Earth and Life Science PDF

WEEK 4 EARTH AND LIFE SCIENCE EXOGENIC PROCESSES (The process on the surface of the earth) Occur on or near the surface of Earth. They are usually influenced or driven by gravity, water, wind, and organisms. These could be destructive occurrences th...

WEEK 4 EARTH AND LIFE SCIENCE EXOGENIC PROCESSES (The process on the surface of the earth) Occur on or near the surface of 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 b. Biological Weathering cases, exogenous processes can wipe out the The weakening and subsequent majority of the organism inhabiting that disintegration of rock by plants, area. animals, and microbes. Living WEATHERING organisms contribute to the weathering process in many ways. The disintegration of rocks, soil, and minerals together with other materials through contact with Earth’s subsystems. This process happens even without movement or transportation. c. Chemical Weathering The process by which rocks break down by chemical reactions. New or secondary minerals develop and sometimes replace the original properties of the minerals in the original rock or soil a. Physical Weathering 1. Oxidation – The reaction of The breakdown of rocks by mechanical substance (mineral/rock)on oxygen forces concentrated along rock fractures. 2. Hydrolysis – The chemical This can occur due to changes, whether breakdown of substances when sudden or not, in temperature, pressure, etc. combined with water 3. Acid Rain – May cause metal or rocks to corrode or deteriorate and change their properties because of the reactions to acids by some o the minerals  WEEK 5 DEFORMATION OF THE CRUST Understanding crustal deformation helps explain the forces necessary to bend and fold rocks which help create mountains. CONTENTAL DRIFT THEORY BY ALFRED WEGNER EROSION All continents were once joined together in a single massive landmass and have since The process of erosion moves rock debris drifted apart. The super continent was or soil from one place to another. This named Pangaea. Pangea broke apart and process takes place when there is rainfall, slowly moved toward their present-day surface runoff, flowing rivers, flooding, location. freezing, hurricanes, etc. Wegener’s theory was rejected by scientists MASS WASTING because he could not explain what force pushes or pulls continents. Wegener The movement of large masses of materials searched and found three main pieces of (rock debris, soil, and mud) down a slope or evidence. Geologic, Fossil, and Climate. a steep-sided hill or mountain due to pull of gravity. This process is very destructive in 1.GEOLOGIC – evidence in the layers of areas with increased water flow. rocks across continents. A. Debris Flow happens when a large amount of sediments, usual rocks of various sizes, falls down the slope. Unlike landslides, debris flow does not need water to flow down. B. Mudflow happens when combined soil and water flow down a slope. This usually happens near rivers or streams where soil or sand is always moist or has been soaked in water for a long time. The weight of the mudflow indicates the severity of risk when it flows down a community. C. Slump a slow movement of soil along with a curved surface. In time, they would 2.FOSSIL – evidence in the places certain look curved because of the depression fossils is found. formed by the sinking land. SEDIMENTATION The accumulation of materials such as soil, rock fragments, and soil particles settling on the ground. This usually occurs in streams and sea erosion. Over time, the sediment load becomes thick and forms a new layer of ground.  PLATE TECTONIC THEORY ✓ The basis for the movement of continents progressed, geologists started to use a more precise term to refer to the moving piece of crust as “plate” because it was believed that continents are not the only ones moving (as explained by Wegener). 3.CLIMATE – evidence in the changing climates during the past. CONVERGENT BOUNDERY Where plates meet. This happens when two tectonic plates move toward each other brought by mantle convection. Two possible landforms can be created: Trench and Mountain. DID YOU KNOW? ❖ that Wegener’s theory was rejected by Trench scientists because he could not explain what which is formed from subduction where denser force pushes or pulls continents. plate sinks(subducts) under the other (less ❖ that India was once in the Southern dense) plate. Hemisphere connected Antarctica. ❖ that North America was once surrounded by warm, tropical seas? ❖ that Africa was once covered by glaciers, which were kilometers in thickness? ❖ that the Sahara Desert was once a tropical rain forest? WEGNERS PROBLEM ❖ He could not find the force that was causing the continents to drift. ❖ Because of this, he could not convince Mountain anyone that continents could move. where neither plate is subducted but instead ❖ He died in Greenland on an expedition. crumples into each other and somehow pushed ❖ At the time of his death, no one believed his upward or sideward. hypothesis. ❖ Technology developed during the 1940s changed all that!  CRUSTAL MOVEMENT Folding and Faulting FOLDING The horizontal movement of the Earth’s crust. Folds mountains occur where the crust is pushed up as plates collide which causes the crust to rise up in folds. (e.g. DIVERGENT BOUNDARY Himalayan Mountains) Where plates move away from each other. Plates move apart because of the magma that is being pushed upward in boundaries of the plates. TRANFORM BOUNDARY Where plates slides past each other. Neither plates gets subducted. E.g. San Andreas fault (Between San Francisco and Los Angeles California) FAULTING The vertical movement of the Earth’s crust. Involves uplift or subsidence of crust along the lines of weakness. The cracks or fractures formed is called fault lines. Faulting can form mountains and valleys. p