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Archiver > GENEALOGY-DNA > 2005-03 > 1110227002


From: "" <>
Subject: Irish Sea Bathymetry
Date: Mon, 7 Mar 2005 15:23:22 -0500


A couple of days ago we were talking about access to Ireland during the
Last Glacial Maximum. Here's a set of maps from an Irish Sea study.

http://www.jncc.gov.uk/pdf/irish_finalreport(maps).pdf

The second one is a bathymetric map that seems to indicate the only sure
land access to Ireland was across a stretch of land toward the south of
what would become the Irish Sea. There is a fairly deep trench at the north
end which would have divided proto-Ireland from proto-Scotland. I am not
sure what the seafloor looks like just north of the study area of this map.
Perhaps it was shallow enough to permit a walk-in crossing there. But I
believe that area was under the ice. There is some indication that southern
Ireland may have been unglaciated at this time.

The rule of thumb is this: If the seafloor depth is less than 300 feet (90
meters) today, it would have been walkable in the LGM. That's the three
lightest shades in the exhibit. The fourth lightest shade that indicates
seafloor depth up to 120 m MAY have been walkable except at its deepest.
Even if the original inhabitants did not walk in, I envision them easily
rafting across a narrow shallow channel. (Presuming the availability of
trees or other raftworthy materials.)

This is a graphics-heavy PDF file. If you are on dialup, it will take a
long time to load. The bathymetry map is the second one in the series of
28. The others deal with other matters of maritime interest.

David Wilson



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