The geology of the Canary Islands is dominated by volcanic rock. The Canary Islands and some seamounts to the north-east form the Canary Volcanic Province, whose volcanic history started about 70 million years ago. [1] The Canary Islands region is still volcanically active. The most recent volcanic eruption on land occurred in 2021 [2] and the most recent underwater eruption was in 2011-12. [1]
The Canary Islands are a 450 km (280 mi) long, east-west trending, archipelago of volcanic islands in the North Atlantic Ocean, 100–500 km (60–310 mi) off the coast of Northwest Africa. [3] The islands are located on the African tectonic plate. The Canary Islands are an example of intraplate volcanism because they are located far (more than 600 km (370 mi)) from the edges of the African Plate. [4]
From east to west, the main islands are Lanzarote, Fuerteventura, Gran Canaria, Tenerife, La Gomera, La Palma, and El Hierro. [Note 1] There are also several minor islands and islets. The seven main Canary Islands originated as separate submarine seamount volcanoes on the floor of the Atlantic Ocean, which is 1,000–4,000 m (3,000–13,000 ft) deep in the Canarian region.
Lanzarote and Fuerteventura are parts of a single volcanic ridge called the Canary Ridge. These two present-day islands have sometimes been a single island in the past. Part of the ridge is now submerged, and Lanzarote and Fuerteventura are separate islands, separated by an 11 km (7 mi) wide, 40 m (130 ft) deep strait of ocean water. [6]
Volcanic activity has occurred during the last 11,700 years on all of the main islands except La Gomera. [7]
Volcanic activity in the Canary Volcanic Province started about 70 Ma (million years ago), occurring at numerous seamounts and the Savage Islands, across an area of the ocean floor up to 400 km north of the Canary Islands. The northernmost of this group of seamounts, Lars seamount (about 380 km north of Lanzarote), has been dated to 68 Ma. The seamounts are progressively younger southwestwards towards Lanzarote. [8]
The Canary Islands are built upon one the oldest regions of Earth's oceanic crust (175–147 Ma), part of the slow-moving African Plate, in the continental rise section of northwest Africa's passive continental margin. [9] [10] The oceanic lithosphere is about 60 km thick at the central Canary Islands and about 100 km thick at the western islands. [11]
Two seamounts, Las Hijas (southwest of El Hierro) and El Hijo de Tenerife (about 200,000 years old, located between Gran Canaria and Tenerife) may eventually (in the next 500,000 years) form new islands by future eruptions adding more lava flows to their volcanic edifices. [12]
Volcanic oceanic islands, such as the Canary Islands, form in deep parts of the oceans. This type of island forms by a sequence of development stages: [13]
The Canary Islands differ from some other volcanic oceanic islands, such as the Hawaiian Islands: for example, the Canary Islands have stratovolcanoes, compression structures and a lack of significant subsidence. [13]
The seven main Canary Islands originated as separate submarine seamount volcanoes on the floor of the Atlantic Ocean. Each seamount, built up by the eruption of many lava flows, eventually became an island. Subaerial volcanic eruptions continued on each island. Late-stage fissure eruptions dominated on Lanzarote and Fuerteventura, resulting in relatively subdued topography with heights below 1,000 m (3,300 ft). The other islands are much more rugged and mountainous. In the case of Tenerife, the volcanic edifice of Teide rises about 7,500 m (24,600 ft) above the ocean floor (about 3,780 m (12,400 ft) underwater and 3,715 m (12,188 ft) above sea level). [14] [15]
The volume of volcanic rock that has built up the Canary Islands to thousands of metres above the ocean floor is about 124,600 km3; 96% of this lava is hidden below sea level and only 4% (4,940 km3) is above sea level. [16] The western islands have more of their volume (7%) above sea level than do the eastern islands (2%). [16]
The age of the oldest subaerially-erupted lavas on each island decreases from east to west along the island chain: Lanzarote-Fuerteventura (20.2 Ma), Gran Canaria (14.6 Ma), Tenerife (11.9 Ma), La Gomera (9.4 Ma), La Palma (1.7 Ma) and El Hierro (1.1 Ma). [17] [4]
Volcanic rock types found on the Canary Islands are typical of oceanic islands. The volcanic rocks include alkali basalts, basanites, phonolites, trachytes, nephelinites, trachyandesites, tephrites and rhyolites. [13] [7]
