Hotspots

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. A **hotspot track** results if such a region is moving relative to the mantle. A hotspot's 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.

## Origin

The origins of the concept of hotspots lie in the work of J. Tuzo Wilson, who postulated in 1963 that the formation of the Hawaiian Islands resulted from the slow movement of a tectonic plate across a hot region beneath the surface. It was later postulated that hotspots are fed by narrow streams of hot mantle rising from the Earth's core–mantle boundary in a structure called a mantle plume. Whether or not such mantle plumes exist is the subject of a major controversy in Earth science. Estimates for the number of hotspots postulated to be fed by mantle plumes have ranged from about 20 to several thousands, over the years, with most geologists considering a few tens to exist. Hawaii, Réunion, Yellowstone, Galápagos, and Iceland are some of the most active volcanic regions to which the hypothesis is applied.

## Composition

Most hotspot volcanoes are basaltic (e.g., Hawaii, Tahiti). As a result, they are less explosive than subduction zone volcanoes, in which water is trapped under the overriding plate. Where hotspots occur in continental regions, basaltic magma rises through the continental crust, which melts to form rhyolites. These rhyolites can form violent eruptions. For example, the Yellowstone Caldera was formed by some of the most powerful volcanic explosions in geologic history. However, when the rhyolite is completely erupted, it may be followed by eruptions of basaltic magma rising through the same lithospheric fissures (cracks in the lithosphere). An example of this activity is the Ilgachuz Range in British Columbia, which was created by an early complex series of trachyte and rhyolite eruptions, and late extrusion of a sequence of basaltic lava flows.

The hotspot hypothesis is now closely linked to the mantle plume hypothesis.

## Comparison with island arc volcanoes

Hotspot volcanoes are considered to have a fundamentally different origin from island arc volcanoes. The latter form over subduction zones, at converging plate boundaries. When one oceanic plate meets another, the denser plate is forced downward into a deep ocean trench. This plate, as it is subducted, releases water into the base of the over-riding plate, and this water mixes with the rock, thus changing its composition causing some rock to melt and rise. It is this that fuels a chain of volcanoes, such as the Aleutian Islands, near Alaska.

## Hotspot volcanic chains

The joint mantle plume/hotspot hypothesis envisages the feeder structures to be fixed relative to one another, with the continents and seafloor drifting overhead. The hypothesis thus predicts that time-progressive chains of volcanoes are developed on the surface. Examples are Yellowstone, which lies at the end of a chain of extinct calderas, which become progressively older to the west. Another example is the Hawaiian archipelago, where islands become progressively older and more deeply eroded to the northwest.

Geologists have tried to use hotspot volcanic chains to track the movement of the Earth's tectonic plates. This effort has been vexed by the lack of very long chains, by the fact that many are not time-progressive (e.g. the Galápagos) and by the fact that hotspots do not appear to be fixed relative to one another (e.g. Hawaii and Iceland.)

### Postulated hotspot volcano chains

* Hawaiian–Emperor seamount chain (Hawaii hotspot)
* Louisville Ridge (Louisville hotspot)
* Walvis Ridge (Gough and Tristan hotspot)
* Kodiak–Bowie Seamount chain (Bowie hotspot)
* Cobb–Eickelberg Seamount chain (Cobb hotspot)
* New England Seamounts (New England hotspot)
* Anahim Volcanic Belt (Anahim hotspot)
* Mackenzie dike swarm (Mackenzie hotspot)
* Great Meteor hotspot track (New England hotspot)
* St. Helena Seamount Chain–Cameroon Volcanic Line (Saint Helena hotspot)
* Southern Mascarene Plateau–Chagos-Maldives-Laccadive Ridge (Réunion hotspot)
* Ninety East Ridge (Kerguelen hotspot)
* Tuamotu–Line Island chain (Easter hotspot)
* Austral–Gilbert–Marshall chain (Macdonald hotspot)
* Juan Fernández Ridge (Juan Fernández hotspot)
* Tasmantid Seamount Chain (Tasmantid hotspot)

