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Offline Exodus

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I wrote up these notes for one of my exams... i know it may seem a bit random but there may be information in here that people might find to help them so sod it...





 

Offline Exodus

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Re: A brief History through time in SERIOUS note form
« Reply #1 on: 16/08/2004 13:47:25 »
Frontiers


·   Africans prefer that Europe uses nucleur as we then don’t pollute the whole world, just risk polluting our back yard.
·   Gravity + Orbits of the earth worked on by Kepler, Galileo, Milton, Newton.
·   Fontelle + Voltaire asked “what can science teach us?”
·   At this time – science linked closely to literature.
·   Evolution was under investigation – Darwin theory – Victorian revolution
·   Electro + nucleur physics – 20th Century revolution
·   Biological revolution - DNA

·   Science is the search for truth using reproductable experiments.
·   Stratigraphy is a science as you can always return to the same place.
·   History: Lucretius – “Is earth getting old?”
Da Vinci – Observed sea shells in Greece up high.
Milton – stated “nature unimproved by time”.

Looking at modern day Stratigraphy:
·   Hutton – “ No vestige of a beginning, no prospect of an end” this was his theory of the earth.

·   Sedgwick – (1785 – 1873) “Earth does change”
·   Buckland – (1784 – 1856) “Catastrophism” Earth ends, things start over.
·   Lyell – (1797 – 1875) – Uniformity à His book Principles of Geology was on beagle, read by Darwin. He believed PRESENT IS KEY TO THE PAST.
·   William Smith – Idea of Stratigraphy – He noticed beds seen in different places.
Noticed original horizontal – laid down flat.
Superposition – whats above/below
Clasts in conglomerates
Faunal succession.


THE SYSTEM

TERTIARY – (ADUINO)                                        1760
JURASSIC – (HUMBOLD)                                    1795
CRETACEOUS –                                                     1822
CARBONIFEROUS -                                              1822
TRIASSIC -                                                              1834
CAMBRIAN – (SEDGWICK)                                1835
SILURIAN – (MURCHISON)                                1835
DEVONIAN - (SEDGWICK + MURCHISON)   1840
PERMIAN - (MURCHISON)                                 1841
ORCDIVICIAN – (LAPWOOD)                            1879  

Eras- e.g. – Cenozoic; Mesozoic; Palaeozoic
Aeons- e.g. – Phanerozoic; Proterozoic; Archaen; Hadean.

·   HUTTON, 1700s  – Discovered unconformities.
·   WILL SMITH, 1809 – Discovers dinosaur bone.
·   WILLIAM BUCKLAND, 1818 – Collects Megalosaurus
·   MARY ANNE MANTELL, 1822 – Discovers Iguanadon.
·   SIR RICHARD OWEN, 1841 – Named Dinosaurs.

WERNER (1750 – 1817) believed in Neptunism (All rocks deposited from Noah’s flood) Volcanologists disagreed!
BUCKLAND  believed in catastrophe systems, LYELL believed more in Uniformity.


WORKING OUT THE AGE OF THE EARTH

·   Bishop Usher, Ireland (1658) believed the beginning of earth was 23/10/4004BC. (he used the Bible).
·   Lord Kelvin, thermal calculation – believed earth older than 10Ma, younger than 500Ma.
·   Rutherford and Boltford (~1929) dating and radiogenic heat. Worked out rocks are billions of years old.

RECENT SCIENCE BATTLES

·   Lamarck – suggested evolution by change of the organisms in response to stress.
·   William Smith – Principle of Biological Succession
·   Lyell – Principles of Geology, Uniformity.
·   Darwin – Voyage of the Beagle – evolution.
·   Wallace – similar ideas from Indonesia.



Focus on Mendelian genetics + evolution

TELEOLOGICAL COMPLAINT   : System looks to end point
TAUTOLOGICAL COMPLAINT : Survival of the fittest.



Implications

Social Darwinism – Eugenics – Marie Stopes, birth control on workinf classes
Nazi beliefs.

The idea of Gaia – Lovelock.


Science is based on observation leading to theory…

LUCRETIUS    wrote book on the universe asking “does world get old?
He also supported the theory of the atom.