Outcrops of plutonic rocks (for example, syenites, gabbros and pyroxenites) that formed deep below the surface occur on Fuerteventura, [18] La Gomera and La Palma. Apart from some islands of Cape Verde (another volcanic island group in the Atlantic Ocean, about 1,400 km (900 mi) south-west of the Canary Islands), Fuerteventura is the only oceanic island known to have outcrops of carbonatite. [19]
Examples of the following types of volcanic landforms occur in the Canary Islands: shield volcano, stratovolcano, collapse caldera, erosion caldera, cinder cone, coulee, scoria cone, tuff cone, tuff ring, maar, lava flow, lava flow field, dyke, volcanic plug. [20]
Several hypotheses have been proposed to explain the volcanism of the Canary Islands. [21] Two hypotheses have received the most attention from geologists:
Currently, a hotspot (the Canary hotspot) is the explanation accepted by most geologists who study the Canary Islands. [22] [23]
Evidence in favour of a hotspot origin for Canarian volcanism includes the age progression in the arcuate Canary Volcanic Province occurring in the same direction and at the same rate as in the neighbouring arcuate Madeira Volcanic Province (about 450 km farther north). This is consistent with the African Plate rotating anticlockwise at about 12 mm per year. [24] Also, seismic tomography has revealed the existence of a region of hot rock extending from the surface, down through the oceanic lithosphere to a depth of at least 1,000 km in the upper mantle. [25]
Seventy-five confirmed volcanic eruptions have occurred in the Canary Islands in the Holocene Epoch (the last 11,700 years of Earth's geological history). [26] Sixteen of these eruptions have been during the Modern Era of European history (that is, after c.1480). [26] Therefore, in the last 500 years, volcanic eruptions have occurred, on average, every 30 to 35 years. [27] However, in the Modern Era, the repose period between infrequent eruptions at each volcano has been highly variable (26 to 237 years for Cumbre Vieja on La Palma; 1 to 212 years for Tenerife), making reliable prediction of future eruptions unlikely. [28] [26]
Island | Holocene (last 11,700 years) | Modern Era (since c. 1480) | Modern Era eruption dates | Notes | Ref. |
---|---|---|---|---|---|
Lanzarote | 4 | 2 | 1730–1736, 1824 | [29] | |
Fuerteventura | 0 | 0 | —— | No specific confirmed Holocene eruptions, but they are inferred to have occurred (based on the freshness of lava and volcanic landforms) | [30] |
Gran Canaria | 11 | 0 | —— | [31] | |
Tenerife | 42 | 5 | 1492, 1704–1705, 1706, 1798, 1909 | [32] | |
La Gomera | 0 | 0 | —— | [27] | |
La Palma | 14 | 8 | 1481(±11), 1585, 1646, 1677–1678, 1712, 1949, 1971, 2021 | [33] | |
El Hierro | 4 | 1 | 2011–2012 | [34] |
Volcanic activity at Lanzarote started during the Oligocene Epoch at 28 Ma. [35] For about the first 12 million years, the lava pile of a submarine seamount built up from the 2,500 m deep sea floor. [36] Then, in the Miocene Epoch, from 15.6 Ma to 12 Ma, the Los Ajaches subaerial shield volcano grew as an island on top of the seamount, in an area corresponding to present-day southern Lanzarote. [37] Between 10.2 Ma and 3.8 Ma, volcanic activity was focussed about 35 km to the northeast, forming a second shield volcanic island called Famara. [38] Between Los Ajaches and Famara volcanoes, a central volcanic edifice was also active from 6.6 to 6.1 Ma. [39] The edifices gradually merged to form a single island, Lanzarote, at about 4 Ma. [40] From 3.9 Ma to 2.7 Ma, volcanic activity paused and the island was eroded. [41] Today, although the lavas of Los Ajaches volcano are now mostly covered by calcrete, [42] the eroded remains of the two shield volcanoes are preserved in southern and northern Lanzarote respectively, with small outcrops of the central edifice occurring between them. At about 2.7 Ma, in the late Pliocene Epoch, the rejuvenation stage began. It produced much less lava than the earlier shield stage, mainly at the Montaña Roja and Montaña Bermeja volcanoes in southern Lanzarote. [41] Then, throughout the subsequent Pleistocene and Holocene epochs, the rejuvenation volcanism has continued and has been dominated by strombolian-style eruptions of lava from sets of volcanic cones aligned along numerous NE-SW fissures in the central part of Lanzarote. [43] Geologically recent examples of rejuvenation stage volcanism include eruptions at Montaña Corona (about 21,000 years ago), Timanfaya (1730-1736) and Tao/Nuevo del Fuego/Tinguatón (1824). [44] [45] [46]
