GEOGRAPHY FORM SIX -WATER MASSES-LAKES
Posted by GEOGRAPHY FORM SIX -WATER MASSES-LAKES
UNAWEZA JIPATIA NOTES ZETU KWA KUCHANGIA KIASI KIDOGO KABISA:PIGA SIMU:0787237719
ALSO READ;
WATER MASSES-LAKES
LAKES
Is a hollow of which they vary in different size .Some lakes are natural and other are temporary.
Therefore a lake as a hollow which is filled with water coming from natural sources. A lake can be in liquid or in solid or (glaciers) and it can consist of fresh water or salt water. A lake can be formed from different natural forces and is named after that force together with its size (lake size).
The sources of water in the lake is from
(i) On the surface (e.g. run off, ice melting)
(ii) Underground source (e.g carst region)
(iii) From the atmosphere (rainfall)
CLASSIFICATION OF LAKES
Lakes are classified according to the different criteria as follows:
- Due to earth movement lakes can be formed from folding, warping (especially down warping) and faulting.
- Due to erosion we have lakes which are formed by the wind and graciation.
- Due to deposition there are lakes which are formed due to oxbow and delta.
- Due to volcanicity there are rocks which are formed due to crater, lava blocked and lava subsidence.
- And those which are formed due to different types are solution lakes , mining, ponds and dam.
EARTH MOVEMENT
Folding: Folding lakes can be formed due to compression force .And in young rocks with large piece of rock subsidence occur or down warping.
But also in old rocks with enough force leads to the formation of lakes in syclines.
Faulting: Lakes can be caused by faulting when tension force dominate.
The examplesof folding down wraping lakes include lake Victoria, Lake Tchad ,lake Eyre(Austria),Lake Titicara (Peru) and example of lakes which are formed due to faulting are lake Tanganyika, Laika(the depest) in Russian, lake Nyasa ,Dead sea and ness in Scotland.
EROSION
There are lakes which are formed due to erosion especially by wind and glacial.
By wind: Blocks and when it is strong wind it lead to the drug of blocks of rocks and form depression (oasis). This lead to the creation of lakes especially when the depression reach the water table .
Then when the depression reach the water table is exposed to the surface .It reate the rocks and sometimes underground streams can be opened.
Also by wind can form Playas.Playas are holes which are drugged by the wind.But they are dry and sometimes can contain fresh water and salty water.
By Glaciation:Lake can be formed by glacier erosion when evalanche moving from the Highlands they come and being deposited on the law land especially when they meet the obstacle and prevented.In this sense they may form glacier lake or in melting they form fresh lakes.They called basin rocks especially when they meet an obstacle.Example lake Teleki-Cirque(corrie)lake .Trough lakes(Ribbon lake or tinger lake)
Sometimes glacier can erode the surface and cause alongated depression where after ice to melt they form a lake which is know as Ribbon rock.This happen when the ice erode through the flat surface by accelerating(friction).
Now with graciation three types of lakes can be formed which are:
(i)Trough (ribbon) elongated feature
(ii) Rock basin
(iii)Corrie/Tarn /Cirque
DEPOSITION
Delta lake:A delta lake can be formed by revee.This is due to factor that when the water erode the sides of the banks they form deposition on the sides of the banks.Then on ahead the stream may be blocked due to erosion and create a lake.
VOLCANICITY
Crater:This is formed after the eruption of melting material and create a crater lake.But sometimes a second eruption can take place and lead to the formation of cardera lakes.
Lava Dammed Lakes:These are the lakes formed when the river stream (i)blocked by highly viscous lava that erupts and runs across the river,When lava cools and solidified it forms a dam behind which water collects to forms a lake.Example Kigezi in Uganda
No comments: