Chapter 2 Flashcards
In the Southern Hemisphere … Of the total area is ocean
80%
Four large basins
Pacific, Atlantic, Indian, arctic
What is the oldest and deepest
Pacific
How long do scientist believe earth originated
- 5 bill. Years ago Big Bang THEORY
- 7 Big Bang
- 5 organisms
What is an essential element to sustain life
Location relative to sun allows water to stay liquid
Core
Innermost layer, solid inner core liquid outer, iron rich magnetism
Mantle
Middle layer , semi plastic
Crust
Outermost layer , thinnest portion
Oceanic crust
Basalt , denser than continental
Continental
Granite, construction mainly, less dense than oceanic
Oceanic v. Continental
3.0 density, 2.7 g/cm^3 5 km 20 to 50 km thick Young old Dark light Iron, magnesium / sodium potassium calcium aluminum
Continental drift was proposed in and by
1912 Alfred wegner
Single supercontinent Pangea
When did Pangea break up
180 mill. Years ago
Why was it not widely accepted
Not explain how
Main features of plate tectonics
Covered by crustal plates
Constantly moving spreading in center and sinking at edges being regenerated
Convections currents assist movement
Heat from mantle drives currents
Mid oceanic floor rise from … What are they
Ocean floor , submarine volcanic mountains
What is ridge displaced by
Faults in earths crust called transform faults
Where is very little sediment located and what does it mean
At bottom near mid ocean ridge, not old
Where does sediment get thicker
Farther away from ridge, older, sediment has had time to accumulate
At random intervals earth’s magnetic field….. New rock formed from… Record the orientation of earths ….. at the same time … Cools
Reverses , magma , magnetic fields, magma
Studies of sea floor records stripes of…. That are ….. To the mid ocean ridges. This is evidence of
Alternating magnetization, parallel, continuous formation of new rocks at ridges
As new rocks are formed
Olde dis pushed away forming patterns
Chains of islands are found throughout oceans especially in
Pacific, island arcs
Island arcs are situated along what? No on which side
Deep sea trenches, continental side , other side is sub ducted
Underneath the earth’s crust is a layer of
Heated rock driving creation of new ocean floor
Pangea was surrounded by single world ocean
Panthalassa
What sea separated Eurasia from Africa
Tethys
How long ago were Panthalassa and Tethys in place
200 mill.
180 mill. Years ago a rift formed between
North America and South America +Africa
What two continents were formed form Pangea
Laurasia and Gondwana beginning of mid Atlantic ridge
Split up Gondwana
Indian ocean formed
How long ago did rift between soutbamerica and Africa form
135 mill. Joined mid ocean ridge in North Atlantic to form one single mid Atlantic ridge