Chapter 12: The Dynamic Planet Flashcards
Magnetic Declination
The angular distance in degrees between the direction of the compass needle and the line of longitude.
Constantly on the move.
True North
north according to the earth’s axis, not magnetic north.
Grid North
direction northwards along the grid lines of a map projection
Geomorphology
The science that analyzes and describes the:
- origin
- evolution
- form
- classification
- spatial distribution
.
of landforms.
Geomorphology
The science that analyzes and describes the:
- origin
- evolution
- form
- classification
- spatial distribution
of landforms.
Origin of Earth’s Magnetic field
principally generated by motions in the fluid material of the outer core
Origin of Earth’s Magnetic field
principally generated by motions in the fluid material of the outer core
Uniformitarianism
- A n assumption that physical processes on Earth
- are operating at the same pace
- and intensity
- that has characterized them
- throughout geologic time
- “the present is the key to the past”
- (Hutton and Lyell)
geological time scale broken down by
- Eons
- Eras
- Periods
- Epochs
Core
- deepest inner portion of the Earth
- 1/3 of entire mass
- Inner Core
- Outer Core
Inner Core
- Solid-Iron
Outer Core
- Metallic-Iron outer core
Lithosphere
- Crust and Upper Mantle
- 70km down
Asthenosphere
- Region of the mantle just below the lithosphere
- the part of the mantle which is not solid. it’s a semi liquid
Driving force behind plate motion
- Convection currents in the mantle
- drags the underside of the Earth’s lithospheric plates
Rock
- Assemblage of minerals bound together, or sometimes a mass of a single mineral
Types of Rock
- Igneous
- Metamorphic
- Sedimentary
Igneous Rock
- has solidified and crystallized from hot molten state (magma/lava)
Magma
Molten rock deep inside the Earth
Lava
Molten rock at or near the Earth’s surface
Intrusive igneous rock
Rock that solidifies and crystallizes below the surface (granite)
Extrusive Igneous rock
Rock that solidifies and crystallizes as it extrudes onto the surface (basalt)
Rate of cooling and crystalline texture of a rock
Faster cooling of magma/lava creates finer grained rocks like basalt.
Sedimentary Rock
Formed from the:
- compaction
- cementation
- hardening
of sediments derived from other rocks
Heat energy inside the earth is caused by:
- kinetic energy (from movement in the Earth’s interior)
- Decay of radioactive elements (in the Earth’s interior)
- Pressure: The weight of rock on top exerting pressure towards the core
Metamorphic Rock
- made from existing igneous and sedimentary rock that has undergone profound physical and chemical changes under increased pressure and temperature
- generally more compact than original rock (harder, more resistant to weathering and erosion)
Lithification
The:
- compaction
- cementation
- hardening
of sediments into sedimentary rock
Processes that can cause metamorphism
- Heating
- Pressure
- Heating AND Pressure
- Compression and shear
Processes that can cause metamorphism
- Heating
- Pressure
- Heating AND Pressure
- Compression and shear
Continental Cust
- Lighter in colour (rarely contains anything black)
- thicker, 25 km
- LESS DENSE
- Makes up all land masses
Continental Crust
- Lighter in colour (rarely contains anything black)
- thicker, 25 km
- LESS DENSE
- Makes up all land masses
Erosion
The way in which sediment is set in motion
Transport
The way in which sediment moves once it is in motion
Deposition
The way in which sediment stops moving
Precipitation
The creation of new mineral crystals from elements in solution
Plate Motion process
- hot, semi-liquid rock rises upward
- as it reaches surface, it cools and stops rising
- it is pushed sideways by more rock
- eventually sinks because of increased density
- grabs hold of underside of the crust and drags it along with it
Continental Plate VS Oceanic PLate
- subduction zone forms
- heavier oceanic crust is subjected or pushed beneath lighter continental crust
- magma forms above the subducted plate and erupts through the continetal plate
- forms: volcanic mountains, thick mountain belt, volcanism
- west coast canada
Oceanic vs. Oceanic PLate
- One plate gets subducted
- The one that is not subducted produces a mountain
- causes deep sea trenches, volcanism, and island arc
-
Island arc
Chain of mountainous volcanic islands that form on the non-subducted plate (oceanic vs. oceanic )
Continental vs. Continental
- No subduction
- No melting
- No volcanism
- At collision zone there is fold, fault and lift of the crust
- creation of huge mountain ranges (Himalayas, Everest)
Hot Spot
An area of increased heat flow at the Earth’s surface, often resulting in volcanism.
- does NOT occur at plate margins
- places where plumes of magma rise from mantle, producing volcanic activity as well as thermal effects in the groundwater and crust (cource of geothermal energy)
Subduction Zone
Area where two plates of crust collide and where denser oceanic crust dives beneath less dense continental plate, forming deep oceanic trenches and seismically active regions
Basalt makes up ___% of the Earth’s surface
71% (the bulk of the ocean floor)
- actively forming in Hawaii
IF cooling is so rapid that crystals cannot form, what is the result?
glassy rock such as obsidia or volcanic glass. or pumic
