GEOBIOCARBON GEOBIOlogical mechanisms controlling the formation of CARBONate minerals at low temperatures


The Mg-rich carbonate dolomite is common in Earth’s ancient geological rock record but rarely formed today.
The “dolomite problem” has been the subject of heated debate for decades, specifically if mixed cation (Ca-Mg-
Fe) carbonates are primary or alteration products. In addition, what is the role of biological control in the formation
of primary mixed cation carbonates?
This project will investigate if and how microorganisms control the mineralogy and therefore, the geochemistry
of carbonate minerals that grow at low temperature (<50° C) to establish if these minerals can act as proxies of
the palaeo-conditions of formation. We will examine the hypersaline system in Fuente de Piedra (SW Spain), one
of few places of present-day dolomite formation, and perform biotic and abiotic laboratory experiments that mimic
natural environments (i.e., vary temperature, pH, salinity etc). The different metabolisms involved in carbonate
biomineralization under oxic and anoxic conditions are expected to deliver characteristic nanotextural and
geochemical signatures in both mineral and organic phases. Therefore, the characterization of dolomite in the
hypersaline and evaporitic environment of Fuente de Piedra, coupled with laboratory experiments, will allow a
quantitative interpretation of the processes that cause dolomite formation. Models developed from these data will
be applied to examples of early Earth environments where unaltered carbonates are preserved to determine the
palaeo-environment and possible role of life. This study is designed to understand mechanisms of carbonate
formation in natural systems, which are of fundamental importance not only for understanding modern
environments but also as a window into the geologic past of Earth and potentially Mars.





Dr. M. Sánchez-Román

Verbonden aan

Vrije Universiteit Amsterdam, Faculteit der Bètawetenschappen (Faculty of Science), Earth Sciences


01/01/2020 tot 31/12/2023