Grade 11, Quarter 2 - Exogenic Process and Weathering

Check the ppt for more info about exogenic process

1. Cactus The exogenic processes obtain their energy from the gradients generated by tectonic factors, processes, their corresponding driving forces and atmosphere determined by the energy from the sun. Whole exogenic geomorphic processes are covered under a common term, Denudation which means to uncover. EXOGENIC PROCESS

2. WEATHERING It is primary source is the energy coming from the Sun which drives the weather. Earth’s internal heat forms the mountains while the sun’s energy, which is responsible for exogenic processes, slowly and steadily tears the landforms down. Is the on-site breakdown of rock and its eventual transformation into sediments.

3. 2 TYPES OF WEATHERING CHEMICAL occurs when there are chemical changes in at least some of the composition of the rock. It is a surface or near-surface process that is not influenced by high temperature or pressure. is the physical breakdown of a rock into unconnected grains or chunks without changes in its composition. MECHANICAL

4. Exfoliation - it is a process usually happen in granite that split into onion-like sheets parallel to the surface. Frost wedging - it is the process when water inside fractures freezes that cause the joints to expand grow. Root wedging - it is a process that joints expand when plants growing on its surface pry it open. Salt wedging - it is a process when the salt cystallized that pushes apart the surrounding grains and weakens the rock Thermal Expansion - occurs when a rock is exposed to high temperature SOME TERMS FOR MECHANICAL WEATHERING

5. the common chemical reactions that occur in rocks are the following: 1. Dissolution - happens in certain minerals which are dissolved in water. 2. Hydrolysis - occurs when water reacts with the minerals and breaks them down. 3. Oxidation - reaction of oxygen with minerals in the rock, forms oxides. 4. Hydration - occurs when water is absorbed into the crystal structure of the mineral causing it to expand. 5. Biological weathering - certain bacteria that consume certain minerals. CHEMICAL WEATHERING

6. Answer the following: What is weathering? Why is it important? SEATWORK #1