Sejarah Bumi/History of Earth FOR CLASS X SENIOR HIGH SCHOOL GEOGRAPHY
Sejarah Bumi
(Sumber: Sudibyakto, H. A. 2009. Geografi.Jakarta: Departemen Pendidikan Nasional.)
A) Proses Terbentuknya Bumi.
Para ilmuwan berpendapat proses pembentukan bumi sudah dimulai sejak bermiliar tahun yang lalu. Planet Bumi bermula dari awan raksasa yang selalu berputari di antariksa. Awan raksasa tersebut akan membentuk bola yang menarik butir debu dan gas. Bola debu dan gas inilah awal mula terbentuknya bumi, planet, serta bulan lain.
Saat gravitasi bumi semakin besar, gas dan debu tersebut akan termampat dan semakin lama semakin padat. Hal ini menyebabkan bumi semakin panas dan menjadi bola berpijar. Bagian luar bumi lambat laun mulai mendingin dan mengeras. Tetapi bumi belum dingin sama sekali. Bagian tengah bumi masih sangat panas.
Proses pembentukan bumi di atas hampir sama dengan pendapat Kant-Laplace (Teori Nebula) yang mengemukakan bahwa Bumi ini mulai terbentuk selama bermiliar tahun yang lalu ketika dilepaskan dari matahari dalam bentuk gas pijar yang lambat laun mendingin dan membentuk kerak batuan.
B) Karakteristik Pelapisan Bumi
1) Lapisan Udara Bumi. Bumi dikelilingi lapisan udara yang disebut atmosfer. Atmosfer Bumi terbentuk dari gas beracun seperti metana, hydrogen dan ammonia yang berasal dari gunung berapi di permukaan Bumi. Sementara itu selama miliaran tahun, uap air yang jatuh (berupa hujan), mengisi bagian Bumi dan samudera mulai terbentuk di dalam cekungan kerak bumi. Massa daratan yang tersisa membentuk daratan. Tebal atmosfer sekitar 1.000 km. udara dalam lapisan atmosfer terdiri dari gas nitrogen, oksigen, karbon dioksida dan gas lainnya yang sangat penting bagi kehidupan manusia. Lapisan atmosfer terdiri atas lapisan troposfer, stratosfer, mesofer, termosfer dan eksofer.
2) Lapisan dalam Bumi. Jari-jari Bumi diperkirakan 6.400 km sedangkan lubang penggalian terdalam baru sekitar 5 km. Sehingga rasanyatidak mungkin dilakukan penggalian hingga menembus sisi lain bumi.
Pengetahuan manusia tentang bagian dalam Bumi masih sangat sedikit. Orang yang pertama kali mengemukakan pendapatnya mengenai bagian dalam Bumi adalah Plato. Ahli filsafat ini berpendapat bahwa bumi terdiri dari sebuah massa pijar dan dikelilingi lapisan batuan atau kerak bumi. Massa pijar tersebut kadang mencapai permukaan bumi melalui pipa gunung api dalam bentuk lava. Dahulu, pendapat ini pada umumnya diterima dunia ilmu pengetahuan.
Padangan dari Plato, lambat laun bergeser. Penyelidikan seismologi dengan pertolongan alat seismograf telah memberikan pandangan lain mengenai perlapisan dalam Bumi. Penyelidikan ini membuktikan bahwa di dalam lapisan Bumi ditemukan lapisan yang dibatasi oleh bidang kontinyu (tidak bersambung). Bidang tersebut ditemukan pada kira-kira 60 km dan diberi nama bidang diskontinu dari Mohorovicic, bidang lain yang ditemukan pada jarak 1.200 km dan 2.900 km dari permukaan bumi. Pada jarak 2.900 km terdapat inti Bumi yang memiliki jari-jari 3.500 km. banyak ahli berpendapat bahwa inti bumi terdiri atas susunan besi dan nikel.