The Timanfaya eruption (1730–1736) erupted more than one billion cubic metres (1 km3) of lava, and a large volume of pyroclastic tephra, from more than 30 volcanic vents along a 14 km-long fissure in western Lanzarote. The lava flows cover one quarter of the island (an area of about 225 km2) with some of the flows reaching about 50 m in thickness. It is the largest Modern Era eruption in the Canary Islands, and the third largest eruption of basaltic lava on Earth in historical times. [47] [48] [49] [50] [51]
Almost all the volcanic rocks of Lanzarote are basaltic. [52]
Fuerteventura is situated on Mesozoic oceanic crust, about 70 km from the edge of the African continental shelf and about 100 km from the African mainland, making it the Canarian island closest to Africa.
Due to its old age, the oceanic crust at Fuerteventura is relatively rigid and this has prevented subsidence and allowed weathering and erosion to expose deep levels of the island's geological structure. [53]
The two main rock sequences of Fuerteventura are (1) a lower, older (Cretaceous to early Miocene) sequence of sedimentary, plutonic and submarine volcanic rocks with intrusive dykes, often called the "basal complex", which is unconformably overlain by (2) a younger sequence of Miocene, Pliocene and Quaternary subaerial volcanic rocks.
The oldest rocks of Fuerteventura are a set of mafic plutonic rocks, marine sedimentary rocks and volcanic rocks, which are intruded by igneous dykes. [54] The sedimentary rocks of the basal complex were deposited on the seafloor and represent the uppermost part of the oceanic crust that was uplifted and incorporated into the volcanic edifice during volcanic activity. The Mesozoic sedimentary rocks are mostly metamorphosed, and they are steeply tilted. The tilting occurred in the mid-Cretaceous and was probably caused by the uplift of Africa. [55] [56] The igneous rocks of the basal complex probably represent the seamount stage of Fuerteventura’s volcanic history, exposed due to uplift and erosion. [57]
In the early Miocene, volcanic activity transitioned from submarine to subaerial while the volcanic edifice was gradually built up above sea level. Fuerteventura has the oldest subaerial volcanic rocks of the Canary Islands, which have been dated to 20.6 Ma. [58] There were three main shield volcanoes built on the seamount base (from north to south): the Northern Edifice, the Central Edifice and the Jandia Edifice. [59] [60] The central shield volcano is the oldest, built mostly from 22 to 18 Ma but with a later phase from 17.5 to 13 Ma. The southern shield volcano formed from 21 to 14 Ma. The northern shield volcano was built mainly from 17 to 12 Ma. [61] These shield volcanoes erupted mostly basaltic and trachybasaltic lava flows. [62]
In the late Miocene (from about 11.5 Ma), there was a pause in volcanic activity (the erosional stage). Minor volcanic eruptions resumed in the Pliocene, at about 5.1 Ma (the rejuvenation stage) and they continued sporadically into the Quaternary, with basaltic lava flows dominating again. [63]
The most recent volcanic eruption on Fuerteventura that has been dated occurred 134,000 years ago in the middle Pleistocene. [64] Some undated volcanic cones in northern Fuerteventura may have formed more recently. [65]
Weathering, erosion and sedimentation during the Pliocene and Quaternary formed coastal and shallow-sea sedimentary rocks that were eventually covered by younger aeolian sediments, alluvial fan deposits and palaeosols. [66]
After early Miocene submarine volcanic eruptions created a seamount, subaerial volcanic activity at Gran Canaria occurred in three phases: shield stage (middle- and late-Miocene, 14.5 to 8.5 Ma), erosional stage (late Miocene, 8.5 to 5.3 Ma) and rejuvenated stage (Pliocene to Quaternary, 5.3 Ma to present). [67]
The shield stage started with an early phase of eruptions of basaltic lava flows, from 14.5 to 14.1 Ma, which built the main subaerial shield volcanic edifice that forms three quarters of the subaerial volume of Gran Canaria. [68] At least three shield volcanoes were active during this stage of island development and their lava flows gradually merged together into a single large landform. [69] This was followed by a later phase, from 14.1 to 8.5 Ma, of explosive volcanic eruptions of differentiated felsic lavas (phonolites, trachytes and rhyolites) with many pyroclastic flows (that deposited ignimbrites). In central Gran Canaria, Tejeda caldera and a cone sheet swarm were formed in this phase. [70]