### List of volcanic regions postulated to be hotspots

#### Eurasian Plate

* Eifel hotspot (8)
	+ &title=Eifel+hotspot Template:Coord/dec2dms/dmN Template:Coord/dec2dms/dmE﻿
	 ﻿ , w= 1 az= 082° ±8° rate= 12 ±2 mm/yr
* Iceland hotspot (14)
	+ &title=Iceland+hotspot Template:Coord/dec2dms/dmN Template:Coord/dec2dms/dmW﻿
	 ﻿
		- Eurasian Plate, w= .8 az= 075° ±10° rate= 5 ±3 mm/yr
		- North American Plate, w= .8 az= 287° ±10° rate= 15 ±5 mm/yr
	+ Possibly related to the North Atlantic continental rifting (62 Ma), Greenland.
* Azores hotspot (1)
	+ &title=Azores+hotspot Template:Coord/dec2dms/dmN Template:Coord/dec2dms/dmW﻿
	 ﻿
		- Eurasian Plate, w= .5 az= 110° ±12°
		- North American Plate, w= .3 az= 280° ±15°
* Jan Mayen hotspot (15)
	+ &title=Jan+Mayen+hotspot Template:Coord/dec2dms/dmN Template:Coord/dec2dms/dmW﻿
	 ﻿
* Hainan hotspot (46)
	+ &title=Hainan+hotspot Template:Coord/dec2dms/dmN Template:Coord/dec2dms/dmE﻿
	 ﻿ , az= 000° ±15°

#### African Plate

* Mount Etna (47)
	+ &title=Mount+Etna 37°45′N 15°00′E﻿
	 ﻿
* Hoggar hotspot (13)
	+ &title=Hoggar+hotspot Template:Coord/dec2dms/dmN Template:Coord/dec2dms/dmE﻿
	 ﻿ , w= .3 az= 046° ±12°
* Tibesti hotspot (40)
	+ &title=Tibesti+hotspot Template:Coord/dec2dms/dmN Template:Coord/dec2dms/dmE﻿
	 ﻿ , w= .2 az= 030° ±15°
* Jebel Marra/Darfur hotspot (6)
	+ &title=Darfur+hotspot Template:Coord/dec2dms/dmN Template:Coord/dec2dms/dmE﻿
	 ﻿ , w= .5 az= 045° ±8°
* Afar hotspot (29, misplaced in map)
	+ &title=Afar+hotspot Template:Coord/dec2dms/dmN Template:Coord/dec2dms/dmE﻿
	 ﻿ , w= .2 az= 030° ±15° rate= 16 ±8 mm/yr
	+ Possibly related to the Afar Triple Junction, 30 Ma.
* Cameroon hotspot (17)
	+ &title=Cameroon+hotspot Template:Coord/dec2dms/dmN Template:Coord/dec2dms/dmE﻿
	 ﻿ , w= .3 az= 032° ±3° rate= 15 ±5 mm/yr
* Madeira hotspot (48)
	+ &title=Madeira+hotspot Template:Coord/dec2dms/dmN Template:Coord/dec2dms/dmW﻿
	 ﻿ , w= .3 az= 055° ±15° rate= 8 ±3 mm/yr
* Canary hotspot (18)
	+ &title=Canary+hotspot Template:Coord/dec2dms/dmN Template:Coord/dec2dms/dmW﻿
	 ﻿ , w= 1 az= 094° ±8° rate= 20 ±4 mm/yr
* New England/Great Meteor hotspot (28)
	+ &title=Great+Meteor+hotspot Template:Coord/dec2dms/dmN Template:Coord/dec2dms/dmW﻿
	 ﻿ , w= .8 az= 040° ±10°
* Cape Verde hotspot (19)
	+ &title=Cape+Verde+hotspot Template:Coord/dec2dms/dmN Template:Coord/dec2dms/dmW﻿
	 ﻿ , w= .2 az= 060° ±30°
* St. Helena hotspot (34)
	+ &title=St.+Helena+hotspot Template:Coord/dec2dms/dmS Template:Coord/dec2dms/dmW﻿
	 ﻿ , w= 1 az= 078° ±5° rate= 20 ±3 mm/yr
* Gough hotspot (49), at 40°19' S 9°56' W.
	+ &title=Gough+hotspot Template:Coord/dec2dms/dmS Template:Coord/dec2dms/dmE﻿
	 ﻿ , w= .8 az= 079° ±5° rate= 18 ±3 mm/yr
* Tristan hotspot (42), at 37°07′ S 12°17′ W.
	+ &title=Tristan+hotspot Template:Coord/dec2dms/dmS Template:Coord/dec2dms/dmW﻿
	 ﻿
* Vema hotspot (Vema Seamount, 43), at 31°38' S 8°20' E.
	+ &title=Vema+hotspot Template:Coord/dec2dms/dmS Template:Coord/dec2dms/dmW﻿
	 ﻿
	+ Related maybe to the Paraná and Etendeka traps (c. 132 Ma) through the Walvis Ridge.
* Discovery hotspot (50) (Discovery Seamounts)
	+ &title=Discovery+hotspot Template:Coord/dec2dms/dmS Template:Coord/dec2dms/dmW﻿
	 ﻿ , w= 1 az= 068° ±3°
* Bouvet hotspot (51)
	+ &title=Bouvet+hotspot Template:Coord/dec2dms/dmS Template:Coord/dec2dms/dmE﻿
	 ﻿
* Shona/Meteor hotspot (27)
	+ &title=Shona+hotspot Template:Coord/dec2dms/dmS Template:Coord/dec2dms/dmW﻿
	 ﻿ , w= .3 az= 074° ±6°
* Réunion hotspot (33)
	+ &title=R%C3%A9union+hotspot Template:Coord/dec2dms/dmS Template:Coord/dec2dms/dmE﻿
	 ﻿ , w= .8 az= 047° ±10° rate= 40 ±10 mm/yr
	+ Possibly related to the Deccan Traps (main events: 68.5–66 Ma)
* Comoros hotspot (21)
	+ &title=Comoros+hotspot Template:Coord/dec2dms/dmS Template:Coord/dec2dms/dmE﻿
	 ﻿ , w= .5 az=118 ±10° rate=35 ±10 mm/yr

