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Minoan eruption

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Satellite image of Thera

The Bronze Age Minoan eruption of Thera (or Santorini) It is considered to be one of the largest volcanic eruptions on Earth during the last few thousand years.[1] The eruption would likely have caused significant climatic changes in the eastern Mediterranean region, Aegean Sea and possibly the entire world. The eruption is usually referenced as the "Minoan eruption" as a result of its effect the Minoan civilization on Crete.

Physical effects of the eruption

The violent eruption was centered on a small island just north of the existing island of Nea Kameni in the centre of the caldera, the roughly circular remnant of a previous volcanic eruption. The caldera itself was formed several hundred thousand years ago by the collapse of the volcano as a result of the emptying of the magma chamber during the eruption. It has been filled several times by ignimbrite, or the ash flowing down the volcano's sides during the eruption. This process had been repeated numerous times until approximately 23,000 years ago when the volcano went dormant.[2] The northern part of the caldera was refilled by the volcano and then collapsed again during the Minoan eruption. Immediately prior the eruption, the caldera formed a nearly continuous ring with the only entrance between the tiny island of Aspronisi and Thera. The eruption destroyed the sections of the ring between Aspronisi and Therasia, and between Therasia and Thera, creating two new channels.[2]

Currently, on Santorini, there is a 60 m thick deposit of white tephra, or volcanic material, thrown from the eruption that overlies the soil marking the ground level prior to the eruption. The layer is divided into three distinct bands indicating the different phases of the eruption.[3]

Since no bodies have been found at the Akrotiri site, it is assumed that there were early indications of vulcanism which would induce the local population to leave the area. The thinness of the first ash layer and the likelihood of its being eroded by winter rains indicate that the volcano may have given the local population several months warning of impending volcanic activity and not years as previously believed.[4] Further archeological excavations at the site may eventually result in finding bodies similar to those found at Pompeii and Herculaneum that were buried by the ash of the catastrophic eruption of Mount Vesuvius in 79 AD.

The Minoan eruption probably resulted in a plume 30-35 km in height, extending into the stratosphere, characteristic of a plinian eruption. In addition, magma came into contact with the shallow marine embayment, resulting in a violent phreatic eruption. The eruption also generated a 35 to 150 m high tsunami that devastated the north coast of Crete, 110 km (70 mi) away. The tsunami impacted coastal towns such as Amnisos, where building walls have been knocked out of alignment. On the island of Anaphi, 27 km to the east, ash layers 10 feet deep have been found, as well as pumice layers on slopes 250 meters above sea level. Elsewhere in the Mediterranean there are pumice deposits that could be caused by the Thera eruption.[5] Ash layers in cores drilled from the seabed and from lakes in Turkey, however, show that the heaviest ashfall was towards the east and northeast of Santorini. However, ash found in Crete is now known to have been from a precursory phase of the eruption, some weeks or months before the main eruptive phases, and would have had little impact on the island.[6] Santorini ash deposits were at one time claimed to have been found in the Nile delta, but this is now known to be a misidentification.[7]

Recent archaeological research by a team of international scientists in 2006 have revealed that the Santorini event was much larger than the estimated 39 cubic kilometres of Dense-Rock Equivalent (DRE), or total material erupted from the volcano, published in 1991.[8]. With an estimated DRE in excess of 60 cubic kilometers, [1] the volume of ejecta was up to four times what was thrown into the stratosphere by Krakatau in 1883, a well-recorded event, placing the Volcanic Explosivity Index of the Thera eruption at approximately 6. The Thera volcanic events and subsequent ashfall probably sterilized the island, similar to what had occurred on Krakatau. Only the Mount Tambora volcanic eruption of 1815 released more material into the atmosphere during historic times.[9]

Dating the volcanic eruption

The Minoan eruption provides a fixed point for aligning the entire chronology of the 2nd millennium BC in the Aegean, because evidence of the eruption occurs throughout the region. However, its exact date is unknown. Current opinion based on radiocarbon dating indicates that the eruption occurred between about 1630 and 1600 BC. These dates, however, conflict with the usual date from archaeology, which is around 1550 BC. Radiocarbon dating of one sample to 1630-1600 BC,[10] Radiometric dating of many other samples has lead to estimates of approximately 1654-1611 BC;[11] for the eruption. However, archeological studies, utilizing Conventional Egyptian chronology has placed a date of approximately 1525-1500 BC for the eruption.[12]

