@article{PourteauBousquetVidaletal.2014,
  author    = {Pourteau, Amaury and Bousquet, Romain and Vidal, Olivier and Plunder, Alexis and Duesterhoeft, Erik and Candan, Osman and Oberh{\"a}nsli, Roland},
  title     = {Multistage growth of Fe-Mg-carpholite and Fe-Mg-chloritoid, from field evidence to thermodynamic modelling},
  series = {Contributions to mineralogy and petrology},
  volume    = {168},
  journal   = {Contributions to mineralogy and petrology},
  number    = {6},
  publisher = {Springer},
  address   = {New York},
  issn      = {0010-7999},
  doi       = {10.1007/s00410-014-1090-7},
  pages     = {25},
  year      = {2014},
  abstract  = {We provide new insights into the prograde evolution of HP/LT metasedimentary rocks on the basis of detailed petrologic examination, element-partitioning analysis, and thermodynamic modelling of well-preserved Fe-Mg-carpholite- and Fe-Mg-chloritoid-bearing rocks from the Afyon Zone (Anatolia). We document continuous and discontinuous compositional (ferromagnesian substitution) zoning of carpholite (overall X-Mg = 0.27-0.73) and chloritoid (overall X-Mg = 0.07-0.30), as well as clear equilibrium and disequilibrium (i.e., reaction-related) textures involving carpholite and chloritoid, which consistently account for the consistent enrichment in Mg of both minerals through time, and the progressive replacement of carpholite by chloritoid. Mg/Fe distribution coefficients calculated between carpholite and chloritoid vary widely within samples (2.2-20.0). Among this range, only values of 7-11 correlate with equilibrium textures, in agreement with data from the literature. Equilibrium phase diagrams for metapelitic compositions are calculated using a newly modified thermodynamic dataset, including most recent data for carpholite, chloritoid, chlorite, and white mica, as well as further refinements for Fe-carpholite, and both chloritoid end-members, as required to reproduce accurately petrologic observations (phase relations, experimental constraints, Mg/Fe partitioning). Modelling reveals that Mg/Fe partitioning between carpholite and chloritoid is greatly sensitive to temperature and calls for a future evaluation of possible use as a thermometer. In addition, calculations show significant effective bulk composition changes during prograde metamorphism due to the fractionation of chloritoid formed at the expense of carpholite. We retrieve P-T conditions for several carpholite and chloritoid growth stages (1) during prograde stages using unfractionated, bulk-rock XRF analyses, and (2) at peak conditions using compositions fractionated for chloritoid. The P-T paths reconstructed for the Kutahya and Afyon areas shed light on contrasting temperature conditions for these areas during prograde and peak stages.},
  language  = {en}
}
@article{DuesterhoeftQuinterosOberhaenslietal.2014,
  author    = {Duesterhoeft, Erik and Quinteros, Javier and Oberh{\"a}nsli, Roland and Bousquet, Romain and de Capitani, Christian},
  title     = {Relative impact of mantle densification and eclogitization of slabs on subduction dynamics: A numerical thermodynamic/thermokinematic investigation of metamorphic density evolution},
  series = {Tectonophysics : international journal of geotectonics and the geology and physics of the interior of the earth},
  volume    = {637},
  journal   = {Tectonophysics : international journal of geotectonics and the geology and physics of the interior of the earth},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0040-1951},
  doi       = {10.1016/j.tecto.2014.09.009},
  pages     = {20 -- 29},
  year      = {2014},
  abstract  = {Understanding the relationships between density and spatio-thermal variations at convergent plate boundaries is important for deciphering the present-day dynamics and evolution of subduction zones. In particular, the interaction between densification due to mineralogical phase transitions and slab pull forces is subject to ongoing investigations. We have developed a two-dimensional subduction zone model that is based on thermodynamic equilibrium assemblage calculations and includes the effects of melting processes on the density distribution in the lithosphere. Our model calculates the "metamorphic density" of rocks as a function of pressure, temperature and chemical composition in a subduction zone down to 250 km. We have used this model to show how the hydration, dehydration, partial melting and fractionation processes of rocks all influence