Weathering is the gradual breakdown of pre-existing rock due to natural processes. These processes can be very quick but some may take thousands of years to occur. Natural elements like rain, acid rain, thaw and freeze weather rocks as they are exposed to them. They break them into smaller pieces and then these pieces undergo chemical changes. The process for moving these weathered materials is called erosion. There are different types of weathering such as Physical or Mechanical Weathering, Chemical Weathering and Biological Weathering.
Mechanical Weathering is the process of weathering that mainly leads to the disintegration of rock whereas chemical weathering causes de-composition of rocks. Physical weathering is due to the rising temperature during the day. Minerals in the rock expand and as the temperature falls during the night, they contract. This process goes on continuously, stresses develop in the rock mass, the grains are separated and the rocks break away. The rocks get disintegrated when rain water seeps into the gaps and ice is formed. This continuous change in temperature and the combine action of natural sources leads to weathering which is also known as exfoliation.
Chemical weathering depends upon the properties of the rock. In this process carbon dioxide in the atmosphere dissolves in rain water. This leads to the formation of mild carbonic acid, salts like calcium carbonic in limestone. The water or moisture in the air reacts with the ferrous minerals in the rocks. There rusting leads to decomposition of rocks. Biological weathering happens when root or trees grow in the cracks of rocks. This creates stresses in the rock mass and the cracks widen. Different animals and insects dig the lands to make holes. The products of weathering are sediments and cool landforms. Normally Chemical weathering makes way for Physical weathering.
Erosion is the movement of weather rock, agents of erosion that are more active are winds, floods, waves, streams etc. There are various types of erosion. Mass wasting is one of them that are the downhill movement of material due to gravity. As the slop of the material increases, the rate increases. The steepest slop at which the material will remain stable is called the angle of repose. This is determining by the shape, density and size of the particles. The types of mass wasting are slum, rock slides, and rock fall and mud flow.
Erosion by moving water results in streams. The running water transports sediments with them. The running water cuts into the surface of the earth, and builds a channel that is surrounded by a bank on either side. When the load of a stream is a resistant rock it can abrade the surface of bed rock. The prolonged scratching can gouge rock, and eventually a canyon can be formed. Ocean erosion results in the formation of sea clips, terraces, stack and caves.
Abrasion is the process in which windblown sediment collides and wears rocks down. Deflation is processing of wind picking up sediments and transporting them. This is called Wind Erosion. When deflation is concentrated, a deflation hollow is formed. There are thousands of such hollows on the Great Plains. Areas formed with this process are called deserts. As sand travels through the desert, being eroded by wind, dunes start to form. Streams too are agents of erosion. When a stream is young it generally flows quickly and forms a long V shaped valley in the ground. In matured stream, the slop gets eroded over time and becomes much less steep. Gradually the water slows down and deposits its load and a broad flat flood plain is formed.
In an old stream peneplain is formed. This peneplain has oxbow lakes and cutoffs. Gradually the stream meanders and becomes heavily eroded where you find cliffs. The inside of the meander is where a sand beach can be deposited. Glaciers are formed after long periods of snow fall usually in the mountains. As the snow begins to crystallize into solid ice, the pressure continues to increase. This squeezing motion forces the ice to flow as liquid. These glaciers carry sediments that are the size of boulders for thousands of miles. This causes deep groves in the rock called glacial scratches. As the glacier begins to recede, the sediment that is deposited is called Morraine. Long Island is an example of the same.
Utah (USA)/ Slick Rock
This is the result of Chemical Weathering due to oxidation. The result is much the same as an Iron nail. When these bonds are re-arranged the bonds of the rock are weakened. If you compare a rusty nail to a new nail the unweathered nail is much stronger. It is the unweathered part of the rock which is the favorite site for tourists known as Red rocks ride. Here mountain bikers patronize for adventure as the rocks are rustier than the bikes in this climate.
Hyden Perth- Australia / Hyden Rock
Wave rock and Hyden rock are part of a 160-hectare nature reserve, Hyden Wild Life Park. This rock is a natural formation shaped like a tall breaking ocean wave. It is about 14 meters high and 110 meters long. More than 150 thousand tourists visit this site every year. It is an example of weathering of granite bed rock beneath a lateralized land surface about 130 million years ago. The wave rock is an example of chemical weathering of the bed rock by ground water. The wave rock has been used as a back drop for TV programs and even movies. It is known for its weekend musical festival held once a year.
Arizona USA/Grand Canyon
Grand Canyon is one of the 7 natural miracles. It is one of the most visited places on the earth and a most popular tourist destination. This is a simple natural effect of erosion. The 3 main weathering processes that have formed the Grand Canyon are Ice, Wind and Water of which water is the primary cause. Located in the desert of Arizona where the soil is very hard and dry, it leads to weak absorption of water. This wind erosion erupts away the softer part of the rock and soil and leaves the harder layers. The stream erosion carries the light weight particles in suspension. The small particles do not sink and the heavier particles are moved by a processed called traction. During the winter months, ice erosion takes place as the water seeps into the cracks between the rocks. The water freezes, expands and pushes the rocks apart and thereby widening the cracks.
Mascarene Islands, Mauritius/Reunion and Rodrigues
These islands are the tops of great volcanic cones that have risen from the Ocean floor. Mauritius has emerged from the sea millions of years ago. These Islands were formed over a hot spot caused by a mantle plume welling under the African Plate with a source in the lower mantle. These are ocean islands characteristic by distinct volcanic phases. Mauritius is a tourist destination, an island with splendid primary volcanic features. It is known for its smaller islands where tourists from all over the world visit.
This hanging valley opens onto Tar inlet, Alaska, part of Glacier Bay National Park. This is a hanging valley which is formed by the ice moving through the tributary glaciers being less than that in the main glacier. As the base in the tributary glaciers is not lowered to the level of the main glacier, they remain at some elevation. When the ice melts, these values of tributary glaciers appear to be hanging over the main glacier. The National Park is visited by tourist from all over the world. It has a beautiful waterfall and the Death Valley lodging is well known to tourist.
Ngaurehoe New Zealand/ Tongariro National Park
This is the fourth biggest national park in the world and the 1st in New Zealand. It is situated on 3 active volcanoes and is the result of the eruption of Ngauruhoe that has erupted at least every nine years. More than a million people visit Tongariro National Park every year. In summer the tourist go on hiking and walking adventures and the tourist visit this site during winter too.
Western Ganges Garhwali Himalayas/ Hanging Valley of Gods
It is also known as Ha Ki Doon. It is a cradle shape valley which is bounded by dense forest of pines and gleaming mountain peaks. It is a result of physical and chemical weathering and erosion with the help of snow. This place has the Swarga-Rohini peak as its main attraction, the Govind wild life sanctuary with beautiful villages, all located in the Fateh Parvat Region.
Sumbawa Island/ Indonesia/ Mount Tambora
This forms its own peninsular on Sumbawa known as the Sanggar peninsula. To its north is the Flores Sea and in the South the Saleh Bay. This location is abundant with luxurious resorts where celebrities from all over the world spend their holidays. The tourists are attracted here for hiking and wild life activities. These Islands are a string of volcanic islands that are resulted from physical and chemical weathering.