Sues dan Wiechert mengadakan pembagian perlapisan di dalam bumi, sebagai berikut:
a) Kerak Bumi. Bagian ini memiliki ketebalan 30-70 km, terdiri atas batuan basa dan masam yang memiliki berat jenis kira 2,7 gram/cm3. Bagian atas dan bagian tengah kerak bumi disebut lapisan sial karena sebagian besar terdiri atas zat silisium dan aluminium sedangkan bagian bawah disebut sima karena sebagian besar terdiri atas zat silisium dan magnesium. Kerak bumi dibagi menjadi dua, yaitu kerak benua dan kerak samudera. Kerak benua memiliki ketebalan lebih besar dibandingkan dengan kerak samudera. Di bagian kerak bumi dapat dilihat berbagai bentuk muka bumi seperti gunung api, pegunungan, lembah, sungai, danau, perairan laut, ataupun samudera yang terbentuk pada lapisan ini.
b) Selubung Bumi atau Sisik Silikat. Lapisan ini memiliki ketebalan kira 1.200 km dan memiliki berat jenis 3,4-4 gram/cm3. Kerak bumi dan selubung bumi ini merupakan lapisan litosfer.
c) lapisan antara atau Chalkosfera. Lapisan ini memiliki ketebalan sekitar 1.700 km dengan berat merupakan sisik oksida dan sulfide.
d) Inti Besi Nikel atau Barysfera. Inti bumi tersusun dari nikel dan besi sehingga disebut juga lapisn nife (niccolum= nikel dan ferrum = besi). Lapisan ini memiliki jari kira 3.500 km dan terdiri atas inti luar dan inti dalam. Inti luar memiliki suhu hampir 2.200oC dan ketebalan lapisan kira 2.000 km. sedangkan pada bagian pusat inti dalam memiliki suhu mencapai 4.500OC.
C) Teori Lempeng Tektonik. Deksripsi gerakan ini dijelaskan dalam teori lempeng tektonik. Teori lempeng tektonik muncul setelah Alfred Luther Wagener, seorang ahli meteoroligi dan geologi dari Jerman dalam buku The Origin of Continents an Oceans (1915), mengemukakan bahwa benua yang padat sebenarnya terapung dan bergerak di atas massa yang relative lembek (continental drift). Selain itu, berdasarkan hasil pengamatannya beberapa bagian benua terdapat kesamaan bentuk pantai antara benua satu dengan lainnya. Ia juga mendapati kesamaan geologi dan kekuasaan makhluk yang hidup di pantai seberang. Inti dari teori lempeng tektonik adalah kerak bumi sebetulnya terdiri atas lempengan besar yang seolah mengapung dan bergerak pada lapisan inti bumi yang lebih cair. Teori ini dibuktikan oleh pakar geologi dengan waktu hampir setengah abad dan diterima sejak tahun 1960-an. Hingga kini teori ini telah berhasil menjelaskan berbagai peristiwa geologis, seperti gempa bumi, tsunami, dan meletusnya gunung berapi, serta bagaimana bentuknya gunung, benua dn samudera. Teori membuktikan bahwa benua selalu bergeser.
Perpindahan arus panas di selubung menekan lempeng (baik yang berupa lempeng benua ataupun lempeng samudera). Panas naik dan terjadi perpindahan dari inti bumi ke selubung bumi. Arus panas mengalir dengan sangat lambat sambil menggerakkan lempek. Ketika selubung bumi mendingin, tempatnya digantikan oleh selubung baru yang panas, demikian seterusnya terjadilah pergantian antara selubung yang panas dengan selubung yang dingin. Selubung bumi perlahan berubah ketika terjadi perpindahan arus panas dan kemudian memberikan sebagian unsurnya menjadi magma yang membentuk tepi baru lempeng.
Ternyata posisi Indonesia di himpit oleh ketiga lempeng tektonik tersebut. Lempeng Indo-Australia mendesak kea rah utara sedangkan lempeng Pasifik mendesak ke Barat. Hal ini menyebabkan Indonesia termasuk dalam rangkaian Pegunungan Mediteran dan sirkum Pasifik. Rangkaian Pegunungan Mediterania dimulai dari Pegunungan Atlas, Balkan, Himalaya, Sumatera, Jawa, Nusa Tenggara, sampai Maluku. Sedangkan Sirkum Pasifik memanjang dari Pantai Pasifik Amerika, Kamsyatku, Jepang, Filipina, Irian (Papua), Australia sampai Selandia Baru.
