Multiscale structural analysis in the subducted continental crust of the internal Sesia-Lanzo Zone (Monte Mucrone, Western Alps)

Delleani, Francesco; Spalla, Maria Iole; Castelli, Daniele; Gosso, G.

doi:10.3809/jvirtex.2011.00287

Cited by 10 publications

(26 citation statements)

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“…In all rock types, blueschist-facies mineral assemblages (Table 3) define S2. This finding is in contrast with the nearby metaintrusive of M. Mucrone, where eclogitic mineral assemblages mark the pervasive fabric (Delleani et al, 2012;Delleani et al, 2013;Zucali et al, 2002). Thus, different FE and MT would have affected the retrograde blueschist re-equilibration and potentially generated km-scale heterogeneities within the EMC.…”

Section: Resultscontrasting

confidence: 53%

“…For instance, in the nearby area of M. Mucrone the correlation between FE and MT shows that the dominant tectono-metamorphic imprint is related to high degree of FE and MT (Delleani et al, 2012;Delleani et al, 2013;Zucali et al, 2002). Similar results have been also obtained in the Mont Morion complex of the Dent Blanche nappe (Roda & Zucali, 2008) and in the LanguardTonale unit in the central Austroalpine domain .…”

Section: Resultsmentioning

confidence: 99%

“…M0 stage consists of undeformed, most probably pre-Alpine, igneous intrusion (Zucali, 2011). D1-D5 structures consist of fold systems, foliations, and shear zones that are comparable, in terms of their structural features and relative chronology, to the Alpine structures described by Zucali et al (2002) and Delleani et al (2012) in the nearby area of M. Mucrone. M6 stage is represented by andesite dyke intrusion that is quite common in the area and dated at the Oligocene (e.g.…”

Section: Structural Analysismentioning

confidence: 99%

“…In order to evaluate whether rock volumes record the same tectono-metamorphic history, mapping petro-structural heterogeneities in adjacent rock volumes is crucial (e.g. Delleani, Spalla, Castelli, & Gosso, 2012;Delleani, Spalla, Castelli, & Gosso, 2013;Gosso et al, 2015;Salvi et al, 2010;Zucali, Spalla, & Gosso, 2002). Since deformation heterogeneity commonly affects crystalline basements (e.g.…”

Section: Introductionmentioning

confidence: 99%

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Analysis of fabric evolution and metamorphic reaction progress at Lago della Vecchia-Valle d’Irogna, Sesia-Lanzo Zone, Western Alps

et al. 2017

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The Lago della Vecchia-Valle d'Irogna rocks are part of the Eclogitic Micaschists Complex (EMC) of the Sesia-Lanzo Zone, western Austroalpine domain. The 1:10,000 scale map includes metaintrusive, minor micaschist, banded gneiss, and metabasic boudins. The multiscale structural analysis reveals successive magmatic and tectono-metamorphic stages: during M0 the metaintrusive protoliths emplaced; D1 took place under eclogite-facies conditions; during D2 stage, a pervasive foliation developed under retrograde blueschist-facies conditions; D3-D4 and D5 structures developed under greenschist-facies conditions; during M6 andesitic dykes intruded. The mapped degree of fabric evolution (FE) and metamorphic transformation (MT) related to D2-foliation shows that the MT was not only controlled by bulk rock and mineral compositions, but also by FE. The development of a pervasive blueschist-facies D2-foliation is in contrast with the eclogitic dominant fabric generally recorded in the EMC. This difference suggests that FE and MT are potentially responsible for km-scale heterogeneities in the tectono-metamorphic record.ARTICLE HISTORY

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Section: Resultscontrasting

confidence: 53%

Section: Resultsmentioning

confidence: 99%

Section: Structural Analysismentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Analysis of fabric evolution and metamorphic reaction progress at Lago della Vecchia-Valle d’Irogna, Sesia-Lanzo Zone, Western Alps

et al. 2017

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“…The Biella pluton, which is also known as the Valle del Cervo pluton, shows a concentric zoning in which the outer part consists of monzonite grading to syenite and the inner part consists of granite (Bigioggero et al, 1994 and references therein). The Biella and Traversella plutons are 30 Ma Bigioggero et al, 1994;Krummenacher & Evernden, 1960;Romer et al, 1996) and are emplaced in the internal Sesia-Lanzo Zone of the western Austroalpine domain (Figure 1(b)), which shows a pervasive structural imprint under eclogite facies conditions (Delleani, Spalla, Castelli, & Gosso, 2012, 2013Giorgetti, Tropper, Essene, & Peacor, 2000;Koons, 1986;Rubbo, Borghi, & Compagnoni, 1999;Tropper & Essene, 2002;Tropper, Essene, Sharp, & Hunziker, 1999;Zucali, 2002;Zucali & Spalla, 2011;Zucali, Spalla, & Gosso, 2002) dated 60 -80 Ma (Bussy, Venturini, Hunziker, & Martinotti, 1998;Cenki-Tok et al, 2011;Roda, Spalla, & Marotta, 2012;Rubatto, Gebauer, & Compagnoni, 1999;Rubatto et al, 2011) and related to the Alpine subduction. The Sesia-Lanzo Zone preserves scattered granulite to amphibolite facies relicts, which are related to Permian-Triassic lithospheric thinning that predates the Alpine convergence (Cenki-Tok et al, 2011;Lardeaux & Spalla, 1991;Rebay & Spalla, 2001;Spalla et al, 2014).…”

