plate tectonics and the rock cycle. three types of plate boundaries divergent plate boundaries –...
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Three types of plate boundaries
• Divergent plate boundaries– Plates move apart from one another
• Convergent plate boundaries– Internal forces push two plates together
• Transform faults– Plates slide and grind past one another along a fault line
When a tectonic plate sinks, it sinks down into the mantle and becomes very hot. So hot, in fact, that the rock melts. This molten
rock will gradually make its way up to the surface of the earth through a series of cracks. When it reaches the surface of the earth, we refer to it as lava. As layer upon layer of lava builds up, a volcano
is formed.
How much stronger is an earthquake with a magnitude of 9.0 versus an earthquake with a magnitude of 4.0?
9.0 – 4.0 = 5.0
105 = 100000 times stronger
Three types of rock
• Igneous– Granite, lava rock
• Sedimentary– Sandstone, shale, dolomite, limestone, lignite, bituminous coal
• Metamorphic– Anthracite, shale, marble
Igneous rock
Forms below earth’s surface, when molten
rock comes up from the upper mantle, cools, and hardens
Sedimentary rock
Forms from sediments deposited
in layers which accumulate over time – the weight
and pressure “cements” these layers together
Cementation – minerals are precipitated in the pores of sediments, forming cements that bind
sediments and rock
Lithification – the process that converts sediments into solid rock by compaction and
cementation
Metamorphic rock
Forms when preexisting rock is subjected to high
temperatures, high pressures, chemically
active fluids, or a combination of these
agents
Rock cycle
• Interaction of physical and chemical processes
• Recycles the earth three types of rocks
• Slowest of earth’s cyclic processes
• Concentrates the planet’s nonrenewable minerals
• Without it we would not exist
Closure
Why is it important to understand the three major
processes (tectonic cycle, rock cycle, and soil formation) of the
geologic cycle?
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