Asymmetrical to symmetrical magnetic fabric of dikes: Paleo-flow orientations and Paleo-stresses recorded on feeder-bodies from the Motru Dike Swarm (Romania)

Féménias, Olivier; Diot, Hervé; Berza, Tudor; Gauffriau, A.; Demaiffe, Daniel

doi:10.1016/j.jsg.2003.12.003

Cited by 63 publications

(50 citation statements)

References 51 publications

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“…Within field-based studies there is a long history of using mineral and vesicle alignment and imbrication, measured using petrological or magnetic techniques, to delineate magma flow in sheet intrusions (e.g., Knight and Walker, 1988;Tarling and Hrouda, 1993;Launeau and Cruden, 1998;Tauxe et al, 1998;Gudmundsson and Marinoni, 1999;Archanjo and Launeau, 2004;Callot and Geoffroy, 2004;Cañón-Tapia, 2004;Cañón-Tapia and ChavezAlvarez, 2004;Féménias et al, 2004;Liss et al, 2004;Philpotts and Philpotts, 2007;Cañón-Tapia and Herrero-Bervera, 2009;Magee et al, 2012a;Neres et al, 2014). Such mineral alignment analyses have shown that the long axes of intrusive steps, bridge structures, and magma fingers, which are commonly super imposed onto the larger scale sheet intrusion morphology, correlate to the primary magma flow axis ( Fig.…”

Section: Constraining Magma Flow Patterns In Outcrop and Seismic Datamentioning

confidence: 99%

Lateral Magma Flow in Mafic Sill‐complexes

Magee

Muirhead

Karvelas

et al. 2016

Acta Geologica Sinica (Eng)

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The structure of upper crustal magma plumbing systems controls the distribution of volcanism and influences tectonic processes. However, delineating the structure and volume of plumbing systems is difficult because (1) active intrusion networks cannot be directly accessed; (2) field outcrops are commonly limited; and (3) geophysical data imaging the subsurface are restricted in areal extent and resolution. This has led to models involving the vertical transfer of magma via dikes, extending from a melt source to overlying reservoirs and eruption sites, being favored in the volcanic literature. However, while there is a wealth of evidence to support the occurrence of dike-dominated systems, we synthesize field-and seismic reflection-based observations and highlight that extensive lateral magma transport (as much as 4100 km) may occur within mafic sill complexes. Most of these mafic sill complexes occur in sedimentary basins (e.g., the Karoo Basin, South Africa), although some intrude crystalline continental crust (e.g., the Yilgarn craton, Australia), and consist of interconnected sills and inclined sheets. Sill complex emplacement is largely controlled by host-rock lithology and structure and the state of stress. We argue that plumbing systems need not be dominated by dikes and that magma can be transported within widespread sill complexes, promoting the development of volcanoes that do not overlie the melt source. However, the extent to which active volcanic systems and rifted margins are underlain by sill complexes remains poorly constrained, despite important implications for elucidating magmatic processes, melt volumes, and melt sources.

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Section: Constraining Magma Flow Patterns In Outcrop and Seismic Datamentioning

confidence: 99%

Lateral Magma Flow in Mafic Sill‐complexes

Magee

Muirhead

Karvelas

et al. 2016

Acta Geologica Sinica (Eng)

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“…The reason can be increasing viscosity of the magma (e.g. Petford 1996;Mathieu et al 2008) and/ or effect of regional stress field (Féménias et al 2004). Indeed, the regional stress conditions in the WMZ changed from the NW-SE compression to subvertical shortening of the crust due to exhumation of orogenic root domain (e.g.…”

Section: Discussionmentioning

confidence: 99%

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

J. 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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“…2) have been subdivided into the Upper and Lower Danubian on the basis of their Mesozoic cover (Stȃnoiu 1973;Kräutner et al 1981). The Lower Danubian nappes of Lainici and Schela-Petreanu (Kräutner et al 1981(Kräutner et al , 1988 contain the same basement and Féménias et al (2004) Fig. 2 Schematic cross-section of the Alpine Danubian nappe system in the Southern Carpathians of Romania.…”

Section: Geological Settingmentioning

confidence: 99%

“…Generally, the high-density large field dykes are sub-parallel, following the main structural trends of the Danubian domain. In a given area, two distinct populations of dykes have been identified (Féménias et al 2004) on the basis of their size, mean orientation and magnetic fabric: (1) narrow dykes (<1 m) with an 80°N mean wall direction and a symmetrical AMS (anisotropy of magnetic susceptibility) fabric; (2) thicker dykes (>1 m to several metres) with an N-S mean wall direction and an asymmetrical AMS fabric. The two populations have been related to a common regional stress field during a continuum of brittle emplacement (Féménias et al 2004).…”

Section: The Motru Dyke Swarm (Mds)mentioning

confidence: 99%

Nature and significance of a Cambro-Ordovician high-K, calc-alkaline sub-volcanic suite: the late- to post-orogenic Motru Dyke Swarm (Southern Carpathians, Romania)

Féménias¹,

Berza²,

Tatu³

et al. 2007

Int J Earth Sci (Geol Rundsch)

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The Motru Dyke Swarm intrudes the Precambrian Danubian basement of the Southern Carpathians (Romania). It is a marker of a sub-volcanic event that occurred during the early Palaeozoic (Cambrian to Ordovician). The geographical distribution of dykes on ã 2,000 km 2 area is heterogeneous; several areas of high dyke density have been the subject of a detailed petrological and geochemical study. Taken altogether, the 150 samples define a single complete magmatic series, from basaltic andesite to rhyolite. Whole-rock major element variations show a medium-to high-K, calc-alkaline magmatic suite. The compositional variations and the general decrease of trace element contents (both compatible and incompatible, including REEs) from basaltic andesite to rhyolite are consistent with 1) the fractionation of the observed phenocryst assemblages, Ca-amphibole (Tipargasite to magnesiohornblende) followed by intermediate plagioclase, clinopyroxene and accessory biotite and quartz and 2) the absence of lower and/or upper crustal contamination. Trace elements diagrams display typical arc patterns (LILE, Pb and LREE enrichment and relative depletion in Nb-Ta, Zr-Hf and Ti). The Th/U, Nb/Ta and Zr/Hf ratios are constant and close to the mantle values throughout the whole series, which argues that the parental magma was generated from a single and homogeneous enriched lithospheric mantle source. The field regional evidence implies that melting occurred during a late-to post-orogenic period of lithospheric extension, and thus took place quite lately after the cessation of Pan-African subduction.

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Asymmetrical to symmetrical magnetic fabric of dikes: Paleo-flow orientations and Paleo-stresses recorded on feeder-bodies from the Motru Dike Swarm (Romania)

Cited by 63 publications

References 51 publications

Lateral Magma Flow in Mafic Sill‐complexes

Lateral Magma Flow in Mafic Sill‐complexes

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

Nature and significance of a Cambro-Ordovician high-K, calc-alkaline sub-volcanic suite: the late- to post-orogenic Motru Dyke Swarm (Southern Carpathians, Romania)

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