Week 10 - Earth's Structure

Lab

In lab this week we worked to create different types of rocks including sedimentary, metamorphic, and igneous rocks. To do this, we used different colored starburst to represent different material being mixed together and used different methods to do so. The igneous rocks are hot and cool and some metamorphic rocks are created from heat but not melting, so we used both a candle and torch to mimic the heating of the rocks. For the sedimentary rocks we squished them together using different amounts of pressure to create the different types of rocks. We also used a bit of heat to cement the materials together. 

Lecture

Earth/Volcanoes

• On fault lines

• Either sliding by 

• Pulling apart 

• Or smashing into each other 

• Earthquakes in the US

• Due to fracking 

• Unstabilizing the Earth

Plate Tectonics

• When plates smash together we get mountains

• Two kinds of plates

• When two of the same type of plates hit each other, they create a set of mountains

• If they’re opposite they create a ridge 

• Continental Plates: in a continental

• Up to 60 miles thick

• Oceanic plates: in the ocean basin

• 10 miles thick

• When continental and oceanic plates hit, the bottom is gooey allowing for the denser crust to move down and into the convection currents 

• What? something about Coralville having coral and being filled with water, but mountains formed drying it up? 

• Iceland is constantly being ripped apart, so volcanos/mountains are forming within the ridge - filling new cracks with magma and building up 

• Hawaii -

• The older the island, the smaller it is 

• A new island in Hawaii - won't surface for another thousand years 

• Volcanoes in the crust and it’s building themselves within the ocean 

• South America and Africa used to be together but because of the tectonic plates they’re constantly moving apart.

Rock Cycle

• Igneous - fire 

• Metamorphic - morphing together to create something new 

• Sedimentary 

• There are more stars then there are grains of sand on our planet

• Most abundant rock is igneous, next is metamorphic

• Sedimentary rock is the smallest and only on the surface 

• Cycle

• Everything started as magma

• Initial early earth was gooey- magma; its hot

• Can stay magma or cool down

• If it cools on the surface its igneous

• Can cool in ocean, snowfield 

• Time it takes to cool determines what rock it is

• Weathering and erosion breaks down rocks into different parts 

• Heat and pressure are what make them metamorphic 

• Not enough heat to melt it though just ot change the rock type

• One of three things can happen to a rock:

• Melt 

• Extrusive - on the earth’s surface

• Intrusive - inside the earth, protected by earth, cools slower (inside is hot!)

• Weathering and erosion

• Chemically:  changing the rock

• mechanical/physical: does not change the rock 

• Warter - most prevalent, V shaped,young/mature determined by energy levels

• Wind - weakest small particle sand blasting

• Glaciers - most powerful, U shaped, bulldozer, kettle lakes MN 

• Chemical changes 

• Mechanical breaks

• Heat and pressure

Textbook

    I learned that continental plates are actually thicker than oceanic plates, as the sea floor is far lower than the land we stand on. I also learned that there are actually two different types of volcanic eruptions: explosive and effusive. Explosive eruptions is when magma is directly fragmented and expelled from the volcano. Effusive eruptions are when lava steadily flows out of a volcano onto the ground.

    The pictures describing the differences between the plate boundaries was helpful when reviewing the differences between them. I also liked that for each boundary, each type is also addressed and defined as convergent boundaries can look 3 different ways.