The St. Helena Seamount chain, also known as the St. Helena Seamounts, is an underwater chain of seamounts in the southern Atlantic Ocean. The chain has been formed by the movement of the African Plate over the Saint Helena hotspot.
|St. Helena Seamount chain|
|Location||South Atlantic Ocean|
In geology, the places known as hotspots or hot spots are volcanic regions thought to be fed by underlying mantle that is anomalously hot compared with the surrounding mantle. Their position on the Earth's surface is independent of tectonic plate boundaries. There are two hypotheses that attempt to explain their origins. One suggests that hotspots are due to mantle plumes that rise as thermal diapirs from the core–mantle boundary. The other hypothesis is that lithospheric extension permits the passive rising of melt from shallow depths. This hypothesis considers the term "hotspot" to be a misnomer, asserting that the mantle source beneath them is, in fact, not anomalously hot at all. Well-known examples include the Hawaii, Iceland and Yellowstone hotspots.Outline of oceanography
The following outline is provided as an overview of and introduction to Oceanography.St. Helena hotspot
The St. Helena hotspot is a volcanic hotspot located in the southern Atlantic Ocean. It is responsible for the island of St. Helena and the St. Helena Seamount chain. It is one of the oldest known hotspots on Earth, which began to produce basaltic lava about 145 million years ago.