P–T Alpine metamorphic evolution of the Monte Rosa nappe along the Piedmont Zone boundary (Gressoney Valley, NW Italy)

Gasco, Ivano; Borghi, Alessandro; Gattiglio, Marco

doi:10.1016/j.lithos.2011.09.007

Cited by 23 publications

(35 citation statements)

References 41 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…(3) As concerning the Internal Crystalline Massifs, the mineral chemistry of all the studied samples preserving the HP stage (M 1 assemblages) shows different degrees of re-equilibration and all the samples which are re-equilibrated at LP conditions (M 2 assemblages) always preserve some HP relic, mostly high-celadonitic Phe and Grt. The southern Monte Rosa and the eastern Gran Paradiso reached higher pressure during the D 1 /M 1 eclogite facies tectono metamorphic stage around 24-27 kbar and 550-600 • C (Le Bayon et al, 2006b;Gabudianu Radulescu et al, 2009;Gasco et al, , 2011a while the northern Dora-Maira was subducted to 20-21 kbar at 500-520 • C (Gasco et al, 2011b). The exhumation paths are different too and are characterized by isothermal to cooling decompression in the MR and GP, while the DM registered a decompressional heating.…”

Section: Discussionmentioning

confidence: 94%

“…Peak-pressure conditions estimated with the pseudosection approach for talc-chloritoid-phengite-quartz whiteschist gave 25 kbar and 580 • C (Le Bayon et al, 2000) and 24 ± 3 kbar and 505 ± 30 • C followed by decompression to 8 ± 3 kbar and 475 ± 30 • C (Le Bayon et al, 2006a). Gasco et al (2011b) obtained 550-570 • C and 24-27 kbar in the metapelitic basement of the southern portion of the MR.…”

Section: The Internal Crystalline Massifsmentioning

confidence: 99%

“…Geological mapping and structural analysis revealed the presence of a tectono-metamorphic gap (TC 2 ) within the Piedmont Zone respectively named Gressoney Shear Zone (Reddy et al, 1999;Gasco and Gattiglio, 2011), Orco Shear Zone (Gasco et al, 2009; and Susa Shear Zone (Gasco et al, 2011b).…”

Section: The Gressoney Orco and Susa Shear Zonesmentioning

confidence: 99%

“…9. Alpine PT path reconstructed for the southern Monte Rosa massif (Gasco et al, 2011b), the eastern Gran Paradiso massif and northern Dora-Maira Massif (Gasco et al, 2011a). The depth is calculated on the base of an average crustal density of 2.95 kg/dm 3 .…”

Section: Tectonic Interpretationmentioning

confidence: 99%

See 3 more Smart Citations

Review of metamorphic and kinematic data from Internal Crystalline Massifs (Western Alps): PTt paths and exhumation history

Gasco

Gattiglio

Borghi

2013

Journal of Geodynamics

Self Cite

View full text Add to dashboard Cite

Section: Discussionmentioning

confidence: 94%

Section: The Internal Crystalline Massifsmentioning

confidence: 99%

Section: The Gressoney Orco and Susa Shear Zonesmentioning

confidence: 99%

Section: Tectonic Interpretationmentioning

confidence: 99%

See 2 more Smart Citations

Review of metamorphic and kinematic data from Internal Crystalline Massifs (Western Alps): PTt paths and exhumation history

Gasco

Gattiglio

Borghi

2013

Journal of Geodynamics

Self Cite

View full text Add to dashboard Cite

“…2). Pressure conditions for the development of the mylonitic lineation were estimated to be 8 AE 3 kbar, whereas the temperature was estimated to be 450e500 C by Borghi et al (1996) and Le Bayon et al (2006a;2006b) and 550e600 C by Gasco and Borghi (2011).…”

Section: Sample Description: Mesostructures Microstructures and Chemmentioning

confidence: 98%

The 3D quantitative lattice and shape preferred orientation of a mylonitised metagranite from Monte Rosa (Western Alps): Combining neutron diffraction texture analysis and synchrotron X-ray microtomography

