Evolution of mica fish in mylonitic rocks

Grotenhuis, Saskia M. ten; Trouw, Rudolph Allard Johannes; Passchier, Cees W.

doi:10.1016/s0040-1951(03)00231-2

Cited by 106 publications

(45 citation statements)

References 38 publications

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“…This contradicts frequent field observations of rigid inclusions that show stable fabrics and no signs of rotation (e.g. ten Grotenhuis et al, 2003). Consequently research over the last few decades has been conducted in order to establish factors that can change the rotation behaviour of rigid inclusions.…”

Section: Fundamental Solutions: Aspect Ratio Inclination and Materimentioning

confidence: 80%

Applications of inclusion behaviour models to a major shear zone system: The Nordfjord-Sogn Detachment Zone in western Norway

Marques

Schmid

Andersen

2007

Journal of Structural Geology

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Rigid inclusion models have reached a stage where one should be able to use them to obtain quantitative values from ductile shear zones. We used natural data collected in three sites and combined analogue and theoretical modelling to assess vorticity, strain, nature of rigid inclusion/ matrix interface and confinement in the large-scale, ductile Nordfjord-Sogn Detachment Zone (NSDZ) of the Caledonides of western Norway. Our study shows that: (1) the observed shape preferred orientation (SPO) at higher structural levels of the NSDZ at Site 1, Gjervika, can be explained by simple shear (pure shear/simple shear ratio S r ¼ 0) associated with a slipping inclusion/matrix interface. (2) The observed SPO at deeper structural levels of the NSDZ at Site 2, near Sandane can be produced by simple shear associated with a significant amount of shortening across the shear zone (S r z 1), acting upon rigid inclusions in slipping contact with the enclosing matrix. The large scale extensional NSDZ under investigation shows evidence of strain partitioning: rocks vary from protomylonites to ultramylonites, and the simple shear and pure shear components are heterogeneously distributed. Therefore, we conclude that flow in the NSDZ was very heterogeneous both at the kilometre and the metre scale. However, the present study suggests that the amount of shortening across the shear plane throughout the NSDZ increases with depth, and the flattening component contributes to exhumation of the eclogite facies rocks in its footwall.

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Section: Fundamental Solutions: Aspect Ratio Inclination and Materimentioning

confidence: 80%

Applications of inclusion behaviour models to a major shear zone system: The Nordfjord-Sogn Detachment Zone in western Norway

Marques

Schmid

Andersen

2007

Journal of Structural Geology

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“…[19] Following the mica fish morphological grouping proposed by ten Grotenhuis et al [2003], mica grains in the NSRD footwall form lenticular mica fish (group 1) and, toward the very top of the mylonitic footwall, cleavage planes that have sigmoidal shapes converging at one or both tips of the mica grains (group 2). Migration recrystallization Figure 6.…”

Section: Muscovitementioning

confidence: 99%

“…Their cleavage planes are parallel to the mylonitic foliation or at a small synthetic angle. According to ten Grotenhuis et al [2003], these mica grains result from synthetic slip on (001) planes. The lack of pressure shadows or trails of fine mica extending from the tips suggest that this muscovite may be part of the Cretaceous metamorphic assemblage and did not undergo significant recrystallization during mylonitic deformation in the NSRD footwall.…”

Section: Muscovitementioning

confidence: 99%

Oligo‐Miocene extensional tectonics and fluid flow across the Northern Snake Range detachment system, Nevada

