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E-M:/Re: Great Lakes Satellite Imagery



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Enviro-Mich message from "Timothy Carpenter" <geodynamics@home.com>
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The imagery of Lake Michigan ca. July through Sept 1999
(http://seawifs.gsfc.nasa.gov/SEAWIFS/IMAGES/NEW/USA/S1999205-1999250.LakeMi
chigan.jpg) is referenced at several locations on the net, sometimes
referring to "inorganic precipitation of calcium" and at others to "algae
bloom". Based on a very incomplete search and correlation of dates, it seems
that early interpretations of the imagery leaned to the assumption that the
patterns were from algae. Later, the interpretations are leaning to
precipitation of naturally occurring calcium carbonate ( see
http://explorezone.com/snapshots/1999/09_24_whiting.htm ). It is
particularly fascinating that the interpretation of calcium is based on an
image from Sept 24, 1999. {As related previously, try downloading the images
then adjust the contrast and brightness with a photo editor to enhance the
patterns in the water.}

Calcium is a common mineral in the LP's soil and groundwater. Evidence of it
is found in the thick marl deposits at the bottom of peat bogs, in
calcareous fens (wetlands below springs with a high alkalinity) and
typically as "hard" water from domestic wells. Lime Lake, up near Traverse
City, has a bed made of precipitated calcium carbonate. A major source of
the calcium in our soil and groundwater is from limestone fragments abraded
and transported by glacial action from the Niagara Escarpment (
http://www.escarpment.org/Geology/about_geology.htm ).

Given no further information, I'd lean to expecting that the patterns in
Lake Michigan are from the calcium rather than algae. To find out for sure
what it is, I'll offer my services to sail up and down Lake Michigan taking
water samples all summer long -- if someone will supply the boat, grub, crew
and sunblock.


-Tim-

Please note that my @home.com address will be gone after the 28th -- it is
replaced by geodynamics@comcast.net



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