Dear Listmembers,

We are looking at shallow water marine Miocene clams to determine growth
rates from O-18 measurements determined every mm.  We seem to get pretty
good annual "wiggles" but the magnitude of the seasonal signal changes as
the specimens get older. Is it real or alteration in the older thinner
parts of the shells?

Is there a consensus on what the best method of determining carbonate
alteration might be in Miocene to Cret age samples of bivalves?  We are
discussing thin sectioning, acetate peels & SEM analysis, or staining with
Feigl's solution (a mixture of AgSO4, MnSO4 and water) which stains calcite
white and aragonite black?  Are staining techniques sensitive enough?

Bill Showers

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William J. Showers
Dept. of Marine, Earth, & Atm Sciences
1125 Jordan Hall
North Carolina State University
Raleigh, NC  27695

(919) 515-7143 - voice
(919) 515-7802 - fax
[log in to unmask] - email

"Never be afraid to try something new. Remember: Amateurs built the
ark.  Professionals built the Titanic."