Gébelin¹,

Mulch²,

Teyssier

et al. 2011

Tectonics

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[1] The Northern Snake Range (Nevada) represents a spectacular example of a metamorphic core complex and exposes a complete section from the mylonitic footwall into the hanging wall of a fossil detachment system. Paired geochronological and stable isotopic data of mylonitic quartzite within the detachment footwall reveal that ductile deformation and infiltration of meteoric fluids occurred between 27 and 23 Ma. 40 Ar/ 39 Ar ages display complex recrystallization-cooling relationships but decrease systematically from 26.9 ± 0.2 Ma at the top to 21.3 ± 0.2 Ma at the bottom of footwall mylonite. Hydrogen isotope (dD) values in white mica are very low (−150 to −145 ‰) within the top 80-90 m of detachment footwall, in contrast to values obtained from the deeper part of the section where values range from −77 to −64 ‰, suggesting that time-integrated interaction between rock and meteoric fluid was restricted to the uppermost part of the mylonitic footwall. Pervasive mica-water hydrogen isotope exchange is difficult to reconcile with models of 40 Ar loss during mylonitization solely by volume diffusion. Rather, we interpret the 40 Ar/ 39 Ar ages of white mica with low-dD values to date syn-mylonitic hydrogen and argon isotope exchange, and we conclude that the hydrothermal system of the Northern Snake Range was active during late Oligocene (27-23 Ma) and has been exhumed by the combined effects of ductile strain, extensional detachment faulting, and erosion.

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“…The S-C fab ric is very well-de vel oped with dis tinc tive, elongated mus co vite fish, most sim i lar to group 2 (len tic u lar fish with points in clined in the fo li a tion di rec tion) in the Grotenhuis et al (2003) clas si fi ca tion. Be low this area, nar row sheared mica bands (about 1 mm wide) and quartz "rib bons" struc tures par allel to the S-fo li a tion planes are ob served in the cataclasites with mylonitic fo li a tion fea tures (S-C cataclasites).…”

Section: Fig 3 Examples Of Microstructures From Domain Nomentioning

confidence: 91%

Microstructures of shear zones from selected domains of the Western Tatra Mountains

Kania

2015

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1 In sti tute of Geo log i cal Sci ences, Jagiellonian Uni ver sity, Oleandry 2a, 30-063 Kraków, Po land Kania, M., 2015. Micro struc tures of shear zones from se lected do mains of the West ern Tatra Moun tains. Geo log i cal Quarterly, 59 (4): 679-699, doi: 10.7306/gq.1243The pa per is fo cused on the meso-and microstructural char ac ter is tics of se lected shear ing zones in the West ern Tatra Mts. The do mains of crys tal line rocks stud ied (D³ugi Up³az Ridge, Rakoñ Mt., Zabraty Ridge and Zabraï Pass, Wo³owiec Mt., Trzydniowiañski Wierch Mt., Czubik Mt. and Jarz¹bczy Wierch Mt.) show ev i dences of het er o ge neous shear ing with de velop ment of shear zones. Four types of shear zones were dis tin guished: (1) duc tile shear zones in gneiss es, (2) brit tle-duc tile com plex shear zones, (3) gneiss es with clear later brit tle de for ma tion, (4) leucogranites, pro duced by anatexis with later brittle de for ma tion. The de vel op ment of these shear zones is char ac ter ized by oc cur rences of var i ous types of fault rocks: cataclasites, S-C cataclasites and mylonites. The dif fer ent shear ing-re lated rocks and struc tures are in ter preted as an ef fect of protolith di ver sity and strain par ti tion ing. Shape-pre ferred ori en ta tion is an im por tant struc tural fea ture of all the shearing-re lated rocks. Ki ne matic anal y ses re vealed gen er ally a south ward sense of shear ing doc u mented by struc tures re lated to brit tle con di tions and north wards sense of shear ing rec og nized in ductily sheared crys tal line rocks. The time re la tion ships be tween dif fer ent shear zone types are dis cussed, lead ing to the con clu sions that the 1st type of shear zone is pure Variscan, the 2nd type is Variscan with Al pine brit tle de for ma tion, and the 3rd and 4th types are mainly Al pine brit tle de for mations of Variscan syntectonic anatectic leucogranites.

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Evolution of mica fish in mylonitic rocks

Cited by 106 publications

References 38 publications

Applications of inclusion behaviour models to a major shear zone system: The Nordfjord-Sogn Detachment Zone in western Norway

Applications of inclusion behaviour models to a major shear zone system: The Nordfjord-Sogn Detachment Zone in western Norway

Oligo‐Miocene extensional tectonics and fluid flow across the Northern Snake Range detachment system, Nevada

Microstructures of shear zones from selected domains of the Western Tatra Mountains

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