Mysa or Syra (whey); Subglacial Volcanism Definitions
James A. Landau
JJJRLandau at AOL.COM
Tue Jul 17 16:40:46 UTC 2001
In a message dated 7/17/01 11:57:02 AM Eastern Daylight Time, His Honor
Bapopik at AOL.COM writes:
> OED also doesn't have "shield glaciers," or ice-cap glaciers resting on a
> single mountain. OED does have "shield volcanoes."
> From the pamphlet HVERAVELLIR: STOPOVER IN THE MOUNTAINS:
> Table mountains, _stapar_ such as Hrutfell, or tuff were formed in
> eruptions under glacial caps. The shield volcano, or _dyngja_; Kjalhraun
> formed by thinly flowing lava soon after the glaciers receded.
I think you are confusing two very different geologists' meanings of "shield".
A "shield volcano" is one formed by flows of very fluid lava. The Hawaiian
islands are shield volcanoes. The other extreme is a "cinder cone" formed
from solid pieces of volcanic rock (e.g. the "tuff" cited above, the idea is
"volcanic cinders"). A good example is Paracutin in Mexico.
As long as they're dormant, a shield volcano and a cinder cone can have very
"ice-cap glacier" is an ambiguous term.
There are two kinds of glaciers. One is called I think (I don't have a
geology text handy) a "mountain glacier" or "valley glacier". This is the
type of glacier that in the right climate would form on either a shield or a
cinder cone volcano.
The other type is a "continental glacier" (again, check a geology text).
This is a mass of ice of continental scope that covers both plains and
mountain ranges with icy indifference. Greenland is covered by such a
continental glacier. It may be that "shield glacier" is a synonym for
- Jim Landau
P.S. Your Honor, the controversy over Bush's nominee for Solicitior General
has brought to my mind the question: why is the office called "Solicitor
General" when in fact the occupant is the Barrister General of the US
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