Posted on 09/11/2006 2:55:50 PM PDT by blam
nitrogen the Vikings left behind
11 September 2006
From New Scientist Print Edition.
Discovering ancient settlements is often rather hit and miss, but the odds would be improved with a bit of chemical analysis. Plants growing over old sites of human habitation have a different chemistry from their neighbours, and these differences can reveal the location buried ruins.
Plants mostly take in nitrogen from the soil as the isotope nitrogen-14, with just a dash of nitrogen-15. Plants growing above archaeological sites in Greenland, however, seem to have absorbed a larger dose of nitrogen-15.
Rob Commisso and Erle Nelson from Simon Fraser University in British Columbia, Canada, spent three summers collecting plants from sites in south-west Greenland. Some of their samples were unusually rich in nitrogen-15, and subsequent digs revealed that these plants had been growing above long-abandoned Norse farmsteads (Journal of Archaeological Science, vol 33, p 1167).
(Excerpt) Read more at newscientist.com ...
GGG Ping.
The grass is always greener over the septic tank.
btt
Still doesn't explain why N-15 is more abundant than N-13 or N-14 in human habitats. Its not like there is radioactive decay happening. Nitrogen is nitrogen, regardless of the isotope.
the difference in isotope is what got Landis in trouble.
Tons of dust fall on every acre over the eons. That's what a geologist pal told me, anyway.
Parts of Ukraine have some of the deepest topsoil in the world, 150 feet. It blew there from Russia.
When I lived in Florida, I frequently had to wash the thick orange (iron laden) dust from the Sahara desert off my car.
They get behind on their yard work.
It might be the wind in the desert, but one fellow,at least credits the earthworms. They chew their way through the soil and put their droppings(?) on top.
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In the South, the Fire Ant has replaced the earth worm as the #1 'turner of the soil.'
Wonder if there is enough distinction that a satellite could use color enhancement to spot them?
Maybe. I've read that something along that line is used in a small plane to detect people in this rural area who have leaking septic systems. We're near the bay and a nice fresh water river.
When I was in Israel, I was told by a tour guide that when a new group of people moved into an area, they would just cover with dirt the ruins of whoever had been there before.
Typical for Mitchner, it starts at the beginning.
Is there any benefit to Fire Ant castings?
I would blame the wind less, and trees more. Most of these ancient sites are in depositional areas. Every year they are coated with a layer of fallen leaves and other debris from plants around them. This layer of detritus eventually breaks down into soil. Some sites are subject to frequent flooding, that deposits a layer of mud over the entire site, burying it, unless it is removed, and most of the ancient civilizations had a habit of knocking down the exposed parts of structures and building right over the older structures.
Well in the 21 years I've lived in my house, my lawn has raised at least 2 inches. Some areas have gotten so high above the sidewalk that we've had to scrape off the weeds, remove dirt and re-seed (hoping for grass this time instead of weeds!) Every 5 years or so, we have to add another landscape timber on top as the others have gotten too low. Imagine a few thousand years of the same.
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