Do Irish Bog Oaks Date the Shang Dynasty?

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In CA 111 Chris Scarre pointed  out that the explosion of Thera  could be dated to 1626 BC. This  may, however, only be the beginning.  There are at least 4 other  prehistoric dates that the readers of  CA should learn by heart; I believe  that our work on tree-rings has  revealed several major volcanic  eruptions which may have caused  climatic upset on a world wide  basis.

When these major eruptions  occurred, the climate of the northern  hemisphere may have been  altered for several years. We have  to envisage the possibility of failed  harvests, famine – and no doubt  plague and pestilence as well.  Empires could have been destroyed  and vast tracts of land rendered  uninhabitable. In such circumstances  the survivors would  have been those who were more  war-like than their neighbours –  the consequences of such  “aggression means survival” could  have changed social behaviour for  centuries.

While such claims may  seem like rather fanciful extrapolation  from a few dated “events” in  the Irish oak record, they need to  be suggested in the form of an  hypothesis for archaeological testing.  The most dramatic claim,  which can ultimately be tested, is that the dust veils recognised in the  Irish tree-rings may date the start  and end of the Chinese Shang  Dynasty.

Before we begin let us recap on  the methodology. There are three  major lines of research which  appear to provide evidence for  environmental  catastrophes. The  earliest to surface was the work of  Danish glaciologists led by Dr C U  Hammer. They analysed long cores  from the Greenland ice sheets and  found layers of sulphuric acid deposited  by volcanic eruptions.

These could be broadly dated because  the layers in the ice sheets  are basically annual in character  (see Nature, 288 [1980] and 328  [1987]).

Then in 1984 an American  dendrochronologist, Val Lamarche, who worked at the Tucson tree ring  laboratory, drew attention to  frost damaged rings which occurred  in a lot of his high-altitude  bristlecone pines. In recent times  such frost rings tended to occur in  the years following major volcanic  eruptions e.g. the eruption of Krakatoa  was in 1883, the bristlecones  showed frost damage in their  growth rings for 1884. One notable  frost-ring event occurred in 1626  BC and he suggested that this  might well be the result of the  explosion of Santorini – if so, the  actual eruption would have occurred  in 1626 BC “or one or two years  earlier”.

Click hear to read Colin Burgess’ thoughts on volcanoes and population

To clarify one point at this  stage, all the American prehistoric  dates have to be moved back by  one year. This was due to La-Marche’s use of a “zero year”  between AD 1 and 1BC. No such  year is recognised in the historical  calendar hence the frost ring  actually relates to the growth ring  for 1627 BC.

In Ireland our approach was  rather different. One has to be clear  that there are two populations of  oaks. Archaeological timbers are  assumed to be “land grown” oaks.  The oaks we studied divided down  fairly neatly by period – the last  two millennia were mostly landgrown  timbers while the prehistoric  trees were almost exclusively bog  oaks. These bog trees grew rooted  on deep peat and hence their existence  was marginal at best.

It became  clear that it was these trees  which were sensitive recorders of  worsening conditions. The starting  point was the observation that  some of our bog trees showed very  narrow bands of rings in the decade  of the 1620s BC – tending to  support the notion that something  big had happened at that time.

When the effect was quantified it  was discovered that seriously reduced  growth episodes, indicated  by the “widespread occurrence of  narrowest growth rings”, were infrequent  and tended to occur at the  same times as Hammer’s ice-core  acidity peaks i.e. clusters of narrowest  rings in Irish bog oaks  appeared to be related to large  volcanic dust veil events (see Nature  332 [1988]). Interestingly recent  climate research by the Climatic  Research Unit at the University of  East Anglia has shown that in the  months following eruptions in recent  times, we tend to get low  pressure anomalies over Britain  and Ireland.

One can imagine that  the more extreme conditions which  might have been related to much larger eruptions in the past could  have supplied just the right conditions  to cause stress to the marginal  bog trees.

