Rb/Sr record of fluid-rock interaction in eclogites: The Marun-Keu complex, Polar Urals, Russia

Glodny, Johannes; Austrheim, Håkon; Molina, J.F.; Rusin, A. I.; Seward, Diane

doi:10.1016/s0016-7037(03)00370-3

Cited by 102 publications

(101 citation statements)

References 71 publications

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“…Fluids are important in catalyzing prograde metamorphic transformations, for instance during eclogitization processes (e.g., Austrheim, 1987;Putnis and John, 2010). Fluids in highpressure (HP) metamorphic rocks also play a key role in promoting equilibration of isotopic systems used as geochronometers (Glodny et al, 2003). Multimineral isochrons record fluidinduced recrystallization events rather than stages of cooling because full isotopic homogenization is not achieved in rocks that remain devoid of fluids (Glodny et al, 2003(Glodny et al, , 2008.…”

Section: Introductionmentioning

confidence: 99%

“…Fluids in highpressure (HP) metamorphic rocks also play a key role in promoting equilibration of isotopic systems used as geochronometers (Glodny et al, 2003). Multimineral isochrons record fluidinduced recrystallization events rather than stages of cooling because full isotopic homogenization is not achieved in rocks that remain devoid of fluids (Glodny et al, 2003(Glodny et al, , 2008. Without fluids, isotopic resetting is kinetically locked or restricted to sluggish intermineral diffusion.…”

Section: Introductionmentioning

confidence: 99%

“…The Rb-Sr system has been applied to provide constraints on sources and nature of fluids at depth (e.g., Glodny et al, 2003), and Sr isotopes can indicate the presence of a metamorphic fluid in mélange rocks (King et al, 2006) or previous seafloor alteration (Miller et al, 1988).…”

Section: Introductionmentioning

confidence: 99%

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A stable (Li, O) and radiogenic (Sr, Nd) isotope perspective on metasomatic processes in a subducting slab

et al. 2011

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Two distinct types of eclogites from the Raspas Complex (Ecuador), which can be distinguished based on petrography and trace element geochemistry, were analyzed for their stable (Li, O) and radiogenic (Sr, Nd) isotope signature to constrain metasomatic changes due to fluid-overprinting in metabasaltic rocks at high-pressure conditions and to identify fluid sources. MORB-type eclogites are characterized by a relative LREE depletion similar to MORB. High-pressure (HP) minerals from this type of eclogite have highly variable oxygen isotope compositions (garnet: +4.1 to +9.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A stable (Li, O) and radiogenic (Sr, Nd) isotope perspective on metasomatic processes in a subducting slab

et al. 2011

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“…Apatite is also an important container of Sr and contains up to ∼ 7000 -ppm Sr (Fig. 7) (Glodny et al, 2002(Glodny et al, , 2003Schärer and Labrousse, 2003;Meffan -Main et al, 2004;Glodny et al, 2008). Apatite is rare, but present in the sample studied here.…”

Section: Discussionmentioning

confidence: 86%

“…This study underscores the need for careful petrographic analysis prior to use of geochemical data in interpretation of subduction -zone cycling. Compiled data for Sr and Rb contents of omphacite and apatite in eclogitic rocks (Thöni and Jagoutz, 1992;Glodny et al, 2002Glodny et al, , 2003Schärer and Labrousse, 2003;Meffan -Main et al, 2004;Glodny et al, 2008).…”

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Sr-sulphate and associated minerals found from kyanite-bearing eclogite in the Moldanubian Zone of the Bohemian Massif, Czech Republic

