The role of amorphous P-bearing precursors on barite formation
Metadatos
Afficher la notice complèteEditorial
European Association of Geochemistry
Date
2021-09-03Referencia bibliográfica
Ruiz-Agudo, C., Ibáñez-Velasco, A., Ruiz-Agudo, E. (2021) The role of amorphous P-bearing precursors on barite formation. Geochem. Persp. Let. 18, 32–36. doi: [10.7185/geochemlet.2121]
Patrocinador
SFB 1214 (project A07) German Research Foundation (DFG) Zukunftskolleg from the University of Konstanz; Spanish Government (grant RTI2018-099565- B-I00); Junta de Andalucía (research group RNM-179); University of Granada (Unidad Científica de Excelencia UCE-PP2016-05)Résumé
Past climate variations on Earth are recorded in sedimentary rocks by chemical and
biological indicators. In this sense, investigations of sedimentary marine barites
(BaSO4) have been fundamental to reconstruct geochemical evolution of palaeoenvironments.
Despite the significant advances achieved during the past decade, the
mechanism of barite formation in the ocean water column in undersaturated conditions
and the role of microorganisms remain controversial. Phosphorus-rich, amorphous
precursor phases have been suggested to play a key role, although the exact
mechanism of marine barite formation from this precursor is not well constrained. In
this paper, we evidence that barite can precipitate by replacing amorphous Ba-P precursor
phases formed in the absence of living organisms. This occurs by a mineral
replacement reaction, yielding an abiotic scenario for barite particles with morphologies, mesostructure and composition resembling
barite formed in the marine water column. This demonstrates the need to investigate how this formation process, via the
replacement of an amorphous precursor, affects the isotopic and trace element signatures of barite, and how this influences the
environmental information obtained from this proxy.