Czech eclogites: Terrane settings and implications for Variscan tectonic evolution of the Bohemian Massif

Medaris, Gordon; Jelínek, Emil; Mísař, Z.

doi:10.1127/ejm/7/1/0007

Cited by 103 publications

(89 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…5). This points to a intermediate to lower nrf"'"""rp as is common in other (Messiga et al , 1992;Medaris et al , 1995} Plagjoc!ase Most of the is found defining coronas around garnet, thus suggesting a post-eclogitic character 2). Nevertheless, three textural types of were inclusions, coronas and matrix.…”

Section: Cunopyroxenementioning

confidence: 91%

Eclogite facies relics in metabasites from the Sierra de Guadarrama (Spanish Central System): P-T estimations and implications for the Hercynian evolution

Barbero

Villaseca

2000

Mineral. mag.

View full text Add to dashboard Cite

Relics of HP-MT eclogitic assemblages related to the first metamorphic stage of the Hercynian nrr"TP'TlU in the Sierra de Guadarrama (Spanish Central SCS) are as boudins of IJi'-' -'JJLU-V metabasites enclosed by felsicTextures indicate a iHUUU--'H('Ll<.'-' metarnolrph the MT eclogite facies (as deduced from the presence of and rutile included in garnet) and through medium to Iow pressure and retrograde amphibolite-greenschist facies. Thermobarometric calculations in the ecIogitic yield pressures of -14 kbar for ternp,eraLtUlres in the range 725-775°C.for the indicates a Sl.ll� nlltlC,;m( drop in (P < 10 kbar) for similar temperatures vary from gab bro to lellCC)tonaJlltc:s showing the typical Fe enrichment of the tholeiitic series. Chemical characteristics indicate a derivation from low-pressure of tholeii tic melts more enriched than typical MORB compositions. Their original location far from continental margins as evidenced by the absence of ophiolitic material in the area and their association with platform sediments suggests that eclogitization was related to intracontinental crustal subduction and The P-T conditions estimated in the metabasites for the first metamorphic stage are similar to ones deduced for the metasediments and suggest that the Hercynian crust could have reached a thickness of -70-80 km, which is more than the double the present thickness.

show abstract

Section: Cunopyroxenementioning

confidence: 91%

Eclogite facies relics in metabasites from the Sierra de Guadarrama (Spanish Central System): P-T estimations and implications for the Hercynian evolution

Barbero

Villaseca

2000

Mineral. mag.

View full text Add to dashboard Cite

show abstract

“…Although the stable P -T conditions of epidote in eclogite are not well -known, further subduction of eclogite to deeper levels (>> 100 -km depth) probably destabilizes epidote and releases fluid with Sr. Indeed, epidote and other high -P hydrous phases are mostly absent from eclogites in the Moldanubian Zone of Czech Republic (Medaris et al, 1995), which is probably due to the extremely high -P and high -T (>4 GPa, 1000 °C) metamorphic conditions that they suffered. Under such high -P and high -T conditions, almost all hydrous phases including epidote would have been decomposed and disappeared from the eclogites.…”

Section: Discussionmentioning

confidence: 99%

“…The Moldanubian Zone is subdivided into the Monotonous and Varied units and the structurally overlying Gföhl unit (e.g., Franke, 1989). Metamorphic grade is generally higher in the Gföhl unit than in the Monotonous and Varied units (e.g., Medaris et al, 1995). The Gföhl unit mainly consists of felsic granulite and migmatitic Medaris et al (2006).…”

Section: Geological Settingmentioning

confidence: 99%

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

View full text Add to dashboard Cite

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.

show abstract

“…Metamorphic evolution in the Strážek Unit is similar to the metamorphic record in other parts of the Moldanubian Zone. High-temperature and high-pressure conditions identified in granulites, eclogites and garnet peridotites were followed by the nearly isothermal decompression at high temperatures (Medaris et al 1995;Owen and Dostal 1996;Tajčmanová et al 2006). The structural pattern of the Strážek Unit is defined by three superimposed regional metamorphic foliations with associated mineral lineations: (i) earlier, steeply dipping foliation with regional ~NNE-SSW strike is heterogeneously reworked into (ii) flat-lying fabric occurring in the central part of the Strážek Unit and (iii) gently to moderately ~NE or ~SW dipping metamorphic foliation, defining the northern boundary of the Moldanubian Zone, bearing a ~NW-SE trending mineral lineation (Fig.…”

Section: North-eastern Part Of the Moldanubian Zonementioning

confidence: 99%

“…The northeastern part of the Moldanubian Zone (designated as the Strážek Unit) is composed of migmatized paragneisses with calc-silicate intercalations and migmatites with a amphibolite layers (Medaris et al 1995;Owen and Dostal 1996;Hanžl ed. 2008).…”

Section: North-eastern Part Of the Moldanubian Zonementioning

confidence: 99%

Tectonometamorphic features of geological units along the northern periphery of the Moldanubian Zone

Verner¹,

Buriánek²,

Vrána³

et al. 2012

J. Geosci.

View full text Add to dashboard Cite

In this paper are reviewed structural, petrological and geochronological data from the main units at the NE periphery of the Moldanubian Zone, i.e. Kutná Hora Complex, Svratka Unit, Polička and Zábřeh units, as well as the Strážek Unit of the Moldanubian Zone. In this domain of the Bohemian Massif, the lower-and upper-crustal units are dominated by metamorphic fabrics produced during the Variscan orogeny. The mid-to upper-crustal Svratka, Polička and Zábřeh units are affected by ~MP/MT "long-lived" (~350-339 Ma) tectonometamorphic event reflecting ~WNW-ESE right-lateral strike-slip shearing (transpressional to transtensional tectonics). These regional fabrics are in the Polička and Zábřeh units related with syn-tectonic emplacement and crystallization of calc-alkaline intrusions (Zábřeh Intrusive Complex, Miřetín nad Budislav plutons). In the three structurally high units in the Kutná Hora Complex, Orlice-Sněžník and the Strážek units the strike-slip, "long-lived" tectonics is rather localized; the high-pressure, high-temperature events followed by heterogeneous and polyphase exhumation of deep-seated rocks to mid-crustal levels are preserved. Ultrapotassic rocks (durbachites) of the Strážek Unit, dated at ~339 Ma, intruded posttectonicaly.

show abstract

Czech eclogites: Terrane settings and implications for Variscan tectonic evolution of the Bohemian Massif

Cited by 103 publications

References 0 publications

Eclogite facies relics in metabasites from the Sierra de Guadarrama (Spanish Central System): P-T estimations and implications for the Hercynian evolution

Eclogite facies relics in metabasites from the Sierra de Guadarrama (Spanish Central System): P-T estimations and implications for the Hercynian evolution

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

Tectonometamorphic features of geological units along the northern periphery of the Moldanubian Zone

Contact Info

Product

Resources

About