Zucali

Voltolini

Ouladdiaf³

et al. 2014

Journal of Structural Geology

View full text Add to dashboard Cite

This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues.Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. a b s t r a c tTwo complementary 3D techniques, neutron diffraction and synchrotron X-ray microtomography (SXRmCT), were used to compare the Shape and Lattice Preferred Orientations of a mylonitised metagranite from the Monte Rosa unit (Western Alps, Italy). The goal of using these techniques was to obtain two different orientation distribution functions. Although the two functions describe relatively independent characteristics of the rock fabric, nonetheless they also exhibit close relationships to macroscopic fabrics and may be complementarily used to quantify rock fabrics and microstructures, thereby highlighting 3D features that cannot be obtained with either technique, if used independently. We describe an approach that can be potentially useful in various disciplines, e.g., structural geology, rock mechanics, tectonics and geophysics, when a complete data set of preferred orientations and size distribution is needed. Micas display a strong orthorhombic symmetry between mesoscopic lineation and microscopic SPO and LPO, whereas quartz and feldspars are characterised by a monoclinic symmetry between mesoscopic lineation and LPO. These observations suggest a rheological decoupling between the weak phase mica layers and the stronger quartz þ feldspar layers. This mechanical decoupling occurred during the Alpine subduction-collision, when the Monte Rosa unit was part of the Insubric Line system and accommodated large vertical strain.

show abstract

The Alps 2: Controls on crustal subduction and (ultra)high‐pressure rock exhumation in Alpine‐type orogens

2014

View full text Add to dashboard Cite

Building on our previous results, we use 2-D upper mantle-scale thermomechanical numerical models to explore key controls on the evolution of Alpine-type orogens and the Alps per se, focusing on (ultra)high-pressure ((U)HP) metamorphic rocks. The models show that UHP rocks form and exhume by burial and subsequent buoyant ascent of continental crust in the subduction conduit. Here we test the sensitivity of the models to surface erosion rate, crustal heat production, plate convergence/divergence rates, geometry of the subducting continental margin, and strength of the retrocontinent. Surface erosion affects crustal exhumation but not early buoyant exhumation. Metamorphic temperatures increase with crustal radioactive heat production. Maximum burial depth prior to exhumation increases with plate convergence rates, but exhumation rates are only weakly dependent on subduction rates. Onset of absolute plate divergence does not trigger exhumation in these models. We conclude that contrasting peak pressures, exhumation rates, and volumes of (U)HP crust exhumed in the Alps orogen primarily reflect along-strike contrasts in the geometry, thermal structure, and/or strength of the subducting microcontinent (Briançonnais) and continental (European margin) crust. The experiments also support the interpretation that the Western Alps (U)HP Internal Crystalline Massifs exhumed as composite, stacked plumes and that these plumes drove local crustal extension during orogen-scale shortening. For weak upper plate retrocrusts, postexhumation retrothrusting forms a retrowedge. Overall, these results are consistent with predictions using the exhumation number (ratio of buoyancy to side traction forces in the conduit), which expresses the combined parameter control of the depth/volume of crustal subduction and the transition to buoyant exhumation.

show abstract

P–T Alpine metamorphic evolution of the Monte Rosa nappe along the Piedmont Zone boundary (Gressoney Valley, NW Italy)

Cited by 23 publications

References 41 publications

Review of metamorphic and kinematic data from Internal Crystalline Massifs (Western Alps): PTt paths and exhumation history

Review of metamorphic and kinematic data from Internal Crystalline Massifs (Western Alps): PTt paths and exhumation history

The 3D quantitative lattice and shape preferred orientation of a mylonitised metagranite from Monte Rosa (Western Alps): Combining neutron diffraction texture analysis and synchrotron X-ray microtomography

The Alps 2: Controls on crustal subduction and (ultra)high‐pressure rock exhumation in Alpine‐type orogens

Contact Info

Product

Resources

About