ACTA MUSEI MORAVIAE - SCIENTIAE GEOLOGICAE 95/1, 2 2010

Abstract
Houzar, S., Cempírek, J., Fojt, B., Gadas, P., Hrazdil, V., Novák, M., Sejkora, J., Škoda, R. (2010): Přehled nových minerálů nalezených na Moravě a ve Slezsku v letech 1985–2009. – Acta Mus. Moraviae, Sci. geol., 1, 95, 5–60.
New minerals found in regions of Moravia and Silesia between 1985 and 2009; a review
Since the last topographic mineralogy review in 1985, the number of mineral species described from Moravia and Silesia rose significantly, especially due to more freqent use of advanced analytical techniques, e.g. EMP or powder XRD. This paper provides their review, based on published information of diverse provenance and quality, as well as on unpublished data of the authors. Problematic determination of several species is discussed. The mineralogical research in past 25 years was focused on several distinct fields. Research of particular rock environment was common, e.g. granitic pegmatites and related granites, primary and secondary minerals of ore deposits, metamorphic rocks (marbles, serpentinites, granulites). Detailed studies of several mineral groups provided valuable scientific data (e.g. tourmaline, axinite, aeschynite, euxenite, jarosite, beryllophosphates, borosilicates, Fe-Mn-Mg phosphates).
Key words: topographic mineralogy, new minerals, Moravia, Silesia, Czech Republic.
Stanislav Houzar*, Jan Cempírek, Vladimír Hrazdil, Department of Mineralogy and Petrography, Moravian Museum, Zelný trh 6, 659 37 Brno, Czech Republic, *shouzar@mzm.cz
Bohuslav Fojt, Petr Gadas, Milan Novák, Radek Škoda, Department of Geological Sciences, Masaryk University, Kotlářská 2, 611 37 Brno.
Jiří Sejkora, Department of Mineralogy and Petrology, National Museum, Václavské nám. 68, 115 79 Praha 1, Czech Republic.

Abstract
Cempírek J., Novák M., Dolníček Z. (2010): Nový výskyt grandidieritu, ominelitu, boralsilitu a Febohatého werdingitu v Horních Borech – přehled. – Acta Mus. Moraviae, Sci. geol., 1, 95, 61–70.
New occurrence of grandidierite, ominelite, boralsilite and Fe-rich werdingite in Horní Bory, Czech Republic – overview
A new occurrence of four anhydrous borosilicates (grandidierite, ominelite, boralsilite, Fe-rich werdingite) was found in Horní Bory quarry, Bory Granulite Massif, Moldanubicum, Czech Republic. The borosilicates were found associated with dumortierite, tourmaline and corundum. They occur in a thin veinlet (Kfs + Qtz ± Pl) cross-cutting a leucocratic, garnet- and kyanite-bearing granulite. Primary grandidierite to ominelite is enclosed in quartz; its crystals are locally overgrown by prismatic aggregates of boralsilite and Fe-rich werdingite. Boralsilite also occurs as separate radial aggregates with Fe-rich werdingite in quartz. Grandidierite-ominelite is commonly rimmed by a narrow zone of secondary tourmaline or is partially replaced by the assemblage tourmaline + corundum ± hercynite. Other accessory minerals in the veinlet involve monazite-(Ce), ilmenite, rutile to Nb-rich rutile, ferberite to Nb,Sc-rich ferberite, srilankite, löllingite, arsenopyrite and apatite.
Key words: borosilicates, grandidierite, ominelite, boralsilite, Fe-rich werdingite, granulite, partial melting, Moldanubicum, Bohemian Massif.
Jan Cempírek, Mineralogicko-petrografické oddělení, Moravské zemské muzeum, Zelný trh 6, 65937 Brno
Milan Novák, Ústav geologických věd, Masarykova univerzita, Kotlářská 2, 611 37 Brno
Zdeněk Dolníček, Katedra geologie, Palackého univerzita, třída 17. listopadu 12, 771 46 Olomouc

