I would like to know what is the maximum amount of Sr measured in sedimentary carbonates. I do not say in oolites or in claim shells, but I am looking for true sedimentary rocks with calcitic mineralogy.
Thanks in advance
michele
Dear Alican, thanks for the hint, but what I am looking for is more recent. The article you suggest is nearly 50 years old...
Cheers,
michele
Dear Michele,
are you drifting away from basalts? I had a quick look into the GeoReM reference material data base and attached the extract as a file. I must say, I did include clams, corals and limestone so in your view propably not (pure) sedimentary carbonates.
Best,
TCM
Also take into account that the Sr concentration depends on the modal abundance of strontianite (SrCO3), of biogenic aragonite (which has a higher affinity for Sr than calcite), and on the possible presence of sulfates (e.g. celestine, SrSO4). Average compilations from the literature do not cover the most exceptional samples that you may be interested in.
Hi Kenneth,
with true carbonate I was meaning the lithified rock, not the shell of a still living claim or a recent ooid or similar stuff. I know that during the diagenesis the Sr content drastically decreases from the original values (that can be >1000-2000 ppm).
Cheers,
michele
Thanks also to Mathias, Thomas and Igor.
I have not moved too much from my favourite field (igneous petrogenesis). I am working on carboante inclusions within olivine from central Spain. Some colleagues have inferred that these are carbonatitic phases, but I believe that these are simply sedimentary carbonate partially digested from a cooling silicate magma. You can understand that the difference is really a lot...
The carbonate I found is almost pure calcite to Mg-calcite (MgO content ranging from 0 to 5-6 wt%). The carbonate is almost completely sterile in terms of incompatible element budged (i.e., less than 0.1 ppm La, just to understand), but has a variable Sr content (ranging from 0 to 1.14 wt% SrO). The samples with the highest Sr are pure calcite/aragonite (i.e., no Mg and Fe-Mn).
For this reason, I was looking for the maximum Sr content measured in sedimentary carbonates (calcite/aragonite only).
Thank you all for the interesting hints,
cheers,
michele
I have found that Miocene limestones can contain up to 1600 ppm Sr (about 0.19 wt% SrO).
Source: Westphal, Munnecke and Brandano, 2008. Effects of diagenesis on the astrochronological approach of defining stratigraphic boundaries in calcareous rhythmites: The Tortonian GSSP. Lethaia
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