corridors or passageways cut in desert floors relatively softer rocks
  • Loess – It is the example of most significant windblown deposits. Loess (German term loess meaning thereby fine loam, loose or unconsolidated materials) represents thick deposits of unstratified, non indurated, buff- coloured, well sorted, fine-grained sediments consisting of quartz silt
  • Badland topography –The regions of weak sedimentary formation are extensively eroded by numerous rills and channels which are occasionally developed due to occasional rain storms.

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