Dike transport of granitoid magmas

Petford, Nick; Kerr, Ross C.; Lister, Joseph

doi:10.1130/0091-7613(1993)021<0845:dtogm>2.3.co;2

Cited by 287 publications

(130 citation statements)

References 0 publications

Supporting

Mentioning

116

Contrasting

Unclassified

Order By: Relevance

“…Large magma reservoirs and plutons indeed probably grow by small increments over long time scales [Petford et al, 1993[Petford et al, , 1994Petford and Gallagher, 2001;Annen and Sparks, 2002;Glazner et al, 2004;Jaupart, 2006, 2011]. Long-term rates of magma transfer to the crust are quite well constrained [Crisp, 1984;Jellinek and de Paolo, 2003].…”

Section: Introductionmentioning

confidence: 99%

“…[11] Numerous field and geochronological studies indicate that large-scale intrusions such as plutons, batholiths and magma chambers form and grow by increments of small magma pulses over very long time scales of 10 5 to >10 6 years [Petford et al, 1993[Petford et al, , 1994Metz and Mahood, 1991;Sisson et al, 1996;Coleman et al, 2004]. In this paper, I focus on intermediate-scale intrusions such as sills, laccoliths and bysmaliths.…”

Section: Shallow Magmatic Intrusionsmentioning

confidence: 99%

See 1 more Smart Citation

Dynamics of magmatic intrusions in the upper crust: Theory and applications to laccoliths on Earth and the Moon

Michaut

2011

J. Geophys. Res.

136

View full text Add to dashboard Cite

[1] To understand the dynamics of shallow magmatic intrusions, I propose a theoretical model of magma spreading laterally below an elastic crust. Nondimensionalization of the flow equation leads to the identification of characteristic scales for the intrusion: while the characteristic intrusion length is controlled by the elastic response of the crust, its characteristic thickness primarily depends on magma properties and injection rate. Three spreading regimes are identified and characterized by different morphologies as well as by scaling laws for thickness versus length and thickness versus time. The first spreading regime is controlled by the elastic response of the crust and the shape of the flow is self-similar. When the time, length, and thickness become larger than an elastic time, length, and thickness scale, the edges of the flow become steeper and the system transitions to a gravity current regime. When the intrusion is thick enough to accommodate the pressure head, the flow enters a regime of lateral propagation and keeps a constant thickness. The intrusion shape in the elastic regime fits the observed shape of terrestrial laccoliths. The elastic scaling law for intrusion thickness versus length fits observations of laccoliths at Elba Island, Italy, and provides for a physical explanation for the observed relationship between length and thickness on terrestrial laccoliths. Laccoliths are predicted to form over short time scales, depending on magma viscosity, that vary between approximately a month to several years for felsic magmas on Earth. On the Moon, several elongated low-slope domes have recently been identified as possibly formed by laccolith intrusions at depth, although they are much larger than terrestrial laccoliths. Because the Moon has a smaller gravity than on the Earth, a deeper magma source, and a more mafic magma composition than for terrestrial laccoliths (implying smaller pressure gradient and dike width), lunar intrusions have a larger characteristic length and a smaller characteristic thickness. After nondimensionalization, the morphologies (length versus thickness) of terrestrial and inferred lunar laccoliths follow the same curve and are well fitted by the elastic scaling law. This model thus explains the size discrepancy between terrestrial laccoliths and lunar low-slope domes. Therefore, low-slope domes identified on the Moon are good candidates for laccolith-type intrusions at depth.

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Shallow Magmatic Intrusionsmentioning

confidence: 99%

Dynamics of magmatic intrusions in the upper crust: Theory and applications to laccoliths on Earth and the Moon

Michaut

2011

J. Geophys. Res.

136

View full text Add to dashboard Cite

show abstract

“…At low levels in the crust, ductile conditions promote the intrusion of pegmatites with lenticular to bulbous shapes, compared with tabular pegmatite dykes emplaced in the upper crust where brittle conditions prevail (Brisbin, 1986). Hydrofracture propagation is a brittleelastic process, which is envisaged to occur in thin narrow fractures (Lister and Kerr, 1991;Petford et al, 1993). To our knowledge, no dyking model exists that predicts bead-like structures to form during fracture propagation and magma transport.…”

Section: Emplacement Mechanismmentioning

confidence: 99%

Apparent boudinage in dykes

Bons

Druguet

Hamann

et al. 2004

Journal of Structural Geology

View full text Add to dashboard Cite

Intrusive rocks may be arranged in the form of strings of lenses or beads, as found on the Cap de Creus Peninsula, NE Spain, and in the South Finland Migmatite -Granite Belt. These structures first appear to be the result of stretching and boudinage of intrusive sheets or dykes. However, closer examination reveals that they are not boudins, but are instead primary intrusive structures. A detailed study was performed on a swarm of pegmatite intrusions at Cap de Creus. Layering is often continuous between beads, and, in some cases, individual beads exhibit a very irregular shape. These observations are shown to be incompatible with an origin by boudinage. Analogue experiments were used to test the effect of the two models (boudinage and emplacement) on the structures around beads, and show that an emplacement model of local expansion and collapse of magmatic sheets is the most compatible with field observations. Such structures can only form when dykes intrude hot rocks, when magma solidifies slowly enough to allow enough ductile flow of the wall rock to accommodate the formation of the beads. The fact that the pegmatite bead strings are not boudins has repercussions for the interpretation of the deformation at Cap de Creus and necessitates caution in the interpretation of deformation based on apparent boudins in intrusive rocks in other areas. q