ARATUS (Astronomer) wrote phenomena (THE FIRST REAL SCIENCE TEXT)
PLINY  (Geology) was interested in natural history

Science and Metaphysics

·   King Canute was the first to attempt to separate science from metaphysics. He proved by chair on beach stunt! He told sea to stay back and it didn’t.


Methodology of empirical science

·   Truth and curiosity
à repeatability, usefulness, prediction, trial + error, multiple working hypothesis QUOTE POPPER wrote book on it.



Overall comes to Reductionism vs Holistics

Reductionism means breaking down topic into smaller pieces to better understand it

Holistsics involves looking at the subject as a FULL picture. QUOTE S.AFRICAN LEADER à SMUTTS.






EARTH CATASTROPHES

Recent: 10,000 to present.

Great volcanic events
Great slumps e.g. Off Norway coast
Great Earthquakes e.g. 1960 Chile. Earth shook like a bell
Great Floods e.g. after last glaciation, Nile flooding of Black Sea




Less Recent

Glacial controversy
Atmospheric change

More distant past

Meteorite impact – Mexico, all global creatures above 75kg died
Plume eruptions – during Cretaceous, much CO2 released.


LAWS OF THERMODYNAMICS

FIRST LAW:
You cant get something for nothing, there’s no free lunch.
In any process heat energy change equals work done.

SECOND LAW:
You always lose part of something if you do something – nothing is 100% efficient.

THIRD LAW:
The entropy factor is zero at absolute zero – you can’t get to zero.


What is entropy?
It is a measure of order

This ordering factor goes one way in any ‘change’ e.g. falling cans. If you want to create order in one place, you have to increase disorder somewhere else and the process is never 100% efficient.



Perpetual motion machines are not possible as no machine is 100% efficient.

Activation Energy?
Depends on how stable the compound is, a stable compound requires more energy in order to make it react.





MELTING

The mantle is solid, why does melting occur in the mantle?

Convection in the mantle can lead to areas of mantle rising. As this solid mantle intersects the melting curve (continental geotherm) which results in partial melting.

SOURCES OF MELT – passive melting at ridges
               Plumes e.g. Hawaii, Iceland.

THE MELT CURVE
As mantle rises to melt curve it begins to melt. On left of line is solidus, on right is melt. As mantle rises and expands – this is  known as adiabatic rise.

Latent heat + partial melting : Between liquidus and solidus is  the partial melt. The slope of the melt curve depends on the latent heat.

The liquid is normally less dense. When partial melt goes above a small percentage, the liquid escapes from the host crystals and rises upwards leaving behind a residue of depleted crystals.

E.g. At mid-ocean ridges the escaping liquid is basaltic , and the residue of olivine and orthopyroxine becomes a depleted harzburgite.

THERMAL GRADIENT IN THE ASTHENOSPHERE

The Lithosphere – conductive – Gradient is not adiabatic
The Asthenosphere – Convective – The gradient is adiabatic

·   The adiabatic gradient + the melt curve gradient are different
·   Partial melt occurs when the rising mantle, which cools along the adiabat, hits the melt curve.

ADIABAT IN SOLID MANTLE IS ABOUT 0.5 DEGREES C PER KM.
ADIABAT IN LIQUID MAGMA IS ABOUT 1 DEGREES C PER KM.

POTENTIAL TEMPERATURE – Is a temperature at which an adiabatically rising melt or solid would have at the earth’s surface.


POTENTIAL TEMPERATURE OF ANY RISING MANTLE UNDER A MID OCEAN RIDGE IS ABOUT 1300 DEGREES.

UNDER A MAJOR PLUME VOLCANO SUCH AS ICELAND, IT CAN BE AS HIGH AS 1500 DEGREES.



Computer modelling – can investigate mantle convection and how this circulation can lead to hot spots.

Use of vats of golden syrup heated from below, observe convection.

REFER TO RAYLEIGH MODEL AND NUMBER à Above Rayleigh number, convection starts.



KOMATITES

These are magmas with MgO > 18% by weight.
Komatites are possible Archaen plume rocks.  E.g. Gorgona (young komatites)
Possible, earth’s temperature fallen by 200 degrees over last 4 billion years.