Abstract
Houzar, S., Gadas, P., Čopjaková, R., (2010): Minerální asociace geikielit-baddeleyit v dolomitických mramorech moravského moldanubika v kontaktní aureole třebíčského plutonu. – Acta Mus. Moraviae, Sci. geol., 1, 95, 71–82.
Geikielite-baddeleyite in mineral assemblage of dolomite marbles from the contact aureole of the Třebíč Pluton (Moldanubian zone)
Within the inner part of metamorphic aureole of the Třebíč Pluton, geikielite-ilmenite and baddeleyite occur as accessory minerals in spinel-forsterite marbles. The most abundant is geikielite (or Mg-ilmenite) which forms opaque grains up to 1 mm long in dolomite, calcite, forsterite and spinel. Chemical composition of geikielite (XMg ~ 0.55–0.78) varies in contents of Mg (0.557–0.770 apfu), Fe (0.212–0.400 apfu) and Mn (0.004–0.015 apfu), only trace contents of Ca (0.024 apfu), W (~ 0.001 apfu) and Nb (~ 0.002 apfu) were found. Baddeleyite occurs mainly as microscopic grains (<0.1 mm) in calcite or as intergrowths with zirconolite (<0.2 mm). Chemical composition of baddeleyite is simple, as minor elements it contains only Hf (0.013–0.018 apfu) and Ti (0.001–0.025 apfu). Mineral assemblages and mutual relations among the minerals indicate their origin during replacement of phlogopite by spinel and forsterite (± clinohumite). The source of Ti for geikielite was in phlogopite, the source of Zr for baddeleyite remains unknown (probably zircon?). In some cases, geikielite and baddeleyite were most probably consumed during subsequent reactions forming zirconolite and Ti-clinohumite. Zirconolite is, with few exceptions, characteristic for the clinohumite-rich marble. Although provenance of Ti and Zr is more likely inside the marble, their import into the marble from the host rocks can not be excluded due to their increased mobility in K- P- and F-rich fluid.
Key words: baddeleyite, geikielite, zirconolite, marble, mineral assemblage, Moldanubian zone, Czech Republic.
Stanislav Houzar, Department of Mineralogy and Petrography, Moravian Museum, Zelný trh 6, 659 37 Brno, Czech Republic, shouzar@mzm.cz
Petr Gadas, Masaryk University, Kotlářská 2, 611 37 Brno, e-mail: pgadas@centrum.cz
Renata Čopjaková, Czech Geological Survey, Leitnerova 23, 658 69 Brno; and Masaryk University, Kotlářská 2, 611 37 Brno, e-mail: copjakova@sci.muni.cz

Abstract

Potočková, T., Dolníček, Z., Houzar, S., Škrdla, P., Vokáč, M. 2010: Primární zlatonosná mineralizace v okolí Hor u Předína, západní Morava. – Acta Mus. Moraviae, Sci. geol., 1, 95, 83–104.
Primary gold mineralization from Hory near Předín, western Moravia
In the Předín ore district, gold was exploited between 13th and 16th century. Gold-bearing quartz veins penetrate Moldanubian sillimanite-biotite gneisses and quartzites at three sites near Hory village (localities “Štůlně”, “Malý Štítek” and “Zákopy”). The Předín district is characterized by simple mineral assemblages in quartz veins. Fine-grained, ochre-coloured quartz or rarely limonitized white quartz are the typical gold-bearing ores (Štůlně, Malý Štítek). At Zákopy, the gold-bearing white translucent quartz forms tiny veinlets in the quartzite. Besides gold, the only commonly occurring ore mineral is pyrite. Rare primary accessory phases include acanthite, galena, chalcopyrite and unidentified Ni, As, S-bearing phase. Limonite, barite and goethite are supergene minerals. Gold typically fills infrequent small vugs in quartz. It commonly contains 17–34 wt. % Ag which is the only element present in elevated amount. Sporadically, isometric inclusions or tiny veinlets of gold significantly depleted in silver (1.5–4.2 wt. % Ag) were observed. Fluid inclusions were studied in quartz gangues. Only aqueous fluid inclusions were identified, the fluid system is H2O-MgCl2-NaCl with bulk salinity between 2.4 and 9.9 wt. % NaCl eq. The temperatures of homogenization range between 129 and 259 °C for primary inclusions. Both the relatively low homogenization temperatures and apparent absence of volatiles in fluid inclusions are distinctly different from the other gold-bearing mineralizations in Moldanubicum. The origin of goldbearing fluids is probably related to the late-magmatic and/or late-metamorphic fluids, however, the available data do not allow definite conclusion.
Key words: Moldanubicum, gold, electrum, microprobe analyses, quartz vein, fluid inclusions, Czech Republic.
Tereza Potočková, Zdeněk Dolníček, Department of Geology, Palacký University, Třída 17. listopadu 12, 771 46 Olomouc; e-mail: Tereza.Potockova@seznam.cz; dolnicek@prfnw.upol.cz
Stanislav Houzar, Department of Mineralogy and Petrography, Moravian Museum, Zelný trh 6, 659 37 Brno; e-mail: shouzar@mzm.cz
Pavel Škrdla, Lípová 36, 674 01 Třebíč; e-mail: japs@atlas.cz
Milan Vokáč, Muzeum Vysočiny, Masarykovo nám. 55, 586 01 Jihlava; e-mail: vokac@muzeum.ji.cz

