Download Samuel Lasco - Hunter Supreme

Samuel Lasco
June 17, 2003
ELED 305-01
Fredric Tarnow
The Rock Cycle
1. Is sedimentary rock is a mineral? T or F
2. Is a mineral a rock? T or F
3. Dirt is soil?
T or F
4. Igneous meaning formed from: a.) water, b.) fire. c.) air
5. Sediments were formed from: a.)Elmer’s glue, b.)Cemented together c.)silly putty
6. Metamorphic rocks are change by: a) heat and pressure, b.) gravity c.) water
pressure
7. Please match the box:
IGNEOUS
SEDIMENTARY
METAMORPHIC
granite, slate, calcite, quartz, feldspar, mica, andesite, breccia, , schist, gneiss, marble,
travertine ,silica, flint, jasper, mudstone, limestone
1 short answer: What are the 4 layers of earth?
THERE ARE FOUR MAIN LAYERS THAT MAKE UP THE EARTH:
1. Inner Core - A mass of iron with a temperature of about 7000 degrees F. Although
such temeratures would normally melt iron, immense pressure on it keeps it in a solid
form. The inner core is approximately 1,500 miles in diameter.
2. Outer Core - A mass of molten iron about 1,425 miles deep that surrounds the solid
inner core. Electrical currents generated from this area produce the earth's magnetic field.
3. Mantle - A rock layer about 1,750 miles thick that reaches about half the distance to
the center of the earth. parts of this layer become hot enough to liquify and become slow
moving molten rock or magma.
4. Crust - A layer from 4-25 miles thick consisting of sand and rock.
1 essay question:
How does the rock cycle work?
As you might expect - since most of the earth's surface is covered by water - molten
material from inside the earth often breaks through the floor of the ocean and flows from
fissures where it is cooled by the water resulting in the formation of igneous rocks. Some
low grade metamorphism often occurs during and after the formation of the rock due to
the intrusion of the material by the sea water. As the molten material flows from the
fissure, it begins forming ridges adjacent to it. If we examine the rock cycle in terms of
plate tectonics, as depicted in the figure above, we see that igneous rocks form on the sea
floor as spreading ridges. As the rocks cool, and more magma is introduced from below,
the plate is forced away from the spreading ridge, and acquires a sediment cover. As
shown in the figure, in this case, the oceanic plate eventually "dives" under the adjacent
continental plate. As the oceanic plate travels deeper, high temperature conditions cause
partial melting of the crustal slab. When that occurs, the surrounding "country rock"
(existing adjacent rock) is metamorphosed at high temperature conditions by the contact.
The molten material is either driven to the surface as volcanic eruptions, or crystallizes to
form plutonic igneous rocks. There are three basic types of rocks. They are sedimentary,
igneous, and metamorphic .Weathering is the process by which rocks are broken down
into rock particles. Weathering agents include wind, water, temperature changes, gravity,
glaciers, and plant and animal activity. Erosion moves weathered rock particles from one
place to another. Erosion agents are wind, running water, glaciers, gravity, and plant and
animal activity. Rock sediments are deposited layer upon layer, sometimes under water,
sometimes in cracks of rock and in other low- lying places. As the layers deepen, the
weight of the upper, newer layers and any water that might be on top of them, press the
sediments together very tightly. In time, the sediments can become cemented together
into rock. Compaction and cementation are processes that press sediments together to
form sedimentary rocks. Cementation sometimes occurs when pebbles are "cemented" to
each other by calcium carbonate. Rocks formed this way are called conglomerates. Heat
and pressure deep in the crust of the Earth causes rocks to melt and form magma
(liquified, molten rock that is between the crust and the core of the Earth). Magma
reaches the surface of the Earth through volcanic action or through cracks in the Earth's
crust, to form igneous rocks. When magma is under the surface of the Earth, it is called
lava .When it is on the surface and is cooled, it is called basalt .If the lava cools before it
reaches the surface, the rock is dense and the molecules are close together. If it cools after
it reaches the surface, the lava is lighter with air bubbles in it. The rate of cooling is the
factor that makes the difference in the kind of rock that results. Cooling causes
crystallization to occur. Crystallization is the lining up of molecules to form rocks and
minerals with geometric shapes which have edges, corners, and flat surfaces. When
broken, rocks of a crystalline nature break along the flat surfaces. Heat and pressure form
metamorphic rocks. The elements in them are changed and crystallized. Rocks of any
type may be affected by any of the processes described above. All rocks do not follow a
given cycle. There are many "shortcuts" within the cycle. For example, metamorphic rock
may be buried beneath the Earth and, through pressure and heat, can be changed to a
different form of metamorphic rock. Sedimentary rocks often are weathered and become
a different rock by being eroded and elsewhere combined with other sediments. Rocks
are mostly heterogeneous .That is, they usually have more than one kind of mineral in
them. One can observe different minerals in rocks by noticing differences in color, shape
of particles, and crystal formation. SOME COMMON ROCKS LISTED BY TYPE
IGNEOUS: obsidian, rhyolite, granite, diorite, andesite, breccia, gabbro, basalt
METAMORPHIC: slate, schist, gneiss, marble, quartzite, SEDIMENTARY: sandstone
gypsum, salt (halite), calcite, travertine ,silica, flint, jasper, mudstone, limestone There
are more sedimentary rocks than other types of rock found on the surface of the Earth.
But, there are probably many times more metamorphic and igneous rocks than
sedimentary rocks under the surface of Earth.