D) Dinamika Muka Bumi. Pendapat bahwa benua bergerak seperti balok kayu yang mengapung di kolam sempat di cemohoh oleh orang selama bertahun-tahun. Namun, pada akhirnya ditemukan bukti yang menguatkan pendapat tersebut. Berdasarkan bukti itu, para ahli yakin bahwa dahulu benua yang ada sekarang ini pernah menyatu yang disebut Pangaea. Bumi dapat dijelaskan sebagai berikut:
i) Keadaan Bumi pada 200 juta tahun yang lalu. Benua tergabung dalam satu super benua bernama Pangaea. Amerika utara dan Eurasia merupakan bagian utara Pangaea dan disebut Laurasia. Benua lain bergerombol di segmen selatan yaitu Gondwana. Di sebelah timur trdapat Lau Tethys.
ii) Keadaan Bumi pada 180 juta tahun yang lalu. Benua Pangaea mulai pecah, dengan munculnya Samdudera Atlantik Utara di antara Laurasia dan Gondwana. Gondwana sendiri pecah menjadi tiga bagian dan Laut Tethys menjadi lebih sempit.
iii) Keadaan Bumi pada 135 juta tahun yang lalu. Sebuah retakan melebar antara Amerika Utara dan Eurasia dengan memperlebar Atlantik Utara. Amerka Selatan dan Afrika mulai terpisah sepanjang suatu retakan yang menjadi Samudera Atlantik Selatan. India bergerak ke utara menuju Asia.
iv) 65 juta tahun yang lalu. Amerika Selatan dan Afrika telah menempuh jalan masing-masing. Amerika Utara dan Eropa masih berhubungan dengna Greenland sedangkan India mendekati Asia.
v) Keadaan Bumi pada Saat ini. Greenland telah terpisah, sementara Australia telah berpindah ke utara dari Antartika. India telah menabrak Asia.
vi) Prediksi Keadaan Bumi pada 50 juta tahun yang akan datang. Samudera Atlantik terus melebar, Samudera Pasifik menciut. Australia mendekati Asia. Lembah retakan Afrika terbuka dan tergenang. Laut Merah melebar dan Teluk Persia lenyap.
IN ENGLISH (with google translate Indonesian-english):
History of Earth
(Source: Sudibyakto, HA 2009. Geografi.Jakarta: Ministry of Education.)
A) The process of formation of the Earth.
The scientists suggest that the process has been started since the formation of the earth billions of years ago. Planet Earth originated from a giant cloud in space that is always berputari. Giant clouds will form an interesting ball of dust and gas. The ball of dust and gas is the beginning of the formation of Earth, the planet, as well as other months.
When the greater gravity, gas and dust will be compressed and increasingly congested. This causes the Earth is getting hotter and a glowing ball. The outside world slowly began to cool and harden.But the earth has not been cold at all. The middle of the earth is extremely hot.
The process of formation of the earth similar to the opinions of the Kant-Laplace (Theory Nebula), which suggests that the Earth is beginning to take shape during the billions of years ago when released from the sun in the form of incandescent gas that cools slowly and form a crust rocks.
B) Characteristics Coating Earth
1) The air layer of the Earth. Earth surrounded by a layer of air called the atmosphere. Earth's atmosphere is made up of toxic gases such as methane, hydrogen and ammonia coming from the volcano on Earth's surface. Meanwhile, over billions of years, the water vapor that falls (in the form of rain), fill the earth and ocean basin began to form in the earth's crust. The remaining land masses forming the mainland. About 1,000 km thick atmosphere. air in the upper atmosphere consists of nitrogen, oxygen, carbon dioxide and other gases that are very important for human life. Layer of the atmosphere consists of the troposphere, stratosphere, mesofer, thermosphere and eksofer.
2) The inner layer of the Earth. The radius of the Earth estimated 6,400 km whereas the deepest digging new holes about 5 km. So rasanyatidak possible excavations to penetrate the other side of the earth.
