Hekla 3 eruption
{{Short description|Severe eruption of Hekla circa 1000 BC}}
{{Infobox eruption
| name = Hekla 3 eruption
| image =
| caption =
| date = {{circa|1000 BC}}
| volcano = Hekla
| type = Plinian
| location = Iceland
| coordinates = {{coord|63|59|N|19|42|W|dim:20000_region:IS|display=inline, title}}
| volume = {{convert|7.3|km3|mi3|abbr=on}}
| VEI = 5{{cite gvp|vn=372070|vtab=Eruptions|name=Hekla}}
| map = {{Location map|Iceland|label=Hekla |lon_dir=W|lat_dir=N|lat_deg=63|lat_min= 59|lon_deg= 19|lon_min = 42|position=center|width=250|caption=}}
| map_caption = Hekla on the map of Iceland
| impact = Caused worldwide temperatures to drop for 18 years
}}
The Hekla 3 eruption (H-3) {{circa|1000 BC}} is considered the most severe eruption of Hekla during the Holocene.{{cite journal |last1=Eiríksson |first1=Jón |year=2000 |title=Chronology of late Holocene climatic events in the northern North Atlantic based on AMS 14C dates and tephra markers from the volcano Hekla, Iceland |journal=Journal of Quaternary Science |volume=15 |issue=6 |pages=573–580 |url=http://www3.interscience.wiley.com/cgi-bin/abstract/73001062/ABSTRACT |archive-url=https://archive.today/20121217233146/http://www3.interscience.wiley.com/cgi-bin/abstract/73001062/ABSTRACT |url-status=dead |archive-date=2012-12-17 |doi=10.1002/1099-1417(200009)15:6<573::AID-JQS554>3.0.CO;2-A |bibcode = 2000JQS....15..573E |display-authors=etal|url-access=subscription }} It threw about 7.3 km3 of volcanic rock into the atmosphere, placing its Volcanic Explosivity Index (VEI) at 5. This would have caused a volcanic winter, cooling temperatures in the Northern Hemisphere for several years afterwards.
An eighteen-year span of global cooling that is recorded in Irish bog oaks has been attributed to H-3.{{cite journal |last=Baillie |first=Mike |year=1989 |title=Hekla 3: how big was it? |journal=Endeavour |series=New Series |volume=13 |issue= 2|pages=78–81 |doi=10.1016/0160-9327(89)90006-9 }}{{cite journal |last=Baillie |first=Mike |year=1989 |title=Do Irish bog oaks date the Shang dynasty? |journal=Current Archaeology |volume=10 |pages=310–313}} The eruption is detectable in Greenland ice cores, the bristlecone pine sequence, and the Irish oak sequence of extremely narrow growth rings. Andy Baker's team of researchers dated it to 1021 BC ±130.{{cite journal |last1=Baker |first1=Andy |year=1995 |title=The Hekla 3 volcanic eruption recorded in a Scottish speleothem? |journal=The Holocene |volume=5 |issue=3 |pages=336–342 |doi=10.1177/095968369500500309 |bibcode=1995Holoc...5..336B |s2cid=130396931 |display-authors=etal}}
A "high chronology" (earlier) interpretation of the above results is preferred by Baker, based also on growth of stalagmites. In Sutherland, northwest Scotland, a spurt of four years of doubled annual luminescent growth banding of calcite in a stalagmite is datable to 1135 BC ±130.Dated by uranium-thorium thermal ionization mass spectrometry to 1135 BC ±130 in {{cite journal |last=Baker |first=Andy |year=1995 |title=The Hekla 3 volcanic eruption recorded in a Scottish speleothem? |journal=The Holocene |volume=5 |issue=3 |pages=336–342 |doi=10.1177/095968369500500309 |bibcode=1995Holoc...5..336B |s2cid=130396931 |display-authors=etal}}
A rival, "low-chronology" interpretation of the eruption has been made by Andrew Dugmore: 2879 BP (929 BC ±34).{{cite journal|last1=Dugmore |first1=AJ |author2=G. T. Cook, J. S. Shore, A. J. Newton, K. J. Edwards and Guðrún Larsen |year=1995 |title=Radiocarbon Dating Tephra Layers in Britain and Iceland |journal=Radiocarbon |volume=37 |issue=2 |pages=379–388 |doi=10.1017/S003382220003085X |bibcode=1995Radcb..37..379D |doi-access=free }} In 1999, Dugmore suggested a non-volcanic explanation for the Scottish results.Andrew Dugmore, Geriant Coles, Paul Buckland, "A Scottish speleothem record of the H-3 eruption or human impact? A comment on Baker, Smart, Barnes, Edwards and Farrant" The Holocene 9.4 501-503 (1999). In 2000 skepticism concerning conclusions about connecting Hekla 3 and Hekla 4 (probably 2310 BC ±20) with paleoenvironmental events and archaeologically attested abandonment of settlement sites in northern Scotland was expressed by John P. Grattan and David D. Gilbertson.{{cite book |chapter=Prehistoric 'settlement crisis', environmental changes in the British Isles, and volcanic eruptions in Iceland: An explorarion of plausible linkages |title=Volcanic Hazards and Disasters in Human Antiquity |last1=Grattan |author2=Gilbertson |editor=McCoy, Floyd W. |editor2=Heiken, Grant |year=2000 |series=GSA Special Paper |volume=345 |publisher=Geological Society of America |location=Boulder, CO |isbn=0-8137-2345-0}} Some Egyptologists have firmly dated the eruption to 1159 BC, and blamed it for famines under Ramesses III during the wider Bronze Age collapse.{{cite book |chapter=End of the Late Bronze Age and Other Crisis Periods: A Volcanic Cause |title=Gold of Praise: Studies on Ancient Egypt in Honor of Edward F. Wente |last=Yurco |first=Frank J. |editor=Teeter, Emily |editor2=Larson John|year=1999 |series=Studies in Ancient Oriental Civilization |volume=58 |publisher=Oriental Institute of the Univ. of Chicago |location=Chicago, IL |isbn=1-885923-09-0 |pages=456–458 }} Dugmore has rebutted this dating based on calculation of solifluction, knocking the date down to 900BC.[http://sp.lyellcollection.org/cgi/content/abstract/242/1/145 Late Holocene solifluction history reconstructed using tephrochronology], Martin P. Kirkbride & Andrew J. Dugmore, Geological Society, London, Special Publications; 2005; v. 242; p. 145-155. An earlier study on bog-oak tree rings by another geologist, John Grattan, adds some weight to the other side of the argument noting a shrinking tree-rings and disappearing tree species during this period.Dr. J. P. Grattan, 1995, in “The impact of Icelandic Volcanic Eruptions Upon the Ancient Settlement and Environment of Northern and Western Britain.” [Graduate thesis] Other scholars have held off on this dispute, preferring the neutral and vague "3000 BP".[http://gsa.confex.com/gsa/inqu/finalprogram/abstract_54866.htm TOWARDS A HOLOCENE TEPHROCHRONOLOGY FOR SWEDEN] {{Webarchive|url=https://web.archive.org/web/20090407061552/http://gsa.confex.com/gsa/inqu/finalprogram/abstract_54866.htm |date=2009-04-07 }}, Stefan WastegÅrd, XVI INQUA Congress, Paper No. 41-13, Saturday, July 26, 2003.