There exists several archaeological chronologies for the Late Bronze Age, each based on a point of origin for a given material culture. For example, international commerce shipped materials from Crete, mainland Greece, Cyprus, and Canaan to locations throughout the eastern Mediterranean. If the Thera eruption could be dated and then associated with a given layer of Cretan (or other) culture, chronologists could use the date of that layer of cultural artifacts to date the eruption. Since Thera's culture at the time of destruction was similar to the "Late Minoan IA (LMIA)" culture on Crete, LMIA is the baseline to establish chronology elsewhere. The eruption also aligns with Late Cycladic I (LCI) and Late Helladic I (LHI) cultures, but predates "Peloponnesian LHI".[13] Archeological digs on Akrotiri have also yielded fragments of nine Syro-Palestinian "Middle Bronze II (MBII)" gypsum vessels.[14]

At one time, it was believed that data from Greenland ice cores and dendrochronology, that is tree-ring dating, would be useful in ascertaining the exact date of the eruption. A large eruption, identified in ice cores and dated to 1644 BC +/- 20 years was suspected to be Santorini. Tree ring data showed that a large event interfering with normal tree growth in America occurred in 1629-1628 BC.[15] Previously, it was assumed that the ice core and tree-ring data were related. However, volcanic ash retrieved from an ice core demonstrated that this was not from Santorini, leading to the conclusion that the eruption may have occurred on another date.[6] The late Holocene eruption of the Mount Aniakchak, a volcano in Alaska, is proposed as the most likely source of the glass in the GRIP ice core.[16]

In 2006, two research papers were published arguing that new radiocarbon analysis dated the eruption between 1627 and 1600 BC. Samples of wood, bone, and seed collected from various locations in the Aegean, including Santorini, Crete, Rhodes and Turkey, were analyzed at three separate labs in Oxford, Vienna, and Heidelberg in order to minimise the chance of a radiocarbon dating error. Results of the analysis indicated a broad dating for the Thera event between 1660 to 1613 BC.[11]

The date of the eruption of Thera was recently narrowed to between 1627-1600 BC, with a 95% probability, after researchers analyzed material from a olive tree that was found buried beneath a lava flow from the volcano.[17] Because the tree grew on the island, the results may have been affected by volcanic outgassing, which would have skewed the accuracy of the radiometric studies.

As a result of the inconsistencies in radiocarbon dating, archeologists believe that the earlier date for the eruption is contradicted by findings in Egyptian and Theran excavations. For example, some archeologists have found buried Egyptian and Cypriot pottery on Thera that is dated to later period than the radiometric dates for the eruption. Archeologist Peter Warren states, "there are no current grounds for thinking that the Egyptian historical chronology could be out by more than a few years. This chronology has been constructed by hundreds of expert Egyptologists over many decades." The exact dating of the eruption remains controversial. [18]

Historical impact

Minoan civilization

Tsunamis from the pyroclastic flows and caldera collapse may have had an effect on the navy, merchant vessels and ports of the Minoans on the north side of Crete. As the Minoans were a sea power and depended on their naval and merchant ships for their livelihood, the Thera eruption must have impacted the Minoans to some degree. Whether these effects were enough to trigger the downfall of the Minoans is under intense debate. Early conclusions held that the ash falling on the eastern half of Crete may have choked off plant life, causing starvation. It was alleged that 7-11 cm of ash fell on Kato Zakro, while 0.5 cm fell on Knossos. However, when field examinations were carried out, this theory has lost credibility, as no more than 5 mm of ash had fallen anywhere on Crete.[19][6]

Earlier historians and archaeologists assumed that the effect on Minoa was more substantial because of the depth of pumice found on the sea floor. Recently, though, it has been established that the pumice resulted from a lateral crack in the volcano below sea level.[20] Also, significant Minoan remains have been found above the LM I-era Thera ash layer, implying that the Thera eruption did not cause the immediate downfall of the Minoans. The Mycenaean conquest of the Minoans occurred in LM II not many years after the eruption, and many archaeologists speculate that the eruption induced a crisis in Minoan civilization, which allowed the Mycenaeans to conquer them. For instance, the palaces adopted a "Kouros"-god from the hills in addition to the Minoan goddess.[21]

Chinese records

Some scientists correlate a volcanic winter from the Minoan eruption with Chinese records documenting the collapse of the Xia dynasty in China. According to the Bamboo Annals, the collapse of the dynasty and the rise of the Shang dynasty, approximately dated to 1618 BC, was accompanied by "'yellow fog, a dim sun, then three suns, frost in July, famine, and the withering of all five cereals".[12]

