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PowerPoint Presentation - UNL Earth and Atmospheric Sciences

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PowerPoint Presentation - UNL  Earth and Atmospheric Sciences Powered By Docstoc
					                                 animation for Keeling Curve

Keeling Curve
Mauna Loa Observatory




              The atmospheric “tub” of carbon dioxide
              is filling faster than it is draining.




                    Is Global Warming True?



                            MIT Bathtub Model 1
animation demonstrating Coriolis "force"

                                   2
Gulf Stream carries heat from the Neotropics
to high-latitude Europe                        3
At the equator (red line),
warm water lies above
cold water;

At the poles (black line),
water is cold all the way
down.




                    4
5
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Evaporation and cooling make Gulf Stream water
denser, causing it to sink.




 “North Atlantic Conveyor”
                                                 7
                                                                          Large river entering
                                                                          the Arctic Ocean

The vast delta of the Lena River, Russia, which is some 250 km wide.
Large rivers such as this collect water from Eurasia and northern North
America, and discharge it into the Arctic seas. About half of the total
volume delivered to the Arctic comes from Eurasian river systems.
Discharge from Eurasian rivers may increase by 20–70% by the end
of this century .




                                                                                          8
Climate Data from Greenland Ice Cores




   Is climate’s “flickering switch” a signal of conveyor
   shut-down?
   Earth’s climate has been relatively stable for the
                                                           9
   last 10,000 years; how long will it last?
10
Evaporation exceeds precipitation in dark
areas (which are the major source of water
for the hydrologic system on the continents).
                                                11
           Precipitation exceeds evaporation here and here




Evaporation exceeds precipitation in dark
areas (which are the major source of water
for the hydrologic system on the continents).
                                                        12
                                        Evaporation wins here
 Water becomes depleted
 in nutrients when plankton
 falls to sea floor.




Water becomes nutrient-rich




                     13
                 Upwelling
                 (Nutrients returned
                 to surface waters
                 where plankton can
                 use them).




Good place for organic-rich
mudrocks to accumulate
(future petroleum, natural gas)
Today: West coast of South America
Geologic past: ?
                            14
If continents move into different latitudes, their sedimentary
          rocks will record changing climatic zones

    (but what if Earth’s tilt also changes through time?)
        No evidence that tilt has had major change.
                                                            15
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True or False?
Each point on Earth’s surface has the same number of
hours of daylight each year.
A: True;       B: False
Earth’s tilted axis causes the changing seasons.
    Change in the Earth-Sun distance is a minor factor.
   Without the tilt, there would be no seasons anywhere,
                                                         19
      and every day and night would be 12 hours long
20
Question #1: Why is the sea salty?

Question #2: Where does mud come from?

One Answer: Weathering



                                     21
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   Mechanical vs. Chemical
        Weathering
• Mechanical weathering breaks big rocks
  into small ones.
• Main effect of mechanical weathering is
  to increase surface area available for
  chemical weathering.
• During chemical weathering, minerals in
  rocks are decomposed, and new
  minerals form.

                                        23
Mechanical Weathering
   Exfoliation
   Ice wedging
   Salt wedging
   Heating and Cooling



                         24
Jointing increases the surface area
available for chemical weathering.



    10 m




 600 m2      1,200 m2    6,000 m2
                                    25
Sheets of granite exfoliating from an exposed batholith.
Rock mass was under great pressure at depth, and thin slab
at the surface of the rock mass are now expanding and
bursting loose.
                                                  26
Exfoliation (arrows) at
Yosemite Nat. Park,
California

Rock is granite (Sierra
Nevada batholith)
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posted:5/9/2013
language:English
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