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Eruptive history of the Santorini volcanoThe island of Santorini is the result of a complex history of volcanic eruptions over about 2 million years, during which the island has changed its shape and size repeatedly. Before any volcanic activity took place (caused by the subduction of the African plate under the Eurasian one), there was a small island in the area, similar to the other Islands of the Cyclades. This non-volcanic island forms the Profitis Ilias and Mesa Vouno mountains, as well as the shists at Athinios harbour and in the Plaka bay connected to Profitis Ilias mountain through the ridge of Pirgos, the Gavrilos ridge (the "windmill hill" south of Emborio) and the islolated rick of Monolithos.
Volcanism in the area of Santorini started about 2 million years ago when the first eruptions occurred from the sea floor in the area of the Akrotiri Peninsula and probably also at the location of the Christiania Islands 20 km SW of Santorini.
The activity built dacitic lava domes that eventually formed a series of islands, still visible in the hills of the Akrotiri peninsula. In a second stage, a stratovolcano (Peristeria volcano) was formed in the northern part of Santorini, parts of which are still visible in the cliffs and slopes of Mikro Profitis Ilias and Megalo Vouno.
Starting about 400,000 years ago, the focus of volcanic activity shifted to where it has been since then, the center of the present-day caldera. The most characteristic type of activity over the last 400.000 years has been the cyclic construction of shield volcanoes interrupted by large explosive and destructive events like the Minoan eruption about 3600 years ago.
In detail, the volcanic evolution of Santorini can be divided into six main stages (Druitt and others, 1989):
- Akrotiri Volcanoes (approx. 2 mio - 600,000 years ago)
- Cinder cones of the Akrotiri peninsula (around 600 - 300 ka)
- Peristeria Volcano (530 - 300 ka)
- Products of the first eruptive cycle (360-180 ka)
- Products of the second eruptive cycle (180 ka - 1613 BC)
- Kameni shield (1613 BC - present)
Eruptions of Santorini since the Bronze Age:1613 BC +-7 years (the so-called "Minoan eruption")
Historic eruptions:
197 BC (Palea Kameni)
46/47 AD (Palea Kameni ? Bankos Reef ?)
726 AD (Palea Kameni)
1570-1573 (perhaps only one year of the interval, Mikri Kameni, now part of Nea Kameni)
1707-1711 (formation of Nea Kameni)
1866-1870 (Nea Kameni)
1925-1928 (Nea Kameni)
1939-1941 (Nea Kameni)
1950 (Nea Kameni)
???? (? -> when will the next eruption occur?)
Summary table of Volcanic eruption sequence on Santorini
| Event |
|
Magma composition |
Dating |
|
(note: Plinian eruptions in bold) |
|
|
|
|
|
|
Formation of the Kameni lava
shield |
|
dacite |
197 BC to 1950 [1] |
|
! Caldera
collapse 4 ! |
|
|
|
Minoan eruption |
|
rhyodacite, andesite |
3,6 ka [2] |
|
! Caldera collapse
3 ! |
|
|
|
Cape Riva eruption |
|
rhyodacite, andesite |
21 ka [3] |
|
Formation of Therasia lava shield |
|
rhyodacite, andesite |
|
|
Eruption of the andesites of Oia |
|
andesite |
|
|
Upper Scoriae 2 eruption |
|
andesite |
40 ka [4] |
|
Construction of Skaros lava shield |
|
basalt-andesite |
|
|
! Caldera collapse
2 ! |
|
|
|
Upper Scoriae 1 eruption |
|
andesite |
60-40 ka [4] |
|
Vourvoulos eruption |
|
andesite, dacite |
|
|
Megalo Vouno and Kokkino Vouno
cinder cones |
|
andesite |
50-70 ka [5] |
|
Aspronisi tuff ring (also Kolumbus
tuff ring ?) |
|
|
|
|
Middle Pumice eruption |
|
dacite, andesite |
60 ka [4] |
|
Cape Thera eruption |
|
andesite |
|
|
Construction of Simandiri lava
shield |
|
andesite |
172+-33 ka [5] |
|
! Caldera collapse
1 ! |
|
|
|
Lower Pumice 2 eruption |
|
rhyodacite, andesite |
180 [6] |
|
Lower Pumice 1 eruption |
|
rhyodacite, andesite |
203+-24 ka [5] |
|
Cape Therma 3 eruption |
|
andesite |
|
|
Extrusion of rhyodacites of Cape
Alonaki + NE Thera |
|
rhyodacite |
257+- 36 ka; 224+-5 ka [5] |
|
Cape Therma 2 eruption |
|
rhyodacite |
|
|
Cape Therma 1 eruption |
|
andesite |
|
|
Extrusion of the andesites of Cape
Alai |
|
andesite |
364+-85 ka; 229+- 85 ka[5] |
|
Balos, Kokkinopetra and
Mavrorachidi cinder cones |
|
basalt, andesite |
344+- 25 ka [5] |
|
Eruption of lavas of Peristeria 3 |
|
basalt, andesite |
308-480 ka [5] |
|
Extrusion of domes and flows of
Peristeria 2 |
|
andesite |
496+-16 ka [5] |
|
Construction of Peristeria 1 core
complex |
|
andesite |
528+-8 ka [5] |
|
Eruption of early submarine centres
of Akrotiri |
|
rhyodacite |
ca. 2,000-600 [4,5] |
|
|
|
[1] Historic records |
|
[2] Mean of radiocarbon
ages on plant remains in tuffs (Friedrich and others, 1990) |
|
[3] Mean of radiocarbon
ages on plant remains in tuffs (Pichler and Friedrich, 1976) corrected using the data of
Bard and others (1990) |
|
[4] Friedrich (2000) |
|
[5] Ar 39-40 data from
Druitt and others (1989) |
|
[6] Constrained by age
of Lower Pumice 1 and Simandiri Shield |
Cited references:- Bard, E., Hamelin, B., Fairbanks, R.G., and Zindler, A. (1990) "Calibration of the C-14 timescale over the past 30,000 years using mass spectrometric U-Th ages from Barbados corals", Nature, v. 345, p. 405-410.
- Bond, A. & Sparks, R. S. J. (1976) "The Minoan eruption of Santorini, Greece", Journal of the Geological Society of London, Vol. 132, 1-16
- Druitt, T. H., et al. (1989) "Explosive volcanism on Santorini, Greece." GEOLOGICAL MAGAZINE , Vol. 126, No. 2, p. 95-126
- Friedrich, W. L., et al. (1990) "Radiocarbon dated plant remains from the Akrotiri excavation on Santorini, Greece." Hardy, D. A., et al. THERA AND THE AEGEAN WORLD - PROCEEDINGS OF THE 3rd INTERNATIONAL CONFERENCE, Vol. 3, p. 188-196
- Friedrich, W.L. (1994) "Feuer im Meer", Spektrum Akademischer Verlag, Heidelberg, Berlin Oxford, 256 p.
- Friedrich, W.L. (2000) "Fire in the Sea. Volcanism and the Natural History of Santorini", Cambridge Univ Pr., Cambridge, 256 p.
- Pichler, H., and Friedrich, W. (1976) "Radiocarbon dates of Santorini volcanics" Nature (London) 262, 373-374
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