Impact on Egyptian history

There are no surviving Egyptian records of the eruption, and the absence of such records is sometimes attributed to the general disorder in Egypt around the Second Intermediate Period. There appears to be connections between the Thera eruption and the calamities of the Admonitions of Ipuwer, a text from Lower Egypt during the Middle Kingdom or Second Intermediate Period.[22]

Heavy rainstorms that devastated much of Egypt and were described on the Tempest Stele of Ahmose I have been attributed to short term climatic changes caused by the Theran eruption[23][24][25] The theory is not supported by current archaeological evidence which show no pumice layers at Avaris or elsewhere in Lower Egypt during the reigns of Ahmose I and Thutmosis III. It has also been argued that the damage from this storm may have been caused by an earthquake caused by the Thera Eruption. However, it has also been argued, on account of the verbs used in the Tempest Stele, specifically, "entering", "dismantling", "hacking up", and "toppling", all words which indicate defacement by humans, that the damage was caused during a war with the Hyksos, and the storm reference is merely an exaggerated figurative reference to chaos, upon which the Pharaoh was attempting to impose order.[26]

There is a consensus that Egypt, being far away from areas of significant seismic activity, would not be significantly affected by an earthquake in the Aegean. Furthermore, other documents, such as Hatshepsut's Speos Armedios, depict similar storms, but are clearly speaking figuratively, not literally.[26] It is thus considered likely that this stele is just another such reference to the Pharaoh overcoming the powers of chaos and darkness. Contrarily, it was recorded, on the verso of the Rhind Mathematical Papyrus, that during Ahmose's Hyksos campaign, "the sky rained", which was an extremely rare event in ancient Egypt, and could quite possibly indicate a rainstorm that was related to the eruption.[27]

Greek traditions

The eruption of Thera and volcanic fallout may have inspired myths of the Titanomachy in Hesiod's Theogony. The background of the Titanomachy is known to derive from the Kumarbi cycle, a Bronze Age Hurrian epic from the Lake Van region. However, the Titanomachy itself could have picked up elements of western Anatolian folk memory as the tale spread westward. Hesiod's lines have been compared with volcanic activity, citing Zeus' thunderbolts as volcanic lightning, the boiling earth and sea as a breach of the magma chamber, immense flame and heat as evidence of phreatic explosions, among many other descriptions. [28]

Biblical traditions

It has been proposed that one or more of ten plagues may be attributed to the eruption of Thera.[29] According to the Bible, Egypt was beset by such misfortunes as the transforming of their water supply to blood, the infestations of frogs, gnats, and flies, darkness, and violent hail. These effects are compatible with the catastrophic eruption of a volcano in different ways. While the "blood" may have been red tide which is poisonous to human beings, the frogs could have been displaced by the eruption, and their eventual death would have given rise to large numbers of scavenging insects. The darkness could have been the resulting volcanic winter, and the hail the large chunks of ejecta spewn from the volcano. The tsunami that resulted from the Thera eruption is also speculated to have caused the parting of the sea that allowed the Israelites, under Moses, safe passage of the Red Sea, possibly devastating the Egyptian army with the returning wave. Exodus mentions that the Israelites were guided by a "pillar of smoke" during the day and a "pillar of fire" at night, which many scholars have speculated could be references to volcanic activity. However, unambiguous dating of bristlecone pines and other dating methodologies places the Thera eruption at a date significantly different from the supposed dates of the Exodus from Egypt. It is possible that there was a distorted memory amongst the Hebrews of the Theran eruption.[30]

Association with Atlantis

Spyridon Marinatos first proposed that the cataclysmic volcanic event at Santorini may have lead to the fall of the Minoan Civilization centered on Crete.[31] This same event is sometimes regarded as the likely source or inspiration for Plato's story of Atlantis. Detractors of the theory say that Santorini and Crete combined would not be the size of Plato's Atlantis, and the date of the Minoan collapse does not match Plato's dates for the fall of Atlantis. Scholars such as James W. Mavor and A. G. Galanopoulos argue that the error in date and size could be caused by a mistranscription of the Ancient Egyptian or Mycenaean Linear B symbol for "hundred" as "thousand". There would be little confusion in the visual appearance of hieroglyphic symbols of Egyptian numeric values; but if the Atlantis story does derive from Egypt, it was at some point been translated into Greek, which Galanopoulos suggests is the point of confusion.[32][22]

