Hello Penny,
How did you pretreat your samples to remove inorganic carbonates? It
maybe that you have diagenetic siderite in the sample which is
difficult to remove with the normal room temperature acid pretreatments.
Take care,
Jennifer
On Jan 18, 2013, at 6:38 PM, Penny Higgins wrote:
> Hi all,
>
> I'm running organic carbon from a series of shales. Everything's
> running great. I'm running them on the Costech EA that was having
> issues a couple of weeks ago. Most of my data are spectacular.
>
> The problem: I have a bunch from one particular stratigraphic
> section that are giving very, very positive values (like -4 permil V-
> PDB), that are reproducible, and that show up between other analyses
> yield 'expected' results (between -30 and -20 permil).
>
> I've done a literature search and can't find any good explanation
> for what this could be. The samples were pretreated to eliminate any
> inorganic carbonates. I wonder if it's alteration? Diagenesis? Or
> I've discovered a new life form?
>
> Any ideas or suggestions? Has anyone seen anything similar before?
>
> Thanks,
>
> ~Penny
>
> *******************************************************************
> Dr. Pennilyn Higgins
> Research Associate
>
> "SIREAL"
> Stable Isotope Ratios in the Environment Analytical Laboratory
>
> Department of Earth and Environmental Sciences
> University of Rochester
> 227 Hutchison Hall
> Rochester, NY 14627
>
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> Sent from the interwebs!!!
Jennifer McKay
Assistant Professor (Senior Research)
College of Earth, Ocean & Atmospheric Sciences
Oregon State University
104 CEOAS Admin. Building
Corvallis, OR 97331
Office: 541-737-4054
Fax: 541-737-2064
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