10 Things to Know About…
Tectonic Plates and the Rock Cycle
1. The earth is divided into three major zones; the core, mantle, and crust. The core is the
inner most zone, extremely hot and a solid center then a semisolid material known as the
out core. Mantle is the largest layer where molten rock flows and can be formed. The
crust is the thinnest and outer most layer consisting of the continental (land) and oceanic
(seafloor) crusts that move.
2. The continental and oceanic crusts are divided into twelve or so parts called tectonic
plates that move very slowly because of the convection cells or currents occurring in the
mantle.
3. There is three type of tectonic plate movement; divergent plate boundaries, convergent
plate boundaries, and transform faults.
4. Divergent is when two plates are moving apart from one another creating oceanic ridges.
Convergent is two plates coming together, creating subduction (one rises over another; i.e
continental over oceanic), create mountain ranges with two continental plates colliding or
trenches with two oceanic plates. Transform faults is when two plates are sliding past
each other.
5. The movement of the plates causes hazards such as earthquakes, volcanoes, or tsunamis.
Plus the constant moving of the plates is ever changing the size, shape, and location of
the continents. For example North and South America are moving away from the eastern
side of Africa and will eventually meet with Japan and Australia.
6. The rock cycle is the interaction between physical and chemical processes that change
rocks from one type to another
7. The rock cycle focuses on the formation on the different types of rocks; igneous,
sedimentary, and metamorphic. Rocks are defined as minerals combined from the earths
crust. There are ore rock that is high concentration of minerals, high-grade ore which is
fairly large amount of desire mineral, and them low-grade ore where contains smaller
amount.
8. Igneous: forms below the earth’s surface when molten rock (magma) wells up from the
earth’s upper mantle or deep crust, cools, and hardens. Igneous is the bulk of the earth’s
crust, for example- granite and lava rock. And the main source of metal and nonmetal
resources.
9. Sedimentary: Forms from sediment produced when existing rocks are weathered and
eroded into small pieces, transported by water, wind, or gravity downstream. The
sediments are deposited into layers and accumulate over time. Heat and pressure binds
sediment particles together to form the rock. Examples are sandstone, shale, dolomite,
limestone, lignite, and bituminous coal.
10. Metamorphic: forms when preexisting rock is subjected top high temperatures, high
pressures, chemically active fluids, or a combination of these three agents. These factors
transform the rock by reshaping its internal crystalline structure and physical properties.
Examples include anthracite, slate, and marble.