Abstract

Kocourková, E., Houzar, S., Hrazdil, V., 2010: Pyromorfit z jihlavského rudního revíru. – Acta Mus. Moraviae, Sci. geol., 1, 95, 105–120.
Pyromorphite from Jihlava ore district (Czech Republic)
The supergene mineral assemblage of the Jihlava district, where Pb-Zn-Ag ores were exploited in the medieval age, is characteristic by pyromorphite occurrences. Pyromorphite forms yellow-green to green hexagonal crystals up to 1 cm in size and sometimes also brown or white, needle-like aggregates overgrowing goethite in quartz or baryte gangue material. It commonly forms oscillatory zoned crystals, with strong variations in Ca content (0.01–0.95 apfu), which is low in brown (<_0.09 apfu) and high in white (<_0.83 apfu) varieties. Some zones already exhibit composition of phosphohedyphane. Major part of the data correspond to almost pure end member, with trace amounts of Al3+ (<_0.03), As5+ (<_0.05), Ba2+ (<_0.02), Fe3+ (<_0.04), Si4+ (<_0.03), S6+ (<_0.01), V5+ (<_0.02), Zn2+ (<_0.04) and (OH–) <_0.09 (all in atom per formula unit). Besides pyromorphite and goethite, the supergene mineral assemblage also contains rare kintoreite, plumbogummite and acanthite. Kintoreite crystallised during dissolutionreprecipitation reactions of pyromorphite in conditions of high Fe activity, while plumbogummite is related to Al-rich solutions. Pyromorphite formed in deeper parts of the oxidation zone due to alteration of galena-bearing ore veins extremely poor in pyrite or pyrrhotite.
Key words: pyromorphite, chemical composition, supergene mineral, Jihlava
Eva Kocourková: Department of Mineralogy and Petrography, Moravian Museum, Zelný trh 6, 659 37 Brno, Czech Republic, retty@centrum.cz.
Stanislav Houzar: Department of Mineralogy and Petrography, Moravian Museum, Zelný trh 6, 659 37 Brno, Czech Republic, shouzar@mzm.cz.
Vladimír Hrazdil: Department of Mineralogy and Petrography, Moravian Museum, Zelný trh 6, 659 37 Brno, Czech Republic, vhrazdil@mzm.cz.

Abstract

Dokoupilová, P., Houzar, S., Sejkora, J. (2010): Minerální asociace na prohořelých odvalech Rosickooslavanského revíru, Česká republika. – Acta Mus. Moraviae, Sci. geol., 1, 95, 121–140.
The mineral assemblages at the abandoned burning spoil-heaps in the Rosice-Oslavany Coalfield, Czech Republic
Mineral assemblages formed recently at the abandoned burning spoil-heaps of the Kukla coal mine in Oslavany and Ferdinand coal mine in Zastávka. They originated in three stages. Pyrometamorphic stage I Tmax >1 100 °C produced hematite, corundum, cristobalite and various glasses (Si-rich sandstone dominant protolith). Minerals of ellestadite group, periclase, magnesioferrite, srebrodolskite, and accessoric cuspidine, kumtyubeite and rondorfite are typical for pyrometamorphosed dolomite-anhydrite-gypsum dominant protolith. Relics of early “fumarolic” phase, with minerals crystallizing from gas exhalations at T >100 °C (sulfur, sal ammoniac), including products of rock decomposition by hot gases, are present only locally. The spoil-heaps cooling stage II produced calcite, aragonite, gypsum and anhydrite. In the final stages III the atmospheric water infiltration and evaporation produced gypsum, jarosite and magnesian sulfates (hexahydrite, and others).
Key words: hematite, periclase, ellestadite, kumtyubeite, sulphates, burning spoil-heaps, pyrometamorphism, Rosice-Oslavany Coalfield, Czech Republic.
Pavla Dokoupilová, Department of Geology, UP Olomouc, Tř. 17. listopadu 12, 771 46 Olomouc, email: pavla.dokoupilova@upol.cz
Stanislav Houzar, Department of Mineralogy and Petrography, Moravian Museum, Zelný trh 6, 659 37 Brno, e-mail: shouzar@mzm.cz
Jiří Sejkora, Department of Mineralogy and Petrology, National Museum, Václavské nám. 68, 115 79, Praha 1, e-mail: jiri_sejkora@nm.cz