More from Colin Burgess on ancient volcanic disasters

1628 BC  
The date of 1628 for Thera (or  Santorini) presents a problem.  Although it is backed up by the  radiocarbon dates from Akrotiri on  Thera, the conventional dating –  based on cross-links with Egypt –  is around 1500 BC. One possible  solution is to look closely at the  conventional dates. It is tempting  to see the Thera explosion in  dramatic terms as marking the  “end” of the Minoan civilisation.  However the dates and the linkage  has always been a problem ever  since the connection between  Thera and the Minoan civilisation  was first mooted.

The problem is  that the Thera eruption is dated –  by the pottery on Thera itself – to  Late Minoan 1A, while the destructions  on Crete are LM1B. In the  original article in Antiquity in 1939  when Marinatos linked Thera with  the end of Crete, he suggested in  effect that LM1A and LM1B were  merely two different styles and  could be contemporaneous.

However our date of 1628 for Thera  would make this impossible.  The best current compromise –  adopted as a resolution at the  recent Thera Congress – is that  Thera marks the end of LM1A,  when there was considerable damage  on Crete that was rapidly repaired.  The “end” of the Minoan
empire came at the end of LM1B,  some time later. There are still  chronological problems: the end of  LM1B is still usually dated around  1500 BC by cross links with Egypt,  and this is usually considered to be  “a generation” later than LM1A.  The problem undoubtedly needs  further examination.

 Explosive news from Medieval London –  mass graves and the largest  volcanic eruption of the last Millennium.

1159 BC
In many ways, an even more interesting  catastrophe was that of  1159 BC. Hammer had noted a  significant ice signature at HOO –50 BC. The Irish trees show a very  spectacular narrow band of rings  beginning in 1159 BC – 43% of the  trees from six sites have their narrowest  rings during this period.

The event is almost certainly the  third great eruption of the Icelandic  volcano Hekla. The case for something  unpleasant happening in Britain
has been noted by John Barber,  director of the Scottish Central  Excavation Unit. He has noted both  extensive abandonment of upland  sites and a decline in the numbers  of “burnt mounds” – related to  cooking at temporary hunting sites  – in Scotland in the 12th century  BC.

This can be coupled with  Andrew Dugmore’s discovery of a  fine layer of volcanic dust first in  South Uist and the Shetlands and  more recently in a wide area of  northern Scotland. This tephra can  be positively identified to the Hekla  3 eruption. So the evidence,  precisely dated by the tree-rings, is  accumulating to present a firm  picture of effects on human populations.

Colin Burgess has long  argued (notably in his book “The  Age of Stonehenge”) that around  this same date the Earlier Bronze  Age came to a sudden end, and was  replaced by a very different Later  Bronze Age. It looks as if, for want  of a better suggestion, that we may  be able to argue that the Earlier  Bronze Age ended, and the Later  Bronze Age began in 1159 BC –  precisely.

AD 540
Coming forward, there is another  major event in AD 540. The most  obvious association with this date  is the occurrence of the Justinian  plague. If there really was a dust  veil event at that time – and European  dry fogs in 536 and 537 testify  to that – then what better to follow  any famine but plague.

The Neolithic and  beyond
Earlier than 1628 BC there are two  other events which may feature in  the archaeological record. These are  at 3195 BC and 4375 BC. It is
Sections of three bog oaks reveal  the 1159 lacuna.  Ring patterns from three sites,  Gortgole, Toome and Tullyroan,  show the catastrophic reduction  in ring widths in the 1150s and  1140s. It is  tempting at first to link the 3195 BC  event to the elm decline, but unfortunately  that doesn’t work.

Since 3195 BC is a tree-ring date, it  has to be de-calibrated to convert it  to the radiocarbon time scale. So  this suggested dust veil event  could be related to happenings  around 2500 bc, to use the old  lower case notation that everyone  understands – distinctly too late for  the elm decline. How about trying  it out for the interface between the  Early and Middle Neolithic – a nice  catastrophe to end the causewayed  camp/chambered tomb complex?

The same goes for 4375 BC which  de-calibrates to something like  3600 bc in radiocarbon years. This  could have made life difficult for  Mesolithic people – or indeed for  any really early farmers who had  just sneaked in. Only time will tell  how we interpret this date!

