000088380 001__ 88380
000088380 005__ 20240122154813.0
000088380 0247_ $$2doi$$a10.1016/j.sedgeo.2019.04.003
000088380 0248_ $$2sideral$$a111446
000088380 037__ $$aART-2019-111446
000088380 041__ $$aeng
000088380 100__ $$0(orcid)0000-0003-0410-6948$$aMayayo, M.J.$$uUniversidad de Zaragoza
000088380 245__ $$aFe-rich microspheres pseudomorphs after pyrite framboids in Holocene fluvial deposits from NE Spain: Relationship with environmental conditions and bacterial activity
000088380 260__ $$c2019
000088380 5060_ $$aAccess copy available to the general public$$fUnrestricted
000088380 5203_ $$aThree iron oxides-rich microsphere types (Type I to III) were detected in an Holocene 17 m-thick stratigraphic succession located in the Iberian Range (NE Spain). Lithofacies features indicate that the studied materials were generated in an alluvial-dominated setting, with a channeled area fringed by floodplain zones. During high water levels and high-energy floods, gravels and sands deposited in the active area and in lateral overbank areas. In these lateral areas, mud settling took place when flood decreased and then anoxic conditions could be reached due to microbial oxidation of organic matter and the low permeability of the marly sediment. X-ray diffraction (XRD) analysis of 32 samples and microtextural observation of 10 samples by Field Emission Scanning Electron Microscopy (FESEM) revealed the occurrence of Fe oxi-hydroxides microspheres showing different surficial structure. These microspheres are pseudomorphs after pyrite framboids although the formation of some primary Fe oxy-hydroxides aggregates cannot be rejected. Pyrite framboids genesis in sediments underlying oxic-dysoxic water column would have been favored by anoxic conditions reached in lateral overbank areas after main flooding, involving the activity of Fe reducing bacteria and sulfate-reducing bacteria (SRB), given the high SO 4 = availability provided by the highly mineralized groundwater from the upstream Baños de Ariño spring. Subsequent change to oxic conditions during the exposition of the floodplain enhanced the transformation of pyrite into Fe oxy-hydroxides, as well as in microenvironments around cracks and roots. Pyrite oxidation likely took place with the implication of neutrophilic iron oxidizing Bacteria and Archaea living in microaerophilic conditions, as well as cyanobacteria, given the close association of Fe oxides framboids with microbial features. In addition, pyrite and/or Fe oxi-hydroxides framboids from marl levels could have been incorporated to sand sediments during further overbank flooding episodes. Under these new oxic conditions pyrite oxidation would have been favored and even the formation of primary Fe oxy-hydroxides.
000088380 536__ $$9info:eu-repo/grantAgreement/ES/UZ/UZ2015-CIE-08$$9info:eu-repo/grantAgreement/ES/UZ/UZ2014-CIE-04
000088380 540__ $$9info:eu-repo/semantics/openAccess$$aby-nc-nd$$uhttp://creativecommons.org/licenses/by-nc-nd/3.0/es/
000088380 590__ $$a2.728$$b2019
000088380 592__ $$a1.468$$b2019
000088380 591__ $$aGEOLOGY$$b8 / 47 = 0.17$$c2019$$dQ1$$eT1
000088380 593__ $$aStratigraphy$$c2019$$dQ1
000088380 593__ $$aGeology$$c2019$$dQ1
000088380 655_4 $$ainfo:eu-repo/semantics/article$$vinfo:eu-repo/semantics/acceptedVersion
000088380 700__ $$0(orcid)0000-0002-2169-4561$$aYuste, A.$$uUniversidad de Zaragoza
000088380 700__ $$0(orcid)0000-0002-8929-9429$$aLuzón, A.$$uUniversidad de Zaragoza
000088380 700__ $$aCorzo, A.
000088380 700__ $$0(orcid)0000-0001-5700-6495$$aMuñoz, A.$$uUniversidad de Zaragoza
000088380 700__ $$0(orcid)0000-0001-6285-2522$$aPérez, A.$$uUniversidad de Zaragoza
000088380 700__ $$0(orcid)0000-0002-2842-517X$$aSoriano, A.$$uUniversidad de Zaragoza
000088380 7102_ $$12000$$2427$$aUniversidad de Zaragoza$$bDpto. Ciencias de la Tierra$$cÁrea Geodinámica Externa
000088380 7102_ $$12000$$2280$$aUniversidad de Zaragoza$$bDpto. Ciencias de la Tierra$$cÁrea Estratigrafía
000088380 7102_ $$12000$$2120$$aUniversidad de Zaragoza$$bDpto. Ciencias de la Tierra$$cÁrea Cristalografía Mineralog.
000088380 773__ $$g386 (2019), 103-117$$pSediment. geol.$$tSedimentary Geology$$x0037-0738
000088380 8564_ $$s1538204$$uhttps://zaguan.unizar.es/record/88380/files/texto_completo.pdf$$yPostprint
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000088380 951__ $$a2024-01-22-15:32:26
000088380 980__ $$aARTICLE