Geologic Processes on Earth PDF

Geologic Processes on Earth The term "geological processes" describes the natural forces that shape the physical makeup of a planet.  PLATE WEATHERI TECTONI NG CS SEDIMENTATI EROSIO ON N These processes are closely studied by geologists and earth scientist...

Geologic Processes on Earth The term "geological processes" describes the natural forces that shape the physical makeup of a planet.  PLATE WEATHERI TECTONI NG CS SEDIMENTATI EROSIO ON N These processes are closely studied by geologists and earth scientists: to improve their understanding of the planet’s history; to help locate useful resources, and  to aid the prediction of potentially disastrous events, such as earthquakes, tsunamis and volcanic eruptions.  GEOLOGIC PROCESSES Exogenous Endogeno (external) us (internal)  Chapter 4: Earth Materials and Processes EXOGENI C PROCES S  EXOGENIC PROCESS These are processes that take place at or near the earths surface, that makes the surface wear EXOGENOUS PROCESSES  This process occur on or near the surface of the Earth.  They are usually influenced or driven by gravity, water, wind, and organisms.  These could be destructive occurrences that leave significant changes on the landscape and even in the ecosystem of an area.  In extreme cases, these process can wipe out majority of the organisms inhabiting that area. DIFFERENT TYPES OF EXOGENIC PROCESS WEATHERING EROSION MASS MOVEMENT (Mass Wasting)  WEA THERI NG  mechanical and chemical hammer that breaks down and  It is the disintegration of rocks, soil, and minerals together with other materials through contact with Earth’s subsystems.  It happens even without movement or transportation (as opposed to erosion that involves movement)  The breaking down of soil and rocks happen on the spot.  TYPES OF WEATHERING PHYS ICAL Weatherin g Physical Weathering mechanical weathering the breakdownof rocks without a change in its composition. Example: * Soil cracks because of extreme heat and drought. In some cases, water, wind or ice may abrade or scrape rocks or soil. Physical Weathering Chemical Weathering 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.  The process by which rocks breakdown by chemical reaction.  In this process, new or secondary minerals develop and sometime replace the original properties of the minerals in the original rocks or soil. Oxidation – the reaction of a substance with oxygen. Hydrolysis – the chemical breakdown of a substance when combined with water. Another contributor of chemical weathering is Acid Rain which may cause metal or stone to corrode or deteriorate and change their properties because of the reaction to acids by some of the minerals in the soil and rocks that make them up. Chemical Weathering  a key factor in the Chemical creation of caves / weathering caverns. It can also hollow out caves and damage cliffs. Processes that can Cause Physical Weathering 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).  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. Processes that can Cause Physical Weathering 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 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.  Frost Wedging Salt Wedging Processes that can Cause Physical Weathering 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 Chemical weathering 1.HYDRATION/ HYDROLYSIS Process where molecules of some substance in rocks chemically combine with water molecules Processes that can Cause Chemical weathering 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 This land form is made entirely of limestone and formed by rainwater carbonation and the freezing and thawing process. This land form is also made of limestone. It was created by large amount of calcium being Processes that can Cause Chemical Weathering 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. Erosion  Erosion 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 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.  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 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 wind 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. Mass movement (mass wasting)  Mass movement (mass wasting) 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  Mass movement (mass wasting) 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) 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 A massive 300-ton boulder blocks a road in Southern California  Landslides Can cause much destruction Talus Cones in the Canadian Rockies Talus – pieces of rock at bottom of a rock fall La Conchita Landslide, January 10, 2005 Monterey Park Debris Flow, 1980 PCH near Pacific Palisades, November 1956 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.