Human knowledge about the interior of the Earth is still very small.The person who first put forward his opinion on the interior of the Earth is Plato. Philosophers, that the Earth consists of a mass of incandescent and surrounded by a layer of rock or earth's crust.Incandescent mass is sometimes reach the earth's surface through volcanic pipes in the form of lava. Previously, this opinion is generally accepted world of science.
Padangan of Plato, gradually shifted. Seismological investigation with the help of tools seismograph has provided another view of the perlapisan the Earth. This investigation proved that the Earth was found in the lining layer bounded by continuous fields (not continued). The field was discovered at about 60 km and is named from Mohorovicic discontinuous fields, other fields were found at a distance of 1200 km and 2900 km from the Earth's surface. At a distance of 2900 km are the core of the Earth has a radius of 3500 km. many experts argue that the core is composed of iron and nickel composition.
Sues and Wiechert held perlapisan distribution within the earth, as follows:
a) the Earth's crust. This section has a thickness of 30-70 km, consisting of alkaline and acidic rocks that has a specific gravity about 2.7 gram/cm3. The upper and middle crust layer called unlucky due largely made up of substances silisium and aluminum, while the bottom is called sima due largely made up of substances silisium and magnesium. The earth's crust is divided into two, namely the continental crust and the oceanic crust. Continental crust has a thickness greater than the oceanic crust. In the earth's crust can be seen various forms of earth like volcanoes, mountains, valleys, rivers, lakes, seas, or oceans are formed in this layer.
b) The sheath Earth Silicate or scales. This layer has a thickness of about 1,200 km and has a specific gravity of 3.4 to 4 gram/cm3.The crust of the earth and the sheath is a layer of the lithosphere.
c) intermediate layer or Chalkosfera. This layer has a thickness of about 1,700 km with a weight of oxide and sulfide scales.
d) Core Iron Nickel or Barysfera. The core is composed of nickel and iron that is also called lapisn NiFe (niccolum = Ferrum = nickel and iron). This layer has a finger about 3500 km and consists of the outer core and inner core. The outer core has almost 2.200oC temperature and layer thickness about 2,000 km. while in the central core has a temperature reaching 4.500OC.
C) Theory of Plate Tectonics. Deksripsi movement described in the theory of plate tectonics. The theory of plate tectonics came after Luther Alfred Wagener, an expert meteoroligi and geology of Germany in the book The Origin of Continents an Oceans (1915), suggests that the actual floating solid continents and moves over the relatively soft masses (continental drift). In addition, based on their observations of the continent there are some similarities between the beaches form one continent to another. He also found geological similarity and power of the living creatures on the far shore. The core of the theory of plate tectonics is the crust of the earth is actually composed of a large slab that seems to float and move in the core layer of the earth that is more fluid. This theory was proved by geologists at the time and received nearly half a century since the 1960's. Until now this theory has successfully explained various geological events, such as earthquakes, tsunami and volcanic eruption, and how to form mountains, continents oceans dn. Theory proves that the continent is always shifting.
Transfer of heat flow in the sheath pressing plate (either in the form of the continental shelf or oceanic plate). Heat up and moving event from Earth's core to the envelope of the earth. Thermal flow very slowly while moving lempek. When the veil of the Earth cools, where he was replaced by a new sheath heat, so then there was a shift between the thermal envelope with a cool sheath. Sheath earth turns slowly when the transfer of heat flow and then give some of its elements into new magma that forms the edge of the plate.
Apparently the position of Indonesia in the third himpit by the tectonic plates. Indo-Australian Plate urged toward the north, while the Pacific plate pushed into the West. This led to a series of mountains in Indonesia including the Mediterranean and circum-Pacific region. The series begins Mediterranean mountains of the Atlas Mountains, the Balkans, the Himalayas, Sumatra, Java, Nusa Tenggara, to the Moluccas. While the circum Pacific region extending from the Pacific Coast American, Kamsyatku, Japan, the Philippines, New Guinea (Papua), Australia to New Zealand.
