GEOLOGI FISIK P2 - Sejarah, Struktur & Komposisi

1

Geologi Fisik(Sejarah, Struktur & Komposisi Bumi)

Oleh :Irvani

Universitas Bangka Belitung Jurusan Teknik Pertambangan

Referensi :• Thomson, G. R. and Turk, J. 1991. Modern Physical Geology.

Saunder College Publishing, USA.• Lutgens, F. K., Tarbuck, E. J. and Tasa, D. 2012. Essentials of

Geology, 11th Edition, Pearson Prentice Hall, New Jersey.• Freeman, T. 2004. Environmental Geology Laboratory. John Wiley &

Sons, Inc., USA.• Monroe, J. S. and Wicander, R. 2009. The Changing Earth:

Exploring Geology and Evolution. 5th Edition. Pre-Press PMG, USA.• Carlson, D. H., Plummer, C. C. and Hammersley, L. 2011. Physical

Geology : Earth Revealed. 9th Edition. McGraw-Hill, New York.• Bates, R.L. and Jackson, J.A., 1987. Glossary Geology. 3th Edition.

American Geological Institute Elexandria, Virginia.• Williams, L. 2004. Earth Science Demystified. McGraw-Hill, New

York.• DLL


2

Materi :- Pendahuluan (P.1)- Sejarah, Struktur & Komposisi Bumi (P.2)- Proses-Proses Geologi & Tektonik Lempeng (P.3-4)- Pengenalan Unsur, Mineral & Batuan (P.5-8) :

- Unsur & Mineral- Batuan Beku- Batuan Sedimen- Batuan Metamorf

- Prinsip Stratigrafi, Paleontologi & Umur Geologi (P.9)- Pengenalan Struktur Geologi (P.10-11)- Pengenalan Hidrogeologi & Geomorfologi (P.12)- Pengenalan Kebencanaan Geologi (P.13)- Pengenalan Peta, Kompas, Navigasi dan Peralatan

Geologi (P.14)- Kuliah Lapangan (Situasional)


FENOMENA KEBUMIAN SEBAGAI OBJEK ILMU PENGETAHUAN

Permukaan Tanah/Laut

Atmosfer (Tentang Udara / Non Geologi)

Litosfer (Tentang Bumi / Geologi)

Meteorologi – Klimatologi Cuaca / Iklim (Angin; Curah Hujan)

Topan, Badai, Tornado Temperatur Bumi, Kekeringan

Geofisika – Geokimia - PaleontologiPetrologi – Mineralogi - Stratigrafi

Geografi Geodesi

Bachtiar (2008)-Slide


3

Specialties of Geology and Their Broad Relationship to the Other Sciences

Monroe & Wicander (2009)


Pencatatan Sejarah Bumi

The nature of our Earth—its materials and its processes—has been a focus of study for centuries. Writings about fossils, gems, earthquakes, and volcanoes date back to the Greeks, more than 2300 years ago.


Lutgens, Tarbuck and Tasa (2012)

4

Catastrophism (mid. 1600an)Catastrophists believed that Earth’s landscapes had been shaped primarily by great catastrophes. Features such as mountains and canyons were explained as having been produced by sudden and often worldwide disasters produced by unknown causes that no longer operate.

..... Sejarah Pembentukan BumiUniversitas Bangka Belitung Jurusan Teknik Pertambangan


“Competition of ideas: catastrophismor uniformitarianism?”

Examples of catastrophic events: asteroid impacts, mass extinctions, eruptions of supervolcanoes

...... Catastrophism

Georges Cuvier (1769-1832)father of catastrophism and vertebrate, paleontology, established extinction as a fact. Professor and later secretary of a National Institute, held important government positions during both Napoleon and Bourbons.

Durant (?) - Slide


5

Uniformitarianism: physical, chemical and biological laws that operate today also operated in geologic past. All changes wereslow and gradual.

‘The Present is a key to the past’

Uniformitarianism (1700an)

Durant (?) - Slide


James Hutton (1726-1797)Most famous advocate ofuniformitarianismThe Principles of Geology(3 volumes, 1830-33)

Charles Lyell (1797-1875)Father of uniformitarianism,trained as lawyer andDoctor. Recognized theimmensity of geologic time.Theory of the Earth

........ Uniformitarianism

Durant (?) - Slide


6

Big Bang dan Teori Nebula (Geologi modern)Pembentukan Bumi & Semesta

Scenario begins about 13.7 billion years ago with the Big Bang. The debris from this explosion (almost hydrogen and helium), began to cool and condense into the first stars and galaxies.



Subsystems of Earth :The atmosphere,hydrosphere,biosphere, lithosphere, mantle, and core.


