The Balleny hotspot is a volcanic hotspot located in the Southern Ocean. The hotspot created the Balleny Islands, which forms a chain that extends for about 160 km (99 mi) in a northwest-southeast direction. Due to plate tectonics the hot spot was under different parts of the ocean bed in the past, and this has resulted in a chain of seamounts extending from the East Tasman Plateau. Isotopes and trace elements in the volcanic rocks indicated a high U/Pb mantle source. The same pattern is seen in basalt from Tasmania, but not from Victoria.
The Balleny Islands (66°55′S 163°45′E) are a series of uninhabited islands in the Southern Ocean extending from 66°15' to 67°35'S and 162°30' to 165°00'E. The group extends for about 160 km (99 mi) in a northwest-southeast direction. The islands are heavily glaciated and of volcanic origin. Glaciers project from their slopes into the sea. The islands were formed by the so-called Balleny hotspot.
The group includes three main islands: Young, Buckle and Sturge, which lie in a line from northwest to southeast, and several smaller islets and rocks:
northeast of Young Island: Seal Rocks, Pillar
southeast of Young Island: Row Island, Borradaile Island (with Swan Base shelter hut)
south of Buckle Island: Scott Cone, Chinstrap Islet, Sabrina Islet (with Sabrina Refuge shelter hut), and The MonolithThe islands are part of the Ross Dependency, claimed by New Zealand (see Territorial claims in Antarctica).Hotspot (geology)
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.