The Plate system à overall, it is rising solid mantle. Works in a cyclic fashion.

1.   Earth is hot, hot light solids rise
2.   Rising solid mantle partly melts
3.   Liquids cool on surface, solids cool too.
4.   Solid surface falls in
5.   Other material rises


LITHOSPHERE – Mechanically strong layer at surface of earth that loses heat by conduction.
   
   Because its losing heat, it gets thicker with age.

Oceanic lithosphere from ridge to subduction zone grows (thickness with age)


Lithosphere under continents is like the analogy of a ping pong ball on a whale’s spray… eventually it falls down


AS YOU MOVE FURTHER FROM MID ATLANTIC RIDGE, THICKENING OCCURS AS SQUARE ROUTE OF AGE.

Impact of Plumes
à can lead to the re-alignment of mid-ocean ridge e.g. Iceland.

EULER’S THEOREM – Any motion on the surface of a sphere can be described as a rotation around a pole of rotation.
à closer to rotation pole = less splittage
EVERYTHING ON EARTH IS MOVING RELATIVE TO PLUMES.


PLATES : HORIZONTAL VS VERTICAL FORCES.

Transform Faults à
On ridges –discovery, earthquake fault motions….
On Land – Transform transpression e.g. San Andreas.



Vertical + Horizontal Motions

Vertical motion in plate tectonics
·   At rift margins
·   Ridge push
·   Subduction

Direct movements of plates:
·   Ridge separation; plates; continental extension
·   Transform motion; transpression e.g. San Andreas.


VERTICAL MOTION II – ABOVE SUBDUCTION ZONES

Heat driven vertical motion – isostatic uplift from compositional contrast


VERTICAL MOTION III – AT ZONES OF COLLISION

Heating of underlying continent
Isostacy from thick crust

HORIZONTAL MOTION III – GRAVITY SPREADING OF MOUNTAINS.

Erosion spreads out sediment, bouyant crust keeps moving up so erosion continues until flattened out.

Quote – McKENZIE + PARKER, NORTH PACIFIC TECTONICS, NATURE, V216, 1276-1280.




FOCUSSING ON ARCHAEN
HYDROTHERMAL COMMUNITIES

By 4Ga, meteor impacts of rocks around 100km across. Earth therefore not habitable till 3.8 billion years ago.

When Meteors boiled oceans, some life (around hydrothermal vents) were used to hot conditions and would therefore survive.

Subsequent bottle neck of animals – some bacteria may survive through periods of harsh conditions frozen in ice.


HOT SPRINGS – Favoured idea for life origin – lots of clay etc… means a high surface area to bring molecules together.


Most hydrothermal activity in the world is on Mid Ocean Ridges
·   Black smokers
·   Disequilibrium of temperature
·   Here is redox contrast – provides energy for life


No evidence of photosynthesis before 3.8 billion years ago.
We see evidence of stromatolites 3 billion years ago.
The first communities live from Redox reactions.


RESEARCH:  EUCARYA, BACTERIA, ARCHAEA


LCA – Last Common Ancestor – A cell with DNA, had 100 or so basic proteins.
From this descended the three forms of life named above
QUOTE N.PACE, SCIENCE v276, 1997.

PHOTOSYNTHESIS – evidence of photosynthesis in Isua, Greenland (3.8Ga). Believed photosynthesis released no oxygen = ANOXYGENICPHOTOSYNTHESIS

Oxygenic photosynthesis was first seen from blue/green algae



EVOLUTION OF PLANTS

QUOTE KNOLL AND CAROL, 1999

Initially plants required water present in order to survive e.g. with spores etc…, evolution saw them moving away- development of waxy surface (epidermis) which allows water retention.



·   With movement of plants away from water, animals also follow and are better able to spread. THIS AIDED BY BEGINNING OF AMNIOTE EGG.

·   Amniote egg also allows animals to have young away from water as it retains water and contains a food source.

·   V. diverse plant life – results in an ecology capable of managing a planet.



IDEA OF GAIA – J.E LOVELOCK
Self regulation of climate, chemical inventory – all leads to stabilising environment.

Quote Memory (long term chemical inventory) and Messengers (carry signals from one part of system to another)



With movement of plants + animals across globe, get different habitats, thus diversification, leading to new species.