the metamorphic density and greatly depend on the temperature field within the subduction system. These processes are largely neglected by other approaches that reproduce the density distribution within this complex tectonic setting. Our model demonstrates that the initiation of edogitization (i.e., when crustal rocks reach higher densities than the ambient mantle) of the slab is not the only significant process that makes the descending slab denser and generates the slab pull force. Instead, the densification of the lithospheric mantle of the sinking slab starts earlier than eclogitization and contributes significantly to slab pull in the early stages of subduction. Accordingly, the complex metamorphic structure of the slab and the mantle wedge has an important impact on the development of subduction zones. (C) 2014 Elsevier B.V. All rights reserved.},
  language  = {en}
}
@article{BergerSchmidEngietal.2011,
  author    = {Berger, Alfons and Schmid, Stefan M. and Engi, Martin and Bousquet, Romain and Wiederkehr, Michael},
  title     = {Mechanisms of mass and heat transport during Barrovian metamorphism: A discussion based on field evidence from the Central Alps (Switzerland/northern Italy)},
  series = {Tectonics},
  volume    = {30},
  journal   = {Tectonics},
  number    = {2},
  publisher = {American Geophysical Union},
  address   = {Washington},
  issn      = {0278-7407},
  doi       = {10.1029/2009TC002622},
  pages     = {17},
  year      = {2011},
  abstract  = {Tectonic and metamorphic data for the Central Alps (Switzerland/Italy) are used to discuss this classic example of a Barrovian metamorphic terrain, notably the evolution of its thermal structure in space and time. Available P-T-t data indicate variable contributions of advective and conductive heat transport during collision and subsequent cooling and exhumation. Some areas experienced a prolonged period of partial melting while other areas, at the same time, show but moderate heating. The Barrow-type metamorphic field gradient observed in the final orogen is the result of two distinct tectonic processes, with their related advective and conductive heat transport processes. The two tectonic processes are (1) accretion of material within a subduction channel related to decompression and emplacement of high-pressure units in the middle crust and (2) wedging and related nappe formation in the continental lower plate. The second process postdates the first one. Wedging and underthrusting of continental lower plate material produces heat input into lower crustal levels, and this process is responsible for predominantly conductive heat transport in the overlying units. The interacting processes lead to different maximum temperatures at different times, producing the final Barrovian metamorphic field gradient. The south experienced rapid cooling, whereas the north shows moderate cooling rates. This discrepancy principally reflects differences in the temperature distribution in the deeper crust prior to cooling. Differences in the local thermal gradient that prevailed before the cooling also determined the relationships between cooling rate and exhumation rate in the different areas. Citation: Berger, A., S. M. Schmid, M. Engi, R. Bousquet, and M. Wiederkehr (2011), Mechanisms of mass and heat transport during Barrovian metamorphism: A discussion based on field evidence from the Central Alps (Switzerland/northern Italy), Tectonics, 30, TC1007, doi:10.1029/2009TC002622.},
  language  = {en}
}
@article{WiederkehrBousquetZiemannetal.2011,
  author    = {Wiederkehr, Michael and Bousquet, Romain and Ziemann, Martin Andreas and Berger, Alfons and Schmid, Stefan M.},
  title     = {3-D assessment of peak-metamorphic conditions by Raman spectroscopy of carbonaceous material an example from the margin of the Lepontine dome (Swiss Central Alps)},
  series = {International journal of earth sciences},
  volume    = {100},
  journal   = {International journal of earth sciences},
  number    = {5},
  publisher = {Springer},
  address   = {New York},
  issn      = {1437-3254},
  doi       = {10.1007/s00531-010-0622-2},
  pages     = {1029 -- 1063},
  year      = {2011},
