Science test November 5 Flashcards
Continental Drift
Continental drift is the movement of the Earth’s continents relative to each other,
theory of plate tectonics
Plate tectonics is the theory that Earth’s outer shell is divided into several plates that glide over the mantle, the rocky inner layer above the core. The plates act like a hard and rigid shell compared to Earth’s mantle. This strong outer layer is called the lithosphere.
hypothesis of the continental drift
The theory of continental drift simply stated that continents drifted from one location to another over time. Wegener noticed that the coasts of South America and Africa seemed to fit together like a puzzle.
who is responsible for the hypothesis of the continental drift
Alfred Wegener’s
Whats was the evidence to support that hypothesis
Wegener used fossil evidence to support his continental drift hypothesis. The fossils of these organisms are found on lands that are now far apart. Wegener suggested that when the organisms were alive, the lands were joined and the organisms were living side-by-side
why was his hypothesis not excepted by most scientists
Wegener attempted to explain how continental drift took place. He suggested that the continents plowed across the ocean floors. Unfortunately, Wegener could not provide a satisfactory explanation for the force that pushes or pulls the continents.
what did he call his big super land mass
pangea
what was seafloor spreading
Seafloor spreading is a process that occurs at mid-ocean ridges, where new oceanic crust is formed through volcanic activity and then gradually moves away from the ridge. Seafloor spreading helps explain continental drift in the theory of plate tectonics.
what evidence do we have to support seafloor spreading
Abundant evidence supports the major contentions of the seafloor-spreading theory. First, samples of the deep ocean floor show that basaltic oceanic crust and overlying sediment become progressively younger as the mid-ocean ridge is approached, and the sediment cover is thinner near the ridge.
where is the seafloor the oldest
north-eastern Atlantic Ocean and north-eastern Pacific Ocean/ near the continents
where is the seafloor the youngest
on the mid-ocean ridge
Divergent plate boundaries
two plates are moving away from each other and new crust is forming from magma that rises to the Earth’s surface between the two plates.
Convergent
a convergent boundary, also known as a destructive plate boundary (because of subduction), is an actively deforming region where two (or more) tectonic plates or fragments of the lithosphere move toward one another and collide.
transform plate boundary
since these faults neither create nor destroy lithosphere, is a type of fault whose relative motion is predominantly horizontal in either sinistral or dextral direction.
what is the evidence for seafloor spreading
Abundant evidence supports the major contentions of the seafloor-spreading theory. First, samples of the deep ocean floor show that basaltic oceanic crust and overlying sediment become progressively younger as the mid-ocean ridge is approached, and the sediment cover is thinner near the ridge.
