Earth-prints repository, logo   DSpace

About DSpace Software
|earth-prints home page | roma library | bologna library | catania library | milano library | napoli library | palermo library
Please use this identifier to cite or link to this item: http://hdl.handle.net/2122/9147

Authors: Censi, P.*
Cangemi, M.*
Brusca, L.*
Madonia, P.*
Saiano, F.*
Zuddas, P.*
Title: The behavior of rare-earth elements, Zr and Hf during biologically-mediated deposition of silica-stromatolites and carbonate-rich microbial mats
Title of journal: Gondwana research
Series/Report no.: /27(2015)
Publisher: Gondawa Research Group
Issue Date: Jan-2015
DOI: 10.1016/j.gr.2013.09.014
Keywords: Rare Earth Elements, Zr/Hf ratio, Silica-stromatolites, Pantelleria Island
Abstract: Venere Lake, in the Pantelleria Island thermal system (Central Mediterranean Sea) consists of a mix of seawater and hydrothermal volcanic fluids containing high levels of dissolved SiO2. Close to the lake's thermal springs, siliceous stromatolites are deposed under high bacterial activity conditions whereas roughly interlaminated Ca-carbonates and microbial mats are widely scattered in the lake. The dissolved REE speciation in lake waters is dominated by [REE(CO3)2]−, [REE(CO3)]+ and [REE(H3SiO4)]2+ complexes. On the contrary the most abundant Zr and Hf species are hydroxyl- and fluoride-complexes. The behavior of REE Zr and Hf in the Venere lake waters is controlled by precipitation of amorphous silica, carbonates and bacterial activity. Chondritenormalized REE patterns in stromatolites are characterized by positive La anomalies, superchondritic Y/Ho ratios and negative Eu anomalies. The Eu depletion is also found in microbial mats where is associated to a “chondritic” Y/Ho signature. Zr and Hf differently behave in dissolved phase and in newly-formed siliceous and carbonatic material: Hf reacts easily into amorphous silica surfaces whereas Zr is preferentially partitioned onto phosphate binding sites on microbial cell surfaces similar to the observed behavior of heavy REE (HREE).Wesuggest that the Zr-Hf relationship reflect the interface processes between mineral phases and bacterial membranes or compounds produced by bacterial activity.
Appears in Collections:04.04.08. Sediments: dating, processes, transport
Papers Published / Papers in press

Files in This Item:

File Description SizeFormatVisibility
Gondwana-Specchio di Venere.pdfMain article1.22 MBAdobe PDFonly authorized users View/Open


Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.


Share this record
Del.icio.us

Citeulike

Connotea

Facebook

Stumble it!

reddit


 

Valid XHTML 1.0! ICT Support, development & maintenance are provided by CINECA. Powered on DSpace Software. CINECA