  abstract  = {This study monitors regional changes in the crystallinity of carbonaceous matter (CM) by applying Micro-Raman spectroscopy to a total of 214 metasediment samples (largely so-called Bundnerschiefer) dominantly metamorphosed under blueschist- to amphibolite-facies conditions. They were collected within the northeastern margin of the Lepontine dome and easterly adjacent areas of the Swiss Central Alps. Three-dimensional mapping of isotemperature contours in map and profile views shows that the isotemperature contours associated with the Miocene Barrow-type Lepontine metamorphic event cut across refolded nappe contacts, both along and across strike within the northeastern margin of the Lepontine dome and adjacent areas. Further to the northeast, the isotemperature contours reflect temperatures reached during the Late Eocene subduction-related blueschist-facies event and/or during subsequent near-isothermal decompression; these contours appear folded by younger, large-scale post-nappe-stacking folds. A substantial jump in the recorded maximum temperatures across the tectonic contact between the frontal Adula nappe complex and surrounding metasediments indicates that this contact accommodated differential tectonic movement of the Adula nappe with respect to the enveloping Bundnerschiefer after maximum temperatures were reached within the northern Adula nappe, i.e. after Late Eocene time.},
  language  = {en}
}
@article{LoprienoBousquetBucheretal.2011,
  author    = {Loprieno, Andrea and Bousquet, Romain and Bucher, Stefan and Ceriani, Stefano and Dalla Torre, Florian H. and F{\"u}genschuh, Bernhard and Schmid, Stefan M.},
  title     = {The valais units in Savoy (France) a key area for understanding the palaeogeography and the tectonic evolution of the Western Alps},
  series = {International journal of earth sciences},
  volume    = {100},
  journal   = {International journal of earth sciences},
  number    = {5},
  publisher = {Springer},
  address   = {New York},
  issn      = {1437-3254},
  doi       = {10.1007/s00531-010-0595-1},
  pages     = {963 -- 992},
  year      = {2011},
  abstract  = {The Valais units in Savoy (Zone des BrSches de Tarentaise) have been re-mapped in great detail and are subject of combined stratigraphic, structural and petrological investigations summarized in this contribution. The sediments and rare relics of basement, together with Cretaceous age mafic and ultramafic rocks of the Valais palaeogeographical domain, represent the heavily deformed relics of the former distal European margin (External Valais units) and an ocean-continent transition (Internal Valais unit or Versoyen unit) that formed during rifting. This rifting led to the opening of the Valais ocean, a northern branch of the Alpine Tethys. Post-rift sediments referred to as "Valais trilogy" stratigraphically overlie both External and Internal Valais successions above an angular unconformity formed in Barremian to Aptian times, providing robust evidence for the timing of the opening of the Valais ocean. The Valais units in Savoy are part of a second and more external mid-Eocene high-pressure belt in the Alps that sutured the Brian double dagger onnais microcontinent to Europe. Top-N D1-deformation led to the formation of a nappe stack that emplaced the largely eclogite-facies Internal Valais unit (Versoyen) onto blueschist-facies External Valais units. The latter originally consisted of, from internal to external, the Petit St. Bernard unit, the Roc de l'Enfer unit, the MoA >> tiers unit and the Quermoz unit. Ongoing top-N D2-thrusting and folding substantially modified this nappe stack. Post 35 Ma D3 folding led to relatively minor modifications of the nappe stack within the Valais units but was associated with substantial top-WNW thrusting of the Valais units over the Dauphinois units along the Roselend thrust during W-directed indentation of the Adria block contributing to the formation of the arc of the Western Alps.},
  language  = {en}
}
@article{OberhaensliBousquetCandanetal.2012,
  author    = {Oberh{\"a}nsli, Roland and Bousquet, Romain and Candan, Osman and Okay, Aral I.},
  title     = {Dating subduction events in East Anatolia, Turkey},
  series = {Turkish journal of earth sciences = T{\"u}rk yerbilimleri dergisi},
  volume    = {21},
  journal   = {Turkish journal of earth sciences = T{\"u}rk yerbilimleri dergisi},
  number    = {1},
  publisher = {T{\"u}bitak},
  address   = {Ankara},
  issn      = {1300-0985},
  doi       = {10.3906/yer-1006-26},
  pages     = {1 -- 17},
  year      = {2012},
