Also how does the seafloor differ from the continents in its geology and topography?
2006-10-14 08:50:49 · 2 answers · asked by The word Fan! 1 in Science & Mathematics ➔ Earth Sciences & Geology
Heat and pressure has a lot to do with it. Also, water will cool the magma much more quickly.
2006-10-14 08:59:15 · answer #1 · answered by njyecats 6 · 0⤊ 0⤋
Well, for one thing, different minerals crystallize at different temperatures and pressures. The "mafic" minerals like olivine, pyroxene, amphiboles, biotite, etc. form early and fall out of solution leaving the magma that's left very "felsic" or rich in silica -- quartz and feldspars.
Another reason why magmas of different compositions are formed is that different parent rocks are being melted. Continental rocks melted down will create felsic magmas (typically) whereas oceanic rocks will create mafic magmas.
Geologically speaking, oceanic crust is more mafic and extrusive in nature. Continental rocks are typically more felsic and tend to have larger crystal size....but not always. Topographically speaking, not much difference (in my opinion). Both have mountains, valleys, river beds, etc. One's just underwater.
2006-10-14 16:16:54 · answer #2 · answered by Anonymous · 0⤊ 0⤋