ROCKSMINERALS Heterozygous Can be organic or non- organic
Follow the rock cycle Three types: sedimentary, igneous,
metamorphic Homozygous Organic Must follow rules of minerals
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Intrusive igneous rocks are formed from magma that cools and
solidifies within the crust of a planet Granite and Pumice
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Extrusive igneous rocks form when magma makes its way to
Earth's surface. The molten rock erupts or flows above the surface
as lava, and then cools forming rock. The lava comes from the upper
mantle layer, between 50 km and 150 km below the Earth's surface.
When lava erupts onto the Earth's surface, it cools quickly. If the
lava cools in less than a day or two, there is no time for elements
to form minerals. Instead, elements are frozen in place within
volcanic glass. Often, lava cools over a few days to weeks and
minerals have enough time to form but not time to grow into large
crystals. Basalt is the most common type of extrusive igneous rock
and the most common rock type at the Earth's surface.
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Sedimentary rocks are types of rock that are formed by the
deposition of material at the Earth's surface and within bodies of
water. Weathering and erosion are vital pieces needed in order to
form sedimentary rock.
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GRAND CANYONSANDSTONE
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Metamorphic rocks make up a large part of the Earth's crust and
are classified by texture and by chemical and mineral assemblage
They may be formed simply by being deep beneath the Earth's
surface, subjected to high temperatures and the great pressure of
the rock layers above it. They can form from tectonic processes
such as continental collisions, which cause horizontal pressure,
friction and distortion. They are also formed when rock is heated
up by the intrusion of hot molten rock called magma from the
Earth's interior.
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Weathering: break down of rocks on or near Earths surface.
Erosion: the removal and transport of weathered material Erosion
has been occuting since the formation of the crust.
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The break down of rock caused by the climate. Some things that
add to mechanical weathering is Temperature: frost wedging, which
is the repeated freezing and thawing of water in cracks.
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Pressure Bedrock is under lots of pressure from all of the rock
which lies on top. Once the top rock is removed, pressure is
reduced. Eventually this will be uncovered and it will be exposed.
The peeling of the layers over time is called exfoliation.
Exfoliation= dome shaped formations
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The process by which rocks and minerals undergo changes in
their composition as the result of chemical reactions. The
composition of a rock will determine what effects of chemical
weathering will have. Lichens Acid Rain Water- hydrolysis Oxygen +
other substances= oxidation CO2: dissolves calcite and
limestone
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Climate: the amount of precipitation, temperature, and
evaporation. The interaction between temperature and precipitation
is the most important. Chemical weather occurs primarily in warm
weather. Occurs with abundant rainfall, warm temperatures and lush
vegetation. Mechanical weathering occurs more in colder climates.
Another affect would be rock type: some are more resistant than
others.
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O Horizon: leaf litter/detritus A: Topsoil: dark decomposed
organic materials B: consists of mineral layers which may contain
concentrations of clay or minerals such as iron or aluminum oxides
or organic material moved there by leaching C: bedrock
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Polar: Good drainage but no horizons, permafrost Temperate
soils: lots of humus, Al and FeO2 rich soils, rainfall consistent
Desert Soils: high level of salts ( less precipitation). Thin A
horizon. Tropical Soils: intense weather, little hummus, few
nutrients. Soils rich in Fe and Al.
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1977: Soil & Water Conservation Act- continued evaluations
for soil and water 1985: Food Security Act: Swampbuster Discouraged
drying out wetlands 1990 funds were denied to farmers who dried out
their lands