From 8.5 to 5.3 Ma, in the erosional stage, there was minimal volcanic activity. Erosion occurred along with deposition of alluvial sediments on the island and deposition of submarine turbidite sediments offshore. [71]
In the rejuvenation stage, from 5.3 Ma to present, volcanic activity has occurred in three phases. The first phase, from 5.3 to 2.7 Ma, was dominated by the formation of Roque Nublo statovolcano in the central part of Gran Canaria. This produced lava flows, ignimbrites and debris avalanche deposits. [72] The second phase (3.5 to 1.5 Ma) had strombolian-style effusive eruptions of lava flows along a northwest-southeast trending volcanic rift. [73] The current phase, from 1.3 Ma to the present, has featured scattered phreatomagmatic and strombolian eruptions of very alkaline lavas. [74] The most recent volcanic eruption on Gran Canaria occurred about 2,000 years ago at Bandama crater, in the northeast part of the island. [75] [76]
Sand dunes, with a total volume of 18 million cubic metres, cover an area of 3.6 km2 of the Maspalomas cuspate foreland on Gran Canaria's south coast. [77] Aeolian landforms found in this dune field include barchan dunes and dune ridges (transverse dunes). The dunes are made of sand grains and pebbles. The average thickness of the dunes is 5–10 m but some dunes reach 20 m thick. [78] In a few areas, the underlying deltaic sediments are exposed. [79] The sand that has built the dunes has been moved about 2 or 3 kilometres by water waves and wind from the sediment source area (an offshore submarine shelf at Playa del Inglés). Since the 1960's, urbanisation has affected the local winds and this has caused the gradual reduction in volume and area of the dune field because sediment erosion now exceeds sediment deposition. [80] The dunes had long been thought to have formed during the last several thousand years [81] but a 2021 study found evidence supporting a hypothesis that the dunes formed less than 300 years ago, as a consequence of a tsunami generated by the 1755 Lisbon earthquake. [82] [83]
The seismicity of the Canary Islands is low. Earthquakes that occur on or near the Canary Islands are linked to volcanism and tectonism. On the Modified Mercalli Scale (an earthquake intensity scale ranging from I for "not felt" to XII for "extreme"), most earthquakes in the region have had an intensity of VI or less. The Timanfaya eruptions on Lanzarote in 1730, however, were accompanied by earthquakes with intensities of up to X on the same scale. [84]
From 1 January 1975 to 31 December 2023, 168 earthquakes of magnitude 2.5 or larger, with epicentres on or close to the Canary Islands, were recorded; the largest of these earthquakes had a moment magnitude of 5.4 and an intensity of VII with its epicentre on the ocean floor about 28 km west of El Hierro in 2013. [85]
In 2004, an earthquake swarm occurred on Tenerife, which raised concern that a volcanic eruption may have been about to occur but no such eruption followed the swarm. [86] [87]
Earthquake swarms, due to the underground movement of molten magma, were detected before and during the volcanic eruptions of 2011–2012 and 2021. In the week before the 2021 eruption on La Palma, a swarm of more than 22,000 earthquakes occurred, with mbLg magnitudes up to about 3.5. The hypocentres of successive earthquakes migrated upwards as magma rose slowly to the surface. [88] [89] [90] During the eruption, larger earthquakes were detected, for example an earthquake of mbLg magnitude 4.3 occurred 35 km below the surface. [91]
At least four tsunamis, triggered by distant earthquakes, have hit the coasts of the Canary Islands in the Modern Era. They occurred in 1755 (1755 Lisbon earthquake), 1761 (1761 Lisbon earthquake), 1941 (1941 Gloria Fault earthquake) and 1969. [92]
The Canary Islands, also known informally as the Canaries, are a Spanish autonomous community and archipelago in Macaronesia in the Atlantic Ocean. At their closest point to the African mainland, they are 100 kilometres west of Morocco and the Western Sahara. They are the southernmost of the autonomous communities of Spain. The islands have a population of 2.2 million people and are the most populous special territory of the European Union.