Nakamura

Kobayashi

Shimobayashi

et al. 2010

Journal of Mineralogical and Petrological Sciences

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Sr -sulphate, celestine, was newly found in a kyanite -bearing eclogite associated with the Nové Dvory peridotite mass in the Moldanubian Zone of the Bohemian Massif, Czech Republic. Celestine is closely associated with anhydrite, pyrite, pyrrhotite and chalcopyrite, and those minerals occur in the matrix, where fine -grained omphacite aggregate and kelyphites after garnet develop. A common Sr reservoir in eclogite is known to be epidote, but the maximum pressure -temperature (P -T) conditions of the studied eclogite was estimated as about 1050 -1150 °C, 4.5 -4.9 GPa. In such extremely high P -T conditions, epidote should be unstable. In fact, epidote is absent from most of eclogites in the Moldanubian Zone of Czech Republic. These facts suggest that a Sr -reservoir after the epidote -breakdown in subducting eclogite might be celestine, or its high -P polymorph, although the formation stage of celestine in the study sample and maximum stability limits of celestine are not known. Another idea is that celestine in the study sample was formed at relatively shallow levels after the ascent of the eclogite. In this case, omphacite and apatite would have contained significant amount of Sr under the eclogitefacies conditions. Otherwise, metasomatic infiltration of Sr -rich fluids into the eclogite is necessary for the formation of celestine in order to provide sufficient amount of Sr. A Ba -rich alumino -silicate, probably celsian, was also found as a retrograde product around pyrrhotite in kelyphite and in symplectites mainly composed of augite and plagioclase after omphacite. Several grains of biotite are also present along the margin of garnet and in the symplectites after omphacite. In addition, small amounts of muscovite and amphibole are present in the symplectites after omphacite. These findings suggest that metasomatism with Sr -and Ba -rich fluids may have occurred during decompression of the eclogite and may not be indicative of the UHP history of these rocks.

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Probing the transition between seismically coupled and decoupled segments along an ancient subduction interface

Angiboust

Kirsch

Oncken

et al. 2015

Geochem Geophys Geosyst

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100

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The transition zone at the downdip end of seismic coupling along subduction interfaces is often the site of megathrust earthquake nucleation and concentrated postseismic afterslip, as well as the focus site of episodic tremor and slip features. Exhumed remnants of the former Alpine subduction zone found in the Swiss Alps allow analyzing fluid and deformation processes near the transition zone region (30-40 km paleodepth). The Dent Blanche Thrust (DBT) is a lower blueschist-facies shear zone interpreted as a fossilized subduction interface where granitic mylonites overlie a metamorphosed accretionary wedge. We report field observations from the DBT region where multiple, several tens of meters thick foliated cataclastic networks are interlayered within the basal DBT mylonites. Petrological results and microstructural observations indicate that the various cataclasis events took place at near-peak metamorphic conditions (400-5008C, 1.1-1.3 GPa) during subduction of the Tethyan seafloor in Eocene times (42-48 Ma). Some of these networks exhibit mutual crosscutting relationships between mylonites, foliated cataclasites, and vein systems indicating mutual overprinting between brittle deformation and ductile creep. Whole-rock chemical compositions, in situ 40 Ar age data of recrystallized phengite, and Sr isotopic signatures reveal that DBT rocks also underwent multiple hydrofracturing and metasomatic events via the infiltration of fluids mainly derived from the oceanic metasediments underneath the DBT. From the rock fabrics, we infer strain rate fluctuations of several orders of magnitude beyond subduction strain rates (10 212 s 21) accompanied by fluctuation of supralithostatic and quasi-lithostatic fluid pressures (1 k > 0.95). DBT brittle-plastic deformation switches highlight the diversity of deformation processes and fluid-rock interactions in the transition zone region of the subduction interface.

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Rb/Sr record of fluid-rock interaction in eclogites: The Marun-Keu complex, Polar Urals, Russia

Cited by 102 publications

References 71 publications

A stable (Li, O) and radiogenic (Sr, Nd) isotope perspective on metasomatic processes in a subducting slab

A stable (Li, O) and radiogenic (Sr, Nd) isotope perspective on metasomatic processes in a subducting slab

Sr-sulphate and associated minerals found from kyanite-bearing eclogite in the Moldanubian Zone of the Bohemian Massif, Czech Republic

Probing the transition between seismically coupled and decoupled segments along an ancient subduction interface

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