Anisotropy of magnetic susceptibility in the Ponta Grossa dyke swarm (Brazil) and its relationship with magma flow direction

Raposo, María Irene Bartolomeu; Ernesto, Márcia

doi:10.1016/0031-9201(94)02970-m

Cited by 101 publications

(47 citation statements)

References 34 publications

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“…This corresponds to the most common type of magnetic fabric in dykes the world over (Type I; Raposo and Ernesto 1995), which no doubt originates through a magma flow, during which the larger surfaces of magnetic minerals orient approximately parallel to the dyke, while the longer dimensions orient parallel to the magma flow direction. It is considered to be relatively free flow that requires relatively open, likely extensional structures.…”

Section: Discussionmentioning

confidence: 89%

“…(c) In most spessartite dykes, both the magnetic foliation and magnetic lineation are perpendicular to the dyke, thus corresponding to the magnetic fabric Type III of Raposo and Ernesto (1995). We assume that the magma movement had character of forceful injection.…”

Section: Discussionmentioning

confidence: 99%

“…These fabric types belong to the most controversial Types IIIa and b, the origins of which are disputable. The magnetic foliation perpendicular to the dyke could indicate the magma movement mechanism hypothesized by Raposo and Ernesto (1995) for the Type II, i.e. compaction of a static magma column along the dyke in which the magnetic minerals reoriented with their larger surfaces perpendicular to the magma movement.…”

Section: Dobříš Composite Dykementioning

confidence: 96%

“…This type was termed reverse by Rochette et al (1991) or inverse by Raposo (2011) or Type III by Raposo and Ernesto (1995) (Fig. 1).…”

Section: Introductionmentioning

confidence: 99%

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Magnetic fabric and emplacement of dykes of lamprophyres and related rocks of the Central Bohemian Dyke Swarm (Central European Variscides)

Hrouda¹,

Verner²,

Kubínová³

et al. 2016

Jour. Geosci.

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Numerous dykes of lamprophyres and various types of granitoid, syenitoid, dioritoid, and gabbroid porphyries of Variscan age crop out in the area of the Central Bohemian Plutonic Complex and adjacent high-to low-grade metamorphic units of the Moldanubian Zone and Teplá-Barrandian Unit. Magnetic fabric in fourteen dykes of lamprophyres and related rocks was investigated. Mostly, the magnetic foliation is roughly parallel to the dyke plane and the magnetic lineation is horizontal with the relics of originally steep fabrics. This type of magnetic fabric originated through magma flow in which the larger surfaces of the magnetic minerals were oriented parallel to the dyke plane and their longer dimensions were parallel to the magma flow. In two localities, the so-called inverse fabrics were found in which the maximum and minimum susceptibility directions were swapped. The dykes of lamprophyres and related rocks were emplaced into already juxtaposed and cooled Teplá-Barrandian Zone, Central Bohemian Plutonic Complex and western Moldanubian Zone not later than 339 Ma. Parallel orientation of dykes giving a steep intrusive contacts mainly in W(NW)-E(SE) trend was caused by the regional stress field of ~WNW-ESE convergence (arc-parallel stretching) during the Variscan Orogeny.

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Section: Discussionmentioning

confidence: 89%

Section: Discussionmentioning

confidence: 99%

Section: Dobříš Composite Dykementioning

confidence: 96%

“…This type was termed reverse by Rochette et al (1991) or inverse by Raposo (2011) or Type III by Raposo and Ernesto (1995) (Fig. 1).…”

Section: Introductionmentioning

confidence: 99%

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Magnetic fabric and emplacement of dykes of lamprophyres and related rocks of the Central Bohemian Dyke Swarm (Central European Variscides)

Hrouda¹,

Verner²,

Kubínová³

et al. 2016

Jour. Geosci.

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“…Subsequent works have used AMS to study both magma movement (Raposo & Ernesto 1995;Tauxe et al 1998;Herrero-Bervera et al 2001) and volcanic stress fields (Poland et al 2004;Porreca et al 2006;Soriano et al 2007;Geshi 2008). Delcamp et al (2014) use AMS to infer magma flow in dykes of a rift zone in Tenerife.…”

Section: Anisotropy Of Magnetic Susceptibility (Ams) As Magmatic Flowmentioning

confidence: 99%

The use of palaeomagnetism and rock magnetism to understand volcanic processes: introduction

Ort

Porreca

Geissman

2015

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This Special Publication provides a snapshot of our understanding of volcanic processes through the use of palaeomagnetic and rock magnetic techniques. Here, we provide a context for the book, placing individual chapters within the milieu of previous work, including some magnetic techniques that were not used in the particular studies described herein. Thermoremanent magnetization is a powerful tool to understand processes related to heating and cooling of rocks, including estimating the temperature of emplacement of pyroclastic deposits, which may allow us to better understand the rates of cooling during eruption and transport. Anisotropy of magnetic susceptibility and anisotropy of remanence are used primarily to investigate rock fabrics, and allow the interpretation of flow dynamics in dykes, lava flows and pyroclastic deposits, as well as the location of the eruptive vents. Rock magnetic characteristics can help in the correlation of volcanic deposits but also provide means to date volcanic deposits and to better understand the processes of cooling of the deposits, as the magnetic minerals can change with temperature. In addition, volcanic rocks may be key recorders of past magnetic fields, allowing a better understanding of changes in field intensity and, perhaps, providing clues of how the magnetic field is formed.

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Magnetic Fabric of Rocks

The Earth’s Magnetism

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Anisotropy of magnetic susceptibility in the Ponta Grossa dyke swarm (Brazil) and its relationship with magma flow direction

Cited by 101 publications

References 34 publications

Magnetic fabric and emplacement of dykes of lamprophyres and related rocks of the Central Bohemian Dyke Swarm (Central European Variscides)

Magnetic fabric and emplacement of dykes of lamprophyres and related rocks of the Central Bohemian Dyke Swarm (Central European Variscides)

The use of palaeomagnetism and rock magnetism to understand volcanic processes: introduction

Magnetic Fabric of Rocks

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