Origin of Our Planet Earth

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ICNSICNS 161161 : Chapter: Chapter 11Origin of Our Planet EarthOrigin of Our Planet Earth

Prinya PutthapibanPrinya Putthapiban

Geoscience Programme,Geoscience Programme,Mahidol University, Kanchanaburi CampusMahidol University, Kanchanaburi Campus

EE--mail : kappt @mail : kappt @ mahidol.ac.thmahidol.ac.th


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Our Planet Earth from Spaceship


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Origin of the EarthOrigin of the EarthThe Famous

Big Bang Theoryfor the

origin of the universe was proposed:

The Famous Big Bang Theory

for the

origin of the universe was proposed:

~ 15 billion years~ 15 billion years

150,000 mps150,000 mps


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Solar system accretionSolar system accretion

Primitive matter in thesolar system is mainly

H and He, organizedin galaxies, in verylarge systems of stars


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Solar system accretionSolar system accretion

Gravitational forces cause renewed contraction of thecloud of matter and a second cycle of star formationis initiated


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Nebular Hypothesis of SolarNebular Hypothesis of Solar

System FormationSystem Formation


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Sizes of the planets

Fig. 9.3

(Mercury)(Mercury) (Venus)(Venus) (Earth)(Earth) (Mars)(Mars)(Jupiter)(Jupiter)(Saturn)(Saturn) Uranus Neptune andUranus Neptune and PlutoPluto


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Fig.Fig. 66..44

. From (A) a homogeneous, low-density protoplanet to (B) a dense,

differentiated planet

Early Stage of the Evolution


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Origin of the EarthOrigin of the Earth

Early history of the earth:Early history of the earth:

molten Femolten Fe

lighter elementslighter elements


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Origin of the EarthOrigin of the Earth

Early history of the earth:Early history of the earth:

lighter elementslighter elements

Fe, NiFe, Ni


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Origin of the EarthOrigin of the EarthThe Earths Interior:The Earths Interior:


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Early EarthEarly Earth

Two lines of evidenceTwo lines of evidence

From accretion of the solar system forwardFrom accretion of the solar system forward

Using the terrestrial rock record and workUsing the terrestrial rock record and work

back in timeback in time


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AAccretionccretion: the isotope record: the isotope record

Chondrite meteoritesAre likely to representThe least modified sampleOf the solar accretion nebula


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AAccretionccretion: the rock record: the rock record

Achondrites


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Iron meteorites:Canyon Diablo


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ShergottiteEETA79001, Elephant Moraine, Antarctica, Dec, 1979


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Age of the EarthAge of the Earth

Istope / Radiometric Dating of all meteroliticIstope / Radiometric Dating of all meterolitic

materials falling on our earth surface is aroundmaterials falling on our earth surface is around 44..55

toto 44..66 Billion years ago (B.Y.)Billion years ago (B.Y.)

The Oldest rock, a gneiss (coarse grainedThe Oldest rock, a gneiss (coarse grained

metamorphic rocks)metamorphic rocks) found on earth is fromfound on earth is from

Northwestern Territories, Canada which dateNorthwestern Territories, Canada which date 44..0303

B.Y.B.Y. from zircon (ZrSiOfrom zircon (ZrSiO44))

However, the Oldest detrital zirconHowever, the Oldest detrital zircon record found torecord found to

be much older atbe much older at 44..44 B.Y.B.Y.


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The terrestrial rock recordThe terrestrial rock record

Acasca gneissSlave Craton4.031 Ga

Isua NorthAtllantic Craton3.9 Ga

Manfred ComplexYilgarn Craton3.75 Ga


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The terrestrial rock recordThe terrestrial rock record

Mt NarryerJack HillsYilgarn Craton4.2 4.4 Ga


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The Terrestrial Rock RecordThe Terrestrial Rock Record

Evidence from detrital zircons forthe existence of continental crustand oceans on the Earth 4.4 Gyr ago

Simon A. Wilde, John W. Valley,

William H. Peck, Colin M. Graham

NATURE, 409 175-178. 2001


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Fig. 6.12bFig. 6.12b

The Acasta Gneiss. Great Slave Province, NW Territories,

Canada. One of the oldest (4.03 B.Y.) dated rocks on Earth.

This must have been one of the first crustal rocks to form

either at Late Hadean or shortly thereafter.


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Fig.Fig. 66..1212aa

Zircon grain from the Acasta Gneiss, Slave Province, NW Territories,Canada. The crystal has been etched with acid to highlight the growth

zones. These zircons have been dated to 4.03 B.Y.


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Composition of theComposition of the

EarthEarth


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Crustal Comp.

By Weight


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Next Two LecturesNext Two Lectures

Minerals and Rocks which make upMinerals and Rocks which make up

our Planet Earthour Planet Earth

Hope to see you all then !Hope to see you all then !

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Origin of Our Planet Earth