LAST+QUESTIONS+FROM+UNIT+1.

1.- The **physical weathering** of a rock is when the rock fragments, breaks up or is pulverised by the action of mechanical processes without any kind of mineral transformation. 2.- During the day, the water infiltrates into the cracks of the rock, at night, the water freezes and increases in volume and the cracks get bigger. Next day, the ice will have melted and a larger amount of water will be able to infiltrate into the cracks. If this process is repeated day after day, the rock will end up by being fractured. 1.- **Bad lands** is an abrupt area where a set of channels of different depths and gullies appear from the rainfall onto homogenous and soft materials which can be easily eroded (e.g sandstone, a sedimentary rock). A **fairy chimney** is a conical formation where there is a resistant, hard rock at the top (eg. granite) in the upper part which has protected the softer material beneath it eroded by wild waters. 1.- A **cliff** is a steep face that runs along the seashore because they have been dug out of hard rocks by means of a progressive process of digging out at the base and the collapsing of the higher parts. An abrasion platform is a flat rocky surface which are slightly sloping towards the sea, produced by the gradual receding of the wall of the cliff. 2.- The most characteristic formations on a **low coastline:** .- **Beaches** which are marine deposits totally joined to the coast. .- **Coastal bars** are marine deposits not totally joined to the coast and which include: **spits or reefs** when one end is joined to the coast**. Barrier islands** which are not joined to the coast at either end and **land-tied island** is a sand bar joining two pieces of land. 1.- There are two types of erosion caused by the wind: 2.- The most typical formations due to the aeolic sedimentation: .- **SAND DUNES,** accumulations of sand which move across the ground as a result of the wind. .- **LOESS DEPOSITS,** accumulations of fine particles in the external and humid areas in deserts.
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 * Chemical weathering** of a rock is when atmospheric agents act on it, transforming the minerals which make up the rock.
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 * Alluvial plains** are extensive deposits of sediments which fill the bottom of valleys. The flat surface and fertility means they are very good for agriculture.
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 * DEFLATION** which is the selective carrying by the wind of small particles, leaving the largest ones on the ground
 * CORROSION OR AEOLIC ABRASION** which is the damage caused to rocks by the repeated impact of the particles carried by the air.