InsightsUnveiled

Kegel karst is a German word and is one of the 3 subjects of the overall category of polygonal karst distinguished by Williams .It's a type of tropical karst.It is known for it's hemispheroidal and sinusoidal hills and star-shaped depressions.  Lehmann ,originally designated it.It is also corresponds largely to a cockpit country of Jamaica and Puerto Rico.there is relative relief of 30 - 120 m and a density of 15 - 30 Km. sq..The cone form is not the most characteristic feature of the area.                        Turm karst or tower karst is also a karst feature of tropics.It's formation is controlled by structures over the lithology and specific solutional processes.As per Balazs's observation they are steep sided residual rising like islands from the plain.they are 100 m - 300 m. high and runs 5-10 Km.sq. they are formed by engulfment of the surrounding ...

Channel pattern mean the configuration of a river as it would appear from an airplane 3 patterns have been identified,one of which is the braided channel pattern.                            A braided channel or stream is one characterized by a network of interconnected converging and diverging channels resembling the stands of a bread.The whole river system is generally shallow,so that intervening single bars and alluvial materials are exposed at low waters.It is mainly due to non-coherence of load,which leads to selective deposition and the alluvial material is exposed at low waters.                           The development of braiding stream is a type of adjustment that a channel makes due to possession of debris load too larg...

There is a close relationship between braided stream and meanders.Example:-The ana branches of a braided stream definitely meanders.On the basis of the works by European engineers, Lelivesky(1955) concluded that meanders are the result of helical flow. Although this mechanism has been important but it isn't clear how helical flow is related to the width,curvature and length of the meanders.                                 According to Matthes ,bank cutting and orderly transfer of sediment to it's place of deposition on the point bars were simple requirements for the meandering Friendkin's concept is essentially identical.     A meander can't exist if the banks were unerodible or if they were completely unstable.The meander pattern of melt water channels on the surface of ...

Drumlins   are roughly ovoid shaped hills of dominantly glacial debris that typically occur within groups or fields of several thousand.They exhibit very strong Enechelon long axis preferred orientation paralleling the main direction of ice flow.The classical drumlins have steeper stross-end slope  and tapered lee-side.Limited relationships appear between drumlins and topography.the topographic locations within which the drumlins are found are many and varied.Drumlins are composed of vast range of sediment types although previously it was thought to be exclusively formed of subglacial Till.Drumlin shapes vary enormously and may reflect post-depositional sub-aerial mass movement. At present 3 main drumlin forming hypothesis are present:- a) Formation by moulding of previously deposited material within a sub-glacial environment ,in which a limited amount of sub-glacial melt water activity occurs which influences moulding and deformational processes  produc...

Cockpits are formed in humid tropical karst regions where simple closed depressions which have convexly inward lobed sides,making them star shaped,with gullies carrying streams after heavy rains are found.They are set among steep residual hills.                         Lehmann   gave an interpretation of the development of humid tropical karst evolution i.e., development of the 'cockpit country'.A prior planation is gently domed, tectonically which rejuvenated surface drainage,which produced ridges and valleys which align down the flank of the dome.This is followed by the development of vertical infiltration and underground drainage causing valleys to breakup into chains of star shaped closed depressions of surface solutional origin.thus,there is centripetal fluvial action supported by rainstorms of ...

Wind erosion is largely controlled and determined by- wind velocity,nature and amount of sands dusts and pebbles,composition of rocks,nature of vegetation,humidity,rainfall amount  and temperature.Wind erosion is believed to be defective only upto 182 cm. above the earth's surface.Maximum wind erosion occurs at a short distance above the ground,say at a height of 20-25cm. because here the wind velocity and sediment movement are moderate whereas at the ground sediment transport is high but velocity of transportation is low.At a height the velocity is high but quantity of sand available for abrasion is small.Due to their variable direction they erode rocks from all directions. There are erosional processes:- a) Deflation:-(derived from the Latin word 'deflatus' meaning blowing away) It includes removing,lifting and blowing away dry and loose particles of sands and dusts i.e., incoherent sediments,by wind.It is controlled by 3 factors:- 1) Surf...

there are 3 processes of deposition (sedimentation,accretion and encroachment) as it is in case of erosion and transportation.Deposition of sand depends on the variations in wind speed,grain size and type,type of obstacle in the path of the wind(i.e.,trees,bushes,lakes etc).Sand is deposited on both windward and leeward side of the obstruction.Accumulated sand mounds on the either side of the obstruction are called sand shadows . sand drifts are sand accumulations between obstacles. there are 3 types of depositional landform in arid region.they are:- A)Sand ripples; B)Sand dunes; C)Loess. A) Sand ripples:- they are small scale depositional features of sand covering most dry,bare sandy surfaces in the deserts.Heights vary from 1cm. - 3cm.; windward slope angle between 8 degree and 13 degree and in extreme 25 degree.their summits are broadly convex with the lee faces having angles upto 30 degrees.some of them have either sharp or smooth brinks. there are 3 mai...

