Ancient and recent terrestrial carbonate-precipitating systems arecharacterised by a heterogeneous array of deposits volumetrically dominated bycalcite whose formation takes place in hydrochemically challenging environments.
While sedimentologists and geochemists acknowledge that early formedcarbonate crystals may suffer a range of diagenetic processes, extracting informationabout the primary hydrochemical conditions triggering micro-crystal growthremains a fundamental question.
Environmental interpretations have been hampered by the fact thatcalcite morphogenesis results from the complex interaction between differentphysico-chemical and biological parameters which often act simultaneously(e.g., carbonate mineral supersaturation, Mg/Ca ratio of the parental fluid,organic and inorganic additives).
To try to experimentally quantify the sedimentological causes ofcalcite morphogenesis, a laboratory approach yielding a first attempt at acalcite growth-form phase diagram for alkaline, saline lake settings ispresented here. The purpose was to relate specific hydrogeochemically common contexts(variations in calcite supersaturation level, and microbial EPS concentration) totypical calcite precipitates observed in nature.
By exploring how hydrochemical variations of the parental fluid impact non-skeletalcalcite precipitate morphology, we can better constrain the nature of therecent and/or ancient fluids driving petrographical changes during eo- to telodiageneticprocesses.
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