Steep steps in the seafloor that can be as tall as a few tens of meters (at fast spreading ridges) to hundreds of meters (at slow spreading ridges). These features are also called abyssal hills and are present on both sides of the ridge axis and are caused cracking of the ocean plate by seafloor spreading.
Volcanic rock that has cooled after magma has erupted on the seafloor. Volcanic rock on the seafloor is mostly basalt. A typical shape for lava to have at the mid-ocean ridge is like big, bulbous pillows. That is why many of the lavas are called pillow basalts.
SA narrow (50-300 meter wide) cleft at the axis of a fast-spreading mid-ocean ridge like the East Pacific Rise at 9-10°N Latitude. The axial trough is only 5 to 20 meters deep and is where most of the eruption of lavas takes place. It is also where much of the hydrothermal venting is occuring
Long, narrow fissures which are filled with molten rock. These fissures serve as the conduits for magma when it erupts from the magma chamber to the seafloor.
Sheeted dikes are the parallel feeders that transported the magma when it was erupted from the magma chamber to the seafloor. The magma cools and forms a dense rock called a diabase. This type of rock is found in the lower part of the ocean crust.
A magma chamber is a region of molten or partially molten rock that has oozed out of the hot mantle beneath the mid-ocean ridge crest.