D) Dynamics Advances Earth. The idea that continents move like logs floating in the pond was in cemohoh by people for many years.However, in the end found corroboration opinion. Based on the evidence, experts believe that the first of today's continents were once united called Pangaea. Earth can be explained as follows:
i) The state of the Earth 200 million years ago. Continent merged into one super continent called Pangaea. North America and Eurasia northern part of Pangaea and called Laurasia. Other continents are clustered in the southern segment of Gondwana. In the east trdapat Lau Tethys.
ii) The state of the Earth 180 million years ago. Continent Pangaea began to break up, with the advent of the North Atlantic Samdudera between Laurasia and Gondwana. Gondwana itself broke into three pieces and Tethys Sea became more narrow.
iii) The state of the Earth 135 million years ago. A widening cracks between North America and Eurasia with the widening of the North Atlantic. South Amerka and Africa began to separate along a fissure into the South Atlantic Ocean. India moves north towards Asia.
iv) 65 million years ago. South America and Africa have been the path of each. North America and Europe are still in contact dengna Greenland while India approaching Asia.
v) Current state of the Earth. Greenland has a separate, while Australia has moved to the north of the Antarctic. India has hit Asia.
vi) The state prediction Earth 50 million years to come. Atlantic Ocean continues to widen, the Pacific Ocean to shrink. Australia approached Asia. Valley African cracks open and flooded.Widening the Red Sea and the Persian Gulf was gone.
(Source: Sudibyakto, HA 2009. Geografi.Jakarta: Ministry of Education.)
A) The process of formation of the Earth.
The scientists suggest that the process has been started since the formation of the earth billions of years ago. Planet Earth originated from a giant cloud in space that is always berputari. Giant clouds will form an interesting ball of dust and gas. The ball of dust and gas is the beginning of the formation of Earth, the planet, as well as other months.
When the greater gravity, gas and dust will be compressed and increasingly congested. This causes the Earth is getting hotter and a glowing ball. The outside world slowly began to cool and harden.But the earth has not been cold at all. The middle of the earth is extremely hot.
The process of formation of the earth similar to the opinions of the Kant-Laplace (Theory Nebula), which suggests that the Earth is beginning to take shape during the billions of years ago when released from the sun in the form of incandescent gas that cools slowly and form a crust rocks.
B) Characteristics Coating Earth
1) The air layer of the Earth. Earth surrounded by a layer of air called the atmosphere. Earth's atmosphere is made up of toxic gases such as methane, hydrogen and ammonia coming from the volcano on Earth's surface. Meanwhile, over billions of years, the water vapor that falls (in the form of rain), fill the earth and ocean basin began to form in the earth's crust. The remaining land masses forming the mainland. About 1,000 km thick atmosphere. air in the upper atmosphere consists of nitrogen, oxygen, carbon dioxide and other gases that are very important for human life. Layer of the atmosphere consists of the troposphere, stratosphere, mesofer, thermosphere and eksofer.
2) The inner layer of the Earth. The radius of the Earth estimated 6,400 km whereas the deepest digging new holes about 5 km. So rasanyatidak possible excavations to penetrate the other side of the earth.
Human knowledge about the interior of the Earth is still very small.The person who first put forward his opinion on the interior of the Earth is Plato. Philosophers, that the Earth consists of a mass of incandescent and surrounded by a layer of rock or earth's crust.Incandescent mass is sometimes reach the earth's surface through volcanic pipes in the form of lava. Previously, this opinion is generally accepted world of science.
Padangan of Plato, gradually shifted. Seismological investigation with the help of tools seismograph has provided another view of the perlapisan the Earth. This investigation proved that the Earth was found in the lining layer bounded by continuous fields (not continued). The field was discovered at about 60 km and is named from Mohorovicic discontinuous fields, other fields were found at a distance of 1200 km and 2900 km from the Earth's surface. At a distance of 2900 km are the core of the Earth has a radius of 3500 km. many experts argue that the core is composed of iron and nickel composition.
