The role of amorphous P-bearing precursors on barite formation Ruiz Agudo, Cristina Ibáñez Velasco, Aurelia María Ruiz Agudo, Encarnación CRA thanks the SFB 1214 (project A07) funded by the German Research Foundation (DFG) and the Zukunftskolleg from the University of Konstanz. ERA acknowledges funding was provided by the Spanish Government (grant RTI2018-099565- B-I00), the Junta de Andalucía (research group RNM-179), and the University of Granada (Unidad Científica de Excelencia UCE-PP2016-05). In addition, we would like to thank the personnel of the “Centro de Instrumentation Científica” (University of Granada) for their support and help with the electron microscopy analysis. 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. 2021-10-21T12:30:16Z 2021-10-21T12:30:16Z 2021-09-03 info:eu-repo/semantics/article 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] http://hdl.handle.net/10481/71032 10.7185/geochemlet.2121 eng http://creativecommons.org/licenses/by-nc-nd/3.0/es/ info:eu-repo/semantics/openAccess Atribución-NoComercial-SinDerivadas 3.0 España European Association of Geochemistry