Rift Zone


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Rift Zone

 

a single system of major tectonic crustal fractures, or rifts, on the earth’s surface. The rifts belong to the mid-oceanic ridge, which stretches for more than 60,000 km from the central regions of the Arctic Ocean along the axis of the Atlantic Ocean and on through the Indian Ocean to the eastern part of the Pacific. The rifts of this ridge are longitudinal depressions having steep walls. The great length of the rift zone shows that extension has been just as important as compression in the development of the structure of the earth’s crust.

The rifts of the mid-oceanic ridge continue onto the continents; these rifts include the belt of rifts in Arabia and Africa and those of the Great Basin in the Cordilleras of North America. These branches of the rift zone are young, dating from the Neogene and Anthropogene (Quaternary) periods. The age of the system of rifts on the ocean floor can only be approximated; in the opinion of some researchers, these rifts are from the Mesozoic and Cenozoic eras. The rift zone exhibits a high level of seismicity throughout and is associated with volcanic activity. The rift zone, geosynclines, and cratons are the chief structural elements of the earth’s crust.

The discovery of the rift zone in the 1950’s was one of the main factors in the development of new tectonic hypotheses of mobilism; the new global tectonics, for example, proposed that the system of ocean rifts corresponds to the boundaries along which the continents first separated from each other. The rift zone, however, can also be viewed as a new formation on the ocean floor related to the rising of magma from the upper mantle; as a result of this process, the earth’s crust was lifted and only to a small degree extended.

V. V. BELOUSOV

References in periodicals archive ?
All statements other than statements of historical fact included in this release, including, without limitation, statements regarding: (i) the current drilling at Snowstorm being expected to provide enough information to refine targeting for subsequent exploration including further geophysical surveys and drilling and (ii)the projected intersection of three of the most important gold trends in Northern Nevada: the Carlin Trend, the Getchell Trend and the Northern Nevada Rift Zone being on the Snowstorm Project.
All statements other than statements of historical fact included in this release, including, without limitation, statements regarding: (i) the current drilling at Snowstorm being expected to provide enough information to refine targeting for subsequent exploration including further geophysical surveys and drilling; and (ii)the projected intersection of three of the most important gold trends in Northern Nevada: the Carlin Trend, the Getchell Trend and the Northern Nevada Rift Zone being on the Snowstorm Project.
It was the collapse of a lava-filled crater in the East Rift Zone on Monday that set off last week's eruption.
Lake Kivu spans 2,400 square kilometres, and lies in the Eastern African Rift Zone. It is one of the world's three so-called "exploding" lakes -- a rare type of natural occurence in which dissolved carbon di- oxide suddenly erupts from deep lake water -- presenting a threat as well as an opportu- nity for local communities.
Lake Kivu spans 2,400 square kilometres, and lies in the Eastern African Rift Zone. It is one of the world's three so-called "exploding" lakes--a rare type of natural occurence in which dissolved carbon dioxide suddenly erupts from deep lake water--presenting a threat as well as an opportunity for local communities.
The collision belt is confined, to the east, by the Siculo-Calabrian Rift Zone (SCRZ) [10] and it represents an incipient divergent margin.
New images from ESA's Venus Express orbiter show three transient bright spots at the edge of a young rift zone, hinting there might be active volcanoes on Venus today.
In Bufford et al., [8], magnetotelluric (MT) and electrical resistivity tomography (ERT) were used to image the geometry and nature of fault activity of the Okavango Rift Zone (ORZ) in Botswana in the Southwestern Branch of the East African Rift System.
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The work is revealing that the crater's lava lake and the East Rift Zone may be physically connected.
The continent of Africa lies on a tectonic plate that is ripping in two (see Rift Zone).
It occurred along the middle of Kilauea's east rift zone, about 2 miles west of Pu'u O'o.