Permain/Triassic boundary EXTINCTION!  -   Unknown why.


After this we see the arrival of the dinosaurs
·   Sauriscians – Carnivores and Herbivores.
·   Bird Hipped – Mainly Herbivores

The Jurassic saw the giantism of Dinosaurs and the growth of plants (e.g.monkey puzzle trees.)

Dinosaurs were able to run but not far as would overheat
Humans have good heat regulation and are able to run all day.


OVERALL THE J/Cr SAW A  TREMENDOUS DIVERSIFICATION.


Pterosaurs had 20ft wingspan!! They never went on to evolve to birds (these came later)

End Creataceous saw a huge impact which could have been part of the wiping out of the dinosaurs. Many died, Crocadiles, birds and mammals survived!!


SUMMARY
Things associated with Cretaceous –
Formation of chalks
Oil (much of that  extracted today is of cretaceous origin
Rise of flowering plants (angiosperms)
Dinosaur diversification.

à

Monotrema – Everything in and out of one hole PLATYPUS
Marsupials – Pouched creatures KANGAROOS
Placentals – Mother has placenta, HUMANS

·   Overall, Southern globe dominated by marsupials
·   Northern globe dominated by placentals

Collision of plates leads to impact on marsupials – world today dominated by placentals.


SUMMARY THUS FAR

Early Eukaryotes (Summons et al.)

It is believed this was the beginning of symbiosis in both plants and animals.
e.g. chloroplasts in plants, mitochondrion in animals.

SNOWBALL EARTH…

Late Proterozoic – 600 –700 Ma ago
Ice moving into tropics à global cooling


An impact on earth would lead to the degassing of the oceans, CO2 would be released to the atmosphre – lead to global warming
RESULTS IN A RAPID CHANGE FROM COLD TO HOT

DIVERSIFICATION IN THE LATE CAMBRIAN OF METAZOANS MAY HAVE BEEN DUE TO CLIMATE.

Creating of organisms can be called a HOMEOBOX – ADDING BITS ON TO MAKE AN OVERALL ORGANISM.

EARLY SOFT BODIED CREATURES – EDIACARA
HARD PARTS NOT TILL AFTER SNOWBALL EARTH.
à Hard parts were a defensive measure
   Aragonite
   Chitin

Quote Burgess Shale

Picaea – Was first with possible spinal cord

Chordata – Organism with vertebrate spine
DURING THIS TIME – HIGH OCEAN DIVERSITY


Devonian sees evolution of vertebrates and plants invading land.





Land plants handle Carbon much more efficiently than sea plants.
·   Development of land biomes
·   Plant is a space suit for bacteria
·   Animals also – we have internal ocean,     symbionts, e.g. mitochondria.

REPRODUCTION

Plants initially used spores… later went on to seeda.
Animals reproduced in water so had a reliance on it e.g. amphibia.

Carboniferous à First tropical rainforests with complex animal life
THIS WAS A COMPLETE TURNOVER AS PLANTS ORIGINALLY COMMON IN SEA WITH BACTERIA ON LAND,  CARBONIFEROUS SEES A GREAT DEAL OF PLANTS ON LAND.

Permian – first mammal like creatures
Key factor – amniote egg.


END CRETACEOUS

Beginning of the break up of Gondwana!

·   After the creataceous disaster, any animals above 25 kg died off.

The early tertiary saw a heavy diversification into herbivores and carnivores

CARNIVORE PREDATOR – CLAENODON.


Mid Tertiary
As continents spread climates changed due to CO2. Miocene sees a very cold period.

·   Antarctica – Marsupials wiped out
·   N. America – Frozen

World goes into glacial/interglacial period
Glacial period sees large creatures die out, then re-appear when temperatures rise.


MAMMOTH died out 3000 years ago.





Middle tertiary – man evolution
SPLIT INTO OLD/NEW WORLD PRIMATES.

New World – Long Tail
Old World – Baboon like.

GRASS APPEARED 6 MILLION YEARS AGO, PRECONCENTRATED CO2.

FOOTPRINT DISCOVERED OF HUMAN LIKE CREATURE, STANDING UP TO SEE OVER GRASS.