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Structure and petrography of the southwestern margin of the Biella pluton, Western Alps

Zanoni

2015

Journal of Maps

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This work presents a new form surface map of the southwestern margin of the Biella pluton at the scale 1:10,000. The Biella pluton is part of the Periadriatic intrusives of the Alps and is emplaced in the continental Sesia-Lanzo Zone of the western Austroalpine domain. The country rocks consist of metapelites and different metagranitoids. Pre-intrusive HP (high pressure) mineral assemblages are dominant in country rocks with the exception of metagranitoids dominated by HT (high temperature) assemblages. The plutonic rocks consist of monzonite with minor syenite. The ductile polyphasic deformation of the country rocks predates the pluton emplacement, with the exception of syn-intrusive folding and shearing, which were recorded in the country rocks of the deeper part of the pluton. Synintrusive deformation may be represented by brittle structures that bear mineralisation; however, the majority of the brittle deformation postdates the final emplacement of the pluton. The orientation of the pervasive foliation in the country rocks controls the space available for magma intrusion and possible magmatic flow during emplacement. The inferred diffusion of the thermal aureole in the country rocks is based on the variation in contact metamorphic minerals, which is described by microscopic analysis. The extent of the aureole appears to be controlled by the type of dominant mineral assemblages, rock permeability, and the orientation of the regional foliation in country rocks with respect to the pluton margin. The multiscale structural analysis reveals that the Biella pluton emplaced at a depth as shallow as the greenschist facies conditions or shallower.

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The tectonometamorphic evolution of the Sesia–Dent Blanche nappes (internal Western Alps): review and synthesis

et al. 2014

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International audienceThis study reviews and synthesizes the presentknowledge on the Sesia–Dent Blanche nappes, the highesttectonic elements in the Western Alps (Switzerland andItaly), which comprise pieces of pre-Alpine basement andMesozoic cover. All of the available data are integrated in acrustal-scale kinematic model with the aim to reconstructthe Alpine tectono-metamorphic evolution of the Sesia–Dent Blanche nappes. Although major uncertainties remainin the pre-Alpine geometry, the basement and coversequences of the Sesia–Dent Blanche nappes are seen aspart of a thinned continental crust derived from the Adriaticmargin. The earliest stages of the Alpine evolution areinterpreted as recording late Cretaceous subduction of theAdria-derived Sesia–Dent Blanche nappes below theSouth-Alpine domain. During this subduction, severalsheets of crustal material were stacked and separated byshear zones that rework remnants of their Mesozoic cover.The recently described Roisan-Cignana Shear Zone of theDent Blanche Tectonic System represents such a shearzone, indicating that the Sesia–Dent Blanche nappes representa stack of several individual nappes. During thesubsequent subduction of the Piemonte–Liguria Oceanlarge-scale folding of the nappe stack (including the Roisan-Cignana Shear Zone) took place under greenschistfacies conditions, which indicates partial exhumation of theDent Blanche Tectonic System. The entrance of the Brianc¸onnais micro-continent within the subduction zone ledto a drastic change in the deformation pattern of the Alpinebelt, with rapid exhumation of the eclogite-facies ophiolitebearingunits and thrust propagation towards the foreland.Slab breakoff probably was responsible for allowing partialmelting in the mantle and Oligocene intrusions into themost internal parts of the Sesia–Dent Blanche nappes.Finally, indentation of the Adriatic plate into the orogenicwedge resulted in the formation of the Vanzone back-fold,which marks the end of the pervasive ductile deformationwithin the Sesia–Dent Blanche nappes during the earliestMiocene

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Multiscale structural analysis in the subducted continental crust of the internal Sesia-Lanzo Zone (Monte Mucrone, Western Alps)

Cited by 10 publications

References 0 publications

Analysis of fabric evolution and metamorphic reaction progress at Lago della Vecchia-Valle d’Irogna, Sesia-Lanzo Zone, Western Alps

Analysis of fabric evolution and metamorphic reaction progress at Lago della Vecchia-Valle d’Irogna, Sesia-Lanzo Zone, Western Alps

Structure and petrography of the southwestern margin of the Biella pluton, Western Alps

The tectonometamorphic evolution of the Sesia–Dent Blanche nappes (internal Western Alps): review and synthesis

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