History Of The Ocean
History of the ocean
History of the ocean, starting when the earth formed about 4.5 billion years ago.
The ocean is not just where the land happens to be covered by water. The sea floor is geologically distinct from the contents.
It is locked in a perpetual cycle of birth and destruction that shapes the ocean and controls much of the geology and geological history of the continents.
Geological processes that mold ocean basins occur slowly, over tens and hundreds of millions of years.
On this timescale, where a human lifetime is but the blink of an eye, solid rocks flow the liquid, entire continents move across the face of the earth and mountains grow from flat plains.
To understand the sea level floor, we must learn to adopt the unfamiliar point of view of geological time.
Geology
Geology is very important to marine biology. Habitats or the places where organisms live are directly shaped by geological processes.
The form of coastlines; the death of the water; whether the bottom is muddy, sandy, or rocky and many other features of a marine habitat are determined by this geology.
The geologic history of marine life is also called Palentology. The presence of large amounts of liquid water makes our planet unique.
Most other planets have very little water and on those that do the water exists only as perpetually frozen ice or as vapour in the atmosphere.
The earth, on the other hand, is very much a water planet. The ocean covers most of the globe and plays a crucial role in regulating our climate and atmosphere. Without water, life itself would be impossible.
The ocean is traditionally classified into large basins. The Pacifics is the deepest and largest, almost as large as all the others combined.
The Atlantic ocean is a little larger than the Indian ocean, but the two are similar in average depth. The Artic is the smallest and shallowest.
Connected or marginal to the main ocean basins are various shallow seas, such as the Mediterranean Sea, the Gulf of Mexico and the South China Sea.
Big Bang
The earth and the rest of the solar system are thought to have originated about 4.5 billion years ago from a cloud or clouds of dust.
The dust was debris remaining from a huge cosmic explosion called the big bang, which astrophysicists estimate occured about 15 billion years ago.
The dust particles collided with each other, merging into larger particles. These larger particles collided in turn, joining into pebble-sized rocks that collided to form larger rocks, and so on. The process continued, eventually building up the earth and other planets.
So much heat was produced as the early earth formed that the planet was probably molten. This allowed materials to settle within the planet according to their density.
Density
Density is the weight, or more correctly, the mass, of a given volume of a substance. Obviously, a pound of styrofoam weights more than an ounce of lead, but most people think of lead as "heavier" than styrofoam.
This is because lead weights more than styrofoam if equal volumes of the two are compared. In other words, lead is denser than styrofoam.
The density of a substance is calculated by dividing its mass by its volume. If two substances are mixed, the denser material will tend to sink and the less dense will float.
During the time that the young earth was molten, the densest material tended to flow toward the centre of the planet, while lighter materials floated toward the surface.
The light surface material cooled to make a thin crust. Eventually, the atmosphere and oceans began to form.
If the earth had settled into orbit only slightly closer to the sun, the planet would have been so hot that all the water would have evaporated into the atmosphere.
With an orbit only slightly farther from the sun, all the water would be perpetually frozen. Fortunately for us, our planet orbits the sun in a narrow zone in which liquid water can exist. Without liquid water, there would be no life on earth.
The earth is composed of three main layers:
* the iron-rich core
* the semiplastic mantle and
* the thin outer crust.
history of the ocean
History of the ocean, starting when the earth formed about 4.5 billion years ago.
The ocean is not just where the land happens to be covered by water. The sea floor is geologically distinct from the contents.
It is locked in a perpetual cycle of birth and destruction that shapes the ocean and controls much of the geology and geological history of the continents.
Geological processes that mold ocean basins occur slowly, over tens and hundreds of millions of years.
On this timescale, where a human lifetime is but the blink of an eye, solid rocks flow the liquid, entire continents move across the face of the earth and mountains grow from flat plains.
To understand the sea level floor, we must learn to adopt the unfamiliar point of view of geological time.
Geology
Geology is very important to marine biology. Habitats or the places where organisms live are directly shaped by geological processes.
The form of coastlines; the death of the water; whether the bottom is muddy, sandy, or rocky and many other features of a marine habitat are determined by this geology.
The geologic history of marine life is also called Palentology. The presence of large amounts of liquid water makes our planet unique.
Most other planets have very little water and on those that do the water exists only as perpetually frozen ice or as vapour in the atmosphere.
The earth, on the other hand, is very much a water planet. The ocean covers most of the globe and plays a crucial role in regulating our climate and atmosphere. Without water, life itself would be impossible.
The ocean is traditionally classified into large basins. The Pacifics is the deepest and largest, almost as large as all the others combined.
The Atlantic ocean is a little larger than the Indian ocean, but the two are similar in average depth. The Artic is the smallest and shallowest.
Connected or marginal to the main ocean basins are various shallow seas, such as the Mediterranean Sea, the Gulf of Mexico and the South China Sea.
Big Bang
The earth and the rest of the solar system are thought to have originated about 4.5 billion years ago from a cloud or clouds of dust.
The dust was debris remaining from a huge cosmic explosion called the big bang, which astrophysicists estimate occured about 15 billion years ago.
The dust particles collided with each other, merging into larger particles. These larger particles collided in turn, joining into pebble-sized rocks that collided to form larger rocks, and so on. The process continued, eventually building up the earth and other planets.
So much heat was produced as the early earth formed that the planet was probably molten. This allowed materials to settle within the planet according to their density.
Density
Density is the weight, or more correctly, the mass, of a given volume of a substance. Obviously, a pound of styrofoam weights more than an ounce of lead, but most people think of lead as "heavier" than styrofoam.
This is because lead weights more than styrofoam if equal volumes of the two are compared. In other words, lead is denser than styrofoam.
The density of a substance is calculated by dividing its mass by its volume. If two substances are mixed, the denser material will tend to sink and the less dense will float.
During the time that the young earth was molten, the densest material tended to flow toward the centre of the planet, while lighter materials floated toward the surface.
The light surface material cooled to make a thin crust. Eventually, the atmosphere and oceans began to form.
If the earth had settled into orbit only slightly closer to the sun, the planet would have been so hot that all the water would have evaporated into the atmosphere.
With an orbit only slightly farther from the sun, all the water would be perpetually frozen. Fortunately for us, our planet orbits the sun in a narrow zone in which liquid water can exist. Without liquid water, there would be no life on earth.
The earth is composed of three main layers:
* the iron-rich core
* the semiplastic mantle and
* the thin outer crust.
history of the ocean
Labels: history of the ocean
posted by seli at
12:24 AM
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