Shear criteria in granite and migmatite deformed in the magmatic and solid states

Blumenfeld, Philippe; Bouchez, Jean‐Luc

doi:10.1016/0191-8141(88)90014-4

Cited by 254 publications

(119 citation statements)

References 24 publications

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“…However granite fabrics study requires the establishment of the microstructures origin, either magmatic or eventually superimposed solid-state. Criteria for this distinction are presented in a number of papers (e. g. Blumenfeld and Bouchez, 1988;Bouchez et al, 1992;Paterson et al, 1989;Vernon, 2000) and the significance of the different microstructures is defined according to magma rheology considerations (Nicolas, 1992;Vigneresse et al, 1996). When the solid fraction of magma does not exceed a certain amount, about 60%, enough melt is supposed to be present to allow free crystal rotation, i.e.…”

Section: Petrography and Microstructural Studymentioning

confidence: 99%

Late-Variscan emplacement and genesis of the Vieira do Minho composite pluton, Central Iberian Zone: Constraints from U–Pb zircon geochronology, AMS data and Sr–Nd–O isotope geochemistry

Martins

Ovaia

Noronha

2013

Lithos

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In the Central Iberian Zone synorogenic (syn-and late-D 3 , the last deformation phase) composite batholiths of biotite-rich granitods with peraluminous character are well represented. We report here U-Pb zircon and monazite ages, geochemical, Sr-Nd-O isotopic data and Anisotropy of Magnetic Susceptibility (AMS) studies for the late-D 3 Vieira do Minho pluton, in northern Portugal. AMS reveals the paramagnetic behaviour of these granites and the magnetic fabric enhances the major role of NW-SE regional anisotropies on controlling the ascent and emplacement of the magmas. Magnetic anisotropy and medium temperature microstructures also point out the evolution of regional tectonics during crystallization of the magma. U-Pb zircon and monazite analyses yield consistent ages of 310 ± 2 Ma and 312 ± 2 Ma, interpreted as emplacement age. The Vieira do Minho pluton consists of two peraluminous monzogranites, the VMG and the MRG. Both have similar ε Nd values (VMG= −5.2 to −5.7; MRG =−4.98 to −5.96) but the VMG is slightly enriched in 87 Sr/ 86 i = 0.7087-0.7098 as well as in δ 18 O in the range of 10.6‰ to 11.0‰ than the MRG with 87 Sr/ 86 i =0.7064-0.7075 and δ 18 O=9.9‰-10.5‰. These granites are associated with coeval scarce grabroic intrusions and/or mafic microgranular enclaves which are not considered as mafic precursors of the associated granitic magmatism. Instead, a lower metaigneous crustal source, at different levels, is proposed based on the available data set.

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Section: Petrography and Microstructural Studymentioning

confidence: 99%

Late-Variscan emplacement and genesis of the Vieira do Minho composite pluton, Central Iberian Zone: Constraints from U–Pb zircon geochronology, AMS data and Sr–Nd–O isotope geochemistry

Martins

Ovaia

Noronha

2013

Lithos

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“…This has motivated the study of¯uid±particle interactions in simple systems to elucidate the dynamical history of magma bodies. A number of experimental and numerical studies of multiphase¯ow at low Reynolds number (creeping¯ow) illustrate di ering approaches and complexity (Freeman, 1985;Fernandez, 1987;Blumenfeld and Bouchez, 1988;Ildefonse and Fernandez, 1988;Ildefonse et al, 1992;Nicolas, 1992;Jezek et al, 1996;Arbaret et al, 1997;Fernandez and Fernandez-Catuxo, 1997;Ildefonse et al, 1997). The absence of a generality emerging from these studies highlights the di culty of using shape-preferred orientations to uniquely describe even geometrically simple¯ows (Ottino, 1989).…”

Section: Introductionmentioning

confidence: 99%

On the dynamics of magma mixing by reintrusion: implications for pluton assembly processes

Bergantz

2000

Journal of Structural Geology

143

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“…e, f Mesoscopic (e) and microscopic (f) S-C structures pointing to submagmatic deformation in the fine-grained biotitemuscovite granite; x biotite and muscovite cap, y dilatational site filled with fine grains of quartz, plagioclase and microcline; cross section parallel to magmatic lineation; arrows show the sense of shear relatively well developed. This granite shows microscopic synmagmatic deformation structures, such as tiling of plagioclase grains (Blumenfeld and Bouchez 1988;Paterson et al 1998), and synneusis and ''train-like'' arrangement of plagioclase (Fig. 8d), usually regarded as evidence of magmatic flow in the presence of 45-50 % of liquid (Blumenfeld and Bouchez 1988;Paterson et al 1998).…”

Section: Synmagmatic Deformation Structuresmentioning

confidence: 99%

“…This granite shows microscopic synmagmatic deformation structures, such as tiling of plagioclase grains (Blumenfeld and Bouchez 1988;Paterson et al 1998), and synneusis and ''train-like'' arrangement of plagioclase (Fig. 8d), usually regarded as evidence of magmatic flow in the presence of 45-50 % of liquid (Blumenfeld and Bouchez 1988;Paterson et al 1998). However, this granite does not reveal any evidence of mineral deformation.…”

Section: Synmagmatic Deformation Structuresmentioning

confidence: 99%

Sequential granite emplacement: a structural study of the late Variscan Strzelin intrusion, SW Poland

Oberc-Dziedzic

Kryza

et al. 2013

Int J Earth Sci (Geol Rundsch)

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The Strzelin Massif in SW Poland (Central European Variscides) records a protracted igneous evolution, with three main magmatic stages: (1) tonalitic I, (2) granodioritic and (3) tonalitic II/granitic. In the northern part of this Massif, the Strzelin intrusion proper comprises three successively emplaced rock types: a medium-grained biotite granite (303 ± 2 Ma), a fine-grained biotite granite (283 ± 8 Ma) and a fine-grained biotite-muscovite granite; based on field evidence, the third variety postdates both types of the biotite granites. The structural data from the three granites, including their parallel, approximately E-W striking and steeply dipping lithological contacts and ENE-WSW trending subhorizontal magmatic lineations, suggest that the emplacement of all three successive granite varieties was controlled by an active, long-lived strike-slip fault, striking ESE-WNW, with a dextral sense of movement. After the emplacement of the youngest biotitemuscovite granite, the intrusion underwent brittle extension which produced ''Q joints'' striking NNW-SSE to N-S and dipping at 55-70°WSW to W, and showing evidence of broadly N-S directed sinistral displacements. The structural observations, supported by new geochronological data, indicate that the internal structure of the composite granitoid intrusion, including the faint magmatic foliation and lineation, formed in a long-lived strike-slip setting, different from the subsequent, post-emplacement extensional tectonics that controlled the development of brittle structures.

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Shear criteria in granite and migmatite deformed in the magmatic and solid states

Cited by 254 publications

References 24 publications

Late-Variscan emplacement and genesis of the Vieira do Minho composite pluton, Central Iberian Zone: Constraints from U–Pb zircon geochronology, AMS data and Sr–Nd–O isotope geochemistry

Late-Variscan emplacement and genesis of the Vieira do Minho composite pluton, Central Iberian Zone: Constraints from U–Pb zircon geochronology, AMS data and Sr–Nd–O isotope geochemistry

On the dynamics of magma mixing by reintrusion: implications for pluton assembly processes

Sequential granite emplacement: a structural study of the late Variscan Strzelin intrusion, SW Poland

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