When glacier reaches its terminus it begin to melt Ice remains stagnant at the

When glacier reaches its terminus it begin to melt

This preview shows page 112 - 114 out of 172 pages.

- When glacier reaches its terminus it begin to melt. - Ice remains stagnant at the point of melting for several years. - Moraine is deposited across widened valley to form a ridge of terminal moraine. - Glacier begins to retreat towards snow field as it melts. - The melt water accumulates behind the ridge of terminal moraine to form a moraine dammed lake. d) - The warm glaciated valleys are suitable for livestock farming. - Glacial upland areas have magnificent features like pyramid peak, an arête which encourage tourism and recreation. - Water falls which form at hanging valleys are exploited for generation of hydro electric power. - Some U-shaped valley form natural route ways and are suitable for settlement and agriculture. - Some fiords form deep, well, sheltered natural harbour and good fishing grounds. - Glaciated mountains discourage human settlement, hence growth of forests and lumbering practiced. 28. a) Mechanical weathering is the physical break up of rock material without any alterations in its chemical composition while chemical weathering involves changes in the chemical composition of minerals making up the rock. It’s the actual decay or decomposition of rocks. b) ) - Climate. - Topography - Nature of the rocks. - Plants and animals. - Time factor. 29. a)- A spring is appoint or a place where underground water flows out naturally onto the land. While a well is a dug in the ground, often with the purpose of getting water
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b)- Zone of non-saturation– lies nearest to the surface. Water passes through this zone as it makes it’s way downwards. - Zone of intermittent saturation – contains water only in wet seasons or after heavy rain. - Zone of permanent saturation – contains water both wet and dry seasons. . c) - The aquifer must be sandwiched between impermeable rocks so that it can retain water. - Aquifer must outcrop in a region which is a source of water e.g Rain y area/beneath a lake. - Aquifer must be dip from a region of water intake and the rock layers must form a broad syncline/basin. - Mouth of well must be lower than the intake area. This allows water to be forced to the surface by pressure with no need of pumping it. . d) - Acts as sources of rivers. - Acts as source of water- wells, springs, boreholes, oases which provide water used in homes and industries. - Used for irrigating agricultural land e.g Sahara desert, where dates grow near oases, Taveta- cotton and bananas are grown using water from springs. - Settlement – in dry areas, people tend to settle near the springs due to the availability of fresh water. - Provision of hot water- water from hot springs may be tapped and pumped into houses through pipes to heat up houses during cold seasons e.g Iceland. - Tourist attraction – Hot springs e.g Olkaria, Lake Bogoria etc, valuable mineral salt are deposited and people exploit them for economic gain.
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