Pyroclastic Surge over Water
Montserat, Caribbean
1996
It is clear from the sedimentary evidence left by the eruption on Santorini that it produced many pyroclastic surges and the volcano's vent generally ejected more material to the southeast. During the upper part of the eruption's second major phase (Minoan B or Bo2) something extraordinary occurred. A tremendously powerful superheated steam surge(s) exploded from the vent and was funneled by the high walls of the Gavrillos Ridge to the east and the Akrotiri hills in the west on a southern course aimed directly at the northern coast of Crete. It was so massively violent that it utterly obliterated the structures in Akrotiri that remained uncovered by tephra from the eruption's previous activity (McCoy, Heiken, 2000).
The chronological association between the Minoan eruption and the LM IB destruction has been debated for decades and remains unresolved. But, I believe there is compelling evidence that the incredible eruption of the Theran marine volcano and the Late Minoan IB destruction event actually describe the cause and one of the effects of the same event. The phenomenon of the pyroclastic steam surge is well documented in modern times (Krakatau, Mt. Pelee, etc.) and should no longer be left unconsidered as a possible cause of the LM IB destruction horizon.
Lifting the Fog in the Evidence
Besides the considerable evidence of fire destruction at many archaeological sites on Crete, the theory calls for literally everything combustible being fiercely set ablaze almost simultaneously within the areas touched by the superheated gas blooms. If this is true, the blanket of fire should have produced an immense amount of soot, charcoal, and other organic or chemical evidence in the LM IB stratigraphy that closely dates to the Minoan eruption. There has been relatively little effort expended on radiocarbon dating the LM IB destruction horizon and only one known to me that incorporates the new IntCal04 calibration curve.
Radiocarbon multi-modal calibrated age distributions that can span 100 years or more are simply not accurate enough to be of any use in this matter. Only the most advanced techniques in radiocarbon dating and dendrochronology like those used by Friedrich et al. in 2006 to date the Santorini eruption can possibly hope to render the greater resolution required to more definitively assemble the true chronological relationships of the events of the LM I period.
Also, there should be wide-spread sedimentary evidence from the pyroclastic surges generated by the Minoan eruption. These highly energetic gas blooms are low-density mixtures of primarily superheated dry steam that contain ash and rock debris held in turbulent suspension. As the bloom jets away from its blast vent it leaves a record of its trajectory and coverage by continually raining ash and rock into the water and onto the land it touches due to the pull of gravity. As the bloom travels farther away from the volcano the thickness of its sediments decrease as more and more ash and debris falls out of its turbulent suspension. The eruption of the marine volcano Krakatau in 1883 left steam surge deposits composed of poorly sorted mixtures of ash and pumice on islands from 20 to 40 kilometers away that were tens of centimeters thick. Krakatau's pyroclastic gas blooms were able to reach out to a distance of about 80 kilometers before finally dissipating.
Using the Krakatau sediments as a reference the magnitude of the surge deposits left by the Minoan eruption need to scaled up considerably. The Bronze Age eruption was about nine or ten times bigger than Krakatau. Its surge deposits should be significantly thicker and have a much greater reach. The sediments on the islets and islands surrounding Santorini that were struck by its gas surges, as some of them must have been, should consist of a thin layer of perhaps fifty to less than ten centimeters depending on the distance from the volcano and be composed of fine-grained, glassy ash that can be found in places resistant to erosion like lakes, depressions, or where the strata has been covered over by fallen structures, landslides, etc.
These deposits will be difficult to identify because they will most likely coexist with the eruption's ash fall and its reworked components laid down in the midst of significant seismic activity. But it is possible that surge-based ash deposits can be found relatively isolated from the ash fall. The deposition of ash fall is quite dependent on the prevailing winds while the course of a high-speed pyroclastic gas bloom would, at least initially, be determined solely by the orientation and configuration of the explosive opening of its blast vent(s).
In the decades following the eruption these deposits may have been disturbed by human activity or destructions during the LM II or Mycenaean period and over the millennia they would have been shaken many times by the perennial scourge of the Aegean - large seismic events. But when provided with good diagnostic samples their definitive detection should not escape the expertise of a qualified volcanic geologist. To the best of my knowledge no published scientific effort has ever been undertaken to look for these deposits in the Aegean.
After the wonderful effort that scholars devoted to more accurately dating the Theran eruption by direct means, I believe a fruitful path for future research would be to apply the most advanced techniques in radiocarbon and sedimentary analysis to the stratigraphy associated with the LM IB destruction on the many islets and islands in the vicinity of Santorini. As the geographical center of mass for the Minoan population, central and eastern Crete should be given special consideration (Baird, 2008). This would surely bring us closer to finally lifting the fog in the evidence so the truth behind the great mystery of the Late Minoan I era can be more clearly revealed.
