27 terms

Science chapter 7 Plate Tectonics

The name _________________ means "all land".
The ridge part of the plates of the _____________ are made of oceanic crust or continental crust and upper mantle.
Convection currents
__________________ _________________, occurring in the mantle, are thought to be the force behind plate tectonics.
continental drift
The main lines of evidence for _____________ ______________ are fossil, rock, and climate clues, and the theory of seafloor spreading.
Earth's ________________ move around on a special layer of the mantle.
Earth's plastic like layer is the ________________.
seafloor spreading
The theory of ____________ ____________ was shown to be correct by age evidence and magnetic clues.
plate tectonics
The theory that describes Earth's crust and upper mantle as being broken into sections is called __________ _______________.
The youngest rocks in the ocean floor are locacted at the mid-ocean _______________.
Harry Hess
The seafloor spreading theory was proposed by ___________ __________.
Plate move apart at _____________ boundries.
convergent boundries
The places between plates moving together are called_____________ ____________.
Where plates slide past one another, __________ occur.
younger than
Ocean floor rocks are _____________ ____________ continental rocks.
The lack of explination for continental drift prevented many scientents from believing a single supercontinent called _____________once existed.
Studying the ocean floor, scientists found rocks showing magnetic _________________.
subduction zones
Oceanic plates are pushed down into the upper mantle in __________________.
fossils and rocks
The presence of the same ___________ __________ on several continents supports the idea of continental drift.
hot, dense material below Earth's surface is forced upward
Seafloor spreading occurs because ______________________________________________________________.
rift valleys & plate boundries
The results of plate movement can be seen at ________________________.
convection current
The cycle of heating, rising, cooling and sinking is called________________ _________________.
samples of rock from different locations
Scientists aboard the Glomar Challenger added to the evidence for the theory of seafloor spreading by providing _____________________.
The ________________ are forming where the Indo-Australian plates collides into the Eurasian plate.
continental drift
The hypothesis that continents have moved slowly to their current locations is called ______________ ____________.
mountains, volcanoes, ocean basins
As Earth's plates move apart at some boundaries, they collide at others, forming___________,_______________,__________________________.
seafloor spreading
Continental drift occurs because of ____________ _______________.
magnetic field
The alignment of iron-bearing minerals in rocks when they formed reflects the fact that Earth's __________ _________ has reversed itself several times in its past.