  abstract  = {Metamorphic studies in the cover sequences of the Bitlis complex allow the thermal evolution of the massif to be constrained using metamorphic index minerals. Regionally distributed metamorphic index minerals such as glaucophane, carpholite, relics of carpholite in chloritoid-bearing schists and pseudomorphs after aragonite in marbles record a LT-HP evolution:This demonstrates that the Bitlis complex was subducted and stacked to form a nappe complex during the closure of the Neo-Tethys. During late Cretaceous to Cenozoic evolution the Bitlis complex experienced peak metamorphism of 1.0-1.1 GPa at 350-400 degrees C. During the retrograde evolution temperatures remained below 460 degrees C. Ar-39/Ar-40 dating of white mica in different parageneses from the Bitlis complex reveals a 74-79 Ma (Campanian) date of peak metamorphism and rapid exhumation to an almost isothermal greenschist stage at 67-70 Ma (Maastrichtian). The HP Eocene flysch escaped the greenschist facies stage and were exhumed under very cold conditions. These single stage evolutions contrast with the multistage evolution reported further north from the Amassia-Stepanavan Suture in Armenia. Petrological investigations and isotopic dating show that the collision of Arabia with Eurasia resulted in an assemblage of different blocks derived from the northern as well as from the southern plate and a set of subduction zones producing HP rocks with diverse exhumation histories.},
  language  = {en}
}
@article{DuesterhoeftBousquetWichuraetal.2012,
  author    = {D{\"u}sterh{\"o}ft, Erik and Bousquet, Romain and Wichura, Henry and Oberh{\"a}nsli, Roland},
  title     = {Anorogenic plateau formation The importance of density changes in the lithosphere},
  series = {Journal of geophysical research : Solid earth},
  volume    = {117},
  journal   = {Journal of geophysical research : Solid earth},
  publisher = {American Geophysical Union},
  address   = {Washington},
  issn      = {2169-9313},
  doi       = {10.1029/2011JB009007},
  pages     = {13},
  year      = {2012},
  abstract  = {Away from active plate boundaries the relationships between spatiotemporal variations in density and geothermal gradient are important for understanding the evolution of topography in continental interiors. In this context the classic concept of the continental lithosphere as comprising three static layers of different densities (upper crust, lower crust, and upper mantle) is not adequate to assess long-term changes in topography and relief in regions associated with pronounced thermal anomalies in the mantle. We have therefore developed a one-dimensional model, which is based on thermodynamic equilibrium assemblage computations and deliberately excludes the effects of melting processes like intrusion or extrusions. Our model calculates the "metamorphic density" of rocks as a function of pressure, temperature, and chemical composition. It not only provides a useful tool for quantifying the influence of petrologic characteristics on density, but also allows the modeled "metamorphic" density to be adjusted to variable geothermal gradients and applied to different geodynamic environments. We have used this model to simulate a scenario in which the lithosphere-asthenosphere boundary is subjected to continuous heating over a long period of time (130 Ma), and demonstrate how an anorogenic plateau with an elevation of 1400 m can be formed solely as a result of heat transfer within the continental lithosphere. Our results show that, beside dynamic topography (of asthenospheric origin), density changes within the lithosphere have an important impact on the evolution of anorogenic plateaus.},
  language  = {en}
}
@article{OberhaensliKoralayCandanetal.2013,
  author    = {Oberh{\"a}nsli, Roland and Koralay, E. and Candan, Osman and Pourteau, Amaury and Bousquet, Romain},
  title     = {Late cretaceous eclogitic high-pressure relics in the Bitlis Massif},
  series = {Geodinamica acta : revue de g{\´e}ologie dynamique et de g{\´e}ographie physique},
  volume    = {26},
  journal   = {Geodinamica acta : revue de g{\´e}ologie dynamique et de g{\´e}ographie physique},
  number    = {3-4},
  publisher = {Routledge, Taylor \& Francis Group},
  address   = {Abingdon},
  issn      = {0985-3111},
  doi       = {10.1080/09853111.2013.858951},
  pages     = {175 -- 190},
  year      = {2013},