DATES

·   100,000 ya, large mammals started to disappear
·   10,000 ya at end of last ice age, 75% animals in Eurasia disappear.
·   10,000/11,000 ya humans go to the Americas.

Extinctions à Humans kill creatures and break down food chains!

AFRICA had only 40% extinctions – prob as Africa had diseases that appeared with and competed with man and thus controlled birth/population.



ICE CORES used to monitor recent climate change

14,000 ya – sudden climate change
3,000 years of hot
A few thousand years of colder
Then we get modern day climate for past 10,000years





 
Oldest Dryas – 14Ka BP
Termination 1A
Boiling
Middle Dryas
Allerod
Younger Dryas – 11-10 Ka BP
Termination 1B
Holocene

The ice on the late glacial earth.

·   Ice domes over N.America + Scandinavia

Sea Level monitoring – Barbados
Ice Cores
Antarctic – vostok à v dry so low detail of climate.
Greenland : 3 separate projects studying climate.




LATE GLACIAL EARTH!!!

·   Low CO2 (~190ppm), present day levels (~360ppm)
·   Low CH4 levels.

Low carbon in biomass, dusty!
Sea level ~125m lower at LGM (~15,000 Ka BP)
Northern boreal forests severely limited.

HOLOCENE EARTH

Higher CO2 (~250ppm)
Higher CH4 (~750ppm)

Regrowth of biomass – tropical forests, boreal forest as ice melts.

Sea level rises in two steps after termination 1A and 1B.


CATASTROPHES

·   Permian + Cretacious extinctions, End glacial.
·   Modern shifts – El Nino, volcanoes
·   Arrival of over competitive species.


The Earth’s atmosphere

At about 10-20 km – cold trap temp ~ -50/-60 --- water condenses out at this point and falls back down to earth à this gives us our oceans.


The solar output is known as : spectrum
Spectrum depends on temperature of source to 4th power.
·   e.g. kitchen cooker ring at ~500 degrees is cherry red.
·   Sun is yellow white as is considerably hotter

Heat on surface – Sensible heat à what you sense (hot air)
Latent heat – Water vapour off plants etc, evaporation.
Radiation  – reflection of sunlight (poles are white, colour of ground – reflective  leaves, infrared from source at 15 –25 degrees (stefani’s law)


LATITUDINAL TRANSFERS

Oceans – salt/heat – ATLANTIC CONVEYOR e.g. Gulf Stream.
If Atlantic conveyor disrupted, ice age in northern Europe follows.



CARBON DIOXIDE AND THE CARBON CYCLE

The Reservoirs
Inorganic/organic balance.
Supply from mantle degassing


Venus + the earth
Inorganic control – Cu2+ weathering, Sr etc…

2CO2 + H20 + CaSiO3 à Ca2+  + SiO2 + 2HCO3-

Like this equation, venus once had water but lost it in this way.


THE CARBON CYCLE TODAY

There is a budget!
INTERGOVERNMENTAL PANEL ON CLIMATE CHANGE REPORTS

1980s model
   Geigertonne (x109) (p/y)
Emissions from fossil fuels   5.4 +/- 0.5
Emissions from deforestation   1.6 +/- 1
Total Emissions                          circa   7
Accumulation in the atmosphere   3.4 +/- 0.2
Uptake by the oceans   2.0 +/- 0.8
Total known uptake                   circa   5.4
Missing Sink   1.6 +/- 1.4


THE METHANE CYCLE

Production –

·   Wetlands, tropical + northern
·   Biomass burning – incomplete combustion
·   Termites
·   Ruminants – cows à Bovine Eructation
·   Rice Paddies
·   Natural gas, coal, oil.
·   Landfills, sewage, waste disposal

Meathane is broken down by OH – Policeman of the air

Major stores – Gasfields –
Thermogenic
Biogenic
Clathrate

Sources – Siberia, Indonesia, Gulf, Caspian, Canada, US, Algeria.

KYOTO AGREEMENTS

The major greenhouse gases:
   H20
   CO2
   CH4

Lifetimes: CO2, N20 – Centuries
CH4 – 10 years


Global Warming Potentials (GWP)
Methane has 62 times the GWP of CO2 after 20 years or 23 times after 100 years.