show abstract

“…Malgré des développements récents dans la théorie du diapirisme (Cruden 1988 ;Weinberg et Podladchikov 1994), les évidences de terrain pour la montée diapirique et de sa trajectoire à travers la croûte restent encore à identifier; ils sont peu observées (Pitcher 1979;Bateman 1984). Cependant, la possibilité que le diapirisme constitue un mécanisme pour la montée du magma n'est pas à exclure (Miller et al 1988;England 1990;Petford et al 1993). (1994) ont établi que le magma granitique peut avoir une viscosité de 10 à 10 (Pa.s) (Carmichael et al 191 A;Pitcher 1979, McBirney 1984Petford et al 1993).…”

unclassified

“…Cependant, la possibilité que le diapirisme constitue un mécanisme pour la montée du magma n'est pas à exclure (Miller et al 1988;England 1990;Petford et al 1993). (1994) ont établi que le magma granitique peut avoir une viscosité de 10 à 10 (Pa.s) (Carmichael et al 191 A;Pitcher 1979, McBirney 1984Petford et al 1993). Ceci a ouvert le chemin pour le développement du mécanisme de la montée du magma sous forme de dyke.…”

unclassified

Géochimie, pétrologie structurale et mode de mise en place du pluton de Father, zone volcanique nord, sous-province de l'Abitibi, Canada /

Moukhsil¹

1996

View full text Add to dashboard Cite

The Father pluton is part of the Northern Volcanic Zone of the Archean Abitibi Subprovince and is located 100 km east of Lebel-sur-Quévillon and 105 km southwest of Chibougamau. It represents one of the large granitoid masses that characterize the Abitibi Subprovince. The pluton has an elongated SW-trending form, and is composed of several faciès from tonalité to granodiorite. It is bordered to the north and to the south by two major E-W structures, the Doda and Hébert faults respectively. Two other faults (Cl and C2) are localized within the pluton in its SW part. These major faults are interpreted to have played a major role in magma transport and in the emplacement of the pluton.The Father pluton includes several faciès of differing chemistry. These faciès are calcoalkaline, meta-aluminous to peraluminous and results of this study suggest they are linked by a process of fractional crystallization. Mineral phases implicated in the fractionation are: hornblende, biotite, oligoclase, apatite and allanite. Rare earth element patterns of the pluton show an enrichment of light rare-earths (LREE) compared to heavy rare-earths (HREE). An enrichment of Ta observed in the granodiorite, is probably linked partly to the accumulation of magnetite as well as titanite in this faciès (Ta= 2 to 5 ppm in the rocks). The abundance of titanite and magnetite (Ta= 2 to 4 ppm) is correlated with the abundance of Ta in the granodiorite phase.The structural analysis of XZ sections (perpendicular to the foliation and parallel to the lineation) shows two distinct mineral orientations. The first direction constitutes the dominant orientation and corresponds to the shear plane (C). This orientation was acquired at the onset and persisted to the end of magmatic flow, as suggested by the parallel orientation of both the quartz and the ferromagnesien minerals. The second orientation, represented by large grains of potash feldspar and some isolated grains of biotite and/or hornblende, probably represents the S plane. This second orientation testifies to the combined effect of preferential orientation (oriented growth) of these minerals and the shingle-like orientation resulting from the latest regional tectonic event.Two sets of foliation are recognized in the Father pluton. The principal foliation, occurring over almost all the pluton, is oriented SW, parallel to the length of the pluton. The second, NW-oriented set is well developed in the SW part of the pluton. The predominant SW-trending foliation corresponds to the magmatic state during the emplacement of the faciès in which it developed. Three hypotheses are postulated for the origin of the NW-trending foliation, it may be the result of: 1) the influence of the pluton contact with the adjacent tonalité; 2) a fabric produced by the NW shearing observed in this sector; or, 3) a vestige of an early flow overprinted by the shear zone Cl.The proposed model for the Father pluton is emplacement in a pull-apart zone. The play of the Doda and Hébert faults was responsible for the format...

show abstract

Dike transport of granitoid magmas

Cited by 287 publications

References 0 publications

Dynamics of magmatic intrusions in the upper crust: Theory and applications to laccoliths on Earth and the Moon

Dynamics of magmatic intrusions in the upper crust: Theory and applications to laccoliths on Earth and the Moon

Apparent boudinage in dykes

Géochimie, pétrologie structurale et mode de mise en place du pluton de Father, zone volcanique nord, sous-province de l'Abitibi, Canada /

Contact Info

Product

Resources

About