Southern Bohemian Massif Research Articles

At the border of peri-Gondwana and Baltica – the structure of the eastern termination of the Variscan belt

The termination of the eastern Variscan belt has been a matter of long-standing debates since it is deeply concealed beneath younger sediments. Its geometry has been addressed by two competing hypotheses of the Variscan orocline and right-lateral strike-slip tectonics. Therefore, a set of new gravity and magnetic maps was compiled for Czechia, Poland and eastern Germany to track Variscan structures in the subsurface. These maps clearly show that the Rheno-Hercynian Suture turns almost 90° east the of the Harz Mts. and continues into Poland toward the ESE. Therefore, our study favours a concept of semi-orocline that terminates in the east against the Brunovistulian Block. The pattern of magnetic and gravity anomalies combined with geological evidence indicates two stages of accretion superimposed in the eastern Variscan belt. The initial W-E convergence led to the formation of NNE-SSW-trending structures that dominate the southern Bohemian Massif. These structures were overprinted by an important N-S shortening event that shaped WNW-ESE oriented features. The latter run parallel to the Baltica margin and dominate the area NE of the Elbe Fault. This is consistent with seismic data showing large-scale underthrusting of the Baltica crust beneath the Variscan belt at a distance of at least 100 km.

Deformation-induced, retrograde transformation of kyanite to andalusite: An example of felsic granulite in the southern Bohemian Massif

Detailed microstructural, microfabric and chemical analyses of felsic granulite within and around a ductile shear zone at the Plešovice quarry in the southern Bohemian Massif revealed deformation-induced, retrograde transformation of kyanite to andalusite. Although andalusite is absent outside the shear zone, its fraction among Al2SiO5 polymorphs significantly increases up to ∼59% inside the shear zone, while the fraction of kyanite significantly decreases from ∼98% outside the shear zone down to ∼22% inside the shear zone. Three examples of andalusite and the relict kyanite pair suggest a common topotaxial relationship such that andalusite (010) is parallel to the precursory kyanite (100), while andalusite [100] and [001] are parallel to the precursory kyanite [010] and [001], respectively, indicating that the growth of andalusite was crystallographically controlled by the precursory kyanite.The felsic granulite in the ductile shear zone at the Plešovice quarry has been repeatedly subjected to brittle shearing accompanied by pseudotachylite formation and plastic shearing with mylonitization, suggesting development of the ductile shear zone at the brittle–plastic transition zone. Mylonitization of the felsic granulite was promoted by deformation-induced K-feldspar replacement by myrmekite at temperatures of 390–440 °C assuming a pressure of 250 MPa.

Formation of low-pressure reaction textures during near-isothermal exhumation of hot orogenic crust (Bohemian Massif, Austria).

Two types of aluminous paragneiss from the Loosdorf complex (Bohemian Massif, NE Austria) contain coarse-grained granulite assemblages and retrograde reaction textures that are investigated to constrain the post-peak history of the Gföhl unit in the southern Bohemian Massif. Both types have a peak assemblage garnet-biotite-sillimanite-plagioclase-K-feldspar-quartz-granitic melt ±kyanite ±ilmenite ±rutile, recording peak metamorphic conditions of 0.9-1.1 GPa and 780-820°Cestimated by isochemical phase equilibrium modelling. The first sample type (Ysper paragneiss) developed (i) cordierite coronae around garnet and (ii) cordierite-spinel and cordierite-quartz reaction textures at former garnet-sillimanite interfaces. Calculated chemical potential relationships indicate that the textures formed in the course of a post-peak near-isothermal decompression path reaching 0.4 GPa. Texture formation follows a two-step process. Initially, cordierite coronae grow between garnet and sillimanite. As these coronae thicken, they facilitate the development of local compositional domains, leading to the formation of cordierite-spinel and cordierite-quartz symplectites. The second sample type (Pielach paragneiss) exhibits only discontinuous cordierite coronae around garnet porphyroblasts but lacks symplectites. The formation of cordierite there also indicates near-isothermal decompression to 0.4-0.5 GPa and 750-800°C. This relatively hot decompression path is explained by the contemporaneous exhumation of a large HP-UHT granulite body now underlying the Loosdorf complex. The timing of regional metamorphism in the granulites and the southern Bohemian Massif in general is well constrained and has its peak at 340Ma. Monazite from Loosdorf paragneiss samples yield a slightly younger age of 335Ma. Although the ages overlap within error, they are interpreted to reflect near-isothermal decompression and exhumation resulting in the formation of the observed reaction textures.

