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60034.  Wed Mar 15, 2006 11:39 am Reply with quote

eggshaped wrote:
No Nobbler, you are correct.

Just like dendochronology, in which you can find the age of a tree by counting its rings, many species of whale deposit one layer of wax in their ears every year. Counting these layers is a failsafe way of finding how old a whale was when it died.

So an advert for Q-tips for whales would claim they eradicate one of the signs of aging???
(I know, 'How would the whale hold the Q-tip?')

Now, being serious for a moment,

(moment over) I am aware of how dendrochronolgy can be used in archaeology/climatology and other -ologies, but one has to know how long the tree has been dead, before saying things like, 'This ring shows that in 545 CE there was a bad summer'. Or am I missing something?

60036.  Wed Mar 15, 2006 11:42 am Reply with quote

That sounds fair enough Tetsabb, I would imagine such claims would be made after comparing dendochronology and carbon dating?

60052.  Wed Mar 15, 2006 12:17 pm Reply with quote

With dendrochronology (blimey, I had to carefully count the number of o's there) archeologists have now managed to build up a database of tree ring widths for a large range of years in the past.

Therefore they are able to compare a selection of adjacent tree rings with the database and, from comparing the relative widths of the rings in the selection with the relative widths in the database, deduce during which years these rings were laid down.

So it's not always necessary to know how long the tree has been dead.

60062.  Wed Mar 15, 2006 12:25 pm Reply with quote

If I remember correctly (unlikely, I know) the rings have differing thicknesses due to the amount of growth. This is controlled by various enviromental factors, so for instance, the year of no sun in 1816 (I think) shows a very thin line, due to the lack of sunlight brought on by a large volcanic eruption the year before.

I think that Krakatoa had a similar effect.

Such events, if of enough magnitude, have a uniform effect on all trees and other plants, so that the rings are all affected in the same way. The pattern that emerges is held on a dendro-chronology data base, and samples can be matched up pretty quickly.



(Damn firewalls for stopping serious research into this....I hate work, some days....mostly ones with a 'y' in them!)

60093.  Wed Mar 15, 2006 1:23 pm Reply with quote

Do you mean 1783/84? This was the year of the Laki eruptions (Iceland) that flooded the skies around Europe with Sulphur Dioxide. The smogs, hot summer and excessively cold winter is now thought to have killed up to 30,000 people.

Krakatoa took place 100 years later in 1883. Those are the 2 major eruptions I can think of.

60172.  Thu Mar 16, 2006 5:40 am Reply with quote

1816 was known as the Year Without A Summer due to freak climatic conditions which caused crop failures across northern europe and north america. It's also referred to as the Pverty Year, or Eighteen Hundred And Froze To Death.

It is thought now that the strange conditions were caused by the volcanic eruptions of Mount Tambora between 5th and 15th April 1815.

60210.  Thu Mar 16, 2006 7:10 am Reply with quote

Thanks Dr B! That's the one I was thinking of, but could not find.



60224.  Thu Mar 16, 2006 7:50 am Reply with quote

There are similar patterns of dateable layers in ice cores and in lake sediments.

There are fully-anchored tree-ring chronologies going back over 10,000 years for some parts of the world.

gerontius grumpus
60912.  Sun Mar 19, 2006 7:50 pm Reply with quote

Fish can be aged by counting the growth rings in their otoliths. Not so very different to whales really.

61873.  Sat Mar 25, 2006 1:15 pm Reply with quote

I must say that an E board would be useful. I would want to start an economics thread (very QI in my view)

gerontius grumpus
61977.  Sun Mar 26, 2006 5:07 pm Reply with quote

Very quite interesting?


62017.  Mon Mar 27, 2006 4:08 am Reply with quote

Totally unrelated to the subject of the thread but did you realise that the posting times aren't matching the actual time at the moment? Somebody hasn't put thier clocks forward.

62079.  Mon Mar 27, 2006 10:00 am Reply with quote

Well it does say at the bottom:

All times are GMT

So I wonder if anyone ever bothers to change the clock?

62157.  Mon Mar 27, 2006 6:09 pm Reply with quote

I was working on a way of being nasty and caustic right up until the moment when I realised you had a point. Then I became introspective and regretful.

62275.  Tue Mar 28, 2006 10:57 am Reply with quote



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