Basaltic magma.
Basaltic/mafic lava.
Volcanoes at spreading centers is referred to as spreading center volcanism. This usually takes place on mid-oceanic ridges where the plates diverge.
Rocks near continents(on the margins of oceanic basins) are generally older and rocks near a center of sea floor spreading are younger
Gravity in the oceanic crust is responsible for seafloor spreading.
Sea floor spreading
Deep-oceanic trenches are most abundant around the rim of the Pacific. Deep ocean trenches are surficial evidence for sinking of oceanic lithosphere into the mantle at a subduction zone.
Basaltic/mafic lava.
The most abundant type of magma erupted at oceanic spread centers is basaltic magma. This type of magma has low viscosity and forms in the mantle part of the Earth that are high in iron and magnesium.
True. Reference: http://www.studystack.com/flashcard-303839
Volcanoes at spreading centers is referred to as spreading center volcanism. This usually takes place on mid-oceanic ridges where the plates diverge.
They are located at spreading centers in the middle of the ocean. As tectonic plates move apart, magma fills it in and creates ridges and rises which are essentially mountain chains.
In 1977, scientists discovered hot springs at a depth of 2.5 km, on the Galapagos Rift (spreading ridge) off the coast of Ecuador. This exciting discovery was not really a surprise. Since the early 1970s, scientists had predicted that hot springs (geothermal vents) should be found at the active spreading centers along the mid-oceanic ridges, where magma, at temperatures over 1,000 °C, presumably was being erupted to form new oceanic crust. More exciting, because it was totally unexpected, was the discovery of abundant and unusual sea life -- giant tube worms, huge clams, and mussels -- that thrived around the hot springs.
Rocks near continents(on the margins of oceanic basins) are generally older and rocks near a center of sea floor spreading are younger
The lavas erupted from mid-oceanic ridges are called basalts. This lava contains quarts, feldspathoid, and plagioclase. Basalts has gray to black color.
Sea floor spreading
Gravity in the oceanic crust is responsible for seafloor spreading.
Igneous. Basalt is the most abundant in oceanic crust and granite is the most abundant in continental crust.
Deep-oceanic trenches are most abundant around the rim of the Pacific. Deep ocean trenches are surficial evidence for sinking of oceanic lithosphere into the mantle at a subduction zone.