Abstract

Gregorová, R. 2010: Osteological and morphological analysis of the scabbardfish Anenchelum glarisianum BLAINVILLE, 1818 (Trichiuridae) from the Menilitic Formation of the Moravian part of West
Carpathians (Oligocene, Rupelian). – Acta Mus. Moraviae, Sci. geol., 1, 95, 141–149, Brno (with Czech summary).
Osteologická a morfologická analýza druhu Anenchelum glarisianum BLAINVILLE, 1818 (Trichiuridae) z menilitového souvrství moravské části Západních Karpat (Oligocén, rupel). A detailed osteological and anatomical analysis of the abundant articulated and disarticulated skeletons of Anenchelum glarisianum BLAINVILLE, 1818 was undertaken. Restoration of the validity of the fossil genus Anenchelum referred previously to recent genus Lepidopus GOUAN, 1770 published by BANNIKOV and PARIN (1995) was confirmed herein on the fossil material from the Moravian part of the Menilitic Formation. It also allowed us to enhance our knowledge of the osteology and morphology of this taxon.
Key words: Menilitic Formation, Carpathians, Anenchelum, Trichiuridae, Oligocene, Rupelian.
Růžena Gregorová. Moravian Museum, Department of Geology and Paleontology, Zelný trh 6, 659 37 Brno, Czech Republic, e–mail: rgregorova@mzm.cz

Abstract

Krmíček, L. (2010): Předmezozoické lamprofyry a související žilné intruze Českého masivu (Česká Republika, Polsko, Německo, Rakousko): komentovaný přehled. – Acta Mus. Moraviae, Sci. geol., 2, 95, 3–61.
Pre-Mesozoic lamprophyres and associated dyke intrusions of the Bohemian Massif (Czech Republic, Poland, Germany, Austria): a review

Abstract

Čopjaková, R. (2010): Vznik autigenního monazitu v drobách kulmu Drahanské vrchoviny ve vztahu k diagenetické teplotě a chemickému složení drob. – Acta Mus. Moraviae, Sci. geol., 2, 95, 63–79.
Authigenic monazite-(Ce) to monazite-(Nd) in the greywackes of the Drahany Upland: formation related to the chemical composition of the greywackes and diagenetic temperature
Poikilitic monazite-(Ce) to monazite-(Nd), irregular in shape, enclosing variety of detrital and authigenic minerals, together with rounded, partly altered detrital monazite, were found in greywackes of the Protivanov Formation, Drahany Upland. Textural evidences suggest authigenic origin of poikilitic monazite. The most likely explanation is that the main source of REE (mainly LREE) in fluids was detrital monazite. Detrital monazite in greywackes of the Protivanov Formation is unstable and underwent a variety of replacement reactions during deep burial with maximal temperature close to 250 °C corresponding to very low-grade metamorphism. The products of the detrital monazite alteration reflect the whole-rock composition of greywackes. Newly-formed poikilitic monazite was observed only in greywackes with low Ca content in the whole-rock compositions. The CHIME dating revealed the precipitation of poikilitic monazite at 324 Ma (± 28 Ma), thus during high-temperature diagenesis. Chemical composition of lowgrade poikilitic monazite significantly differs from that of higher temperature magmatic or metamorphic detrital monazite. Poikilitic monazite shows low concentrations of Th, U, Ca, Y +HREE and weak Eu anomaly. Distribution of the REE in the poikilitic monazite grains shows typical trend. The central part is enriched in Nd, Sm and Gd, whereas the outer part is enriched in La and Ce. Some analyses from the central part yield Nd as dominant REE, therefore it corresponds to monazite-(Nd). Rarely, small core devoid of mineral inclusions with compositional characteristic typical of a high-temperature origin (high Th, U and Y content), interpreted as relict of detrital monazite, was found in central part of poikilitic monazite.
Key words: authigenic monazite; monazite-(Ce); monazite-(Nd); diagenesis; greywackes; Lower Carboniferous Drahany basin.
Renata Čopjaková, Czech Geological Survey, Leitnerova 22, 658 69 Brno, Czech Republic, e-mail: copjakova@sci.muni.cz

