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Author Topic: Where does soil come from to cover archaeological relics?  (Read 10262 times)

Gordon Kubank

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Gordon Kubank asked the Naked Scientists:

Where did all the dirt come from that covers archaeological sites. I watch Time Team occasionally and even going back a few hundred years the area is always covered by lots of earth.

What do you think?


 

Offline Karen W.

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Where does soil come from to cover archaeological relics?
« Reply #1 on: 24/09/2008 23:46:43 »
I would imagine wind decay, animal feces such as worm excrement, dust in layers etc.. perhaps dry conditions water run off bringing more dirt and land into and over areas.. Thats just my guess. Land changes over time with weather and earthquakes and lots of other natural occurrences.
« Last Edit: 27/09/2008 16:31:39 by Karen W. »
 

blakestyger

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Where does soil come from to cover archaeological relics?
« Reply #2 on: 25/09/2008 09:48:23 »
In the (albeit limited) experience I've had, the urban material over archaeological sites - which is general occupation detritus of building material, bones and rubbish - accumulates relatively faster than it does in the rural ones.
For instance, where I live an excavation in the town went down to features from the fourteenth-century at a depth of about 1.5 meters whereas years ago I was on a Roman site in a field that was covered by only about 0.3 meters of topsoil; this site had ceased to be occupied at the end of the Roman period.
« Last Edit: 25/09/2008 09:50:51 by blakestyger »
 

Offline Don_1

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Where does soil come from to cover archaeological relics?
« Reply #3 on: 25/09/2008 10:37:58 »
Land slides, flooding, farming, building over existing sites, airborne dust, soil and so on, animal waste, animal burrowing, sinkage (especially during periods of flood), volcanic fall-out, land heave......

Not an exhaustive list!!!
 

Offline JimBob

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Where does soil come from to cover archaeological relics?
« Reply #4 on: 27/09/2008 16:07:48 »
Soil is formed by many process - in urban sites, plain old garbage. But in non-urban sites, the ground cover - be it grass or forest - has a yearly cycle, dieing off in the winter and growing in the spring. The material is reused by the plants but over time, wind-blown material will be trapped by the ground cover and thus add to the soil layer. Also, the underlying rock, if present, is SLOWLY (1000's of years) broken down by chemical erosion.

The yearly cycle of the vegetation combined with particles blown in by the wind forms soil. Most of the processes mentioned above are active but not dominant.

As an interesting note, fine dust from the Sahara is picked up each summer and blown clear across the Atlantic to the Caribbean and even as far as the southern US (when the Trade winds are shifted north.)

 
« Last Edit: 27/09/2008 16:10:08 by JimBob »
 

paul.fr

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Where does soil come from to cover archaeological relics?
« Reply #5 on: 27/09/2008 22:54:38 »
As an interesting note, fine dust from the Sahara is picked up each summer and blown clear across the Atlantic to the Caribbean and even as far as the southern US (when the Trade winds are shifted north.)

 

yes, this is even tracked on radar, and the reason why Americans awaken with red dust on their cars.
 

Offline frethack

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Where does soil come from to cover archaeological relics?
« Reply #6 on: 28/09/2008 05:14:18 »
Towns/Villages/Cities are also usually built in depositional regions such as a valley between mountains, in river flood plains, or along the coast (which is often subsiding).  All of these areas are very high in sediment deposition and can acquire depth fairly quickly. 
 

blakestyger

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Where does soil come from to cover archaeological relics?
« Reply #7 on: 28/09/2008 10:18:08 »
I remember one summer in the early 1970s (in the UK) there had been a few days of very warm southerlies that were accompanied by a fine yellowish dust that settled everywhere - most noticeable on cars - which was reported as originating in the Sahara.  [:0]
 

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Where does soil come from to cover archaeological relics?
« Reply #7 on: 28/09/2008 10:18:08 »

 

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