Geology Flashcards
What is the continental drift hypothesis?
-It was proposed by Alfred wagner in 1912.
-proposed that the continents used to be connected as a supercontinent called Pangaea (pan for all, gaea means world)
-was supported by several pieces of evidence, including the fit of the continents, the distribution of fossils, the distribution of rock types, and the distribution of ancient climates
What is the lithosphere? (Layers of the earth)
Crust-a thin layer of solid rock (oceanic-made of basalt, and continental-made of granite)
upper mantle- below the crust one of two layers in the mantle solid, but flowy
What is the asthenosphere (layers of the earth)
Lower mantle-below the upper mantle. One of two layers in the mantle. Lower mantle is made of more dense solid material, so less flowy
Outer core-made of iron and nickel, is liquid
Inner core- solid, 5000 degrees, made up of mainly iron and nickel
What is a mid ocean ridge? (Key ocean floor formation)
-Underwater mountains that can stretch 60,000 km long is 3 km tall
-More volcanic eruption’s and earthquakes occur here in the formation of mid ocean ridges
What is a trench (key ocean floor formation)
-Valleys in the ocean floor
-can be thousands of kilometres wide and long
What is seafloor spreading?
When magma is erupted underwater in forms new rock
How are new crusts form?
The rock then pushes the older rock aside in both directions, also pushing down some rock back into the mantle
How did sea floor spreading support the continental drift hypothesis
Explain how the continents could move. It was caused by two plates splitting and moving farther apart.
How did sea floor spreading support the continental drift hypothesis?
It provided a mechanism for how the continents could move, if a new crust was being created at mid ocean ridges, then the continents could be carried along with it
What is the theory of plate tectonics, what does it explain
-The scientific theory that explains how the Earth’s lithosphere is divided into several large rigid plates, that move relative to one another
-explains continents move, and seafloor spreading occurs
Identify and define plate tectonics, lithosphere and asthenosphere
Asthenosphere: made up of extremely hot material that behaves like plastic
lithosphere: outer layer of solid rock, composed of the crust and part of the upper mantle
plate tectonics: large plates float on top of a layer of fluid like rock in the earths mantle
What are types of plate boundaries, what do they form?
Divergent: occur where two plates move away from each other. This type of boundary forms mid ocean ridges, we’re new, oceanic crust is formed as magma rises from the mantle and solidifies
Convergent: occurs where two plates move toward each other. This type of boundary forms subduction zones,where one plate is forced beneath the other and into the mantle .this process can lead to the formation of mountains, volcanic activity and earthquakes
Transform: occur where two plates slide past each other horizontally. This type of boundary form, strike, slip fault, where the plates move in opposite directions, and can cause earthquakes.
What is mantle convection
Earths mantle is partially melted material-warmer, less dense material rises, colder, more dense, material sinks
As the mantle moves the tectonic plates move with it
What is ridge push?
New materials pushes other older material inside, causing tectonic plates to move apart
What is slab pull?
Pulling of tectonic plate due to gravity and subduction, as leading edge of subduction plate sinks, it pulls the rest of the plate with it at convergent plate boundaries
