Lecture 2: Geology Terms and Plate Boundaries
_________________- the solid outer crust of the earth and the hot “plastic like” upper mantle
_________________- the hot plastic like upper mantle
*The core is made of __________ and ______________
*oceanic parts of the crust are more _____________than continental parts, which
means the continents “float” higher than oceanic parts
* Oceanic parts of the crust are made mostly of _____________ rock
* Continental parts of the crust are made mostly of ___________________rock
3 main sources of the Earth’s internal heat:
1.
2.
3.
___________________________ (remaining heat)
_______________________________- a fundamental principle that assumes that most all rock
forms horizontal layers (called strata)
*Rocks can be tilted, folded, or shifted after they are made
_______________________________- the continents had once been joined, but now they have
moved apart
Proof for continental drift
-continents seem to fit together like __________________
-matching ______________ types on different continents
-matching rock types on different continents
-matching glacial scars
Super continent “Pangea” existed ~290 million years ago
_______________________________- large underwater mountain ridges
•
The mid-Atlantic Ridge was studied and shown to be ____________________.
This provided a method of how the continents move.
(_______________________________________)
•
____________________________ (Earth’s magnetic field) periodically flips and
liquid rocks being formed are affected because, as they solidified, the iron inside
aligns with magnetic north at that point in time. This is more proof that the
opposite shore lines were formed at the same time.
________________________- in the mantle (due to heat) help the crust to move
________________________- the theory that the Earth’s surface is divided into large plates
floating on the asthenosphere
________________________- places where plates meet. Plate boundaries are places where
volcanoes and earthquakes are most common
Types- there are ______ major plates on Earth
3 types of plate boundaries:
1.
_____________________
Two plates moving away from each other
When underwater, new crust is formed from magma cooling (due
to seafloor spreading)
When on land, a rift valley is formed
2.
_____________________
Two plates come together and collide
Density matters- if the plates have different densities, the more
dense plate slides under the less dense plate, forming trenches
(this is called subduction)
**volcanoes often associated
If plates have the same density, the two plates collide and form
mountains
3.
_____________________
Two plates sliding along one another
Tension due to friction causes earthquakes when the plates slip.
______________________- hot plumes rise toward the crust from deep within the
asthenosphere. As it cools it sinks back down. A hot spot is formed when the magma breaks
through in the middle of a tectonic plate.
______________________- A sudden release of tensional energy when rocks break and slide
against one another.
______________________- The form of energy produced from an earthquake
Three types of seismic waves:
1. ___-waves- a compressional primary wave. It moves like sound waves
(accordion-like). So p-waves can travel through solids and liquids. These are the
fastest waves.
2. ___-waves- secondary wave. Move in an up and down motion, like ocean
waves. These travel slower than p-waves and can only travel through solids.
3. _________________ waves- these are made by complex interactions of pwaves and s-waves. They result in the rolling motion of the ground during an
earthquake
______________- the area where rock has broken apart violently. This is the starting point of
an earthquake
______________- the area on earth’s surface directly above the focus
_________________________- scientists who study the occurrence of earthquakes and the
properties of the Earth’s interior
_________________________- device used to measure the occurrence and magnitude of
seismic waves.
_________________________-measures the energy released by an earthquake on a scale of 09 and equates the amount to an amount of energy released by TNT/explosions. It is a
logarithmic scale (it is 10X bigger for each 1)