Presentation on theme: "Awesome Links….copy and paste the URL’s"— Presentation transcript:
1 Awesome Links….copy and paste the URL’s minerals-landforms/earthquakes.htmminerals-landforms/volcanoes.htm
2 Plate TectonicsThe theory that explains the movement of Earth’s plates move and cause earthquakes, volcanoes, oceanic trenches, mountain ranges, and other geological phenomenon.
3 What we DO NOT KNOW yet is HOW? We already know that……the lithosphere is broken up into many pieces called plates.…these plates float and move slowly on top of the asthenosphere which is part of the mantle layer of the Earth.…scientist can detect this movement only by using special equipmentWhat we DO NOT KNOW yet is HOW?
4 Convection CurrentsOccurs in the mantle as rock heats up, becomes less dense and rises toward Earth’s surface.As the hot material rises, cold material sinks into the mantle at subduction zones.
5 Convection currents in the mantle make the plates of the lithosphere move.
6 What happens when two plates get close to one another? Plate BoundariesWhat happens when two plates get close to one another?
7 Three things can happen… 1. Plates move away from each other. 2 Three things can happen… 1. Plates move away from each other. 2. Plates move towards each other. 3. Plates move past one another.MOVE AWAY FROM EACH OTHERMOVE TOWARDS EACH OTHERMOVE PAST ONE ANOTHER
8 3 Types of Plate Boundaries 1 3 Types of Plate Boundaries 1. Divergent boundary- two plates move apart. 2. Convergent boundary- two plates move together. 3. Transform boundary- two plates slide past one another horizontally.
9 Divergent Boundary At divergent boundaries, tectonic plates are moving away from each other. If these huge masses of crust are moving apart, what happens in the space left between them?
10 Sea-Floor Spreading Divergent boundaries in the middle of the ocean contribute to sea-floor spreading. As plates made of oceanic crust pull apart, a crack in the ocean floor appears. Magma then oozes up from the mantle to fill in the space between the plates, forming a raised ridge called a mid-ocean ridge. The magma also spreads outward, forming new oceanic crust.
11 Rifts When two continental plates diverge, a valley-like rift develops Rifts When two continental plates diverge, a valley-like rift develops. This rift valley is a dropped zone where the plates are pulling apart. Water may enter the valley and create streams or lakes. Volcanoes and faults may also form in the rift valley.
12 Divergent Boundary Simulations http://www. learner Diverging PlatesRift Valley FormsWater fills up valleyOcean Ridge Forms
13 Example of a rift valley. Various lakes have formed in Africa where the divergent boundary is located.Example of a rift valley.
14 Convergent Boundary Plates move towards one another at convergent boundaries. What will happen to the land where the two plates collide?
15 Uplift When two plates collide, mountains can be formed by the process of uplift.
16 Subduction The process of subduction is the movement of one tectonic plate underneath another. Oceanic crust is subducted because it is denser and thinner than continental crust. A volcano (vent or opening in the Earth’s crust) or a trench (large deep depression on the Earth’s surface) may form where subduction occurs.
17 Convergent Boundary Simulations http://www. learner Some Examples
18 Transform Boundary The boundary between tectonic plates that are sliding past each other horizontally . What happens to the land around transform boundaries?
19 Faults & Earthquakes When two plates move past one another horizontally, a fault (crack in the Earth’s plate), occurs. Stress (tension between the plates) can build up between the two plates over time. Sometimes the stress becomes so great that the plates move in a quick and sudden motion otherwise known as an earthquake.