ROMSO Cyprus Knowledge Base

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Thresholds (also called backs) in the sense of geomorphology are elevations of the earth's surface. they may be above or below sea level; So they rise on the continents, on islands or in the ocean.

Thresholds in the country
Thresholds that lie on land or on continents are often vast landscapes that have folded or continue to fold into mountains. In this case, powerful continental plates can abut each other, so that the tectonic forces occurring thereby create the thresholds; This is accompanied in many places by volcanism (see for example Central African threshold). At their edges, these above-ground thresholds fall partly into the seas off the continental shores, or they border on above-ground depressions, basins and/or (river) lowlands; In some cases, however, they also pass into highlands or mountains.

For example, there are these thresholds located on land (alphabetically sorted):

Africa
The five major African thresholds are, next to the Upper Guinea threshold,
The following four sleepers are arranged quasi-rectangularly around the Congo Basin:
Lundaschwelle (as southern boundary)
Lower Guinea Threshold (as western boundary)
North equatorial threshold (as northern boundary)
Central African threshold (as eastern boundary)

Other African thresholds:
Central Saharan threshold
South African boundary high threshold (large boundary level)

Asia
Examples of Thresholds in Asia
Kazakhstan threshold

Thresholds or backs in the sea

Seabed sills are called sea ridges. In particular, the respective main ridges of the individual oceans, the mid-ocean ridge. On Earth, these ridges total about 70,000 km in length. They are mostly long drawn mountain ranges. Their education continues in many places on earth.

Sea ridges are formed mainly by the formation of new ocean crust at trench quarries, so-called “rift zones”. In contrast, many mountains on the mainland are formed by the collision of continental plates. In the apex regions of the mid-ocean ridge often form burrows, from which magma rises in many places, which swells as lava into the sea water and solidifies. The resulting ridges rise up to 3,000 m above the seabed, so that their peaks extend beyond the sea surface. A good example of this is Iceland, where the North Atlantic threshold (viewed from the south) first rises above the surface of the island and then runs as a mountain ridge across Iceland, then sinks back into the depths of the European North Sea.

Backs are not quite as widespread as a result of plate tectonics. At submarine collision zones, either only oceanic plates or oceanic and continental plates collide. The ones before the subdu