Mineralogical and geomicrobiological investigation of phosphorite from Ervenik, Croatia

Bermanec, Vladimir and Posilović, Hrvoje and Žigovečki Gobac, Željka and Hrenović, Jasna and Mikac, Nevenka and Kniewald, Goran (2012) Mineralogical and geomicrobiological investigation of phosphorite from Ervenik, Croatia. Geologia Croatica, 65 (1). pp. 67-75. ISSN 1333-4875

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Phosphate minerals hydroxylapatite, fl uorapatite and crandallite were identifi ed in nodules within phosphorites from Ervenik, Croatia. The minerals were identifi ed using optical microscopy, XRD, SEM and EDS analyses. The presence of fungi was recognized only in association with phosphate-rich phases. Fungal activity resulted in the dissolution of apatite, producing hollow crystals, particularly in hydroxylapatite–enriched zones. A substantial number of hyphae were observed on the surface of phosphate minerals, in addition to saprophytic bacteria and bacterial spores. Induced activity of phosphate-accumulating bacteria in an aquatic environment caused dissolution of the phosphate minerals. The aqueous phase contained increased concentrations of several elements, including Ca, Sb, U, V and As. These elements are important constituents of minerals of the apatite group. As a consequence of the crystallization of apatite, the concentration of phosphate decreases with a corresponding increase in aluminium concentration, resulting in the prevalence of crandallite as the stable phase, forming the outer sector of the spherulites.

Item Type: Article
Keywords: phosphorite, hydroxylapatite, fluorapatite, crandallite, fungi, bacteria
Date: 2012
Subjects: NATURAL SCIENCES > Geology > Geology and Paleontology
Divisions: Faculty of Science > Department of Geology
Publisher: Hrvatsko geološko društvo
Depositing User: Danica Vujičić
Date Deposited: 02 Jul 2015 10:31
Last Modified: 02 Jul 2015 10:31
URI: http://digre.pmf.unizg.hr/id/eprint/3675

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