Gran Canaria, also Grand Canary Island, is the third-largest and second-most-populous island of the Canary Islands, an archipelago off the Atlantic coast of Northwest Africa and is part of Spain. As of 2023 the island had a population of 862,893 that constitutes approximately 40% of the population of the archipelago. Las Palmas de Gran Canaria, the capital of the island, is the biggest city of the Canary Islands and the ninth of Spain.
La Palma, also known as La isla bonita and historically San Miguel de La Palma, is the most northwesterly island of the Canary Islands, Spain, which is a Spanish autonomous community and archipelago in Macaronesia in the North Atlantic Ocean. La Palma has an area of 708.32 square kilometres (273.48 sq mi) making it the fifth largest of the eight main Canary Islands. The total population at the start of 2023 was 84,338, of which 15,522 lived in the capital, Santa Cruz de La Palma and 20,375 in Los Llanos de Aridane. Its highest mountain is the Roque de los Muchachos, at 2,426 metres (7,959 ft), being second among the peaks of the Canaries after the Teide massif on Tenerife.
Lanzarote is a Spanish island, the easternmost of the Canary Islands in the Atlantic Ocean, 125 kilometres off the north coast of Africa and 1,000 kilometres from the Iberian Peninsula. Covering 845.92 square kilometres, Lanzarote is the fourth-largest of the islands in the archipelago. With 158,798 inhabitants at the start of 2023, it is the third most populous Canary Island, after Tenerife and Gran Canaria. Located in the centre-west of the island is Timanfaya National Park, one of its main attractions. The island was declared a biosphere reserve by UNESCO in 1993. The island's capital is Arrecife, which lies on the eastern coastline. It is the smaller main island of the Province of Las Palmas.
Teide, or Mount Teide, is a volcano on Tenerife in the Canary Islands, Spain. Its summit is the highest point in Spain and the highest point above sea level in the islands of the Atlantic. If measured from the ocean floor, its height of 7,500 m (24,600 ft) makes Teide the third-highest volcano in the world, and is described by UNESCO and NASA as Earth's third-tallest volcanic structure. Teide's elevation above sea level makes Tenerife the tenth highest island in the world.
The Cumbre Vieja is an active volcanic ridge on the island of La Palma in the Canary Islands, Spain. The spine of Cumbre Vieja trends in an approximate north–south direction, comprising the southern half of La Palma, with both summit ridge and flanks pockmarked by dozens of craters and cones. The latest eruption began on 19 September 2021 in a forested area of Las Manchas locality known as Cabeza de Vaca. Voluminous lava flows quickly reached populated areas downslope, fanning out across settlements and banana plantations, destroying thousands of buildings and ultimately pouring over steep cliffs into the ocean to enlarge the island at several locations. The volcano went quiet on 13 December 2021, and on 25 December 2021, the local government declared the eruption to be over.
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Tourism is an essential part of the economy of the Canary Islands, a Spanish archipelago located in the Atlantic Ocean, 100 kilometres west of Morocco. Seven main islands and six islets make up the Canary Islands. They had more than 9 million foreign incoming tourists in 2007. Tourists seeking sunshine and beaches first began to visit the Canaries in large numbers in the 1960s. The Canary Islands are a leading European tourist destination with very attractive natural and cultural resources.
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