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History's Hinge - 'Ain Jalut

[Administration]

Railway Inn Meols

Experts have discovered what they think may be one of Britain�s most important archaeological finds � a Viking longship buried under a pub car park in Merseyside.

The ship was located used a high-tech Ground Penetrating Radar (GPR) device, which traced its outline under 2-3 metres of waterlogged clay below the car park of the Railway Inn in Meols, the Wirral.

Professor Stephen Harding of the University of Nottingham, who made the discovery, is now looking for funding to excavate the site, and believes that its shape and outline matches that of a 1,000-year-old Norse transport vessel.

The ship was first uncovered in 1938 by workmen who were knocking down the old Railway Inn to be rebuilt further away from the road. They found parts of a clinker-built ship but covered it up again to finish converting the site into a car park.

Meol�s has been inhabited since Neolithic times and was given its present name by the Vikings, who occupied most of the Wirral peninsula around the ninth to tenth centuries. Although it is several miles from the sea the ship could have been washed up there during flooding and then sunk in boggy ground.

The only other Viking longship discoveries in the UK have been on Orkney and the Isle of Man.

[Fleamistress]

"Cover it up!  It'll slow down the job!"  Classic construction contractor's nightmare.

So they already knew it was around there somewhere, and they found it with a GPR that cost less than 3K US!

[Administration]

Though one would have to add a 0 to that 3, your point is well made 

And I always though the greatest treasure of a pub is found in barrels... 

[Bart]

If that is so, then we have an extremely well off saloon here.

Bart

[Fleamistress]

Here's my source of the GPR costs, which is under what I stated previously.  They may have used a service and not a purchase.  ANyway, I found the figure most striking.

http://news.bbc.co.uk/1/hi/england/merseyside/6986986.stm

Cyn

[Wopper]

Howdy History Hunters,

I know a little bit about GPR, and clay can play havoc with them. I wonder if the material that the ship is buried in is something other than clay.

Here is part of an article wrote by Lambert Dolphin, formerly Senior Research Physicist
SRI International, Menlo Park, California.

Absorption of radar signals in the earth is dependent on a soil or rock's moisture content, and especially the salt content of that moisture. Clay soils have by nature very high radar losses because of their molecular ionic structure. In wet clay soils it is often impossible for a GPR to penetrate deeper than a few feet no matter how much transmitter power is available. In dry or otherwise favorable rock types 100 to 300 feet of penetration is often possible.

Lambert Dolphin developing the first ground-penetrating radar!
1973 at a Dolomite Mine near Lone Pine, California, with Bob Bollen.
Preparing for our first radar study of the pyramids of Egypt.
This information came from this website http://www.ldolphin.org/GPRbkgnd.html

Sincerely,

Wopper

[Administration]

Ground Penetrating Radar

Introduction and History

The first ground penetrating radar survey was performed in Austria in 1929 to sound the depth of a glacier (Stern, 1929, 1930).  The technology was largely forgotten (despite more than 36 patents filed between 1936 and 1971 that might loosely be called subsurface radar) until the late 1950's when U.S. Air Force radars were seeing through ice as planes tried to land in Greenland, but misread  the altitude and crashed into the ice.  This started investigations into the ability of radar to see into the subsurface not only for ice sounding but also mapping subsoil properties and the water table (Cook, 1964; Barringer, 1965; Lundien, 1966).  In 1967, a system much like Stern's original glacier sounder was proposed, and eventually built and flown as the Surface Electrical Properties Experiment on Apollo 17 to the moon  (Simmons et al., 1972, see also the Apollo 17 Lunar Sounder Experiment).   Before the early 1970's, if you wanted to do GPR, you had to build your own (Ohio State University Electroscience Laboratory).  But in 1972, Rex Morey and Art Drake began Geophysical Survey Systems Inc.  to sell commercial ground penetrating radar systems (Morey, 1974).  Thus began an explosion of applications, publications, and research, fostered in great part by research contracts from the Geological Survey of Canada,  the U.S. Army Cold Regions Research and Engineering Laboratory (CRREL), and others.

Depth
The depth range of GPR is limited by the electrical conductivity of the ground, and the transmitting frequency. As conductivity increases, the penetration depth also decreases. This is because the electromagnetic energy is more quickly dissipated into heat energy, causing a loss in signal strength at depth. Higher frequencies do not penetrate as far as lower frequencies, but give better resolution. Optimal depth penetration is achieved in dry sandy soils or massive dry materials such as granite, limestone, and concrete where the depth of penetration is up to 15 m. In moist and/or clay laden soils and soils with high electrical conductivity, penetration is sometimes only a few centimetres.

The lowest-cost GPR unit I know of is the Zond. In the USA:
Zond Control Unit and Prism Software: $15,026.00
1.5GHz Antenna Unit: $2,732.00

US-made units cost much more.

You're right, dear lady: rental costs much less.