From literature, I am aware that Ce anomaly in marine and carbonate sediments are good indicator of depositional setting, but this alone cannot be used for this purpose as it may be influenced by the detritus phase. I would like to know if there are other geochemical indicators which could be used to reliably predict depositional environments in carbonate sediments.
First and foremost you should spend more time on describing the mineralogy/ petrography of your calcareous rocks. Are they impure limestones with a lot of detrital material or are they almost clean dolo- or limestones. Are the impurities only non-organic or also contain organic matter. In the latter case you can make use of biomarkers determined with organic chemical methods. But be cautious they can be formed in-situ or immigrated hydrocarbons. In case of true mineral impurities different mineralogical and chemical parameters can be harnessed.
Common limestones contain:
Ø calcite
Ø Mg calcite (MgCO3 = 0 to 6 %; > 11 % at T values > 15°C and higher- up 40 %)
Ø ferroan calcite (reducing environment)
Ø dolomite
Ø ferroan dolomite/ ankerite (reducing environment, late diagenetic)
Ø siderite (reducing environment, late diagenetic)
Ø collophanite/ hydroxyl-apatite
Ø clay minerals (e.g,. illite, smectite, sepiolite, glauconite...)
Ø alkaline feldspar
Ø siliceous compounds (derived from spicules, radiolarian tests, diatoms
Ø sulfate (gypsum, celestite)
Ø chloride (halite)
Now you must know which trace elements can be accommodated in the lattice of the major minerals and how can the substitute, e.g., for Ca, P etc.
Fe in calcite is a redox indicator
Cl, S, Mg and Sr are controlled by strong evaporation
Co, Ni, V, Cr are governed by the clay minerals and good redox indicators
In case of phosphates you can use the entire REE spectrum, Eu and Ce anomalies tetrad effects etc.
Feldspar is not relevant it is a diluter.
You can also use Ca, Sr and S isotopes for chemo-stratigraphy and some kind of age dating using the seawater curve.
This is a first approximation
HGD
Thank you for your answer, Prof. @H.G. Dill. I sincerely appreciate this valuable information you have shared.
It is a pleasure for me to have the opportunity and continue what I have done for more than 20 years, now as a retiree.
HGD
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