References

  1. ^ a b Sigurdsson, H; et al. (2006). "Marine Investigations of Greece's Santorini Volcanic Field" (PDF). Eos. 87 (34): 337–348. {{cite journal}}: Cite has empty unknown parameter: |quotes= (help); Explicit use of et al. in: |author= (help)
  2. ^ a b Friedrich, WL (1999). Fire in the Sea, the Santorini Volcano: Natural History and the Legend of Atlantis. Cambridge University Press. ISBN 0-521-65290-1.
  3. ^ DA, Davidson (1979). "Aegean Soils During the Second Millennium B.C. with Reference to Thera". Thera and the Aegean World I. Papers presented at the Second International Scientific Congress, Santorini, Greece, August 1978. UK: The Thera Foundation. pp. 725–739. ISBN 0 9506133 0 4. Retrieved 2007-03-10. {{cite conference}}: Cite has empty unknown parameter: |coauthors= (help); Unknown parameter |booktitle= ignored (|book-title= suggested) (help)
  4. ^ G, Heiken (1990). "Precursory Activity to the Minoan Eruption, Thera, Greece". Thera and the Aegean World III, Vol 2. London: The Thera Foundation. pp. 79–88. {{cite conference}}: Unknown parameter |booktitle= ignored (|book-title= suggested) (help); Unknown parameter |coauthors= ignored (|author= suggested) (help)
  5. ^ "Pumice on south Mediterranean - remnant of the Thera eruption?". 2004. Retrieved 2007-03-10.
  6. ^ a b c Keenan, Douglas (2003). "Volcanic ash retrieved from the GRIP ice core is not from Thera" (PDF). Geochemistry Geophysics Geosystems. 4 (11). AGU and the Geochemical Society: 1097. doi:10.1029/2003GC000608. 1525-2027. Retrieved 2007-03-10. {{cite journal}}: Cite has empty unknown parameter: |coauthors= (help)
  7. ^ Guichard, F; et al. (1993). "Tephra from the Minoan eruption of Santorini in sediments of the Black Sea". Nature. 363 (6430): 610–612. doi:10.1038/363610a0. {{cite journal}}: Cite has empty unknown parameter: |quotes= (help); Explicit use of et al. in: |author= (help)
  8. ^ "Santorini eruption much larger than originally believed". 2006. Retrieved 2007-03-10.
  9. ^ Oppenheimer, Clive (2003). "Climatic, environmental and human consequences of the largest known historic eruption: Tambora volcano (Indonesia) 1815". Progress in Physical Geography. 27 (2): 230–259.
  10. ^ "New research in Science: date of the largest volcanic eruption in the Bronze Age finally pinpointed". 2006. Retrieved 2007-03-10.
  11. ^ a b Manning, Stuart W (2006). "Chronology for the Aegean Late Bronze Age 1700-1400 B.C." Science. 312 (5773). American Association for the Advancement of Science: 565–569. doi:10.1126/science.1125682. Retrieved 2007-03-10. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
  12. ^ a b Foster, KP, Ritner, RK, and Foster, BR (1996). "Texts, Storms, and the Thera Eruption". Journal of Near Eastern Studies. 55 (1): 1–14.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  13. ^ Lolos, YG (1989). On the Late Helladic I of Akrotiri, Thera "On the Late Helladic I of Akrotiri, Thera". The Thera Foundation. Retrieved 2007-03-10. {{cite web}}: Check |url= value (help)
  14. ^ Warren, PM (1989). Summary of Evidence for the Absolute Chronology of the Early Part of the Aegean Late Bronze Age Derived from Historical Egyptian Sources in: Thera and the Aegean World III, Hardy, DA (ed). The Thera Foundation. pp. 24–26. ISBN 0 9506133 6 3. Retrieved 2007-03-10.
  15. ^ Baillie, MGL (1989). "Irish Tree Rings and an Event in 1628 BC". The Thera Foundation. Retrieved 2007-03-10.
  16. ^ Pearce, N. J. G., J. A. Westgate, S. J. Preece, W. J. Eastwood, and W. T. Perkins (2004). "Identification of Aniakchak (Alaska) tephra in Greenland ice core challenges the 1645 BC date for Minoan eruption of Santorini". Geochem. Geophys. Geosyst. 5. doi:10.1029/2003GC000672. {{cite journal}}: Cite has empty unknown parameter: |quotes= (help)CS1 maint: multiple names: authors list (link)