Abstract

Fojt, B., .koda, R., Dolni.ek, Z. (2010): Furutobeit a betechtinit z lo.iska Horni Bene.ov v Nizkem Jeseniku. . Acta Mus. Moraviae, Sci. geol., 2, 95, 81.86.
Furutobeite and betekhtinite from the ore deposit Horni Bene.ov in the Nizky Jesenik Mts. . Czech Republic
The occurrence of two rare Pb-Ag-Cu-Fe sulphides, furutobeite and betekhtinite, is described from the Devonian Zn-Pb stratiform deposit of Horni Bene.ov. Both minerals were found within post-metamorphic veinlets (cutting the pyrite-sphalerite-galena stratiform ore) associated with galena, digenite (both forming myrmekitic intergrowths), covellite, pearceite, stromeyerite, tennantite, quartz and barytocalcite. Aggregates of furutobeite, up to 0.4 mm, display significant substitution of Ag for Cu (0.21.1.05 apfu Ag), and slightly elevated content of Zn (0.09.0.17 apfu). Betekhtinite grains, up to X0 �Ęm in diameter, exhibit also elevated Ag and Zn contents (0.09.0.11 and 0.01.0.08 apfu, respectively). The fluid inclusion study of associated quartz indicates the long-lasting fluid activity, which is manifested by the presence of three types of low-temperature (< 200 �‹C) aqueous fluids in primary fluid inclusions: 1) low-salinity Na-Mg-Cl .metamorphic�g fluids; 2) high-salinity Ca-Na-Cl fluids with high NaCl/CaCl2 ratio; 3) high-salinity Ca-Na- Cl fluids with low NaCl/CaCl2 ratio. The role of high-salinity aqueous solutions for remobilization of heavy metals from the stratiform ores, is emphasized generativy giving rise to the Ag-Cu-enriched vein assemblage.
Key words: furutobeite, betekhtinite, mineralogy, fluid inclusions, genesis, stratiform ore deposit, Horni Bene.ov, Bohemian Massif, Czech Republic.
Bohuslav Fojt, Radek .koda . Institute of Geological Sciences, Masaryk University, 613 00 Brno, Kotla.ska 2, Czech Republic, fojt@sci.muni.cz, rskoda@sci.muni.cz
Zden.k Dolni.ek . Department of Geology, Palacky University, 771 46 Olomouc, T.ida 17. listopadu 12, dolnicek@prfnw.upol.cz

Abstract

.koda, R., Stan.k, J. (2010): Gayit z granitickeho pegmatitu od Cyrilova u Velkeho Mezi.i.i, moldanubikum. . Acta Mus. Moraviae, Sci. geol., 2, 95, 87.94 (with English summary).
Gayite from granitic pegmatite at Cyrilov near Velke Mezi.i.i, Moldanubicum
Gayite, a new dufrenite group mineral with Mn as dominant divalent cation was recently described by KAMPF et al. (2010) from beryl-columbite-phosphate type granitic pegmatite in Cordoba province, Argentina. Similar, Mn-dominant member of the dufrenite group occurs in association with natrodufrenite, mitridatite, fluorapatite and crandalite group minerals at the border of the Al-phosphate nodule from Cyrilov pegmatite, whereas its chemical composition differs from the type locality gayite. The elevated content of Ca (0.18.0.33 apfu; 1.20.2.13 wt. % CaO), Mg (. 0.15 apfu Mg (. 0.68 wt. % MgO), variable Al (0.01.1.03 apfu; 0.05.6.14 wt.% Al2O3) and ratio Mn/(Mn+Fe2+) 0.30.0.81 is typical for natrodufrenite to gayite form Cyrilov. Substitution trends are briefly discussed.
Key words: gayite, natrodufrenite, secondary phosphates, EMPA, Cyrilov pegmatite, Moldanubicum.
Radek .koda, Josef Stan.k . Institute of Geological Sciences, Masaryk University, Kotla.ska 2, 611 37 Brno, Czech Republic, email: rskoda@sci.muni.cz

Abstract:

