Evaluating magnetic lineations (AMS) in deformed rocks
نویسندگان
چکیده
Magnetic lineation in rocks is given by a cluster of the principal axes of maximum susceptibility (Kmax) of the Anisotropy of Magnetic Susceptibility (AMS) tensor. In deformed rocks, magnetic lineations are generally considered to be the result of either bedding and cleavage intersection or they parallel the tectonic extension direction in high strain zones. Our AMS determinations, based on a variety of samples that were taken from mudstones, slates and schists from the Pyrenees and Appalachians, show that strain is not the only factor controlling the development of magnetic lineation. We find that the development and extent to which the magnetic lineation parallels the tectonic extension direction depends on both the original AMS tensor, which in turn depends on the lithology, and the deformation intensity. Rocks having a weak pre-deformational fabric will develop magnetic lineations that more readily will track the tectonic extension. D 2002 Elsevier Science B.V. All rights reserved.
منابع مشابه
Investigation of mineralogical and microstructural changes of Chah Zard granites (East of Jandagh) during mylonitization: using anisotropy of magnetic susceptibility method (AMS)
Chah Zard granitoid pluton with 535.4±3.2 Ma age (U-Pb zircon method, carried on the Zircon) intruded into Jandagh –Arousan metamorphic complex, and strongly mylonitized during later events. For the first time, Chah Zard granitoid pluton investigated by anisotropy of magnetic susceptibility (AMS) method. Mean magnetic susceptibility (Km) of biotite granites (the main constitute of Chah Zard gra...
متن کاملSixty years of anisotropy of magnetic susceptibility in deformed sedimentary rocks
*Correspondence: Josep M. Parés, Geochronology, Research Center for Human Evolution (CENIEH), Paseo Sierra de Atapuerca 3, Burgos 09006, Spain e-mail: [email protected] The use of the Anisotropy of Magnetic Susceptibility (AMS) has become a rather common practice in Earth Sciences since the pioneer note by Graham (1954). The versatility of the technique, and the rapidness in obtaining and p...
متن کاملMagnetic fabrics and strain in pencil structures of the Knobs Formation, Valley and Ridge Province, US Appalachians
Pencil structures, which are found in weakly deformed mudrocks, reflect the bedding–cleavage intersection in weakto moderatelycleaved rocks. Their presence indicates conditions where bedding and cleavage fabrics are approximately equal in intensity. We have determined the anisotropy of magnetic susceptibility (AMS) in pencil structures from a sequence of mudstones of the Ordovician Knobs Format...
متن کاملPotential Use of DNA Aptamer-Magnetic Bead Separation-PCR Assay for Salmonella Detection in Food
Background: Salmonella is one of the most common food-borne pathogens that can cause illness. In this study, the sensitivity and the specificity of Aptamer-Magnetic bead Separation-Polymerase Chain Reaction (AMS-PCR) method were determined for Salmonella spp. detection. Methods: Different concentrations of Salmonella enterica were mixed with streptavidin-magnetic beads coated with biotinylated...
متن کامل