I had a student present some work on carbonate diagenesis of paleosol and siliciclastic cements at GSA and a few people came up to him and asked if he had considered doing cathode luminescence analysis to help distinguish between primary and secondary carbonates.
The carbonates consist of nodules in paleosols, matrix cements in fluvial sediments, and carbonate rinds on conglomerate clasts.
We're trying to come up with ways to determine whether these carbonates precipitated at the time of sediment deposition (paleosol formation) or at some later time. These rocks are Neogene in age.
Thanks for any insight!
The cathodoluminescence microscopy method allows to highlight HMC zones (High Magnesium calcite) which exhibit strong luminescence contrary to LMC (Low Magnesium calcite) which exhibit low luminescence. I had used this for belemnite guard to distinguish original calcite (LMC) from secondary recrystallized calcite (HMC).
For paleosols, I didn't know if they crystallized primary in low or high magnesium calcite, but I'm nearly sure that you can observed difference between primary or secondary calcite precipitation. The luminiscence depends of Mn ions content which vary following the type of carbonate (calcite HMC, calcite LMC, dolomite) and the diagenesis level. I hope that it could help you.
All the best
For some insights, you can have a look at:
http://paleopolis.rediris.es/cg/CG2009_A07/index.html
http://paleopolis.rediris.es/cg/1703/index.html
http://paleopolis.rediris.es/cg/1704/index.html
and the bibliographical references within, as far as cement stratigraphy is concerned.
Good luck.
Best
Bruno
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