Mücke, A., Fojt, B., Dolníček, Z. (2010): Petrography, mineralogy, geochemistry and genetic aspects of the Lahn-Dill type deposit of Malý Děd (= Leiterberg) in the Devonian Vrbno Group (Silesicum), Czech Republic. – Acta Mus. Moraviae, Sci. geol., 2, 95, 95–129.
Petrografie, mineralogie, geochemie a genetické aspekty ložiska typu Lahn-Dill Malý Děd (= Leiterberg) v devonské vrbenské skupině (silesikum), Česká republika

Abstract:

Buriánek, D. (2010): Metamorfní vývoj metadioritové subzóny v brněnském batolitu. – Acta Mus. Moraviae, Sci. geol., 2, 95, 131–150.
Metamorphic evolution metadiorite subzone in the Brno Batholith
Metadiorite subzone forms the western part of the Central basic belt of the Brno Batholith. It can be interpreted as relic of Neoproterozoic ophiolite complex. Cumulate gabbros, diorites and ultramafic rocks were obducted on to the Thaya terrane and subsequently deformed and/or metamorphosed. The mineral assemblage of rocks forming the metadiorite subzone and the mineral textures (zonation in amphibole, chromite) indicate polyphase metamorphic evolution. Three major metamorphic stages can be distinguished. The first stage comprises a regional metamorphism M1, which reached a greenschist facies grade. The second stage is represented by a contact metamorphism (M2) related to the intrusion of the Cadomian granitoids, with intensity reaching greenschist or up to amphibolite facies. The last stage is characterized by a regional Variscan metamorphism (M3) under prehnite–pumpellyite to greenschist facies conditions. Spinels from ultramafic rocks feature heterogeneous chemical zonation. The degree of chromite grains alteration depends on the chemical composition of coexisting silicates and on the P-T conditions of metamorphism. The individual alteration zones represent different steps of the prograde metamorphism (M2) that affected primary chromitites. The estimated thermal metamorphic conditions for the metadiorites and metagabbros are in agreement with the data obtained from metamorphic assemblage of the ultramafic rocks.
Key words: Brno Batholith, metadiorite subzone, cumulate, chromite, ultramafic rocks, P-T conditions, metamorphic overprint.
David Buriánek,Czech Geological Survey, Leitnerova 22,65859,Brno;CzechRepublic; david.burianek@geology.cz

Abstract:

Buriánek, D. (2010): Metamorfované horniny západní části brněnského batolitu. – Acta Mus. Moraviae, Sci. geol., 2, 95, 151–170.
Metamorphic rocks western part Brno batholith
Biotite and amphibole biotite granitoids of the northern part of Thaya terrane (western part of the Brno batholith) contains large enclaves of polyphase-metamorphosed sedimentary and igneous rocks. The enclaves, up to several km long, consist mainly of biotite to muscovite-biotite gneisses (Qtz + Pl + Bt ± Ms ± Sil ± Ky), biotite to cordierite-biotite migmatites (Qtz + Pl + Bt ± Kfs ± Ms ± Sil ± Crd), metagabbros (Amp + Pl ± Px), calc-silicate rocks (Amp + Pl + Px + Qtz ± Cal ± Grt ± Qtz and Cpx ± Grt ± Ves ± Wo ± Cal ± Qtz ± Pl ± Kfs ± Czo) and amphibolites (Amp + Pl ± Qtz). Three metamorphic events with different P-T conditions are distinguished in the studied rocks. The first stage M1 was marked by regional metamorphism under amphibolite facies conditions (700 °C and 6–7 kbar). Regional metamorphism was followed by a decompression stage and intrusion of Cadomian granitoids of the Thaya terrane (Tetčice suite). P-T estimates for low-pressure contact metamorphism M2 correspond to approximately 700–800 °C and 3–5 kbar. The metamorphic assemblage (Pl + Cpx ± Grt ± Ves ± Wo ± Cal ± Qtz ± Kfs ± Czo) of skarnoid layers from enclaves of calc-silicate rocks indicates high water activity (XCO2 < 0.03) during this metamorphic event. The subsequent Variscan metamorphic overprint (M3) was characterized by regional hydrothermal alteration under prehnite-pumpellyite facie (2–3 kbar and >300 °C ).
Key words: Brno massif, P-T conditions, enclaves, migmatites, metagabbros, calc-silicate rocks, skarnoids.
David Buriánek,Czech Geological Survey, Leitnerova 22,65859,Brno;CzechRepublic; david.burianek@geology.cz