Sues and Wiechert held perlapisan distribution within the earth, as follows:
a) the Earth's crust. This section has a thickness of 30-70 km, consisting of alkaline and acidic rocks that has a specific gravity about 2.7 gram/cm3. The upper and middle crust layer called unlucky due largely made up of substances silisium and aluminum, while the bottom is called sima due largely made up of substances silisium and magnesium. The earth's crust is divided into two, namely the continental crust and the oceanic crust. Continental crust has a thickness greater than the oceanic crust. In the earth's crust can be seen various forms of earth like volcanoes, mountains, valleys, rivers, lakes, seas, or oceans are formed in this layer.
b) The sheath Earth Silicate or scales. This layer has a thickness of about 1,200 km and has a specific gravity of 3.4 to 4 gram/cm3.The crust of the earth and the sheath is a layer of the lithosphere.
c) intermediate layer or Chalkosfera. This layer has a thickness of about 1,700 km with a weight of oxide and sulfide scales.
d) Core Iron Nickel or Barysfera. The core is composed of nickel and iron that is also called lapisn NiFe (niccolum = Ferrum = nickel and iron). This layer has a finger about 3500 km and consists of the outer core and inner core. The outer core has almost 2.200oC temperature and layer thickness about 2,000 km. while in the central core has a temperature reaching 4.500OC.
C) Theory of Plate Tectonics. Deksripsi movement described in the theory of plate tectonics. The theory of plate tectonics came after Luther Alfred Wagener, an expert meteoroligi and geology of Germany in the book The Origin of Continents an Oceans (1915), suggests that the actual floating solid continents and moves over the relatively soft masses (continental drift). In addition, based on their observations of the continent there are some similarities between the beaches form one continent to another. He also found geological similarity and power of the living creatures on the far shore. The core of the theory of plate tectonics is the crust of the earth is actually composed of a large slab that seems to float and move in the core layer of the earth that is more fluid. This theory was proved by geologists at the time and received nearly half a century since the 1960's. Until now this theory has successfully explained various geological events, such as earthquakes, tsunami and volcanic eruption, and how to form mountains, continents oceans dn. Theory proves that the continent is always shifting.
Transfer of heat flow in the sheath pressing plate (either in the form of the continental shelf or oceanic plate). Heat up and moving event from Earth's core to the envelope of the earth. Thermal flow very slowly while moving lempek. When the veil of the Earth cools, where he was replaced by a new sheath heat, so then there was a shift between the thermal envelope with a cool sheath. Sheath earth turns slowly when the transfer of heat flow and then give some of its elements into new magma that forms the edge of the plate.
Apparently the position of Indonesia in the third himpit by the tectonic plates. Indo-Australian Plate urged toward the north, while the Pacific plate pushed into the West. This led to a series of mountains in Indonesia including the Mediterranean and circum-Pacific region. The series begins Mediterranean mountains of the Atlas Mountains, the Balkans, the Himalayas, Sumatra, Java, Nusa Tenggara, to the Moluccas. While the circum Pacific region extending from the Pacific Coast American, Kamsyatku, Japan, the Philippines, New Guinea (Papua), Australia to New Zealand.
D) Dynamics Advances Earth. The idea that continents move like logs floating in the pond was in cemohoh by people for many years.However, in the end found corroboration opinion. Based on the evidence, experts believe that the first of today's continents were once united called Pangaea. Earth can be explained as follows:
i) The state of the Earth 200 million years ago. Continent merged into one super continent called Pangaea. North America and Eurasia northern part of Pangaea and called Laurasia. Other continents are clustered in the southern segment of Gondwana. In the east trdapat Lau Tethys.
ii) The state of the Earth 180 million years ago. Continent Pangaea began to break up, with the advent of the North Atlantic Samdudera between Laurasia and Gondwana. Gondwana itself broke into three pieces and Tethys Sea became more narrow.
iii) The state of the Earth 135 million years ago. A widening cracks between North America and Eurasia with the widening of the North Atlantic. South Amerka and Africa began to separate along a fissure into the South Atlantic Ocean. India moves north towards Asia.
iv) 65 million years ago. South America and Africa have been the path of each. North America and Europe are still in contact dengna Greenland while India approaching Asia.
v) Current state of the Earth. Greenland has a separate, while Australia has moved to the north of the Antarctic. India has hit Asia.
vi) The state prediction Earth 50 million years to come. Atlantic Ocean continues to widen, the Pacific Ocean to shrink. Australia approached Asia. Valley African cracks open and flooded.Widening the Red Sea and the Persian Gulf was gone.
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