Plate Tectonics Lecture A-C Flashcards
What crust is used for countertops?
Continental crust, Consists of granite, pink-colored rock
What crust forms from volcanoes?
BASALT, oceanic crust consists of basalt forms from volcanoes and lava flows
What does Earth’s Mantle consist of?
Olivine, makes up Hawaii’s green sandy beaches
Solid inner core and liquid outer core consist of what?
IRON
What creates Earth’s magnetic field?
LIQUID OUTER CORE, turning earth into an electro magnet
Continental Drift Theory
The idea that continents were once together
ALFRED WEGENER (German Meteorologist) AND HARRY HESS (US Navy Captain)
Alfred Wegener Summary of continental drift
1) Puzzle Pieces fit of the continents
2) Matching rocks across coninents
3) Mountain Ranges that line up when the continents are reassembled
4) Glacial features that line up when the conitnents are reassembled
5) Similar land-based fossils found on many different continents
Harry Hess, Mechanism for Continental drift
Seafloor AGES YOUNGEST NEAR RIDGES and OLDEST AWASY FROM RIDGES
1) Underwater mountain ranges
2) Pillow Basalts that indicate an underwater origin for oceanic crust
3) Seafloor is youngest near Midocean ridges
4) Magnetic reversals match across ridges
Normal polarity vs Reverse polarity
Field Points TOWARD NORTH (Normal)
Field points TOWARD SOUTH (Reverse)
SEAFLOOR SPREADING
Magnetic reversals indicate that the Earth is being torn apart along these ridges
Plates and plate boundaries
PLATES : Large stable areas with no Earthquake activity
Plate Boundaries : Spaces Between these plates
Lithosphere and Asthenosphere
Lithosphere : Rigid plate (Crust and Cold uppermost mantle is part of lithosphere)
Asthenosphere : Deformable surface that the rigid plate rides on (Rest of mantle) CAPABLE OF FLOW
Convection within the asthenosphere
WHAT DRIVES MOVEMENT OF EARTH’S PLATES, Convection circular style of mixing
ALSO HOW EARTH CIRCULATES HEAT
MID OCEAN RIDGES
FORM AT DIVERGENT BOUNDARIES BETWEEN TWO oceanic plates
RIFT VALLEY with mid-ocean ridge
The mid-ocean ridge that splits the Atlantic Ocean cuts right through Iceland forming a rift valley
RIFT VALLEYS
Commonly form at divergent boundary between two continental plates
WILL eventually fill with oceanic crust and ocean water as the continents split apart
SUBDUCTION
Convergent Boundaries with OCEANIC LITHOSPHERE ONE PLATE IS SUBMERGED BENEATH THE OTHER
Thickness of Continental lithosphere and oceanic lithosphere
Continental lithosphere is THICK LIKE A CRUISE SHIP
Oceanic lithosphere is THIN LIKE A CANOE
Oceanic lithosphere is submerged from Continental
Magma (Formulation)
Mantle Rock + H20 = Magma
MANTLE ROCK IS NOT MOLTEN
How Magma is generated
Water from wet seafloor being subducted gets evaporated and the water causes mantle to melt to create magma
CONTINTEAL VOLCANOES
Form at convergent boundaries as an oceanic plate is subducted below a continent
It makes up the Andes Mountains
VOLCANIC ISLANDS
Oceanic Plate is subducted below another oceanic plate
Volcanoes grow from the seafloor to sea level
INDONESIA, PHILIPPINES, JAPAN, AND NEW ZEALAND
all volcanic islands from subduction
LARGE MOUNTAINS
Form where two continental plates collide at a convergent boundary
Himalayan Mountains formed from the collision of India and Asia
San Andreas Fault
Transform Boundary
SALTON SEA
Results in the sourthern San Andreas that forms a Pull apart basin
SAN GABRIEL MOUNTAINS
Being pushed up due to compression along San Andreas Big Bend
North American Plate what plate boundaries does it contain?
ALL PLATE BOUNDARIES
Convergent, Transform, and Divergent