W. Sheppard Baird
April 30, 2009
Bibliography:
Walter L. Friedrich, Bernd Kromer, Michael Friedrich, Jan Heinemeier, Tom Pfeiffer, Sahra Talamo. “Santorini Eruption Radiocarbon Dated to 1627-1600 B.C.”. 2006.
The Thera Foundation
J. V. Luce, C. Doumas. "The Chronology of the LM I Destruction Horizons in Thera and Crete ". "Thera and the Aegean World I". Second International Scientific Congress. Santorini, Greece, pp. 785-789, 1978.
W. S. Downey, D. H. Tarling. "Archaeomagnetic Results from Late Minoan Destruction Levels on Crete and the 'Minoan' Tephra on Thera ". "Thera and the Aegean World III". Volume Three: "Chronology", Proceedings of the Third International Congress, Santorini, Greece, pp. 146 - 159, 3-9 September 1989.
Rutter, Jeremy B. "Lesson 14: Late Minoan Painting and Other Representational Art: Pottery, Frescoes, Steatite Vases, Ivories, and Bronzes". "Aegean Prehistoric Archaeology". Dartmouth College. March 18, 2000.
C. Doumas, A. Papagiannopoulou. "A Study of Middle and Late Cycladic Pottery from Akrotiri". Thera and the Aegean World III. Volume One: "Archaeology". Proceedings of the Third International Congress, Santorini, Greece, pp. 441-448, 1989.
M. Marthari. "Investigation of the Technology of Manufacture of the Local LBA Theran Pottery: Archaeological Consideration". Thera and the Aegean World III. Volume One: "Archaeology". Proceedings of the Third International Congress, Santorini, Greece, pp. 449-458, 1989.
Joseph W. Shaw, Aleydis Van de Moortel, Peter M. Day, Vassilis Kilikoglou. "A LM IA Ceramic Kiln in South- Central Crete: Function and Pottery Production". American School of Classical Studies, Hesperia, Supplement 30, 2001.
Rutter, Jeremy B. "Lesson 17: Akrotiri on Thera, the Santorini Volcano and the Middle and Late Cycladic Periods in the Central Aegean Islands". "Aegean Prehistoric Archaeology". Dartmouth College. March 18, 2000.
F. W. McCoy, G. Heiken. "The Late-Bronze Age explosive eruption of Thera (Santorini), Greece: Regional and local effects“. Geological Society of America. 2000.
S. Carey, S. Sigurdsson, C. Mandeville, S. Bronto. “Pyroclastic Flows and Surges over Water: an Example from the 1883 Krakatau Eruption”. Bulletin of Volcanology. 1995.
T. H. Druitt, L. Edwards, R. M. Mellors, D. M. Pyle, R. S. J. Sparks, M. Lanphere, M. Davies, B. Barriero. "Santorini Volcano”. 1999.
Jennifer Susan Gilbert, Robert Stephen John Sparks. “The Physics of Explosive Volcanic Eruptions”. T. H. Druitt. “Pyroclastic Density Currents”. p. 145. Geological Society 1998.
John G. Younger. "Linear A Texts in phonetic transcription and Commentary“. 2009.
John G. Younger. "The Cretan Hieroglyphic Texts“. 2008.
W. Sheppard Baird. "The End of Minoan Linear A Writing and the LM IB Fire Destruction of Crete“. 2009.
W. Sheppard Baird. "The Extent of the Santorini Eruption's Tsunami Inundation of Minoan Crete“. 2008.
W. Sheppard Baird. "The Archaeological Sites of the Aegean Minoans“. 2008.
W. Sheppard Baird. "The Minoan Catastrophe: The Theran Pyroclastic Surge Theory“. "The Thera Foundation“. 2007.
Sturt W. Manning, Christopher Bronk Ramsey, Walter Kutschera, Thomas Higham, Bernd Kromer, Peter Steier, Eva M. Wild. "Chronology for the Aegean Late Bronze Age 1700–1400 B.C.”. 2006.
Rupert A. Housley, Sturt W. Manning, Gerald Cadogan, Richard E. Jones and Robert E. M. Hedges. "Radiocarbon, Calibration, and the Chronology of the Late Minoan IB Phase”. 1999.
OxCal Program. Oxford Radiocarbon Accelerator Unit. University of Oxford.
P. Reimer, et al. "INTCAL04 Terrestrial Radiocarbon Age Calibration, 0–26 CAL KYR BP". Radiocarbon, Vol 46, Nr 3, 2004, p 1029–1058.
Radiocarbon: An International Journal of Cosmogenic Isotope Research
Radiocarbon WEB-info. Tom Higham, Radiocarbon Laboratory, University of Waikato, New Zealand.
Copyright © 2009 W. Sheppard Baird
All Rights Reserved
http://www.minoanatlantis.com/LM_IB_Destruction.php