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GEOLOGI LAUT
II. SUSUNAN LAPISAN
BUMI
Program Sudi Ilmu Kelautan FMIPA UNSRI
BUMI
Pendapat Ahli:
Plato: Bumi terdiri dari massa cair pijar yang
dikelilingi oleh lapisan batuan atau kerak
bumi/kulit bumi.
2. Kant-La Place: bumi selama bermilyar tahun
dilepas dari matahari dalam bentuk bola gas
yang pijar hingga lambat laun mendingin dan
membentuk kerak batuan (kerak bumi)
3. Penyelidikan
dg Seismologi: ditemukan
lapisan yang tidak tersambung bidang
diskontinyu, pada depth + 60 km,
1.
4 lapis utama lingkungan fisik bumi:

1.
Hydrosphere – Air
 Evaporates  falls back as precipitation  runs
back to rivers/oceans/etc
 Oceans = 97% of water on Earth
 3% = groundwater, streams, lakes, and glaciers

Important b/c the sustain life and help create land forms
Atmosphere
2.


Gaseous envelop
100 km above earth
•


90% just within 16 km of earth
Provides air we breath
Protects
Lithosphere
3.

Lithosphere – uppermost mantle
4. Biosphere

– all of life on earth
Ocean floor and upward for several km into
the atmosphere
3 LAPISAN UTAMA
INTERNAL BUMI
1. CRUST
2. MANTEL
3. CORE (INTI)
1. Lapisan dimana kita berjalan : crust.
2. Lapisan selanjutnya is hot, molten
rock disebut mantle.
3. Pusat bumi terdiri: hot rock and is
called the inner core (solid iron and
nickel), dan outer core (liquid iron and
nickel).
Berjalan ke Pusat Bumi??
State 2 things that increase as you go towards Earth’s center:
1. ??????
2. ??????
Pembagian bumi menurut Suess dan
Wiechert :
A. Kerak Bumi : depth 30 – 70 km
Sifat Batuan asam dan basa
Berat jenis + 2,7
A
B
A
C
B. Selubung Bumi : depth + 1200 km
Lapisan silikat
Berat jenis + 3,4 - 4
D
C. Lapisan Antara (Chalcosfer): depth + 1700 km
Lapisan oksida dan sulfida
Berat jenis + 6,4
D. Barisfer (Inti Besi Nikel): r  + 3500 km
Sifat Batuan oksida dan sulfida
Berat jenis + 9,6
L
I
T
O
S
F
E
R
Kerak bumi Menurut HOLMES
1. SiAl (Silisium Alumunium)




Merupakan bagian atas
Tebal + 15 km,
BJ + 2,7
Tipe magma granitis
(asam)
2. SiMa (Silisium Magnesium)







Bagian tengah:
Tebal + 25 km
BJ + 3,5
Tipe magma basaltis
(basa)
Bagian bawah:
Tebal + 20 km, BJ + 3,5
Tipe magma peridotit dan
eglotit (ultrabasa)
1. Inti bumi / burisfera / nife (nicolum dan ferum)
Jari-jarinya = 3.470 km
Berat jenisnya + 8,2 s/d 10
Gradien geometrik (setiap turun 100 m suhu turun 30 C
Isi : Benda padat, keras dan sangat panas (30000 )
Tediri dari inti dalam dan inti luar
2. Astenosfer /pengantara / pyrosfer/ mantel
Tebalnya
= 1700 km
Berat jenisnya = 5,4 s/d 8
Isinya
= magna atau batuan cair pijar dan panas
Terdiri dari mantel bawah dan mantel luar
3. Litosfer / Kulit bumi / kerak bumi
Tebal
= 1.200 km.
Isinya
= batuan padat, keras dan telah mendingin .
Terdiri dari :
a. Sial (silicium Aluminium), (SiO2 dan Al2 O3 )
Tebal rata-rata = 35 km
Berat jenis
= 2,8
Berisi batuan metamorf, granit, andesit, sedimen, batuan lapuk.
Terbagi menjadi dua : - Kerak benua
- Kerak samudera
b. Sima (silicium magnesium), (SiO2 dan MgO)
Tebal rata-rata
= 65 km
Berat jenis
= 3,2
Berisi batuan keras, feromagnesiumdan basalt yang bersifat elastis.
Massa lapisan2 internal bumi  % dari total massa bumi
Apa itu Crust?
Thin layer of rock at the earth’s surface
 Material on ocean floor is different from that on the
continents.

