Chapter 17: Plate Tectonics Test
What is an isochron?
A line connecting points of the same age on a map
Who came up with the Continental Drift idea?
Alfred Wegener
Where is new ocean floor created?
At mid-ocean ridges
Why was Wegener's idea rejected?
Because he could not explain how or why the continents moved
What kind of plate boundary is a mid-ocean ridge?
Divergent Boundary
What are tectonic plates?
Enormous slabs of continental crust and oceanic crust and the upper mantle
What is the evidence of Pangaea?
Fossils, rock formations, coal deposits in Antarctica, and Glacial deposits in Africa, India, Australia, and South America
How do convection currents transfer heat?
From warmer regions to cooler regions
where does the Mid-Atlantic ride run through?
Iceland
What does the Theory of Seafloor Spreading explain?
It explains how new ocean crust is created at ocean ridges and destroyed at deep-sea trenches
What is an example of how rock formations are evidence of Pangaea?
Many layers of the rocks in the Appalachian Mountains were identical to layers of rocks in similar mountains in Greenland and Europe
What are Divergent Boundaries?
Tectonic plate moving apart
What are Convergent Boundaries?
Tectonic plates coming together
What are Transform Boundaries?
Tectonic plates moving side-to-side
What fossil is used as evidence of Pangaea?
The Glossopteris in South American, Africa, and Antarctica
What is the idea of Continental Drift?
The idea that Earth's continents had been joined as a supercontinent called Pangaea
What is the Theory of Plate Tectonics?
The outer rigid layer of the earth (the lithosphere) is divided into a couple of dozen "plates" that move around across the Earth's surface relative to each other
What is Paleomagnetism?
The study of Earth's magnetic history
How are the parts of a convection current in the mantle related to plate motions?
The upward current in a convection cycle is associated with divergent plate boundaries, as heated magma rises and spreads out beneath the plates
What kind of plate boundary is the San Andreas Fault Line?
Transform Boundaries
How do we know that Earth's magnetic field has changed in the past?
We can tell by the ocean floor