#### Antarctic Plate

* Marion hotspot (25)
	+ &title=Marion+hotspot Template:Coord/dec2dms/dmS Template:Coord/dec2dms/dmE﻿
	 ﻿ , w= .5 az= 080° ±12°
* Crozet hotspot (52)
	+ &title=Crozet+hotspot Template:Coord/dec2dms/dmS Template:Coord/dec2dms/dmE﻿
	 ﻿ , w= .8 az= 109° ±10° rate= 25 ±13 mm/yr
	+ Possibly related to the Karoo-Ferrar geologic province (183 Ma)
* Kerguelen hotspot (20)
	+ &title=Kerguelen+hotspot Template:Coord/dec2dms/dmS Template:Coord/dec2dms/dmE﻿
	 ﻿ , w= .2 az= 050° ±30° rate= 3 ±1 mm/yr
	+ Île Saint-Paul and Île Amsterdam could be part of the Kerguelen hotspot trail (St. Paul is probably not another hotspot)
	+ Related maybe to the Kerguelen Plateau (130 Ma)
* Heard hotspot (53)
	+ &title=Heard+hotspot Template:Coord/dec2dms/dmS Template:Coord/dec2dms/dmE﻿
	 ﻿ , w= .2 az= 030° ±20°
* Balleny hotspot (2)
	+ &title=Balleny+hotspot Template:Coord/dec2dms/dmS Template:Coord/dec2dms/dmE﻿
	 ﻿ , w= .2 az= 325° ±7°
* Erebus hotspot (54)
	+ &title=Erebus+hotspot Template:Coord/dec2dms/dmS Template:Coord/dec2dms/dmE﻿
	 ﻿

