Predicting past climates leena
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Transcript of Predicting past climates leena
Schiza. A, Fatana. M,Nerdin. M,
Leena. S
1/16/2011 1
Overview Introduction
Ice cores What are ice cores?
Procedure/ Drilling Technology Video
Testing
Glaciers
Dendrochronology Examining Trees
Coral Reefs
Palynology Examining pollen
Ocean Sediments
Caves
Quiz
Conclusion
References
1/16/2011 2
IntroductionWhat is climate?
o Climate is the weather in a specific location which is
averaged over a long period of time.
What is Paleoclimatology?
o The detailed study of climate of the past.
Proxy records: Stores of information in ice
cores, tree rings, coral reefs, ocean sediments,
caves.1/16/2011 3
Ice Cores What are Ice cores :
o Long cylinders of ice extracted from large ice sheets
Development: Occurs overtime ---> snow falls ---> compact layers of ice
form
Analysis:
o Top layer ----> recent Inner layer ---> older
o Minute bubbles
o Each layer represents different year/season
o Dust particles
Locations found: Lake Vostok, Antarctica, Green land
1/16/2011 4
Ice cores: Procedure/Drilling
Technology Information required prior to procedure:
o The angle of the drill, depth, the power consumption of the machine
Machine consists of :
o A specialized drill head, a core barrel, chip catcher, motor, instrument package, and anti-torque knives, 4000 meter long cable
Steps included within the procedure:
The drill is lowered into a bore hole
A section of the core (2-6 meters long) is cut, broken off and pulled back to the surface
The ice core is then sent to a science trench
1/16/2011 5
Ice coring in Antarctica: Video
1/16/2011 6
Ice cores: Testing Very fragile: easily contaminated
Core processing line
Exterior vs. interior testing
Gas testing:
o Cut into thin slices
o Air bubbles tested for certain gases such as: carbon
dioxide, methane, nitrous oxide, etc
o Separately tested for oxygen --> types --> light to
heavy atom ratio
Dust particles include information regarding precipitation
and volcanic eruptions1/16/2011 7
This ice is 45000 years old, and the gas bubbles are plainly visible
1/16/2011 8
Glaciers
What’s a glacier:
oSlow moving mass of ice
Movement occurs due to gravitational pull
Carve U-shaped valleys ---> in the shape of
rivers
Analysis:
oGlacial ice and surrounding debris
Glacial valleys with no ice, represents evidence
of climate change1/16/2011 9
What’s Dendrochronology?
o The study of climate changes and past events by
comparing the annual growth rings of trees
One dark ring and one light ring (considered as one) are
grown per year/season
Growing conditions (season) of the tree affect:
o Width of rings
o Color of rings
Scars and burn marks
Lifespan of tree
Location of the tree
Dead trees could also be studied, but only if preserved
Dendrochronology
1/16/2011 10
Examining Trees Age of tree determined by number of rings
Dead trees ---> cross sections examined
Living trees ---> increment cores examined
Review of previous points:
Thickness: Width of ring
Shape: Evenly shaped/ or not
Scars: Left due to insects/ diseases
Burn marks: Represent natural/unnatural fires
1/16/2011 11
Coral Reefs Growth patterns affected by:
oSalinity
o Temperature
oAcidity of sea water
Salinity changed due to precipitation
Slightest change in temperature ---> growth
pattern changes
Temperature data states past sea surface
temperatures1/16/2011 12
Coral Reefs Coral bleaching
Symbiotic protozoa
Zooxanthellae
Expulsion of protozoa ---> temperature
change/harmful chemicals present
Corals similar to trees ---> layers
Difference:
Layers in trees ---> growth patterns
Layers in coral ---> sea surface temperatures1/16/2011 13
Palynology
What is Palynology:
Science which studies contemporary and fossil
palynomorphs
Palynomorphs
Found in:
Sedimentary rock, sediments
Trapped pollen---> during build up of
sediments1/16/2011 14
Palynology
Past plant species
Characteristics of fossils:
oSize, shape, pores, furrows, air sacs
Processes used:
oWet sieving
oChemical treatment
oPollen diagram
1/16/2011 15
Ocean SedimentsWhat are sediments
oSolid fragments of material that come from the
weathering of rock and are carried and
deposited by wind, water, or ice.
