exogenic processes.pptx earth & life science
- 2. •These are processes that take place at or near the earths surface, that makes the surface wear away. EXOGENIC PROCESS
- 3. •WEATHERING •EROSION •MASS MOVEMENT (Mass Wasting) DIFFERENT TYPES OF EXOGENIC PROCESS
- 4. W E A T H E R I N G mechanical and chemical hammer that breaks down and sculpts rock.
- 6. • mechanical weathering • the breakdown of rocks without a change in its composition. • Breakdown would mean that the rock is fractured, cracked or fragmented into smaller pieces. Physical Weathering
- 11. • decomposition of rocks due to chemical reactions occurring between the minerals in rocks and the environment. • transforms rocks and minerals exposed to water and gases in the atmosphere into new chemical compounds thus, forming different rocks and minerals. Chemical Weathering
- 14. a key factor in the creation of caves and caverns. It can also hollow out caves and damage cliffs. Chemical weathering
- 15. 1.THERMAL AND PRESSURE CHANGE • Rocks crumble and break into fragments because they are subjected to alternating hot and cold temperatures many times. • When a rock gets hot, it expands an increase in volume), while at night, the rock gets cold causing contraction (a decrease in volume). Processes that can Cause Physical Weathering
- 16. • Temperature weaken the rock and in the process, mineral grains are loosened from the rocks and eventually the rocks break down into pieces. Best examples are the stone in the arid desert that slowly turn to sand. • The rates of expansion and contraction of the outer and inner parts of the rock differ. The outer part expands and contracts much more than the inner part because it is directly exposed to the heat of the sun.
- 19. 2. WIND AND WAVES • Wind and waves can all cause physical weathering. Tiny grains of sand are picked up and carried off by the wind, which are then blasted on the surface of rocks, smoothening them. • On the seashore, the action of waves chips away and cracks the rocks. Processes that can Cause Physical Weathering
- 22. 3. FREEZE AND THAW • You know that if you put a glass in the freezer it will soon break. This is because water expands when it freezes. Similarly, when water collects in the rock pores and slits, it expands when it freezes. Processes that can Cause Physical Weathering
- 24. • Frost Wedging • Salt Wedging
- 26. 4. ORGANIC ACIVITY • Animals and plants also take a heavy toll on rocks and cause them to wear away. • For example, there are animals that dig holes on the ground and exposed rocks. Processes that can Cause Physical Weathering
- 28. 1.HYDRATION/ HYDROLYSIS •Process where molecules of some substance in rocks chemically combine with water molecules Processes that can Cause Chemical weathering
- 30. 2. CARBONATION • Process where Carbon Dioxide may bond with other substances. • A mixture of water and carbon dioxide is called carbonic acid. • Two examples of carbonation weathering are The Limestone Pavement and The Stalactites. Processes that can Cause Chemical weathering
- 31. This land form is made entirely of limestone and formed by rainwater carbonation and the freezing and thawing process.
- 32. This land form is also made of limestone. It was created by large amount of calcium being dissolved in them.
- 33. 3. OXIDATION • Iron, aluminum, copper, and sodium are examples of minerals that readily react with oxygen which then form mineral oxides. • In nature, physical and chemical weathering typically occur together, affecting the rocks. When the latter is destroyed, valuable products are created. Processes that can Cause Chemical Weathering
- 34. Erosion
- 35. • Involves the movement of the weathered rock (snow, soil, sand and pebbles) from their site of weathering by the agents of erosion such as wind, moving water, ice and gravity. Erosion
- 36. • Weathering dos not always occur before erosion. Erosion always follows after the weathering. • Transport makes erosion complete. It complete the movement of the eroded materials and sediments. Weathering can continue during transport. Erosion
- 37. Transport by the water • Rainwater is the most important force or agent of erosion. When there is heavy rain, rock pieces are carried downstream to a suited depositional environment with the action of gravity. • Gravity is the driving force and it gives water the energy to erode and carry away rock materials. • Physical weathering dominates at higher elevation while Chemical weathering takes on a more active role at lower elevation. Transport by the water
- 38. • Water can carry almost any size of rocks. The greater the volume of water and the steeper the slope, the bigger and more rocks can be transported. • Serious problems in the Philippines are soil erosion and mudslide • Rock materials are loosened by heavy rains and strong winds and they can come speeding down slopes, sweeping everything in its path. Transport by the water
- 40. • Wind continuously blows away loose particles of rocks and soil from place to place. • This is common in dry areas such as deserts. • Wind transport can result in stunning landscapes as sand is blown away and creates sand dunes. • Wind can create sandstorms that contain dust particles and deposit them in wide areas. Transport by the wind
- 42. • slope movement • bulk movements of soil, sand, and rock debris downslopes in response to the force of gravity or the rapid or gradual sinking of the Earth’s ground surface in a vertical direction. • The term “mass wasting” was limited only to the variety of processes by which large masses of crustal materials are moved by the action of gravity form one place to another. Mass movement (mass wasting)
- 43. • Recently, the term “mass wasting” has been substituted to include mass wasting processes and the sinking of the Earth’s ground. • Mass wasting is a type of erosion that is capable of making big chances to a mountain. Mass movement (mass wasting)
- 44. • Sinking mass movement that occurs in a relatively rapid fashion is known as subsidence; and a gradual movement is called settlement. • Subsidence involves the roof collapse or breakdown of a subsurface cavity forming a cave. • There is also subsidence in the form of sinkholes caused by underground drainage. Mass movement (mass wasting)
- 50. REFERENCE: • Moncada, M. et. al (2016). Earth and Life Science for Senior High School. Disclaimer: The pictures used in this slideshow presentation were obtained from various internet websites and will be only used for educational purposes only.