GEOLOGI LAUT II SUSUNAN LAPISAN BUMI Program Sudi

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.

Ø 4 lapis utama lingkungan fisik bumi: 1. Hydrosphere – Air l Evaporates falls back as precipitation runs back to rivers/oceans/etc l Oceans = 97% of water on Earth l 3% = groundwater, streams, lakes, and glaciers l Important b/c the sustain life and help create land forms

Atmosphere 2. l l Gaseous envelop 100 km above earth • l l 90% just within 16 km of earth Provides air we breath Protects Lithosphere 3. l Lithosphere – uppermost mantle

4. Biosphere – all of life on earth l 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 A D B C B. Selubung Bumi : depth + 1200 km Lapisan silikat Berat jenis + 3, 4 - 4 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. Si. Al (Silisium Alumunium) Ø Merupakan bagian atas Ø Tebal + 15 km, Ø BJ + 2, 7 Ø Tipe magma granitis (asam) 2. Si. Ma (Silisium Magnesium) Ø Bagian tengah: Ø Tebal + 25 km Ø BJ + 3, 5 Ø Tipe magma basaltis (basa) Bagian bawah: Ø Tebal + 20 km, BJ + 3, 5 Ø Tipe magma peridotit dan eglotit (ultrabasa) Ø

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), (Si. O 2 dan Al 2 O 3 ) 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), (Si. O 2 dan Mg. O) Tebal rata-rata = 65 km Berat jenis = 3, 2 Berisi batuan keras, feromagnesiumdan basalt yang bersifat elastis.

Massa lapisan 2 internal bumi % dari total massa bumi

Apa itu Crust? Thin layer of rock at the earth’s surface Ø Material on ocean floor is different from that on the continents. Ø

The Crust Ø Lapisan yang paling luar Ø Have ketebalan 5 – 100 km Ø Made of Oxygen, Silicon,

CRUST Ø Cool Ø What we live on Ø Composed of rocks, various materials make up the crust Ø 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 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 Ø Still hot! – but not as hot as the core! Ø Largest layer Ø Composed of various materials Ø Solid and liquid

The Mantle Ø Layer of Earth between the crust and the core Ø Contains most of the Earth’s mass Ø Has more magnesium and less aluminum and silicon than the crust Ø Is denser than the crust

Mantle Ø Ø Ø 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 Ø “Lithos” – in Greek means stone 2. Asthenosphere – part of the mantle below the lithosphere; somewhat soft, bends like plastic Ø “asthenes” – in Greek means weak

Apa inti bumi (Core)? Solid metallic Inner Core Ø Liquid metallic Outer Core Ø Both made of iron and nickel Ø Together, they generate the Earth’s magnetic field. Ø

The Core center of the Earth Ø Believed to be mostly Iron, smaller amounts of Nickel, almost no Oxygen, Silicon, Aluminum, or Magnesium Ø

Core (Inti) Di bawah mantel Ø Both parts made of Iron and Nickel Ø Innermost layers Ø 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 Ø

INTI BAGIAN LUAR Ø HOT! (but not as hot as the inner core) Ø Liquid Ø 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 Ø Ø Ø Ø 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……