Tasmantid hotspot

The Tasmantid hotspot is a volcanic hotspot located in the South Pacific Ocean. The northward movement of the Indo-Australian Plate over the last 60 million years coupled with volcanism of the Tasmantid hotspot has resulted in a north–south line of submarine volcanoes called the Tasmantid Seamount Chain.^[3] This includes over 10 seamounts, the youngest of which is the seven million year old Gascoyne Seamount.^[3][4] The Tasmantid hotspot is now 400 km (250 mi) south of Gascoyne Seamount and is defined by a prominent zone of seismic activity.^[3][1][2]

Tasmantid hotspot

800km 500miles Tasmantid Seamounts 55.0 Ma 50.5 Ma 49.3 Ma 46.0 Ma 42.8 Ma 37.0 Ma 31.7 Ma 31.3 Ma 26.4 Ma 26.4 Ma 27.3 Ma 20.9 Ma 17.6 Ma 16.8 Ma 10.3 Ma 7.1 Ma Hotspot (current seismic activity)    Seamount ages from Tasmantid hotspot origin[1][2]
The Tasmantid hotspot is marked 39 on map
Region	South Pacific Ocean
Coordinates	40.24°S 155.30°E / -40.24; 155.30

Main article: Tasmantid Seamount Chain

Due to plate tectonics the hotspot was under different parts of the seabed in the past. It was initially centred under what is now the southern Coral Sea about 60 million years ago somewhere close to where the present Louisiade Plateau is located, so it has been suggested that the Louisiade Plateau might be a large igneous province created by the hotspot.^[5] At the southern boundary of the plateau are volcanic rocks that appear in age and type to be able to be assigned to a Tasmantid volcano.^[1] As the Indo-Australian Plate continued to drift northwards the hotspot became positioned in the northern Tasman Sea 20 million years ago, eventually reaching its current location east of Tasmania in response to ongoing northward plate motion.^[3]

The erupted volcanics are saturated tholeiitic to transitional alkali-olivine basalt.^[1]

Topographic map of Zealandia that includes the line of submerged volcanos to the east of the Australian coast that resulted from the activity of the Tasmantid hotspot . The current location of the Tasmantid hotspot is just below the word Tasman of the label on the map of the Tasman Sea.

References

1. Douglas (Smethurst), Amelia. The East Australian, Tasmantid and Lord Howe volcanoes : exploring the origins of three, contemporaneous, parallel chains of volcanism. (PhD thesis and appendix) (Thesis). doi:10.7488/era/2805. Retrieved 2023-03-30.
2. "USGS". Retrieved 23 March 2024.
3. Johnson, R. W.; Knutson, J.; Taylor, S. R. (1989). Intraplate Volcanism: In Eastern Australia and New Zealand. Australian Academy of Science. p. 52. ISBN 0-521-38083-9.
4. W. J. Morgan and J. P. Morgan. "Plate velocities in hotspot reference frame: electronic supplement" (PDF). Retrieved 2017-02-24.
5. Kalnins, L. M.; Cohen, B. E.; Fitton, J. G.; Mark, D. F.; Richards, F. D.; Barfod, D. N. (2015). "The East Australian, Tasmantid, and Lord Howe Volcanic Chains: Possible mechanisms behind a trio of hotspot trails". AGU Fall Meeting Abstracts. 2015. American Geophysical Union: DI41A–2591. Bibcode:2015AGUFMDI41A2591K.