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Because the oldest parts reach the continental crust and then the ocean floor sinks beneath the continental crust, into the mantle.
Due to its high density relative to continental crust, oceanic crust is subducted along subduction zones and destroyed. This means that old oceanic crust is never preserved, unless it has been emplaced upon a continent as an ophiolite.
Sea floor is being made of basalt is denser then continental crust, about 3.3 grams per cubic centimeter. This means that under the right conditions such as at the edge of a continent sea floor crust can be subducted underneath the continent resulting in a "rapid" recycling of such rock.
The ocean is 4 billion yars old, however due to subduction, the oldest sediment found in the ocean's floor is 180 million years old.
Because the oldest parts reach the continental crust and then the ocean floor sinks beneath the continental crust, into the mantle.
Ocean crust keeps being recycled (by being subducted under continental plates.
(Note, some of the Pacific plate is older than 150 million years old.)
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Where do trilobites live?
Where DID trilobites live? In the ocean, between 530 million and 250 million years ago.
How did drilling samples show that sea-floor spreading really has taken place?
Samples of sea floor basalt reveals that they do not exceed 200 million years of age. With the oldest continental rocks being in the neighborhood of 4 billion years of age, there's obviously some crust creation and destruction going on. Samples also indicate changing magnetic orientation in the magnetic minerals present in the basalt, with a matching orientation on the opposite side of the divergent boundary. This indicates that crust is being formed simultaneously on both sides of the mid-ocean ridge, over time, with the magnetic orientation matching the existing orientation at the time of its formation.
What is the name of your oldest common ancestor?
We evolved about 500 million years ago from fish that evolved to anphibians then mammals then we evolved to primates
How old is the oldest plant fossil?
The oldest indications of the existence of real land plants have been found in cores from boreholes in Oman. The plant fossils have been found in the middle Ordovician and are about 475 million years old.
How wide would an ocean basin be if it formed due to the breakup of a supercontinent 200 million years ago and had an oceanic ridge in the middle that spread at a rate of 2.5 centimeters per year?
The math is fairly simple. Simply multiply the rate of 2.5cm/year by 200 million years and you get an answer of 500 million centimeters. To put it in more familiar units the ocean basin is 5,000 kilometers wide.
Why are the oldest parts of the ocean floor no older than about 200 million years.?
Because the oldest parts reach the continental crust and then the ocean floor sinks beneath the continental crust, into the mantle.
What is the age of the oldest ocean?
The oldest oceanic crust is in the west Pacific and north-west Atlantic. They are about 180 to 200 million years old.
How does the age of the oldest continental crust compare to the age of the oldest ocean crust-?
The oldest continental crust is around 4 billion years old, while the oldest ocean crust is about 180 million years old. Continental crust is significantly older than oceanic crust due to differences in their formation and recycling processes.
How does the age of the oldest continental crust compare to the age of the oldest ocean crust?
The age of the oldest continental crust is around 4 billion years old, while the age of the oldest ocean crust is about 200 million years old. Continental crust is generally older than oceanic crust due to the process of plate tectonics that continuously forms and recycles oceanic crust.
Rocks in ocean crust are as old as how many years?
Rocks in ocean crust are generally as old as 200 million years. The oldest oceanic crust is found near continents, which can be around 250 million years old. However, most of the oceanic crust is continually being formed and destroyed through seafloor spreading and subduction, so rocks are often much younger.
What is the oldest ocean?
The oldest ocean, geologically, is the Panthalassa Ocean which was around 220 million years ago in the Triassic era. It encompassed the whole Earth except the land mass Pangea. See related link for more information.
Rocks in ocean crust are as old as?
200 million
Rocks in ocean crust are as old as years.?
200 million
What is older the continents or the ocean floor?
Continents are generally older than the ocean floor. The ocean floor is constantly being created at mid-ocean ridges and destroyed at subduction zones, whereas continents are more stable and can exist for billions of years.
How does the age of the oldest continental crust compared to the age of the oldest oceanic crust?
The oldest continental crust would be between three and one half to four billion years older than the oldest oceanic crust. This is due to the fact that ocean plates are subducted under the continental plates, subjected to partial melt and essentially recycled in the mantle before reforming.
How old is the oceanic crust?
It varies, but the oldest part is 180 million years old
Rock in ocean crust are as old as how many years?
200 million.