Struktur BumiUniversitas Bangka Belitung Jurusan Teknik Pertambangan

7

Interactions Among Earth’s Principal Subsystems


.....Struktur Bumi


Struktur Tubuh BumiEarth’s interior is divided into three different layers based on compositional differences—the crust, mantle, and core.



8

Schmince (2004)


....Struktur Tubuh Bumi

.....Struktur Tubuh Bumi

Earth’s interior based on physical properties—the lithosphere, asthenosphere, lower mantle, outer core, and inner core.



9

The rigid lithosphere includes the crust and uppermost mantle; it forms the plates. The ductile asthenosphere acts as a lubricating layer beneath the lithosphere. Oceanic lithosphere averages 70 kilometers thick; continental lithosphere varies from 125 to 250 kilometers thick.

Carlson et al. (2011)



Estimated (A) temperature and (B) pressure with depth into Earth


..... Struktur Tubuh Bumi


10

Temperature2800

2600

2400

2200

2000

1800

1600

Tem

pera

ture

(K)

3000200010000

Depth (km)CIDER/ITP Course (2004) - Slide



Pressure350

300

250

200

150

100

50

0

Pre

ssur

e (G

Pa)

6000400020000

Depth (km)

InnerCore

Outer Core

LowerMantle

Tran

sitio

n Zo

ne

Upp

er M

antle

PREM

CIDER/ITP Course (2004) - Slide



11

The P-wave shadow zone, caused by refraction of P waves within the Earth’s core.

The S-wave shadow zone. Because no S waves pass through the core, the core isapparently a liquid (or acts like a liquid).


Geofisika Struktur Bumi


The velocity of seismic P and S waves generally increases with depth except in the low-velocity zone. The plastic asthenosphere slows down seismic waves. Velocity increases at 400 and 670 kilometers may be caused by mineral collapse.


....... Geofisika Struktur Bumi


12

Characteristics of Oceanic Crust and Continental Crust


.....Geofisika Struktur Bumi


slopeshelf Continental crust (SIAL)

ocean ocean

Oceanic crust (SIMA)

Struktur Kulit BumiEarth’s Crust

Durant (?) - Slide


13

Orogenic belt (mountains): deformed,folded and faulted,rocks

Platform: mostly flat (undeformed)Phanerozoic rocks (0-540 ma)

Orogenic belt

shield+ platform= craton

Shield: Oldest(Precambrian)rocks exposed

........ Struktur Kulit BumiIdealized cross section of a continent

Durant (?) - Slide


Profiles of seafloor topography

The vertical scales differ from the horizontal scales, causing vertical exaggeration, which makes slopes appear steeper than they really are.


.......Struktur Kulit Bumi


14

(A) Vertical exaggeration 25 times. The continental slope has an actual slope of only 4 or 5 degrees, but the great vertical exaggerationof this drawing about 60°.

Continental shelf and continental slope

The continental shelf lies upon continental crust, and the continental rise lies upon oceaniccrust.




Passive Continental Margin

A contour current flowing along the continental margin shapes the continental rise by depositing fine sediment. Coarse layers within the continental rise were deposited by turbidity currents flowing down the continental slope.Carlson et al. (2011)



15

Active continental margin




mid-oceanic ridge

(A) Hydrothermal circulation of seawater at ridge crest creates hot springs andmetallic deposits in rift valley.

(B) “Black smoker” or submarine hot spring on the crest of the mid-oceanic ridge in the Pacific Ocean




16

fast-spreading: magma enters a large magma chamber in crust;broad bulge exists at ridgeslow-spreading: magma chamber freezes between pulses ofspreading; axial rift valley occurs

from: http://www.geo.lsa.umich.edu/~crlb/COURSES/270from: http://www.geo.lsa.umich.edu/~crlb/COURSES/270

....... mid-oceanic ridge


(A) Seamounts are conical mountains on the sea floor,

(C) The present depth of a guyot is due to subsidence.

(B) The flat summit of a guyot was probably eroded by waves when the top of a seamount was above sea level.


.......Struktur Kulit BumiSeamounts


17

.......Struktur Kulit BumiShape of Ocean floor

Durant (?) - Slide


Reichard (2011)

Komposisi Bumi


18

Reichard (2011)

........ Komposisi BumiKomposisi Kerak Bumi


Lifetime Mineral UsageAccording to the MineralInformation Institute in Golden, Colorado, the average Americanborn in 2006 has a life expectancy of 77.8 years and will need 1,672,393 kg of minerals, metals, and fuels to sustain his or her standard of living over a lifetime. That is an average of 21,496 kg of mineral and energy resources per year for every man, woman, and child in the United States.



19

Terima Kasih


Documents

GEOLOGI FISIK P2 - Sejarah, Struktur & Komposisi