Rift Valley Ocean Floor

Not only is the mid ocean ridge changing the geography of iceland it s also responsible for the volcanic activity which created the island.

Rift valley ocean floor. Rift valleys occur on the continents as well as on the ocean floor where they arise from seafloor separation. Rift valley any elongated trough formed by the subsidence of a segment of the earth s crust between dip slip or normal faults. Nearly 80 of the ocean floor has been accurately mapped using sonar from ships. Satellites can be used to determine the structure and composition of the sea floor.

The ridge is spreading at an average rate of about 2 5 cm per year. Continental shelf 300 feet continental slope 300 10 000 feet abyssal plain 10 000 feet abyssal hill 3 000 feet up from the abyssal plain seamount 6 000 feet. Such a fault is a fracture in the terrestrial surface in which the rock material on the upper side of the fault plane has been displaced downward relative to the rock. Her work also revealed the presence of a continuous rift valley along the axis.

Marie tharp july 30 1920 august 23 2006 was an american geologist and oceanographic cartographer who in partnership with bruce heezen created the first scientific map of the atlantic ocean floor tharp s work revealed the detailed topography and multi dimensional geographical landscape of the ocean bottom. A rift valley is a lowland region that forms where earth s tectonic plates move apart or rift rift valleys are found both on land and at the bottom of the ocean where they are created by the process of seafloor spreading rift valleys differ from river valleys and glacial valleys in that they are created by tectonic activity and not the process of erosion. Rift valleys usually form where the earth s lithosphere has become thin through extension associated with plate tectonic processes. The following features are shown at example depths to scale though each feature has a considerable range at which it may occur.

A long narrow valley lying between two normal geologic faults. Many existing continental rift valleys are the result of a failed arm of a triple junction although there are two the east african rift and the baikal. As the plates move apart magma from the upper mantle flows out onto the ocean floor in the valleys creating the newest crust on the planet. Rift valley definition graben.

The most extensive rift valley is located along the crest of the mid ocean ridge system and is the result of sea floor spreading examples of this type of rift include the mid atlantic ridge and the east pacific rise. On the continents rift valleys form in divergence zones of tectonic plates. The center of these mid ocean ridges are rift valleys that separate lie between the two separating plates. Multibeam surveys from ships produce very detailed maps of the sea floor.

The global mid ocean ridges are found in all the oceans on earth. A rift valley s walls may stand at heights of hundred feets and they drop away in the form of terraces and steps.