What is the process of rifting?

What is the process of rifting?

Rifting is defined as the splitting apart of a single tectonic plate into two or more tectonic plates separated by divergent plate boundaries. The rifting of a continental tectonic plate creates normal fault valleys, small tilted block mountains, and volcanism.

What is the cause of rifts on continents?

Rifting can be caused when hot material from a mantle plume reaches the base of a continental plate and causes the overlying lithosphere to heat up. In addition to this the uwards movement of the plume against the base of the plate results in extensional forces, which can cause rifting.

Can rifting cause volcanoes?

Rift volcanoes form when magma rises into the gap between diverging plates. They thus occur at or near actual plate boundaries. ... Earthquake swarms and volcanic eruptions occur when the stretching exceeds the strength of the near-surface rocks, which then fracture along steeply dipping cracks parallel to the rift.

What happens during early rifting?

Early rift sediments are downfaulted into the developing rift (graben). Erosion takes place on the sides of the rift valley. The first stage assumes that graben-like faults begin to form in the brittle crust. The second stage shows simultaneous necking of the lithosphere with uprise of an asthenosphere diapir.

Why do rifts fail?

Failed rifts are the result of continental rifting that failed to continue to the point of break-up. Typically the transition from rifting to spreading develops at a triple junction where three converging rifts meet over a hotspot.

How old are rifts?

The rift has been forming for some 30 million years (as Africa and the Arabian Peninsula separated) and has been accompanied by extensive volcanism along parts of its length, producing such massifs as Kilimanjaro and Mount Kenya.

Where do most volcanoes form at?

Most of the world's volcanoes are found around the edges of tectonic plates, both on land and in the oceans. On land, volcanoes form when one tectonic plate moves under another.

What is the hole of a volcano called?

The crater is the bowl shaped opening located at the top of the volcano. The crater is also the steep sided walls made of hardened lava that surround the main vent. Lava can flow from the main vent, but not all volcanoes eject large amounts of lava.

Why are continental rifts developed on high bulges in the crust?

Bulges are initiated by mantle plumes under the continent heating the overlying crust and causing it to expand and fracture. Ideally the dominant fractures created occur in a pattern consisting of three fractures or fracture zones radiating from a point with an angular separation of 120 degrees.

How do failed rifts work?

Failed rifts are the result of continental rifting that failed to continue to the point of break-up. Typically the transition from rifting to spreading develops at a triple junction where three converging rifts meet over a hotspot.

How was the Great Rift Valley formed?

• How the Great Rift Valley was formed? Geologists know that the Rift Valley was formed by violent subterranean forces that tore apart the earth's crust. These forces caused huge chunks of the crust to sink between parallel fault lines and force up molten rock in volcanic eruptions.

What are examples of rift valleys?

• The most extensive of the continental rift valleys are those of the East African Rift System, which extend northward to the Red Sea and eastward into the Indian Ocean. Other notable examples include the Baikal Rift Valley (Russia) and the Rhine Rift Valley (Germany).

What is an example of a rift valley?

• Africa's Great Rift Valley is the world's largest example of a rift valley. Other major rift valleys on the continents include the Rio Grande Valley in New Mexico and the Lake Baikal rift valley in Siberia .