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Structural control on the formation of iron-oxide concretions and Liesegang bands in faulted, poorly lithified Cenozoic sandstones of the Paraiba Basin, Brazil
2013; Geological Society of America; Volume: 125; Issue: 5-6 Linguagem: Inglês
10.1130/b30686.1
ISSN1943-2674
AutoresFabrizio Balsamo, Francisco H.R. Bezerra, Marcela Marques Vieira, Fabrizio Storti,
Tópico(s)Hydrocarbon exploration and reservoir analysis
ResumoResearch Article| May 01, 2013 Structural control on the formation of iron-oxide concretions and Liesegang bands in faulted, poorly lithified Cenozoic sandstones of the Paraíba Basin, Brazil F. Balsamo; F. Balsamo † 1Department of Physics and Earth Sciences, Parma University, Campus Universitario, Parco Area delle Scienze 157/A, I-43124, Parma, Italy †E-mail: fabrizio.balsamo@unipr.it Search for other works by this author on: GSW Google Scholar F.H.R. Bezerra; F.H.R. Bezerra 2Department of Geology, Federal University of Rio G Norte, Campus Universitario, Natal, RN, 59079-970, Brazil Search for other works by this author on: GSW Google Scholar M.M. Vieira; M.M. Vieira 2Department of Geology, Federal University of Rio G Norte, Campus Universitario, Natal, RN, 59079-970, Brazil Search for other works by this author on: GSW Google Scholar F. Storti F. Storti 1Department of Physics and Earth Sciences, Parma University, Campus Universitario, Parco Area delle Scienze 157/A, I-43124, Parma, Italy Search for other works by this author on: GSW Google Scholar Author and Article Information F. Balsamo † 1Department of Physics and Earth Sciences, Parma University, Campus Universitario, Parco Area delle Scienze 157/A, I-43124, Parma, Italy F.H.R. Bezerra 2Department of Geology, Federal University of Rio G Norte, Campus Universitario, Natal, RN, 59079-970, Brazil M.M. Vieira 2Department of Geology, Federal University of Rio G Norte, Campus Universitario, Natal, RN, 59079-970, Brazil F. Storti 1Department of Physics and Earth Sciences, Parma University, Campus Universitario, Parco Area delle Scienze 157/A, I-43124, Parma, Italy †E-mail: fabrizio.balsamo@unipr.it Publisher: Geological Society of America Received: 16 Feb 2012 Revision Received: 21 Dec 2012 Accepted: 05 Jan 2013 First Online: 08 Mar 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 © 2013 Geological Society of America GSA Bulletin (2013) 125 (5-6): 913–931. https://doi.org/10.1130/B30686.1 Article history Received: 16 Feb 2012 Revision Received: 21 Dec 2012 Accepted: 05 Jan 2013 First Online: 08 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation F. Balsamo, F.H.R. Bezerra, M.M. Vieira, F. Storti; Structural control on the formation of iron-oxide concretions and Liesegang bands in faulted, poorly lithified Cenozoic sandstones of the Paraíba Basin, Brazil. GSA Bulletin 2013;; 125 (5-6): 913–931. doi: https://doi.org/10.1130/B30686.1 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract Iron-oxide coloration and deposits in sandstone are significant indicators of the mobility of solutes (Fe2+ and O2) in groundwater, mainly controlled by host-rock porosity and permeability. We describe the occurrence and geometry of different types of iron-oxide deposits developed within the vadose zone along faults affecting poorly lithified, quartz-dominated, heterolithic sands in the Paraíba Basin, NE Brazil. The development of highly permeable damage zones (100–102 Darcy) and low-permeability fault-core–mixed zones (10–3–101 Darcy) promotes the physical mixing of Fe2+-rich waters and oxygenated groundwater. This arrangement favors iron-oxide precipitation as meter-scale sand impregnations, centimeter- to decimeter-scale concretions, and well-cemented decimeter- to meter-thick mineral masses. The formation of hydraulically isolated compartments along hard-linked strike-slip faults promotes: (1) the development of Liesegang bands in a reaction zone dominated by pore-water molecular diffusion of O2 into Fe2+-rich stagnant water, and (2) the precipitation of iron-oxide impregnations and concretions in the fault-core–mixed zone boundaries, likely by O2 diffusion in flowing Fe2+-rich waters. Late-stage fault reactivation provides preferential pathways for the circulation of gravity-driven reducing fluids, resulting in localized dissolution of iron and bleaching along fractures and iron remobilization. These relationships reveal the roles of tectonic activity and near-surface sandstone diagenesis in determining preferential hydraulic pathways for the physicochemical interaction between oxygenated groundwater and iron-rich fluids. Structural setting, fault-zone architecture, and related grain-size–permeability structures determine the dominant mode of solution interaction, leading to the formation of iron-oxide Liesegang bands where O2 diffuses into stagnant Fe2+-rich water, and concretions when diffusion is complemented by Fe2+ advective flow. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.
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