Theoretical models of intermediate and inverse AMS fabrics

Ferré, E. C.

doi:10.1029/2001gl014367

Cited by 118 publications

(94 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…8). A possible explanation is an interchange of the position of magnetic axes, caused by the presence of inverse AMS fabrics that are a relatively common feature of low K m mafic rocks, in which single-domain magnetite is the dominant magnetic phase (e.g., Ferré, 2002). This hypothesis is supported because magnetite occurs as fine-grained crystals (5 to 80 µm) in samples of this site.…”

Section: Directional Datasupporting

confidence: 62%

Transtension y transpresion del Jurasico Medio-Superior al Cretacico Inferior durante la construccion del arco magmatico en Chile central: evidencia a partir de enjambres de diques maficos.

Creixell¹,

Parada²,

Morata³

et al. 2011

Andgeo

View full text Add to dashboard Cite

AbstrACt. The Middle-Late Jurassic mafic dike swarms of central Chile between 33º and 33º45'S register the tectonic activity of the contemporaneous arc represented by the Coastal batholith. These dike swarms evidence alternate episodes of transtension and transpression across NW-striking structures, which controlled the construction of the magmatic arc. The Middle-Upper Jurassic and Lower Cretaceous mafic dike swarms in the Coastal range of central Chile has been studied through field observations, geochronology and AMS (anisotropy of magnetic susceptibility) to document the tectonic and magmatic evolution of the Jurassic-Cretaceous arc at this latitude. Middle to Upper Jurassic dike swarms (Concón and Cartagena mafic dike swarms) were emplaced between 163 and 157 Ma, along NW-SE to WNW-ESE-striking host fractures, registering a first stage of magma emplacement under sinistral transtension. During this stage, dikes acquired a fabric characterized by magnetic foliation clockwise oblique to dike trend and gently plunging lineations. This stage was followed rapidly by dike emplacement under sinistral transpression, with associated steeply plunging lineations in the dikes, reverse shear zones in the country rocks and local occurrence of horizontal mafic dikes. On the other hand, the Lower Cretaceous El Tabo Dike Swarm was emplaced along tensile fractures that do not register shear displacements along their walls. These dikes were emplaced at shallower crustal levels along tensile fractures.Within each dike swarm, differences in the tectonic style of emplacement correlates with changes in the geochemical composition of the dikes, suggesting a strong coupling between tectonics and nature of magma supplies in the arc. Finally, the current results show that the Mesozoic evolution of the Coastal Batholith of central Chile occurred in several stages of deformation and not under a simple scenario of extensional tectonics. This magmatism and deformation were strongly controlled by NW-to WNW-striking fractures. These structures are spatially correlated with regional-scale Cenozoic lineaments that are oblique to the orientation of the Andean orogen. We suggest that these lineaments are features inherited at least from Jurassic times. Middle-late Jurassic to early cretaceous transtension and transpression during arc building in central chile... rEsuMEn. transtensión y transpresión del Jurásico Medio-superior al Cretácico Inferior durante la construcción del arco magmático en Chile central: evidencia a partir de enjambres de diques máficos. Los enjambres de diques máficos del Jurásico Medio-Superior de Chile central entre los 33º y 33º45'S registran la actividad tectónica del arco contemporáneo representado por el batolito costero. Estos enjambres de diques evidencian episodios alternados de transtensión y transpresión a lo largo de estructuras de rumbo NW, las cuales controlaron la construcción del arco magmático. Los enjambres de diques máficos del Jurásico Medio-Superior y del Cretácico Inferior de la Cordillera de la Costa...

show abstract

Section: Directional Datasupporting

confidence: 62%

Transtension y transpresion del Jurasico Medio-Superior al Cretacico Inferior durante la construccion del arco magmatico en Chile central: evidencia a partir de enjambres de diques maficos.

Creixell¹,

Parada²,

Morata³

et al. 2011

Andgeo

View full text Add to dashboard Cite

show abstract

“…6), is related to the presence of single-domain magnetic grains within the rock (Rochette et al, 1999;Ferré, 2002;Airoldi et al, 2012). This fabric type is characterized by minimum susceptibility axes aligned within the intrusion plane, and the magnetic foliation perpendicular to the intrusion.…”

Section: Accepted Manuscriptmentioning

confidence: 99%

Flow dynamics in mid-Jurassic dikes and sills of the Ferrar large igneous province and implications for long-distance magma transport

et al. 2016

View full text Add to dashboard Cite

“…In grains with multiple domains (> 0.1 µm; MD), Bloch walls separate each single domain of parallel electron spins ( Fig. 7.3 (Rochette et al 1999;Ferré 2002;Fig. 7.3).…”

Section: Principles Of Rock Magnetism and The Origin Of Amsmentioning

confidence: 99%

The Significance of Magnetic Fabric in Layered Mafic-Ultramafic Intrusions

et al. 2015

Self Cite

View full text Add to dashboard Cite

Anisotropy of magnetic susceptibility (AMS) has been recognised as a well-established fabric analysis tool for intrusive igneous rocks since the 1990s. The AMS technique provides directional information for magnetic foliation and magnetic lineation fabric components of the AMS ellipsoid, potentially coupled with a quantification of the overall fabric strength and geometry. The magnetic susceptibility (and therefore the AMS) of igneous rocks is often dominated by ferromagnetic mineral phases such as magnetite or low-Ti titanomagnetite, even where present in very minor amounts (e.g., ~ 0.1 vol.%). Fe-bearing silicates exhibit subordinate paramagnetic behaviour but are volumetrically much more important constituents of igneous rocks than Fe-Ti oxides, so may also contribute considerably to the AMS.A significant application of AMS is in the characterisation, constraint and quantification of very weak or subtle mineral fabrics related to flow or tectonic deformation. In particular, studies of magnetic fabrics in sheet intrusions and in granite plutons have enormously enhanced our understanding of the magma flow regimes and emplacement kinematics in these settings. Studies of AMS in layered maficultramafic intrusions have been comparatively sparse. This is despite the fact that magnetic fabrics from layered cumulates may provide information on a range of magma chamber processes, from initial magma emplacement to cumulate textural evolution and solidification, if accompanied by careful petrographic documentation and an understanding of the 'magnetic mineralogy' of the rock. A wide array of rock magnetic and complementary quantitative fabric analysis techniques can be employed to support an AMS dataset in this regard. With studies of layered mafic-ultramafic intrusions currently proceeding at unprecedented (micro-)scales of textural and geochemical detail, AMS offers petrologists a unique approach to investigating the microstructure of cumulates and the textural complexity they exhibit.

show abstract

Theoretical models of intermediate and inverse AMS fabrics

Cited by 118 publications

References 18 publications

Transtension y transpresion del Jurasico Medio-Superior al Cretacico Inferior durante la construccion del arco magmatico en Chile central: evidencia a partir de enjambres de diques maficos.

Transtension y transpresion del Jurasico Medio-Superior al Cretacico Inferior durante la construccion del arco magmatico en Chile central: evidencia a partir de enjambres de diques maficos.

Flow dynamics in mid-Jurassic dikes and sills of the Ferrar large igneous province and implications for long-distance magma transport

The Significance of Magnetic Fabric in Layered Mafic-Ultramafic Intrusions

Contact Info

Product

Resources

About