#### South American Plate

* Trindade/Martin Vaz hotspot (41)
	+ &title=Trindade+hotspot Template:Coord/dec2dms/dmS Template:Coord/dec2dms/dmW﻿
	 ﻿ , w= 1 az= 264° ±5°
* Fernando hotspot (9)
	+ &title=Fernando+hotspot Template:Coord/dec2dms/dmS Template:Coord/dec2dms/dmW﻿
	 ﻿ , w= 1 az= 266° ±7°
	+ Possibly related to the Central Atlantic Magmatic Province (c. 200 Ma)
* Ascension hotspot (55)
	+ &title=Ascension+hotspot Template:Coord/dec2dms/dmS Template:Coord/dec2dms/dmW﻿
	 ﻿

#### North American Plate

* Bermuda hotspot (56)
	+ &title=Bermuda+hotspot Template:Coord/dec2dms/dmN Template:Coord/dec2dms/dmW﻿
	 ﻿ , w= .3 az= 260° ±15°
* Yellowstone hotspot (44)
	+ &title=Yellowstone+hotspot Template:Coord/dec2dms/dmN Template:Coord/dec2dms/dmW﻿
	 ﻿ , w= .8 az= 235° ±5° rate= 26 ±5 mm/yr
	+ Possibly related to the Columbia River Basalt Group (17–14 Ma).
* Raton hotspot (32)
	+ &title=Raton+hotspot Template:Coord/dec2dms/dmN Template:Coord/dec2dms/dmW﻿
	 ﻿ , w= 1 az= 240°±4° rate= 30 ±20 mm/yr
* Anahim hotspot (45)
	+ &title=Anahim+hotspot 52°54′N 123°44′W﻿
	 ﻿  (Nazko Cone)

#### Indo-Australian Plate

* Lord Howe hotspot (22)
	+ &title=Lord+Howe+hotspot Template:Coord/dec2dms/dmS Template:Coord/dec2dms/dmE﻿
	 ﻿ , w= .8 az= 351° ±10°
* Tasmantid hotspot (39)
	+ &title=Tasmanid+hotspot Template:Coord/dec2dms/dmS Template:Coord/dec2dms/dmE﻿
	 ﻿ , w= .8 az= 007° ±5° rate= 63 ±5 mm/yr
* East Australia hotspot (30)
	+ &title=East+Australia+hotspot Template:Coord/dec2dms/dmS Template:Coord/dec2dms/dmE﻿
	 ﻿ , w= .3 az= 000° ±15° rate= 65 ±3 mm/yr

#### Nazca Plate

* Juan Fernández hotspot (16)
	+ &title=Juan+Fern%C3%A1ndez+hotspot Template:Coord/dec2dms/dmS Template:Coord/dec2dms/dmW﻿
	 ﻿ , w= 1 az= 084° ±3° rate= 80 ±20 mm/yr
* San Felix hotspot (36)
	+ &title=San+Felix+hotspot Template:Coord/dec2dms/dmS Template:Coord/dec2dms/dmW﻿
	 ﻿ , w= .3 az= 083° ±8°
* Easter hotspot (7)
	+ &title=Easter+hotspot Template:Coord/dec2dms/dmS Template:Coord/dec2dms/dmW﻿
	 ﻿ , w= 1 az= 087° ±3° rate= 95 ±5 mm/yr
* Galápagos hotspot (10)
	+ &title=Gal%C3%A1pagos+hotspot Template:Coord/dec2dms/dmS Template:Coord/dec2dms/dmW﻿
	 ﻿
		- Nazca Plate, w= 1 az= 096° ±5° rate= 55 ±8 mm/yr
		- Cocos Plate, w= .5 az= 045° ±6°
	+ Possibly related to the Caribbean large igneous province (main events: 95–88 Ma).