Further back still there is an  event which should be noted even  though there is no tree-ring evidence  for it! Hammer’s 5400 + 100  BC ice core date almost certainly  related to Mt. Mazama better  known as Crater Lake, Oregon.  This was a very large eruption and  it is interesting that the Irish bog  oak sequence begins at 5289 BC.

Again the de-calibrated date is  somewhere around 4600 bc in  radiocarbon years.  Having uncovered these events/dates in the Irish oak record and  then having found the coincidence  with the ice-core dates I have been  amazed how additional information  has tended to reinforce the
catastrophic concept. I am convinced  that these dates mean something  in human terms. However  I also recognise that the poor  chronological control normally  available in archaeology presents a  problem. Any sloppily dated  archaeological event, within a century  or so, tends to be “sucked in”  to the precisely dated tree-ring  events. We all have to be on our  guard against circular arguments.

If people really want their catastrophes  they will have to work for  them by refining their archaeological  chronologies.

Mike Baillie

This is an extract from an article published in our ‘Disasters’ special issue,  CA 117


  1. As always Mike, the article is interesting, relevant and well researched. Your work on dendrochronology when cross referenced with ice core data and other emerging dating tools will I’m convinced in time yield precise data on the timing and consequences of these volcanic events.

  2. Your concerns over the cross-links with Egypt may be answered by reference to ‘The Lost Testament’ by David Rohl, who questions conventional accepted chronologies and offers strong arguments for the revision of timelines.

  3. The Chinese Shang Dynasty had a 7 year famine early in the dynasty verifying Joseph’s 7 year global famine in the Book of Genesis chapter 41:1-57/41:57.


    Joseph lived for 110 years 1741-1631 B.C. (Genesis 50:26) Joseph age 30 (Genesis 41:40-46) became governor of Egypt in 1711 B.C. There was 7 years of great harvest and the second year of famine Joseph age 39 in 1702 B.C. met his father Jacob age 130 (Genesis 47:9) in Egypt. Global famine 1704-1697 B.C. (Genesis 41:1-57)

    (1) Jacob brought the starving Hebrew people into Egypt settling near Biblical On (Genesis 41:45) Heliopolis, Egypt in 1702 B.C.

    (2) Starving Hyksos Canaanite chieftain Sheshi lead his people into Avaris, Egypt trading their horses for bread (Genesis 47:13-17) in 1702 B.C. during the world famine. (Genesis 41:57)

    (3) Starving Minoans from Crete also settle in Egypt’s delta in 1700 B.C. Other Minoans migrate to mainland Greece in 1700 B.C. spreading their Minoan culture there.

    (4) Starving Indo-European Sealanders invade Amorite Babylon king Abi-Eshuh 1710-1684 B.C. settling in southern Babylonia in 1700 B.C. Abi-Eshuh dams up the Tigris river trying to starve the Sealanders out.

    (5) Starving Indo-European tribes invade Dravidan dominated India in 1700 B.C. Indo-Europeans destroy the Dravidan Mohenjo-Daro civilizatin in 1700 B.C.

    (6)Starving Indo-European tribes invade western China in 1700 B.C. Chinese archaelogist discovered Indo-European mummies in western China. The Indo-Europeans introduced the Chinese to the horse driven chariot. NOTE: Indo-European Kassites were first to use the horse driven chariot attacking Babylon in the reign of Amorite Babylon king Samsu-iluna 1750-1711 B.C. in his 9th year in 1741 B.C. NOTE: Joseph age 30 was given the Egyptian pharaoh’s 2nd chariot in 1711 B.C. (Genesis 41:43)

    (7) Chinese Shang Dynasty very early in the dynasty recorded a 7 year famine verifying Joseph’s account of the 7 year global famine in Egypt. (Genesis 41:57)

    (8) The American agricultural Indians establish the Poverty Point Mound Culture in Louisiana in 1700 B.C. building their first city in North America during the world famine.

    (9) Olmecs migrate into the Yucatan Peninsula in 1700 B.C. Archaeologist state the Olmecs invented plumbing and the Olmecs were interested in water conservtion at this time in world history.

    (10) Joseph’s account of the world famine (Genesis 41:57) is supported by archaelogy and the migrations of ancient people’s in 1700 B.C. Why not pass this information along to people who are interested in Biblical history.

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