Alright buddy, this time we will discuss about The Theory of the Formation of the Earth’s Plate, no need to linger, let’s just get into the discussion of the article.
The atmosphere is a collection of gases and air in the form of a thin layer surrounding or enveloping the earth’s surface. Like an orange, the earth is its contents while the orange peel is the atmosphere. 99% of the atmosphere is in the lower 30 km layer. In the atmosphere, weather and climate processes occur.
The lithosphere is the layer of the earth below the atmosphere. Lithos means stone and sfhere (sphaira) means sphere (layer). So that the lotosphere is defined as a hard, rigid and rigid layer of the earth with a thickness of approximately 0-70 km. The lithosphere is divided into two plates:
Continental Plate (0-10 km) containing sima layers.
Ocean Plate (0-70 km) with pesky layers.
The following is a table of elements that make up the lithosphere:
This layer is located below the lithosphere with a thickness of 70-2900 km in the form of solid material that is like a fluid. Or in other words, this layer is unstable so that, when affected by convection currents, it will move and move the layer above it like an earthquake. The temperature can reach approximately 3000 oC. Composition The mantle is divided into the upper mantle, the asthenosphere (part of the mantle), and the lower mantle. It can be said that the asthenosphere is part of the mantle.
Barisphere is the layer of the earth’s core. Which is composed of layers of nickel and iron. This layer is divided into 2, namely:
The Outer Core is the outer core of the Earth with a thickness of 2900-4980 km. Composed of elements of iron and nickel which are liquid with a temperature of 3900 oC.
The Inner Core is the inner core of the earth with a thickness of 4980-6370 km. Composed of nickel, which is solid even at a temperature of 4800 oC due to great pressure so that it compresses and keeps the core in the middle.
THEORY FOR THE EARTH’S PLATE
1. Contraction and Expansion
The shrinkage of the Earth occurs due to the cooling process. This analogy is adopted from the event of a dry apple peel shrinking. This theory can explain depressed areas such as a series of volcanoes but cannot explain basins, fissures and valleys. This theory was first put forward by Descretes (1596-1650) and also supported by James Dana and Elie de Baumant.
The expansion of the Earth occurs due to the heating process. This theory was obtained after radioactivity was known. He can explain how the continents disintegrate and easily explain the formation of folds but cannot yet explain pressure zones.
2. Continental Drift
In the early 20th century scientists realized that they could not explain the structure of the Earth and its processes with a single theory. Many scientific hypotheses have been developed to try and support conflicting observations. Alfred Wegner, a German meteorologist who studied ancient climates, proposed the theory of continental drift. The hypothesis is Continental Drift that was put forward in 1910. Like most people, South America and Africa fit together like a jigsaw puzzle and caught his eye.
He combined the facts and the distribution of fossils to formulate the theory that the continents move across the earth’s surface. He suggested that before 200 million years ago, all the continents formed one large and heavy land mass called Pangea. The principle of this theory is that the continents are positioned on a plate or rock, and they float along the earth’s surface all the time. The weakness of Wegner’s theory and the reason it was not accepted by geologists is that he argued that the continents slide over the seabed, even though the seabed was not strong enough to support the continents.
Alexander Du Toit is a South African geologist. After his visit to South America, he became a proponent of Wegener’s theory. He published his observations in A Geological Comparison of South America with South Africa and later he developed his thoughts in Our Wondering Contents (1937). He stated that the separation from Pangea formed two supercontinents namely Laurasia (around the north pole) and Gondwana (around the south pole).
4. Paleomagnetism (ancient magnetic patterns of rocks)
During the second world war, a geologist employed by the military named Harry Hass of Princeton University carried out research on the seabed. The purpose of this research is to understand the topography of the seabed including measuring the depth of the seabed from the surface and finding the hidden places of enemies in submarines. Another type of research uses a magnetometer (to measure magnetic objects) that is placed behind the ship to detect submarines. This study also shows the existence of magnetic anomalies under the sea, with high magnetism on the sea ridge and low magnetism on the other side.
This study states 2 important topography, namely the oceanic ridge and oceanic trench. Harry also stated that continents do not move along oceanic crust, but continents and oceanic crust move together. If new oceanic crust and lithosphere continue to form on ocean ridges, the oceans will expand unless there is a mechanism that destroys the oceanic lithosphere. The Benioff zone and oceanic trench prove that the oceanic lithosphere returns to the mantle by infiltrating the ocean trench (subduction zone). Because oceanic plates are cold and brittle, they will break apart and re-mix with the material and produce very deep earthquakes.
In the 1950s and 1960s, research on the Earth’s magnetic field and its changes over time (paleomagnetism) confirmed the recent fact that continents float. The conclusion of the concept of a magnetic field is (1) Earth has more than one pole that changed over time in the past. (2) the different continents have moved relative to each other over geological time. This study confirms the last hypothesis and also confirms the theory Continental Drift.
5. Convection Current (convection current)
The division of continents and the movement of plates is caused by the energy that moves them. The energy comes from convection currents in the earth’s asthenosphere. Convection current is the transfer of heat energy in the fluid, which is caused by:
The decay of radioactive elements
Due to foreign object attack
Heat stored during planet formation
The movement of plates away from each other was caught by researchers. This movement results in the formation of an elongated ridge in the distant region. Vine, Matthews and Morely gathered important information and found that a newly formed oceanic plate was formed between two plates that were moving away from each other. The infiltration of magma between these plates causes a sea ridge. This theory is called Seafloor Spreading and answers the biggest question about Continental Drift “How do continents move over oceanic crust?” in fact, the continents move along with the oceanic crust as part of the lithospheric system. This phenomenon is caused by convection heat flows from the earth’s upper mantle or asthenosphere.
By combining Sea Floor Spreading with Continental Drift and global seismic information, the latest theory from Plate tectonics initiated by Mc. Kenzie and Robert Parker became the most plausible theory to explain plate movement.
The theory of plate tectonics is based on a simple model of the Earth. The dense lithosphere is composed of oceanic crust and continental crust and lies above the mantle, and consists of several sheets of different sizes called plates.
The plates are composed of oceanic crust with a thickness of 100 km and 250 km thickness of continental crust and float above the asthenosphere. When the continents and oceans can float because they are part of a large plate that floats and moves horizontally at the top of the asthenosphere. These plates are rigid (solid) with elastic ability, but the deformation is visible along the boundaries between plates. And there are times when oceanic plates slip back into the mantle due to differences in thickness and density. Also the event of plate widening due to convection currents. This infiltration and widening event causes the boundaries between plates. There are three types of plate boundaries, namely: Divergent Plate Boundary where plates move away from each other, Convergent Plate Boundary where the plates move closer to each other, and finally Transform Plate Boundary where the plates are pushed against each other. Plate boundaries are what cause tectonic and volcanic events that occur on Earth.
Plate tectonics is a theory that was developed in the late 1960s, this theory explains how the process of movement and formation of the Earth’s outer plates. This theory caused a revolution in human thinking about the Earth. Since the development of this theory, geologists have reexamined almost every aspect of geology. The theory of plate tectonics has proven very useful because it can predict geological events and explain almost every aspect of what we see on Earth. Such as the formation of mountains, earthquakes, and volcanoes.
In the development of the theory of plate tectonics, quite a number of scientists have announced their research in the form of theories that we often hear today.
Alright buddy, this is the discussion this time about The Theory of the Formation of the Earth’s Plate, I hope all of you understand and the knowledge is useful J