Minor greenhouse gases – N2O, CFCs, O3


IT ALL COMES DOWN TO TRADE OFFS I.E OIL/GAS VS NUCLEAR…

Possible disasters from each…

nuclear causes disasters on a local scale
Coal/gas is more global away from source – quote Norway lakes…



GASES MANAGED BY BIOLOGY

Carbon Dioxide and oxygen are not the only gases that are managed by biology.

JUST AS CARBON DIOXIDE IS MANAGED BY THE ENZYME RUBISCO, SO NITROGEN CAPTURE IS MANAGED BY NITROGENASE.

Nitrogen Oxide is a powerful greenhouse gas
On a global scale –
Biological fixation of nitrogen.
Nitrogen fertilizer.
Released by fires.

·   In the past – Worlds supply of nitrate cam efrom Chile. British got a foothold (and as nitrates key factor of explosives) British were able to control world arms market!

Big problems nowadays with huge amounts of Nitrates in seas! Is a global problem.


SULPHUR ALSO A GLOBAL PROBLEM

DiMethyl Sulphide – released into atmosphere and forms SO3 – this is rained out and is taken in by algae.

Volcanoes release large volumes of sulphur gas.

·   Sulphur levels in USA are controlled (done during Ronald Reagan).
·   Coal industries in eastern block collapsed = lower pollution.

Now much cleaner places BUT reducing sulphur reduces efficiency meaning more CO2 is released.


MASSIVE VOLCANIC ERUPTIONS

Pinatubo à 1991
El Chichon à 1981
Tambora à 1815  (the year without a summer, seasons out of sink)


Pinatubo emitted 20 million tonnes of sulphur into the atmosphere.
Tambora was a disaster – led to a frost every month.

URBAN AIR PROBLEMS

Meteorology : Pollution events - Inversions

USE EGHAM AS EXAMPLE
During day, heat from sun warms air above town stopping pollution from rising, this can lead to smoggy conditions. At night heat is radiated back allowing the smog to clear.

SOURCES OF SMOG à

NOx
SOx
CO

 


These come from:
Transport
Industries
Domestic

Worst affecting particles come from diesel.


URBAN WATER PROBLEMS

During Victorian London à
Common problems
·   Cholera
·   Malaria

Engineering of “The Embankment” in London was made to separate dirty river water from fresh water.


OVERALL
à
Local urban pollution is declining in the major western cities.

·   Cities in poorer nations (especially in mega cities), urban environmental quality is often very poor.


IS CLIMATE STABLE?

Sudden changes have occurred  from past catastrophes…
Overall last 10,000 years have seen a stable climate.

Todays climate events:
·   El Nino
·   N. Atlantic Oscillation
·   Large volcanic eruptions e.g. pinatubo, Agong.

IS GLOBAL WARMING HERE?

Quote Oceans Law – “The simplest answer is most likely to be right”

·   Decline of ice sheets (however Greenland, antartica ice sheets growing due to world weather patterns).

·   Temperature record; meteorlogical geotherms.

·   Natural variations; sun à Milankovich Cycles



CONSEQUENCES OF WARMING

·   More vigorous weather e.g. storms
·   Other weather changes – UK will get more gloomy
·   Sea Level – global; past glacial relaxation.

HUMAN IMPACT

Impact on the UK by warming

Farming ; temperature ; precipitation
·   Sea Level
·   Financial
·   Insurance industry
·   Migration


Kyoto
·   Progress of negotiations
·   Present state of agreement
·   Will it put geologists out of work? NO!






 

 

Offline OmnipotentOne

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Re: A brief History through time in SERIOUS note form
« Reply #2 on: 20/08/2004 04:21:21 »
Hmmm I think I might save this page because your note will really come in handy this upcomming year!  Someone pays attention in class.

To see a world in a grain of sand.
 

Offline Exodus

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Re: A brief History through time in SERIOUS note form
« Reply #3 on: 21/08/2004 00:36:56 »
I tried mate, i tried. Hope they help!
 

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Re: A brief History through time in SERIOUS note form
« Reply #3 on: 21/08/2004 00:36:56 »

 

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