Weathering and Erosion PDF

True or False: The Earth’s surface has stayed the same for thousands of years  True or False: The Earth’s surface has stayed the same for thousands of years The Earth’s surface is always changing!  Weathering The breakdown of the material...

True or False: The Earth’s surface has stayed the same for thousands of years  True or False: The Earth’s surface has stayed the same for thousands of years The Earth’s surface is always changing!  Weathering The breakdown of the materials of Earth’s crust into smaller pieces. I. Physical Weathering - rocks break into pieces - changing size and shape - but not their composition.  Water causes weathering What evidence of weathering do you see in this picture?  Wind causes weathering Why wasn’t this mass of land weathered away? What evidence of weathering do you see in this picture?  Ice causes weathering Describe how ice causes weathering? Abrasion- When ice, water, or wind causes sediments to have collisions physical weathering results. Wind abrasion is similar to sandblasting and slowly weathers the rock down. Wind abrasion occurs in arid environments Note the lack of soil and angular rock features. Water abrasion occurs in moist and humid climates Water produces rounded fragments as the sediments are rolled and bounced along the stream bottom.  Glacial Abrasion occurs when sediments are trapped with in the ice and scrape against the bedrock. Forming Striations In the Rock (Scratches) Glaciers are found in cold climates high altitudes latitudes  Erosion The process by which water, ice, wind or gravity moves fragments of rock and soil. What evidence of erosion do you see in this picture?  Erosion is Movement of Sediment! This process, known as Erosion, is gradually wearing down the surface of the earth. Erosion is the process by which weathered rock and soil (sediment) are moved from one place to another. Erosion carves the Earth's surface creating What do you think has caused canyons, gorges, and this rock to look this way? even beaches.  Wind Erosion As the wind blows it picks up small particles of sand/sediment and blasts large rocks with the abrasive particles, cutting and shaping the rock. The intensity of wind erosion is determined by: Sum (amount) Speed Slope Surface Wind Erosion Water Causes Erosion runoff, rivers and, streams  Water causes Erosion When rain falls to the Earth it can evaporate, sink into the ground, or flow over the land as Runoff. When it flows over land, erosion occurs. Runoff picks up pieces of rock and "runs" downhill cutting tiny grooves (called rills) into the land.  Water causes Erosion How much erosion takes place is determined by the: Sum (amount) Slope Speed Surface Can you act increasing and decreasing the four S’s?  Ice Causes Erosion Glaciers wear down the landscape; by picking up and carrying debris that moves across the land along with the ice.  Ice Causes Erosion Glaciers can pick up and carry sediment that ranges in size from sand grains to boulders bigger than houses. Moving like a conveyor belt and a bulldozer, a single glacier can move millions of tons of material!  Ice Causes Erosion How much erosion takes place is determined by the: **Sum (Glaciers are massive!) Slope Speed Surface  Gravity causes erosion Creep, Slump, Landslides, Mudslides, and Avalanches. Slower Faster These are examples of mass movement landslide clip.mpeg (or called mass wasting)  Gravity causes Erosion How much erosion takes place is determined by the: Sum **Slope Speed **Surface Plants CAN CAUSE weathering Plant Action “Biological Action” - With plant growth the root system will increase in volume and cause cracks in the rock to expand. Lichens are primary soil producers creating conditions for larger plant growth. Plants CAN PREVENT erosion  Deposition Rock particles that are picked up and transported during erosion will ultimately be deposited somewhere else Deposition is the process by which sediments (small particles of rock) are laid down in new locations. Together, Erosion and Deposition build new landforms. Deltas Canyons Meanders Floodplains Delta Canyons  Meanders Meandering streams wander side to side as they constantly seek out the lowest elevation. This constant motion creates a series of S-shaped “loops”.  Meanders Stream Velocity varies from one side to the other side of the “S”, resulting in erosion in some places and deposition of sediments in others. Floodplains Chemical Weathering - when agents of weathering chemically change the composition of a rock. AGENTS OF CHEMICAL WEATHERING 1. Oxidation – Oxygen combines with minerals to form oxides. 2. Hydration- minerals absorb water and chemically change the composition of the material 3. Carbonation – When pollutants like Carbon Dioxide, Nitrogen & Sulfuric Oxides mix with rain water creating acid rain, which can dissolve limestone and harm the living environment. 4. Water - Is unique and dissolves most minerals and metals in our environment. (universal solvent).