Science Study Set

Measures the heigh above sea level. 579 Chicago's above sea level. It is along the coast.

Elevation

What are the 3 things that determine topography?

Elevation, Relief, and Landform

A break in Earth's crust. Slip past each other. Meet at plate boundaries.

Faults

What is Wegener's hypothesis of continental drift?

Wegener's hypothesis was that all the continents were once joined together in a single landmass and have since drifted apart.

If subduction occurs more quickly than the creation of the ocean, what will happen to that ocean?

What will happen is that the ocean then will expand.

Maps what mid-ocean ridges look like Uses "ear" sound waves Times sound echoes

Sonar

What technology is used to measure the height of mid-ocean ridges?

Sonar, Alvin, or Elevation

The process by which oceanic crust sinks beneath a deep-ocean trench and back into the mantle at a convergent boundary.

Subduction

How did fossils support Wegener's hypothesis?

The fossil Glossopteris was a fernlike plant that lived 250 million years ago. Glossopteris fossils have been found in Africa, South america, Australia, India, and Antarctica. The occurrence of Glossopteris on landmasses that are now separated by oceans indicated that Pangaea once existed.

Convection currents in Earth's mantle cause the plates to move

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In a process taking tens of millions of years, part of the ocean floor sinks back into the mantle at deep-ocean trenches.

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Mid-ocean ridges are stretches through all the world's oceans, including the Pacific, Atlantic, Indian, Arctic, and Southern Ocean.

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Transform Boundary?

A transform boundary is a place where two plates slip past each other, moving in opposite directions. Beneath the surface of a transform boundary, the sides of the pates are rocky and jagged. So, the two plates can grab hold of each other and "lock" in place. Forces inside the crust can later cause the two plates to unlock. Earthquakes often occur when the plates suddenly slip along the boundary that they form. However, crust is neither created nor destroyed at transform boundaries. The San Andreas fault, is one example of a transform boundary.

Three things that can happen for convergent boundary.

A. Oceanic Crust moves under Continental Crust making a Trench(when they cross) B.Oceanic Crust to Oceanic Crust making it go sorta diving into the mantle cause now where else to go C.Continental to Continental Crust making mountains move up

Believed in the continental drift cause all continents have similar shapes.

Alfred Wegener(German Scientist)

How did climate support Wegener's hypothesis?

As a continent moves toward the equator, its climate gets warmer. As a continent moves toward the poles, its climate gets colder.

What happens to existing rock on the bottom of the ocean?

At the same time, older strips of rock move outward from either side of the ridge.

Wegener's idea that the continents slowly moved over Earth's surface.

Continental Drift

A deep valley along the ocean floor beneath which oceanic crust slowly sinks toward the mantle.

Deep-ocean trench

Identify the key differences between a convergent boundary, a divergent boundary, and a transform boundary. Be prepared to give examples of each.

First, a divergent boundary has plates moving apart or diverging from each other. In Iceland, there is a crack that is so wide, people can walk in it! Recall that plates move away from each other at a divergent boundary. Most divergent boundaries occur along the mid-ocean ridges, where new crust is added during sea-floor spreading. But in a few places, the mid-ocean ridge rises above sea level. Volcanic activity of the mid-Altantic ridge is also seen in Iceland. Where pieces of Earth's crust diverge on land, a deep valley called a rift valley forms. Several rift valleys make up the East African rift system. There, the crust is slowly pulling apart over a wide area. EX. Oxbow lakes

Any trace of an organism that has been preserved in rock

Fossil

What method is used to determine the age of mid-ocean ridge rocks?

Geologist use these methods to determine the ages of rocks. The absolute age of the rock and relative age of the rock. Now because the mid ocean ridges are place of divergent where plates move apart, the rock farther away from the ridges are older than the younger ones that are just form close to the ride. This is called relative dating. The absolute dating use Isotopes and radiometric dating meaning they have to have a hand sample to determine this. But I think the best method here for situation like this is the Relative ages of the rocks.

Extra Credit

Harry Hess, Mt. Everest 29,000ft/8840m, Drilling Sample-1st Ship- Glomar Challenger

How did land features support Wegener's hypothesis?

If you put Africa and South America together, you can see that mountain ranges on the continents line up.

How did pillow lava support sea-floor spreading?

In the central valley of mid-ocean ridges, scientists have found rocks shaped like pillows. Such rocks form only when molten material hardens quickly after erupting under water.

What evidence supported Wegener's hypothesis?

Land Features, Fossils, and Climate.

Feature of topography. Formed by processes....... Ex.Hills and valleys

Landform

The name of the single landmass that began to break apart 200 million years ago and gave rise to today's continents.

Pangaea

An undersea mountain chain where new ocean floor is produced; a divergent plate boundary

Mid-ocean ridge

Describe how a mid-ocean ridge is formed.

Mid-ocean ridges are formed from the uplift of newly formed oceanic crust by rising magma. As the ridge is slowly pushed away from the source of the heat by addition of newer crust, it sinks and is no longer part of the ridge, being replaced by new ridge material. This process means that the rock comprising the ridges among the most recent in geologic age. More likely it will form with divergent boundaries.

Where is a mid-ocean ridge found?

Mid-ocean ridges can be founded lying under thousands of meters of water. Scientists also discovered that a steep-sided valley splits the tops of mid-ocean ridges

What evidence supported sea-floor spreading?

Pillow lava, Magnetic stripes, and Drilling samples.

The theory that pieces of Earth's lithosphere are in constant motion, driven by convection currents in the mantle.

Plate Tectonics

A section of the lithosphere that slowly moves over the asthenosphere, carrying pieces of continental and oceanic crust

Plates

The difference in elevation between the highest and lowest points of an area.

Relief

A deep valley that forms where two plates move apart.

Rift valley

How did magnetic stripes support sea-floor spreading?

Rock on the ocean floor forms from molten material. As the material erupts, cools, and hardens, magnetic minerals inside the rock line up in the direction of Earth's magnetic poles. These minerals form unseen magnetic "stripes" on the ocean floor. But the magnetic poles occasionally revers themselves. So each stripe defines a period when molten material erupted and hardened while Earth's magnetic poles did not change. Scientists found that the pattern of magnetic stripes on one side of a mid-ocean ridge is usually a mirror image of the pattern on the other side of the ridge. The matching patterns show that the crust on the two sides of the ridge spread from the ridge at the same time and at the same rate.

How did drilling samples support sea-floor spreading?

Scientists drilled into the ocean floor to obtain rock samples. They found that the further away from a ridge a rock sample was taken, the older the rock was. The youngest rocks were always found at the center of the ridges. Recall that at the ridge center, molten material erupts and cools to form new crust. The rocks' age showed that sea-floor spreading had taken place.

Mid-ocean ridges continually add new material to the ocean floor.

Sea-floor spreading

Describe sea-floor spreading.

Sea-floor spreading begins at a mid-ocean ridge, which forms along a crack in the oceanic crust. Along the ridge, new molten material from inside Earth rises, erupts, cools, and hardens to form a solid strip of rock. Sea-floor spreading adds more crust to the ocean floor.

Why was Wegener's hypothesis kept getting rejected?

That's because he had all the evidence besides the explanation of what force that pushes or pulls the continents.

Convergent Boundary?

The Andes Mountains were formed by the oceanic crust going under the continental crust. Convergent boundary is when two plates come together, or collide. What happens when two plates collide? The density of the plates determines which one comes out on top. Oceanic crust becomes cooler and denser as it spreads away from the mid-ocean ridge. Where two plates carrying oceanic crust meet at a trench, the plate that is more dense sinks under the less dense plate.

Shapes of the land

Topography