Continental carbonates are distinct from their marine cousins, but like them, contain numerous proxies for the environment in which they formed. Yet, continental carbonates can be of two general types: those formed ambient temperature from calcium bicarbonate–enriched waters and those associated with hyperalkaline thermal springs, from fluids commonly depleted in dissolved inorganic carbon. Both are favored under distinct conditions, yet how closely they each reflect their environment is unclear. To better understand these complexities, Leleu and others examined travertine forming at DIC-depleted hyper-alkaline springs with pH up to 12. Their multi-disciplinary approach ranged from macroscopic to microscopic scale, analyzing travertine samples to assess the relationship between the petrologic features and fabrics and the geochemical and isotopic signatures. The results illustrate the potential of these deposits as proxies of past climatic record and atmospheric CO2 sequestration.
Travertines associated with hyperalkaline springs: evaluation as a proxy for paleoenvironmental conditions and sequestration of atmospheric CO2 by Thomas Leleu, Valérie Chavagnac, Adélie Delacour, Catherine Noiriel, Georges Ceuleneer, Markus Aretz, Céline Rommevaux, and Sandra Ventalon