Glacier not only performs erosive and transportational activity but also depositional activity.    Till is a type of a sediment in which the components have been brought into contact by direct agency og the glacier ice. Inspite of the subsequent glacially induced flow  it does'nt become disaggregated.It's a glacial deposit.there has been little or no sorting by water.       The most widespread evience of the subglacial action is the formation of rolling,low relief till plain,covering vast areas and are indicative of the non-landforming -thrust block ridges,depression and push ridges can be found which reflect localised subglacial differential stress,local variations in sediment rheology or influence of topographic control.they have formed due to uniformity of sunglacial depositional conditions.however,they do not signify till type uniformity.It's sediments are complex reflections of the local and regional bed geology,topography,ice dynamic...

Glacial troughs are formed due to regional linear erosion within the ice sheets probably as a consequence of ice streaming and related fast moving but spatially restricted basal ice. Glaciated bed rock troughs have stepped longitudinal profile relatively few transverse sections while fjords have more than one bed rock sills or thresholds and the many traverse sections of the valleys. Geological control has a secondary influence upon trough orientation.                       they are often described as U-shaped although their characteristic cross profile is not found everywhere, it has been suggested that for U-shaped trough formation the volume of ice moving through a glacial trough should be directly related to drainage or ice evacuation area up-ice of the trough. The U-shaped profile development is probably due to greater erosion not a t the valley base but at some distance la...

It's a french term for a glacially moulded rock mound exhibiting asymmetrical form with a gently sloping and smoothly abraded, upvalley face with steeper,broken,ice-plucked,down valley face(leeward side).It may be also regarded as a streamlined bedrock hill.It's larger variant is called Flyggberg. It's formation is attributed to plucking action on the lee side and in order that the leeside be affected by plucking,there has to be no caity of any size on the leeside of obstruction.As a result ,tensile stresses and freeze and thaw processes in the combination create a plucked lee face.  Rostas and sepala(1981) in an extensive survey of the south Finland found a close relationship between bedrock joint systems, fissures and the size and the morphology of the individual forms of the rochee mountonne.Glacial polish near the crests of the roches mountonnes,gently sloping abraded by clasts will depend on the particle size. The glacialpolosh on the lee side reflect t...

Moraine is an accumulation of the heterogeneous rubbly material including angular blocks of rocks,pebbles,boulders,clay that has been transported and deposited by a glacier or ice sheet.they are classified on the basis of the mode of their formation i.e.,supragalacial,englacial and subglacial environments. the different types of moraines are:- A)rogen or ribbed moraines:- they are found transverse to the main direction.The ridges exhibit slight down-ice pattern.there are 3 main hypothesis of it's formation:- 1)Subglacial; 2)Stagnant ice; 3)subglacial; 4)subglacial meltwater floods; 5)Crevasses fillings; 6)Marginal moraine formation. It exhibit wide range of sdiment types and structures  although stratified sediemnts are often the dominant type.they typically occur beyond  centres of glaciation.they occur at the distances of >200 Km. from ice sheet and rarely within the 200 Km. - 300 Km. of ice margins.        ...

Biological weathering is the decomposition of rocks due to activities of flora and fauna and several chemicals exuded by them or is formed due to their activity.Important biological agents include -bacteria,lichens, algae,fungi,plant roots and organic matter in a state of decay organisms assist rock and mineral breakdown in 2 main ways:- a)by exerting physical stress on the rocks.example-expansion and contraction of plant organic tissue during wetting and drying. b)Release of acids ,carbon di oxide,complexing agents,protons and electrons as part of their life process. a) Faunal weathering:- Fauna include foxes,burrowing animals ,termites etc. small organisms play more decisive roles in rock and soil weathering.micro=organisms including bacteria release the carbon-di-oxide increasing carbon-di-oxide content in the soil air between the percentage 0.5%-20% resulting weakly acidic soil solutions enhancing chemical weathering.  nitrificaton of ammonium ions by bacteria...

It is important to consider the winter monsoon for 2 reasons:- a) It corresponds to the night cycle of the sea breeze & like the summer monsoon is an important component of the global monsoon. b) It has the capacity to generate seasonal rainfall over the southern part of Indian peninsula, Sri Lanka, Malaysia & Indonesia. The onset of winter monsoon is not clearly defined & at times there is no distinction between withdrawal of summer monsoon & the onset of winter monsoon. There is a period of transition of about a week for the winter rains to st in Tamil Nadu.Tamil Nadu experiences north-east monsoon from October to December. Intense convection over Indonesia generates precipitation & releases of latent heat subsequently. This is an ascend corresponding to the rising limb of the Hadley's cell. the ascending air spreads to the north & south which isn't possible for the ascending air over Tibet during the summer monsoon because the northward...

It’s a term introduced by Bjerkness school in Norway(1918) to describe a sloping boundary plane or surface of separating 2 air masses that exhibit different meteorological properties or characteristics. the interface of which may be narrow & on a small scale when it is termed as a -frontal surface(eg.-warm front associated with depression) & may be broad & on scale of a frontal zone(eg.-Atlantic Polar Front). The different types of front are as follows:- 1) The Arctic Front:- this is a distinctive baroclinic zone separating the ice & snow of the high Arctic regions from the more moderate polar/tundra environments to the Pacific portion does move further south into N.W.North America in winter as the high Arctic freeze is acentuated by polar night. 2)P olar Front :-It's well known active zone of frontogenesis in Atlantic & pacific oceans. It’s quite variable depending on the seasonal distribution & extent of polar & tropical air masses. In t...