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Fryesheet 12. Shoreline processes Chapter 12 Section 1. Wave Energy. Waves crash into rocks over long periods of time – rocks are broken down into smaller and smaller pieces - form sand Waves play a major role in building up and breaking down the shoreline
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Fryesheet 12 Shoreline processes Chapter 12 Section 1
Wave Energy • Waves crash into rocks over long periods of time – rocks are broken down into smaller and smaller pieces - form sand • Waves play a major role in building up and breaking down the shoreline • Shoreline– boundary between land and a body of water
Shorelines and Beaches • file://hsa005/staff_docs1$/wfrye/My%20Documents/Holt%20Middle/student/ch12/sec01/vc00/hz512_01_v00mn.htm • http://my.hrw.com/sh2/sh07_10/student/flash/visual_concepts/80172.htm
Waves • Size depends on how hard the wind is blowing and how long it lasts • Summer hurricanes and severe winter storms produce large waves that cause dramatic shoreline erosion • Waves– caused by wind moving across the ocean surface
Wave Trains • Waves travel in groups called wave trains • When waves reach shallow water, the bottom of the wave drags against the sea floor, slowing it down • Upper part of the wave moves faster and grows taller – begins to curl and break • Surf– breaking waves • Wave Period – time interval between breaking waves
..\..\..\Holt PPT for Earth Science\12\WAVE PERIOD.swf • \\hsa005\staff_docs1$\wfrye\My Documents\Holt PPT for Earth Science\14 • file://hsa005/staff_docs1$/wfrye/My%20Documents/Holt%20Middle/student/ch12/sec01/vc01/hz512_01_v01mn.htm
Reading Check #5 How do waves break down rock into sand? Energy from waves – breaks rocks apart, water enters cracks in rocks, washes away sediments
Reading Check #6 Why are large waves more capable of removing large chunks of rock from a shoreline than normal sea waves? More Energy!!
Beach • Area between high and low tide • Shoreline made up of material deposited by waves
Common Beach Materials • Quartz • most common • light sand • Volcanics • basalt weathered into sand • Hawaii
Common Beach Materials • Calcite • Broken shells or coral • tropical • Pebbles/Large Rocks • Caused by stormy seas
Longshore Current • Waves hit shore at an angle • Create longshore currents – currents that flow parallel to the shore • Transport most sediment • Destroys and builds up coastlines • Carries trash and pollution
Sand Movement on a Beach • Longshore currents move sand in a zigzag pattern along the beach • http://my.hrw.com/sh2/sh07_10/student/flash/visual_concepts/80169.htm
Wave Erosion Features #18 on Fryesheet!
Sea Stacks • Offshore columns of resistant rock that were once connected to the mainland
Sea Caves • Waves cut large holes in weak rock at the base of sea cliffs • Common in sedimentary rocks
Sea Arches • Wave action continues to erode a sea cave, cutting completely through the rock
Headlands (Promontories) • Form when cliffs made of hard rock erode more slowly than surrounding rock • “Finger-shaped”
Wave-cut Terraces • Form when a sea cliff is worn back • Flat surface is created beneath the water at the base of the cliff
Section1 Shoreline Erosion and Deposition Chapter 12
Section1 Shoreline Erosion and Deposition Chapter 12
Virtual Lab Wave Erosion Features
Drawing Time! #19 on Fryesheet
Ocean Spit (Hook) Cape Cod, Massachusetts
Next time… Begin Section 12-2! Wind Erosion and Deposition Homework: DR 12-2 Identifying Variables Worksheet For Monday
WAVE FORMATION • WAVES DO NOT MOVE (ILLUSION) • WATER MOVES IN A CIRCULAR MOTION
WAVE FORMATION • DIAMETER OF THE CIRCLE EQUALS THE WAVE HEIGHT • WAVE ENERGY DECREASES WITH DEPTH (SMALLER CIRCLES)
Types of Waves • Deep Water Waves • Water is deeper than ½ the wavelength
Types of Waves • Shallow Water Waves • Water is less than ½ the wavelength • Touch the ocean floor
Types of Waves • Breakers • Water slows down • Height of wave increases • Tops tumble
Breaker Zone • Area where waves begin to tumble downward
Types of Waves • Surf • Between the breaker zone and the shore
Types of Waves • Whitecaps • White foaming waves with steep crests that break in the open ocean • Stormy Weather • Short-lived
Types of Waves • Swells • Rolling waves that move steadily across the ocean • Calm • Longer wavelengths