Answer:
The magma that melts in the upper mantle and erupts at the mid-ocean ridge has a different composition (higher in Ca, Mg, Fe and relatively lower in Si and Al) than the composition of the magma (more Si, Al, Na, K rich in relative terms) that built the continents. Melting different degrees (2%, 5%, 30%) of a rock with a mantle-like composition generates magma of different Al, Si contents. Continents grow at their edges by partial melting of oceanic crust that is being subducted, generating magmas of a somewhat more Si, Al-rich composition than the subducting slab itself. The chemistry and physics of melting a mixture of minerals rather than one homogeneous substance has the wonderful outcome of creating two distinct types of crust:
Answer:
Yes, I would fund it if there are no competing proposals.
Explanation:
There are certainly many other projects that are inclined on improving the lives of people. For example, there are Cancer research projects, Alzheimer research projects, research that speak to diabetes, malaria research projects, etc.
It is pragmatic to weigh whether we want to spend money on knowledge for history's sake or channel money into the above research for the sake of improving lives and creating a better future.
Cheers
The term known as <u>sea floor spreading</u> causes Earth's tectonic plates to shift.
Answer: The Rhine river
Explanation: This big boi flows through Switzerland, Principality of Liechtenstein, Austria, Germany, France and the Netherlands before flowing into the North Sea at Rotterdam.
(Information found from www.primaryhomeworkhelp.co.uk.)
And sorry it took three years for a answer!!! :0
Answer:
Mid ocean ridge are where new crustal material is forced to the surface. The new crustal material is pushed apart forming two different plates moving in two different directions. An ocean trench is where old crustal material is pushed under another plate where it is melted and turned into magma.