| A | B |
|---|
| 4 type of evidence of Continental Drift hypothesis | fossils, rock types, cliimatic patterns, pieces of a puzzle |
| fossils | If the continents had once been joined, folssils of the same plants and animals would be on both coast lines of the adjoining continents |
| rock types | the age and type of rocks in the coastal regions of widely separated areas matched closely |
| climatic patterns | layers of debris from glaciers have been found in southern Africa & South America |
| pieces of a puzzle | the continents seem to fit together like a puzzle |
| What is happening at the Mid-Atlantic Ridge | evidence of sea floor spreading. There may be a break, or fift in the earth's crust & molten rock is welling up through the rift. This moves the ocean floor. |
| What evidence of sea-floor spreading was provided by the "Glomar Challenger"? Glomar Challenger" | Crew aboard a ship observed magma bubbling up from the mantle. Lava formations emerged from the mantle and hardened in the rift valley |
| How is Paleomagnetism used to explain seafloor spreading? | As molten rock rises, it quickly cools and Hardens and its magnetic orientation becomes fixed. Its magnetic orientation will reflect the polarity of the earth's magnetic field |
| Two types of crust | oceanic crust, continental crust |
| three types of plate boundaries | divergent, convergent |
| Continental Drift Theory | theory that continents had moved or "drifted" apart from a single landmass called Pangaea |
| What is subduction zone? | The region along a plate boundary where one plate moves under another plate |
| What is formed along a subduction zone? | a deep ocean trench |
| transform fault boundary | forms where two plates are grinding past each other |
| convection | the transfer of heat through the movement of heated fluid material |
| convection current | the cycle of warm water rising and cool water sinking to replace it |
| asthenosphere | zone of mantle beneath th elithosphere that consists of slowly flowing solid rock |
| continental crust | material that makes up landmasses |
| convergent boundary | the direct collision of one plate with another |
| divergent boundary | two plates moving away from each other |
| island arc | chain of volcanic islands formed along an ocean trench |
| lithosphere | thin outer shell of the earth consisting of the crust and the rigid upper mantle |
| Mid-Atlantic Ridge | undersea mountain range with a steep, narrow valey along its center |
| mid-ocean ridges | system of undersea mountain ranges that wind around the earth |
| ocean trench | deep valley in the ocean floor that forms along a subduction zone |
| oceanic crust | material that makes up the ocean floor |
| Pangaea | single landmass thought to have been the origin of all continents |
| Panthalassa | giant ocean surrounding Pangaea |
| Magnetic orientation of rock determined | when the rock solidifies |
| Magma | molten rock that wells up through fissures in the earth's crust |
| seafloor spreading | movement of the earth's crust away from an oceanic ridge |
| Wegner | first proposed that the continents were once joined in a single landmass called Pangaea |
| glacial debris in southern Africa and South America | evidence that the continents were once joined |
| seamount | isolated volcanic mountain on the ocean floor |
| continental shelf | edge of a continent covered by shallow ocean water |
| rift valley | steep, narrow valley formed as lithospheric plates separate |
| What causes the earth's tectonic plates to move | a convection current |
| suspect terranes | pieces of lithosphere |
| San Andreas Fault | major transorm fault boundary where two plates are grinding past each other |
| "Ring of Fire" | the perimeter of the Pacific Ocean is called this because of the number of volcanoes in that area |
| Mid-Atlanic Ridge | divergent boundary |
| Aleutian Trench | convergent boudary |
| rfit zone | steep, narow valley formed as lithospheric plates separate |
| continental shelf | edge of a continent covered by shallow ocean water |
| oceanic crust | denser |
| continental crust | less dense |
