%0 Journal Article
%A García Romero, Emilia
%A Súarez Barrios, Mercedes
%A Oyarzun Muñoz, Roberto
%A López García, José Ángel
%A Regueiro, M.
%T Fault-Hosted Palygorskite from the Serrata de Nijar deformation zone (SE Spain)
%D 2006
%@ 0009-8604
%U https://hdl.handle.net/20.500.14352/49742
%X Palygorskite fibers growing along fault planes in the outcrops of a large fault zone in SE Spain(Carboneras Fault Zone: CFZ; Serrata de NõÂjar) were studied by X-ray diffraction, scanning electronmicroscopy-energy dispersive X-ray analysis, and transmission electron microscopy-analytical electronmicroscopy. The structural formulae, calculated per half unit-cell, is: Si7.95Al0.05O20(Al1.93Fe0.08Mg1.92)(OH)2(OH2)4Na0.09K0.01Ca0.034(H2O). The samples have minor tetrahedral substitutions, with Mg/Alratios close to one, and contain very small amounts of Fe3+. The number of octahedral cations per half unit-cell is 3.93. The fault-hosted palygorskite shows macroscopic ductile features including incipient foliation.Based on field and laboratory observations, as well as on regional geological evidence indicating theexistence of widespread hydrothermal processes along the Serrata de NõÂjar and surrounding areas, wesuggest that palygorskite may have formed during ongoing deformation in the CFZ, as a precipitate fromMg-rich hydrothermal fluids.
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