Sediment can originate from:
oBiota
oEroded material
oAshes
oPrecipitates
1/16/2011 16
Ocean Sediments
Types of sediment:
oTerrigenous
oBiogenic
oVolcanogenic
oHydrogenous
Data retrieved such as: humidity
variations, wind directions, wind
speeds, dry/wet period1/16/2011 17
Ocean Sediments Location
Examination:
o Large cylindrical cores
oRefrigeration
oPhysical, chemical, biological make-up
Trapped entities:
o Fossils of animals/plants
oAshes
o pollen
1/16/2011 18
Ocean Sediments
Transportation of sediment depends
upon:
oSize
oOriginal location
Transportation: (mainly of terrigenous material)
oWind ---> glacial periods
oWater (rivers)
oEarth quakes1/16/2011 19
Caves: Stalactites and Stalagmites
What is a Stalactite:
oA cylinder of calcium carbonate hanging
from the roof of a limestone cave
What is a Stalagmite:
oA cylinder of calcium carbonate
projecting upward from the floor of a
limestone cave1/16/2011 20
Caves: Stalactites and Stalagmites
Determine data such as:
Record of precipitation
Temperatures
Analysis:
Growth rate
Oxygen atom ratio
1/16/2011 21
Quiz
What is Paleoclimatology?
What gas is separately tested for in ice core testing?
What two things are analyzed in glaciers?
Dead trees cannot be studied when studying Dendrochronology. True
or False.
What’s the difference between coral reefs and trees?
What is Palynology?
1/16/2011 22
Conclusion Predicting past climates is not very easy. It requires a lot of knowledge and basic
understandings.
Some ways of predicting past climate are:
ice cores
glaciers
tree rings
Palynology
ocean sediments
coral reefs
caves
It helps scientists prepare for the future and know what climatic changes occurred in the past.
1/16/2011 23
References Whitaker, Dick. "Dick's Blog: Measuring Past Climates." Dick's Blog. N.p., 12 July 2209. Web. 13 Jan. 2011.
<http://passingparade-2009.blogspot.com/2009/08/measuring-past-climates.html>.
Tyson, Peter. "Stories in the Ice." Warning from the ice. Online producer, NOVA, n.d. Web. 13 Jan. 2011.
<www.pbs.org/wgbh/nova/warnings/stories/>.
Bruckner, Monica. "Paleoclimatology: Climate Proxies." Microbial Life Educational Resources. Montana State
University, n.d. Web. 11 Jan. 2011. <http://serc.carleton.edu/microbelife/topics/proxies/paleoclimate.html>.
Gardiner, Lisa. "How Do We Investigate Climates of the Past?." Windows to the Universe. National Earth Science Teachers
Association, 15 June 2009. Web. 15 Jan. 2011.
<http://WWW.windows2universe.org/earth/climate/CDcourses_investigate_climate.
"Climate Change - Studying Climate Change - Tree Rings." PRIweb.org: Redirecting.... Paleontological Research
Institution, n.d. Web. 9 Jan. 2011. <http://www.priweb.org/globalchange/climatechange/studyingcc/scc_01.html>.
1/16/2011 24
References British Antarctic Survey. "Oldest Antarctic Ice Core Reveals Climate History." ScienceDaily 11 June 2004. 15
January 2011 <http://www.sciencedaily.com /releases/2004/06/040611080100.htm>.
National Science Foundation. "Researchers drill through mile and a half of Greenland ice sheet in search of
climate change insights." ScienceDaily 4 August 2010. 15 January 2011 <http://www.sciencedaily.com
/releases/2010/08/100804133448.htm>.
"esource-stu." Nelson Education - Home Page. N.p., n.d. Web. 12 Jan. 2011.
<http://www.nelson.com/school/secondary/science/scienceperspectives/10/weblinks/esource-
stu.html>.
Christine, Adam-Carr, Gabber Martin, Hayhoe Christy, Hayhoe Douglas, and Hayhoe Katharine. Science
Perspectives 10. Toronto, Ontario: Nelson Education Ltd, 2010. 358-360. Print.
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The EndThank you for listening
1/16/2011 26