Download Biogeochemical_Cycles_PPT

Earth
Cycles
Kim Bergwerff
Biogeochemical
Cycles
“The matter that forms the outer layers of
our planet….rocks, water, and
atmosphere….are forever being shifted from
place to place.”
Overview
• The Earth operates in cycles.
• There are three main Earth Cycles : The
Rock Cycle, The Water Cycle, and The
Atmospheric Cycle.
• Earth’s Cycles are connected and each
influences the others.
• Scientists are using information from the
Earth Cycles to try to determine what our
future climate will be like.
The Rock Cycle
• Geologists classify rocks
into three groups.
Igneous
Sedimentary
Metamorphic
• Form when molten rock cools and becomes
solid.
• Are categorized both by the way they form and
their mineral content.
• All rocks begin as Igneous Rocks.
Two Categories of Igneous Rocks
Based on Mode of Formation
• Result of magma that reaches
the surface, becomes lava,
and cools rapidly.
• Cools down within a few hours.
• Also known as Volcanic rock.
• Individual crystals are too
small to be
seen by the
naked eye.
• Form deep within the Earth’s
crust at very high
temperatures.
• May take thousands of years
to cool down.
• Individual crystals are larger
and can be seen with the
naked eye.
• Also known as
Plutonic rock.
• Eventually
the rock makes
its way to the
surface.
Two Categories of Igneous Rocks
Based on Mineral Content
•
•
•
•
Also known as acidic.
Rich in quartz.
Light colored.
Example - Rhyolite
• Also known as basic.
• Rich in iron and
magnesium.
• Darker colored.
• Example Basalt
* All Rocks Begin as _____ ____ !
• Form from the sediments of igneous rocks.
• Result of weathering and erosion on igneous
rocks.
• Many types, three are very common: Sandstone,
Shale, and Limestone.
• Made from sand grains and igneous rock
sediments.
• Result of sediment that is buried by beach sand
deep underground.
• Pressure and heat from the earth’s interior and
minerals from the water form a “cement” to hold
the grains together.
• Made from silt and clay combined with igneous
rock sediments.
• Most abundant sedimentary
rock-70% of the
sedimentary rocks
are shale.
• Usually found among
layers of sandstone
or limestone.
• Made from compacted decomposed plants and animals
and igneous rock sediments.
• Also arise from skeletons of microscopic organisms.
• Calcium carbonate from decomposed
plants, animals, and microscopic
organisms makes up the majority
of the composition of limestone.
*Igneous rocks weather and erode and combine
with other material to form ________ _____ !
• Form when extreme heat and pressure is applied to
igneous or sedimentary rocks deep within the Earth.
• The heat and pressure cause chemical changes making
the resulting rock very different from the original rock.
• Final rock depends on: amount of pressure, heat, and
time.
Three Common Metamorphic Rocks…
• Limestone
Marble
- grains re-crystallize to
form Marble
• Shale
Slate
- minerals are rearranged
due to heat and pressure
• Coal
Diamond
- 75 to 120 miles below the
surface from the melting
of coal and other rocks,
must be mined
* When extreme heat and pressure change
the composition of a rock it becomes a
________ _____!
And……
* When metamorphic rocks return to the
mantle and join magma they form
_______ _____ once again!
And the Cycle
Continues…
Moh’s Hardness Scale
• Mohs' Scale Is Still Used in
Mineralogy & Gemmology
Crude but Practical
In 1822, Friedrich Mohs, a
German mineralogist devised
a crude but practical method of
comparing hardness or scratch
resistance of minerals. It has
become universally known as
Mohs scale or Moh's scale as
the grammatically challenged
would call it, actually it should
properly be called Mohs' scale.
10
9
8
7
6
5
4
3
2
1
Diamond
Corundum
Topaz
Quartz
Feldspar
Apatite
Fluorspar
Calcite
Gypsum
Talc
Like
,
has a cycle
too!
• Virtually all of the water on earth has been here
since the planet was born.
• The water cycle continuously uses and
replenishes available water.
