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what´s a tectonic plate
A tectonic plate (also called lithospheric plate) is a massive, irregularly shaped slab of solid rock, generally composed of both continental and oceanic lithosphere. Plate size can vary greatly, from a few hundred to thousands of kilometers across; the Pacific and Antarctic Plates are among the largest. Plate thickness also varies greatly, ranging from less than 15 km for young oceanic lithosphere to about 200 km or more for ancient continental lithosphere (for example, the interior parts of North and South America).
How do these massive slabs of solid rock float despite their tremendous weight? The answer lies in the composition of the rocks. Continental crust is composed of granitic rocks which are made up of relatively lightweight minerals such as quartz and feldspar. By contrast, oceanic crust is composed of basaltic rocks, which are much denser and heavier. The variations in plate thickness are nature's way of partly compensating for the imbalance in the weight and density of the two types of crust. Because continental rocks are much lighter, the crust under the continents is much thicker (as much as 100 km) whereas the crust under the oceans is generally only about 5 km thick. Like icebergs, only the tips of which are visible above water, continents have deep "roots" to support their elevations.
Most of the boundaries between individual plates cannot be seen, because they are hidden beneath the oceans. Yet oceanic plate boundaries can be mapped accurately from outer space by measurements from GEOSAT satellites. Earthquake and volcanic activity is concentrated near these boundaries. Tectonic plates probably developed very early in the Earth's 4.6-billion-year history, and they have been drifting about on the surface ever since-like slow-moving bumper cars repeatedly clustering together and then separating.
Like many features on the Earth's surface, plates change over time. Those composed partly or entirely of oceanic lithosphere can sink under another plate, usually a lighter, mostly continental plate, and eventually disappear completely. This process is happening now off the coast of Oregon and Washington. The small Juan de Fuca Plate, a remnant of the formerly much larger oceanic Farallon Plate, will someday be entirely consumed as it continues to sink beneath the North American Plate.
a tectonic plate
a convergent boundry
an animal
whats a convergent boundry
are locations where lithospheric plates are moving towards one another. The plate collisions that occur in these areas can produce earthquakes, volcanic activity, and crustal deformation.
is a dog
is wonderland
is an animal
_____________ ___________are locations where lithospheric plates are moving towards one another. The plate collisions that occur in these areas can produce earthquakes, volcanic activity, and crustal deformation.
convergent boundries
transform boundries
subduction
a trench
what is a trench
are locations where lithospheric plates are moving towards one another. The plate collisions that occur in these areas can produce earthquakes, volcanic activity,
When an oceanic plate is subducted under a continental plate, a deep valley is formed in the ocean.
it is a hole
it is where fossils are
A subduction zone is formed...
when one tectonic plate sinks below another
at every type of convergent plate boundary
at every type of divergent plate boundary
at transform boundaries
What geologic feature/event would you most likely to find at a divergent boundary between two pieces of oceanic crust?
Rift Valley
Mid-Ocean Ridge
Island Arc
Flat land
What geologic feature/event you be most likely to find at a transform boundary?
Volcanoes
Earthquakes
Mountains
Rift Valleys
What geologic feature/event would you most likely to find at a convergent boundary between two pieces of continental crust?
Volcano
Mountain
Rift
island Arc
When convergent plates collide, if both plates are pushed upward, this forms.
divergent
convergent
transform
submergent
trick question
When convergent plates collide, if both plates are pushed upward, this forms.
Fissures
Mountain Ranges
Volcanoes
wonderland
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