The Crust
 Lapisan
yang paling luar
 Have ketebalan 5 – 100 km
 Made of Oxygen, Silicon,
CRUST
 Cool
 What
we live on
 Composed of
rocks, various
materials make
up the crust
 Solid or Liquid?
Crust
Lapisan batuan yang membentuk kulit bumi yang paling luar (lapisan bumi paling
tipis
Includes:
the soil and water
rocks and mountains
dry land and ocean floor
The crust is thinnest beneath the ocean
The crust is thickest beneath high mountains
basalt
2 Jenis Crust:
1. Oceanic Crust – the crust beneath the ocean, consists mostly of dense
rock such as basalt
Basalt – a dark, dense rock with a fine texture
2. Continental Crust – the crust that forms the continents, consists
mostly of less dense rock such as granite
Granite – a rock that has larger crystals than basalt, is less dense and is
usually a light color
granite
MANTLE
hot! – but
not as hot as
the core!
 Largest layer
 Composed of
various
materials
 Solid and liquid
 Still
The Mantle

Layer of Earth
between the crust
and the core
 Contains most of
the Earth’s mass
 Has more
magnesium and
less aluminum and
silicon than the
crust
 Is denser than the
crust
Mantle





Terletak di bawah crust
Lapisan yang paling tebal
Terdiri material solid
Lapisan batuan panas
Contains 2 specially named areas:
1. Lithosphere –all of the crust and the
uppermost part of the mantle together;
hard, rigid layer
 “Lithos” – in Greek means stone
2. Asthenosphere – part of the mantle
below the lithosphere; somewhat soft,
bends like plastic
 “asthenes” – in Greek means weak
Apa inti bumi (Core)?

Solid metallic Inner
Core
 Liquid metallic Outer
Core
 Both made of iron
and nickel
 Together, they
generate the Earth’s
magnetic field.
The Core

center of the Earth
 Believed to be
mostly Iron, smaller
amounts of Nickel,
almost no Oxygen,
Silicon, Aluminum,
or Magnesium
Core (Inti)



Di bawah mantel
Both parts made of Iron and
Nickel
Innermost layers
Terdiri dari 2:
1. Outer Core – layer of molten
material (thick liquid);
surrounds the inner core
2. Inner Core – dense ball of
solid metal; extreme pressure
squeezes Iron and Nickel
atoms together so much they
cannot spread into a liquid

INTI BAGIAN LUAR
 HOT!
(but not as hot
as the inner
core)
 Liquid
 Composed of
Iron and Nickel
The Outer Core
1. The outer part of the core is
liquid and HOT!
2. It gets hotter the deeper you
go (around 9,000 degrees F in
the center—your oven only goes
to about 600 degrees F).
3. It’s so hot that rock melts.
Melted rock is called MAGMA.
4. 1,400 MILES THICK!
INTI BAGIAN DALAM
-
-
HOT!!!! –
Thought to be
as hot as the
surface of the
Sun!
Solid
Composed of
Iron and Nickel
Medan magnet bumi






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Arus dalam inti bagian luar yang lunak mengitari inti bagian
dalam yang padat
Inner core spins slightly faster than the rest of the planet
Inti bagian dalam memutar sedikit lebih cepat dari sisa
planet
Pergerakan yang memintal membentuk medan magnet bumi
Medan magnet mempengaruhi seluruh bumi
Jarum kompas searah medan magnet bumi
North seeking end of needle points to Earth’s magnetic
north pole
TERIMA KASIH
THANK FOR YOUR ATTENTION
WASSALAM WR.WB……