Dynamic Earth Flashcards
Layers of earth
Crust Upper mantle Lower mantle Outer core Inner core
Lithosphere:
Layer of solid crust
Atmosphere
Layer of gases (79% nitrogen, 21% oxygen)
Theory:
Hypothesis with evidence
Law:
Scientifically proven
Theory of continental drift:
Alfred wegener proposed idea:
1912
“One supercontinent named Pangea broke into Laurasia and Gondwana
Convergent:
Plate overlap each other
Divergent:
Pull apart
Transform:
Rub against another
When magma cools down and gets dense nd meets hot magma:
Convection
Divergent cause
Ridges
Convection:
Subduction zone
Normal
Reverse and transcurrent
Faults
Conservative boundaries
Produce earthquake but no mountain/volcan
Transform plates
Rock cycle:
Ingenious> weathering and erosion> sedimentary> heat and pressure> metamorphic> melting
How do fossils help us?
Understand study evolution
Petrifaction:
When minerals slowly replace the original material and decays leaving stone replica
How fossil form:
Amber
Pretrification
Carbonisation
1/ layers of sediment rapidly cover up dead organism
2/ minerals fill up spaces
3/ pressure, chemical reactions and time turn sediment into mineralised fuel
5/ remain until erosion or excavation
Unconformities:
Young sediments deposited on old eroded rock
Basalt dyke
Magna rises from asthenosphere into old rocks as tunnel
Ages of fossil found by what dating
Carbon or absolute dating where dating is found by radioactive method
Pangea broke up into
Laurasia and Gondwana
Epicentre
Begin here and travel outward direction
Don’t originate here
Suffer most damage
Seismic waves:
2 types:
Body waves and surface waves
Body waves only travel inner layers
Surface waves only surface