• Three parts of cycle:
- Evaporation
- Condensation
- Precipitation
• Three main types of water:
- Salt Water (Oceans)
- Frozen Water (Ice Caps and Glaciers)
- Fresh Water
Parts of Cycle
• Evaporation
Sun heats water, turning it
into water vapor.
• Transpiration
Water vapor is released
from leaves of plants and
breathing of humans and
other animals.
• Condensation
Water vapor condenses,
forming clouds.
• Precipitation
Condensed water
particles form droplets
that fall to Earth.
• Salt Water – 97% Found mainly in Oceans
• Frozen Water – 2% Found in Ice Caps and
Glaciers
• Fresh Water – Less than 1% Found mainly in
rivers, streams, and ponds.
• Cover ¾ of Earth’s surface
• Average 3 miles deep
• The deeper the
ocean the colder
and saltier it gets.
• Pressure increases
as water depth
increases.
• Most recent “ice age” was
20,000 yrs ago.
• At one time 5% of water,
now 2%, so what happened?
• There is floating ice in the form
of icebergs, ice shelves, and Arctic
Sea ice..
• And continental ice in the form of glaciers and
ice sheets found in Greenland and Antarctica…
• What would be more detrimental to our
coastlines, melting floating ice or melting
continental ice?
• Only a small amount of Earth’s water is available
as fresh water, in fact…less than 1% is fresh
water.
• Of that 1%...
- 99% goes into underground reservoirs known as
aquifers
- It may take thousands of years for aquifers to fill
up and just as long for humans to “tap” them to
get fresh water.
- Unfortunately seen by many humans as a
resource that can be used with little regard for
long-term consequences or contamination.
The
also has cycles…
Air circulates just as rocks and
water does. It consists of layers
that differ in temperature and
pressure.
- Pressure decreases as distance
from the Earth increases.
- Temperature fluctuates
throughout the atmosphere.
• A “short-term” cycle = Weather
• A “longer-term” cycle = Seasons
• A “much longer-term” cycle = Climate
Formation of the
• Formed during planetary “degassing” – gasses
like carbon dioxide, water vapor, sulphur dioxide
and nitrogen were released from the interior of
the Earth through processes like volcanic
activity. Gas Composition of Earth's
atmosphere:
Nitrogen - 78% of atmosphere
Oxygen - 21% of atmosphere
Trace gases - 1% - Neon, Helium,
Hydrogen, Methane,
Carbon Dioxide
Convection causes weather – the
troposphere is a giant convection system
powered by solar energy.
Prevailing
Westerlies = surface
winds that blow
west-to-east in the
temperate regions of
the northern and
southern
hemispheres
Eaterlies = winds
that blow east-towest in equatorial
regions
Doldrums =
stagnant air at the
equator
Earth rotation stretches convection
currents into three large east-west
convection cells.
Spring
Summer
Fall (Autumn)
Winter
Seasons result due to the tilt of the Earths axis.
Climate is the average and variations
of weather in a region over long
periods of time.
"Are we barreling down a runaway
route toward climatic catastrophe, or
will the future bring relatively benign
changes that will not threaten society?
The accumulation of greenhouse
gases in the atmosphere will almost
certainly cause Earth's surface
temperature to rise. But we do not
know how quickly the planet will warm
or how that warming will affect
different regions of the globe. Answers
to such questions will only come
through intense research into the
mysteries of Earth's climate system."
-- from Reports to the Nation on Our
Changing Planet
Scientists use the climate from many years ago and
the current climate changes to determine what future
climates will be.
Resources
http://www.worldclimate.com/
Website allows you to search for the climates throughout the world.
http://www.teachersdomain.org/
Teacher’s Domain Video and Interactive Resources
http://streaming.discoveryeducation.com/index.cfm
Discover Education United Streaming Video
http://www.usgs.gov/
US Geological Survey, Thristin’s Water Cycle Interactive
http://www.climate.noaa.gov/about_climate/
NOAA Website, Climate Quote and Info
http://www.science-teachers.com/earth.htm
Earth Science Teaching Resources
http://www.livetext.com/doc/3195583/16341175/
Link to my LiveText website and PowerPoint Presentation (Under “What’s Up This
Week”)
Science Matters Textbook