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The Ever Changing Lithosphere. How rock changes. What is Weathering, Erosion, Deposition? Weathering, Erosion and Deposition are: the breaking down, transporting and placing down of Earth material. . . Weathering . What is Weathering? Weathering: the breaking down of Earth's materials
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How rock changes • What is Weathering, Erosion, Deposition? • Weathering, Erosion and Deposition are: the breaking down, transporting and placing down of Earth material. .
Weathering • What is Weathering? • Weathering: the breaking down of Earth's materials Bryce Canyon .
Weathering breaks it down! • + Weather = .
How can you Weather Rock How can Rock be Weathered? Rock can be broken down: 1) Physically / Mechanically (Mop) 2) Chemically (Cleaner) .
Weathering What is Physical Weathering • 1)Physical / Mechanical Weathering - The breaking down of rock without changing it chemically (Mt bike frame bending) rock .
Types of Physical Weathering • Types of Physical Weathering: • A) Gravity (Mass Wasting) – Constant pulling down on earth material until it breaks. .
Types of Physical Weathering • B) Temperature – Changing Temperatures can break rock apart. (Especially rapid changes) • b1) Too Cold • Frost Wedging (Freeze / Thaw) Liquid Water gets in rock, freezes to ice, expands, breaks the rock apart. (ex. potholes) .
Types of Physical Weathering . • b2) Too Hot • Thermal Stress (exfoliation) – Heat expands rock, temperature drops, rock contracts. • Over time the outer layers break apart.
Types of Physical Weathering • C) Biological – Plants and animals breaking • rock apart. .
Types of Physical Weathering • D) Abrasion – Rough material grinding across the surface of rock. (like sand paper) • ex. Mushroom rock Sand blasting Arches .
Weathering • 2) Chemical Weathering - • Changing the Chemical Composition of a rock. • (Mt Bike Rusting) .
Types of Chemical Weathering • Types of Chemical Weathering: • A) Water – The Largest source • - named “Universal Solvent” because over time it can break down almost anything. .
Types of Chemical Weathering • B) Air – (Oxygen and C02) • Ex. Oxidation C02 .
Types of Chemical Weathering • C) Acids – Plant Acids & Acid Rain • - (Acid rain = sulfuric acid) • Ex. Lichens Acid rain .
Air, water, acids…… aren’t they common? Most Rocks are under the surface. When uplifted and exposed to air, water and acids they start to weather.
Chemical & Physical Weathering • Do Chemical & Physical Weathering work alone? • Chemical & Physical weathering work together. • How can physical weathering help chemical weathering • Physical weathering breaks down rock to increase surface area so more chemical weathering can act on it (chewing food). .
Chemical and Physical Weathering • How can chemical weathering help physical weathering? • Chemical weathering can change the make up of the rock, making it softer and easier to physically weather. • Karst • Topography .
Rates of Weathering • What can affect weathering rates? • Effects on Weathering: • 1) Climate: • Hot and Wet is the best • (Rain forest have lots of weather) • 2) Mineral Composition (Chemical to Physical) • 3) Surface Area (Physical to Chemical) .
Product of Weathering . What is the Product (end result) of weathering? Product of weathering: Over time rock will break down into Dirt or Soil Soil is alive – Dirt is dead!
Stages of Soil • Stage 1 = Parent rock (Original bedrock) • This determines what the soil will be like. • Stage 2 = Partially weathered rock • Stage 3 = Young soil • Stage 4 = Well developed soil and Humus • Humus (organic, fully broken down top soil) • - Every cm takes hundreds of years to form .
Soil Layers • Each layer of soil is called a Horizon • O Horizon (Organic matter on top - Humus) • A “ “ (Top soil) (A = best) • B “ “ (Subsoil) • C “ “ (Partially weathered rock) • R “ “ (Bed Rock) • All the horizons together • make up the Soil Profile .
Erosion What is Erosion? Erosion: The movement of Earth Material Erosion like erasing makes sediment go away. What increases erosion? Amount of erosion is based on speed.
Deposition . What is deposition? Deposition is placing down of Earth material. When you Deposit money you “put it down” at a bank Deposition creates new feature.
Gravity Erosion R . • Gravity Erosion • Mass wasting – gravity pulling • Sediment (broken up Earth material) downhill.
Gravity Erosion R . • Types of gravity erosion are based on speed. Soil Creep/slumpEarth FlowsRock Fall Very slow Medium Speed Fast Seen indirectly Addition of H20 Free Fall
Gravity Deposition R . Gravity Deposition: 1) Talus Slope – Collection of Unsorted rocks at the base of a cliff
Wind Erosion R • Wind erodes by picking up and carrying materials.
Wind Erosion R . • Wind erosion is based on wind speed. • Wind typically lifts sand only a few feet high. • - Mushroom rock (what is missing is the eroded part)
Wind Erosion R . • 1) Deflation= The wearing down of rock by wind. • (Like a Balloon Deflating)
Wind Deposition R . • Wind Deposition: • 1) Sand dunes – When wind slows, it drops sand in a wave like pattern. The windward side is a gentle slope and the slip face is steep. (shows direction, like a bike ramp)
Wind Deposition R . • 2) Loess – Lighter sand gets carried further and deposited in layers.
Wave Erosion . • Wave erosion: • Waves carry sediment to the shore, along the shore and back to sea. • Waves form when the shallow ground pushes the water up
Wave Deposition . • Wave Deposition: • 1) Beaches – Sand left behind by waves
Wave Deposition R . • 2) Sand bars – When waves pull sand back out to sea, it can deposit it where the water slows.
Wave Deposition R . • 3) Barrier Islands – When a sandbar builds up so high it comes above the waters surface. • (Blocks future shore erosion)
Running Water Vocabulary . • Running water terms: • Stream? • Stream – A channel of running water. • - From a small creek to a giant river.
Running water vocabulary • Tributary? • Tributary – A smaller stream feeding into a larger stream. (It contributes to the main river) .
Running water vocabulary . • Drainage network? • Drainage network – Group of connecting streams that drain out an area.
Running water vocabulary . • Watershed? • Watershed – The area drained out by a stream. ex. Hudson River Watershed
Running water vocabulary . • Drainage Basin? • Drainage Basin – Large geographic area that will all drain out together.
Running water vocabulary . • Continental divide? • Continental divide – Separates land masses into different drainage basins. (example mountains)
Stream life . Which direction do all streams flow? All streams run DOWNHILL. They start at the Head / Source, end at the Mouth. As they get older they cut down into the ground, and the gradient gets less.
Ages of a Stream . • Life of a stream: • 1) Young Stream – Early stage Very fast Straight Powerful downward cutting of valley Creates a “V” shape valley (ri‘V’er)