The Rock Cycle its Story Forma4on of Rocks in More Detail
Do Now: Every day the man- Mr. Doughman, bakes the cookies. He makes the dough, puts it in the oven, and bakes them. Then he lets them cool and harden. Another man Mr. Crumbles, takes the cookies and crumbles them, building up layer and layer of cookies. Then Mr. Squeezy comes along and takes all the cookies and squeezes them together over and over. The cookies get warm again in his hands as he does this. The sun sets and rises, and Mr. Doughman makes the cookies again, over and over
Hey, that s a lot of cookies Compare the gentlemen in the story to the Rock types we learned about: Mr. Doughman Mr. Crumbles Mr. Squeezy Something that occurs over and over again is?
See p6 ESRT To Read the Rock Cycle, follow the arrows around SEDIMENTARY ROCK Metamorphism Heat and/or Pressure METAMORPHIC ROCK Rock Cycle in Earth s Crust Cementation Compaction and/or Melting Melting (Uplift) Weathering & Erosion Heat and/or Pressure Metamorphism and Burial (Uplift) Weathering & Erosion Melting MAGMA Deposition SEDIMENTS Erosion Solidification Weathering & Erosion (Uplift) IGNEOUS ROCK
Start with Magma, these are types of Igneous Intrusions which will become Igneous Rock
Some4mes pieces of the surrounding rock remain unmelted and become part of the igneous rock (xenolith)
Igneous Intrusions- cut through the parent rock
Making Sediments and Sedimentary Rock UpliU Weathering Erosion Deposi4on Burial Compac4on And Cementa4on (natural glue- silica, calcite or iron oxides)
Sediment Sor4ng in Land Derived Sedimentary Rocks Sor4ng of sediments produces separa4on of the par4cle sizes(p6) Pebbles/gravels are dropped first (form conglomerate) Sands (form sandstone) Silts, clays are dropped last (form shale)
Chemical Origin in Chemically formed Sedimentary Rock Water contains dissolved minerals, which can fall out of solu4on (precipitate) due to evapora4on or chemical ac4on Limestone can be formed from 4ny grains of calcite deposited from sea or lake waters Other examples are rock salt (halite) and rock gypsum
Organic Origin Calcite is dissolved out of rocks on land, carried to an ocean or lake, and taken out of the water by shell- producing organisms (eg. Clams, oysters, sea snails) When these organisms die, their shells pile up and are broken down into fragments, and can form organic limestone
Metamorphism Metamorphic rocks are not formed from magma or sediment Metamorphic rocks morph (change) from exis4ng rock, due to heat, pressure and chemicals Pressure squeezes grains closer together (more dense, less porous) Heat and chemicals may rearrange the par4cles (new minerals may be formed)
Types of Metamorphism Regional Metamorphism: large areas of rock are under intense heat/pressure, which occurs during mountain- building Heat comes from fric4on of rocks, and pressure from overlying weight and the squeezing of moving rocks Contact Metamorphism: when hot magma forces itself into overlying rock (intrusions) and bakes the rock
Contact Metamorphism
Results in Fola4ons if more then one mineral makes up rock Occurs when the pressure on the rocks squeezes minerals into parallel layers The rocks tend to split easily along these layers
What is the Rock Cycle? Is the repeated series of events by which rock gradually and con4nually changes from one type to another Theses events are geological events- meaning they happen in the Earth s crust or on it Another word to describe this is geologic process Can you name some of these processes?
Reading the Rock Cycle Chart See page 6-7 in the ESRT First Classify your Rock Samples- work together with your partner Place them on the Rock Cycle diagram enlarged copy- work together to complete Part II of Lab
Complete Understanding the Rock Cycle- for homework
1. When granite changes into schist, what geologic processes does it have to undergo? 2. Change gneiss into conglomerate, which geologic processes are involved? 3. Which type of rock can change into the same kind of rock without going through the en4re rock cycle?
Sum Up: What are 3 great truths about the Rock Cycle? Think about everything we talked about today and see if you can list them below:
Sum Up: (well maybe 5 truths ) 1. The Rock Cycle is a model of the natural changes that occur in rocks and rock material 2. Shows all Rocks are made from other rocks or rock remains 3. Shows Rocks are classified upon basis of forma4on 4. Shows that there are a variety of ways that rocks can change at the surface or within the Earth 5. It keeps on going and going.and has been since the Earth s Spheres formed
Follow up Assignment: Complete a RAFT to help you understand Rocks and the Rock Cycle beeer. The direc4ons are as follows: Role- You are a Geologist Audience- Students in a High School Earth Science Class Format- Can choose any way to write this- poem, story, email, riddle, song, etc Topic: Earth s Dynamic(Ever Changing) Crust and the Rock Cycle Be prepared to share your RAFT with the class on Tomorrow! (read aloud)
Food for thought Do we have any influence on the Rock Cycle? If so, what? What force is driving the Rock Cycle?