  abstract  = {A new occurrence of eclogites was found in the Kesandere valley in the eastern most part of the Bitlis complex, SE Anatolia. These high-pressure (HP) relics were preserved in calc-arenitic metasediments within the high-grade metamorphic basement of the Bitlis complex. The eclogitic parageneses were strongly overprinted during decompression and heating. These new eclogites locality complements the evidence of blueschist-facies metamorphism documented recently in the meta-sedimentary cover sequence of this part of the Bitlis complex. Thermodynamic calculations suggest peak conditions of ca. 480-540 degrees C/1.9-2.4GPa. New U/Pb dates of 84.4 +/-.9 and 82.4 +/-.9Ma were obtained on zircons from two Kesandere eclogite samples. On the basis of geochemical criteria, these dates are interpreted to represent zircon crystallization during the eclogitic peak stage. Kesandere eclogites differ from those previously described in the western Bitlis complex (Mt. Gablor locality) in terms of lithologic association, protolithic origin, and peak P-T conditions (600-650 degrees C/1.0-2.0GPa, respectively). On the other hand, eclogitic metamorphism of Kesandere metasediments occurred shortly before blueschist-facies metamorphism of the sedimentary cover (79-74Ma Ar-40/Ar-39 white mica). Therefore, the exhumation of Kesandere eclogites started between ca. 82 and 79Ma, while the meta-sedimentary cover was being buried. During this short time span, Kesandere eclogite were likely uplifted from similar to 65 to 35km depth, indicating a syn-subduction exhumation rate of similar to 4.3mm/a. Subsequently, eclogite- and blueschist-facies rocks were likely retrogressed contemporarily during collision-type metamorphism (around 72-69Ma). The Bitlis HP rocks thus sample a subduction zone that separated the Bitlis-Puturge (Bistun?) block from the South-Armenian block, further north. To the south, Eocene metasediments of the Urse formation are imbricated below the Bitlis complex. They contain (post Eocene) blueschists, testifying separation from the Arabian plate and southward migration of the subduction zone. The HT overprint of Kesandere eclogites can be related to the asthenospheric flow provoked by subducting slab retreat or break off.},
  language  = {en}
}
@article{NegroBousquetVilsetal.2013,
  author    = {Negro, Francois and Bousquet, Romain and Vils, Flurin and Pellet, Clara-Marine and H{\"a}nggi-Schaub, Jeanette},
  title     = {Thermal structure and metamorphic evolution of the Piemont-Ligurian metasediments in the northern Western Alps},
  series = {Swiss journal of geosciences},
  volume    = {106},
  journal   = {Swiss journal of geosciences},
  number    = {1},
  publisher = {Springer},
  address   = {Basel},
  issn      = {1661-8726},
  doi       = {10.1007/s00015-013-0119-7},
  pages     = {63 -- 78},
  year      = {2013},
  abstract  = {In the Western Alps, the Piemont-Ligurian oceanic domain records blueschist to eclogite metamorphic conditions during the Alpine orogeny. This domain is classically divided into two "zones" (Combin and Zermatt-Saas), with contrasting metamorphic evolution, and separated tectonically by the Combin fault. This study presents new metamorphic and temperature (RSCM thermometry) data obtained in Piemont-Ligurian metasediments and proposes a reevaluation of the P-T evolution of this domain. In the upper unit (or "Combin zone") temperatures are in the range of 420-530 A degrees C, with an increase of temperature from upper to lower structural levels. Petrological evidences show that these temperatures are related to the retrograde path and to deformation at greenschist metamorphic conditions. This highlights heating during exhumation of HP metamorphic rocks. In the lower unit (or "Zermatt-Saas zone"), temperatures are very homogeneous in the range of 500-540 A degrees C. This shows almost continuous downward temperature increase in the Piemont-Ligurian domain. The observed thermal structure is interpreted as the result of the upper and lower unit juxtaposition along shear zones at a temperature of similar to 500 A degrees C during the Middle Eocene. This juxtaposition probably occurred at shallow crustal levels (similar to 15-20 km) within a subduction channel. We finally propose that the Piemont-Ligurian Domain should not be viewed as two distinct "zones", but rather as a stack of several tectonic slices.},
  language  = {en}
}
@article{BergerBousquetEngietal.2009,
  author    = {Berger, Alfons and Bousquet, Romain and Engi, Martin and Janots, Emilie and Rubatto, Daniela and Schmid, Stefan and Wiederkehr, Michael},
  title     = {Transport of heat and mass in a Barrovian belt : what do we know from nature?},
  issn      = {0016-7037},
  doi       = {10.1016/j.gca.2009.05.002},
  year      = {2009},
  language  = {en}
}