#### Pacific Plate

* Louisville hotspot (23)
	+ &title=Louisville+hotspot Template:Coord/dec2dms/dmS Template:Coord/dec2dms/dmW﻿
	 ﻿ , w= 1 az= 316° ±5° rate= 67 ±5 mm/yr
	+ Possibly related to the Ontong Java Plateau (125–120 Ma).
* Foundation hotspot/Ngatemato seamounts (57)
	+ &title=Foundation+hotspot Template:Coord/dec2dms/dmS Template:Coord/dec2dms/dmW﻿
	 ﻿ , w= 1 az= 292° ±3° rate= 80 ±6 mm/yr
* Macdonald hotspot (24)
	+ &title=Macdonald+hotspot Template:Coord/dec2dms/dmS Template:Coord/dec2dms/dmW﻿
	 ﻿ , w= 1 az= 289° ±6° rate= 105 ±10 mm/yr
* North Austral/President Thiers (President Thiers Bank, 58)
	+ &title=North+Austral+hotspot Template:Coord/dec2dms/dmS Template:Coord/dec2dms/dmW﻿
	 ﻿ , w= (1.0) azim= 293° ± 3° rate= 75 ±15 mm/yr
* Arago hotspot (Arago Seamount, 59)
	+ &title=Arago+hotspot Template:Coord/dec2dms/dmS Template:Coord/dec2dms/dmW﻿
	 ﻿ , w= 1 azim= 296° ±4° rate= 120 ±20 mm/yr
* Maria/Southern Cook hotspot (Îles Maria, 60)
	+ &title=Maria%2FSouthern+Cook+hotspot Template:Coord/dec2dms/dmS Template:Coord/dec2dms/dmW﻿
	 ﻿ , w= 0.8 az= 300° ±4°
* Samoa hotspot (35)
	+ &title=Samoa+hotspot Template:Coord/dec2dms/dmS Template:Coord/dec2dms/dmW﻿
	 ﻿ , w= .8 az= 285°±5° rate= 95 ±20 mm/yr
* Crough hotspot (Crough Seamount, 61)
	+ &title=Crough+hotspot Template:Coord/dec2dms/dmS Template:Coord/dec2dms/dmW﻿
	 ﻿ , w= .8 az= 284° ± 2°
* Pitcairn hotspot (31)
	+ &title=Pitcairn+hotspot Template:Coord/dec2dms/dmS Template:Coord/dec2dms/dmW﻿
	 ﻿ , w= 1 az= 293° ±3° rate= 90 ±15 mm/yr
* Society/Tahiti hotspot (38)
	+ &title=Society+hotspot Template:Coord/dec2dms/dmS Template:Coord/dec2dms/dmW﻿
	 ﻿ , w= .8 az= 295°±5° rate= 109 ±10 mm/yr
* Marquesas hotspot (26)
	+ &title=Marquesas+hotspot Template:Coord/dec2dms/dmS Template:Coord/dec2dms/dmW﻿
	 ﻿ , w= .5 az= 319° ±8° rate= 93 ±7 mm/yr
* Caroline hotspot (4)
	+ &title=Caroline+hotspot Template:Coord/dec2dms/dmN Template:Coord/dec2dms/dmE﻿
	 ﻿ , w= 1 az= 289° ±4° rate= 135 ±20 mm/yr
* Hawaii hotspot (12)
	+ &title=Hawaii+hotspot Template:Coord/dec2dms/dmN Template:Coord/dec2dms/dmW﻿
	 ﻿ , w= 1 az= 304° ±3° rate= 92 ±3 mm/yr
* Socorro/Revillagigedos hotspot (37)
	+ &title=Socorro Template:Coord/dec2dms/dmN Template:Coord/dec2dms/dmW﻿
	 ﻿
* Guadalupe hotspot (11)
	+ &title=Guadalupe+hotspot Template:Coord/dec2dms/dmN Template:Coord/dec2dms/dmW﻿
	 ﻿ , w= .8 az= 292° ±5° rate= 80 ±10 mm/yr
* Cobb hotspot (5)
	+ &title=Cobb+hotspot Template:Coord/dec2dms/dmN Template:Coord/dec2dms/dmW﻿
	 ﻿ , w= 1 az= 321° ±5° rate= 43 ±3 mm/yr
* Bowie/Pratt-Welker hotspot (3)
	+ &title=Bowie+hotspot Template:Coord/dec2dms/dmN Template:Coord/dec2dms/dmW﻿
	 ﻿ , w=.8 az= 306° ±4° rate= 40 ±20 mm/yr

## Former hotspots

* Euterpe/Musicians hotspot (Musicians Seamounts)
* Mackenzie hotspot
* Matachewan hotspot