  17. ^ Friedrich, Walter L (2006). "Santorini Eruption Radiocarbon Dated to 1627-1600 B.C.". Science. 312 (5773). American Association for the Advancement of Science: 548. doi:10.1126/science.1125087. {{cite journal}}: |access-date= requires |url= (help); Text "http://www.sciencemag.org/cgi/content/abstract/sci;312/5773/548" ignored (help)
  18. ^ Balter, M (2006). "New Carbon Dates Support Revised History of Ancient Mediterranean". Science. 312 (5773): 508–509. doi:10.1126/science.312.5773.508. Retrieved 2007-05-01.
  19. ^ Callender, G (1999). The Minoans and the Mycenaeans: Aegean Society in the Bronze Age. Oxford University Press. ISBN 0195510283.
  20. ^ Pichler, H & Friedrich, WL (1980). Mechanism of the Minoan Eruption of Santorini in: Thera and the Aegean World, Volume 2, C. Doumas (ed). Thera and the Aegean World. ISBN 0950613339. Retrieved 2007-05-19.{{cite book}}: CS1 maint: multiple names: authors list (link)
  21. ^ Driessen, Jan (2001). "Crisis Cults on Minoan Crete?" (PDF). Proceedings of the 8th International Aegean Conference Göteborg, Göteborg University, 12-15 April 2000,. Liège, Belgique: l'Université de Liège. Retrieved 2007-03-10. {{cite conference}}: Cite has empty unknown parameter: |coauthors= (help); Unknown parameter |booktitle= ignored (|book-title= suggested) (help)
  22. ^ a b Galanopoulos, AG (1969). Atlantis: The Truth Behind the Legend. Bobbs-Merrill Co. ISBN 978-0672506109. {{cite book}}: Cite has empty unknown parameter: |coauthors= (help)
  23. ^ EN, Davis (1989). "A Storm in Egypt during the Reign of Ahmose". Retrieved 2007-03-10. {{cite web}}: Cite has empty unknown parameter: |coauthors= (help)
  24. ^ Goedicke, Hans (1995). 'Studies about Kamose and Ahmose'. Baltimore: David Brown Book Company. pp. Chapter 3. ISBN 0-9613805-8-6. {{cite book}}: Cite has empty unknown parameter: |coauthors= (help)
  25. ^ Foster, KP & Ritner, RK (1996). "Texts, Storms, and the Theran Eruption". Journal of Near Eastern Studies. 57. University of Chicago Press: 1–14.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  26. ^ a b Wiener, MH (1998). "Separate Lives: The Ahmose Tempest Stela and the Theran Eruption". Journal of Near Eastern Studies. 57. University of Chicago Press: 1–28. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
  27. ^ Redford, Donald B (1993). Egypt, Canaan, and Israel in Ancient Times. Princeton, NJ: Princeton University Press. ISBN 978-0691000862. {{cite book}}: Cite has empty unknown parameter: |coauthors= (help)
  28. ^ Luce, John Victor (1969). The end of Atlantis: New light on an old legend (New Aspects of Antiquity). London: Thames & Hudson. ISBN 978-0500390054. {{cite book}}: Cite has empty unknown parameter: |coauthors= (help)
  29. ^ Bennett, JG (1963). "Geo-Physics and Human History: New Light on Plato's Atlantis and the Exodus". 1 (2). Retrieved 2007-04-13. {{cite journal}}: Cite journal requires |journal= (help); Unknown parameter |ournal= ignored (help)
  30. ^ "The Eruption of Thera: Devastation in the Mediterranean". Retrieved 2007-04-08.
  31. ^ Marinatos, S (1939). "The Volcanic Destruction of Minoan Crete". Antiquity. 13: 425–439.
  32. ^ Mavor, James (1997). Voyage to Atlantis: The Discovery of a Legendary Land. Park Street Press. ISBN 978-0892816347. {{cite book}}: Cite has empty unknown parameter: |coauthors= (help)

Further reading

  • Balter, M (2006). 'New carbon dates support revised history of ancient Mediterranean', Science, vol. 312, pp. 508-509.
  • Forsyth, PY (1997). Thera in the Bronze Age, New York: Peter Lang Publishing. ISBN 0-8204-4889-3
  • Greene, MT (1992). Natural Knowledge in Preclassical Antiquity, Baltimore: Johns Hopkins University Press.

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