The oldest seafloor has been radiometrically dated to only
about 200 million years
(Duxbury et al. 2005:114), whereas continental rocks have been dated to four billion years, and the earth is thought to be about 4.6 billion years old (Dalrymple 2004).
What is the maximum age of the sea floor?
Scientists use the magnetic polarity of the sea floor to determine the age. Very little of the sea floor is older than
150 million years
. This is because the oldest sea floor is subducted under other plates and replaces by new surfaces.
What is the age of the seafloor of?
Because of this correlation between age and subduction potential, very little ocean floor is older than 125 million years and almost none of it is older than
200 million years
.
What is the age of the oldest seafloor crust?
The oldest patch of undisturbed oceanic crust on Earth may lie deep beneath the eastern Mediterranean Sea – and at
about 340 million years old
, it beats the previous record by more than 100 million years.
How old was the seafloor destroyed?
The oldest known ocean floor is dated at
about 200 million years
, indicating that older ocean floor has been destroyed through subduction at deep-sea trenches. It took exploration of the ocean floor to discover sea-floor spreading, the mechanism for the movement of continents that Alfred Wegener lacked.
Where is the youngest crust on Earth is found?
The youngest crust (shown in red) is
near mid ocean ridges and spreading zones
. All three rock types in the earth’s crust—igneous, sedimentary, and metamorphic—can also be recycled back to their original molten magma form. This process occurs when oceanic crust is pushed back into the mantle at subduction zones.
Do younger oceans have deeper sea floors?
The depth of the seafloor on the flanks of a mid-ocean ridge is determined mainly by the age of the oceanic lithosphere;
older seafloor is deeper
.
Why do tectonic plates move?
The heat from radioactive processes within the planet’s interior causes the plates
to move, sometimes toward and sometimes away from each other. This movement is called plate motion, or tectonic shift.
Where is the newest seafloor?
The newest, thinnest crust on Earth is located
near the center of mid-ocean ridge
—the actual site of seafloor spreading. The age, density, and thickness of oceanic crust increases with distance from the mid-ocean ridge.
At which boundaries is seafloor destroyed?
You are correct that the seafloor is destroyed at
subduction zones
, but it is simultaneously being created at mid-ocean ridges. see figure 1 . Figure 1: Seafloor spreading at a mid-ocean ridge(where new crust is being created) and it’s destruction at a subduction zone.
What is the oldest rock on Earth?
In 2001, geologists found the oldest known rocks on Earth,
the Nuvvuagittuq greenstone belt
, on the coast of the Hudson Bay in northern Quebec. Geologists dated the oldest parts of the rockbed to about 4.28 billion years ago, using ancient volcanic deposits, which they call “faux amphibolite”.
Why is there no ocean floor much older than 280 million years?
Why are there no oceanic rocks older than 200 million years? Oceanic crust is eventually destroyed in subduction zones. Although oceanic crust has been forming on Earth for over 4 billion years, all of the sea floor older than about 200 million years
has been recycled by plate tectonics
.
What is the youngest ocean?
The Atlantic Ocean
is the world’s saltiest sea with a water salinity level of between 33 – 37 parts per thousand. It’s the world’s youngest ocean, formed long after the Pacific, Indian and Arctic Oceans of the Triassic Period.
Who discovered seafloor spreading?
Harry Hess
: One of the Discoverers of Seafloor Spreading.
Which is one piece of evidence of seafloor spreading?
There is lots of evidence that proves that seafloor spreading is occurring. One piece of evidence is
mid-ocean ridges
. Rocks found near mid-ocean ridges are young and get older as the distance from the ocean ridge increases.
What causes seafloor spreading?
Seafloor spreading
creates new oceanic crust at a mid-ocean ridge
. When this new material reaches the end of the plate and comes into contact with another plate, whether continental or not, a convergent or a transform boundary will occur.