Graphite thermometry by interactive fitting of Raman spectra

The growth conditions of natural graphite crystals are conventionally estimated by the application of petrological methods on the host rocks. As Raman Spectroscopy records detailed information on the microstructure of a carbon-material, this method is applied empirically to graphite from the southern margin of the Bohemian Massif to investigate the correlation between microstructure and metamorphic peak conditions directly, characterizing an economically important geomaterial. Automated fitting of the second-order Raman-spectrum of graphite assesses the strongly asymmetrical S2-band at ca. 2700 cm−1 by a shape parameter, characterizing the microstructural state of graphite. Applying this concept, a confident parameter (S2-shape) estimates the peak metamorphic temperature of natural graphite crystals between 600 °C and 800 °C. The application in the southern Bohemian Massif maps metamorphic peak temperatures related to Variscan tectonics. Comparing the microstructure of large crystals from graphite seams with tiny crystals dispersed in the rock matrix, there is evidence that small graphite particles are not influenced by a late-stage overprint.

Graphitization during high-grade metamorphism in the southern Bohemian Massif

Raman spectroscopy on carbonaceous matter reconstructs the progressive path of graphitization during granulite facies metamorphism in the Variscan collisional belt of the southern Bohemian Massif. In this area, heating to 650–750 °C gradually altered the graphite microstructure, attributed to a metamorphic field gradient. Late low-pressure and high-temperature metamorphism at temperatures above 800 °C as well as advective heat transport due to rising granulite diapirs improved the graphite lattice ordering significantly. Numerical parameters derived from the Raman spectra of carbonaceous matter, in particular the G-band width and the S2-band dispersion map metamorphic field gradients in high-grade metamorphic terrains.

Geochemical characteristics of the Late Proterozoic Spitz granodiorite gneiss in the Drosendorf Unit (Southern Bohemian Massif, Austria) and implications for regional tectonic interpretations

Geochemical characteristics of the Late Proterozoic Spitz granodiorite gneiss in the Drosendorf Unit (Southern Bohemian Massif, Austria) and implications for regional tectonic interpretations

A genetic classification of caves and its application in eastern Austria

Abstract Based on existing classifications of caves that often involve descriptive terms, a classification is presented that is based purely on genetic processes. An attribute key is developed that allows the classification of caves by means of cave maps, photographs and reports. This method is applied to a dataset of 6007 caves in a study area in eastern Austria. The area comprises diverse geological units of the Eastern Alps and the southern Bohemian Massif. A total of 94% of the caves could be classified with the surprising result that mechanical weathering and erosion caves are almost as common as solution caves even though the vast majority of caves are developed in carbonate rocks. Field checks confirmed the result and showed that the error is acceptable. The classified caves can also be used as indicator of natural phenomena like gravitational mass movements or vulnerable karst areas by decision-makers non-specialized in cave genesis.

Petrography, geochemistry and geochronology of granite hosted rhyodacites associated with a disseminated pyrite mineralization (Arnolz, Southern Bohemian Massif, Austria)

The study focuses on a subvolcanic rhyodacite dyke intruding a fine grained biotite granite and paragneisses of the South Bohemian Massif, part of the Variscan Orogenic Belt in Central Europe. The subvertical dyke strikes NNE, displays a thickness of about 30 m and has been traced by boulder mapping for approximately 7 km. The rhyodacites have been affected by two hydrothermal fluids. An older one of oxidizing condition giving rise to a reddish to brownish type of rock (Type I) and a younger fluid of reducing condition causing a greenish variety (Type II). The hydrothermal alteration is associated with the formation of the clay minerals chlorite, sericite, kaolinite and smectite and a disseminated pyrite mineralization. Bulk chemistries of the rhyodacites emphasize the hydrothermal alterations to be isochemical with the exception of sulphur enriched up to a maximum of 0.6 wt%. Trace element composition of the rhyodacites points to a barren geochemical environment in terms of base and precious elements. Sulphur isotope investigations of pyrites from the rhyodacites and the hosting granites respectively yield d34S data ranging from +0.07 to −2.22 ‰, emphasizing a magmatic origin of the sulphur. Geochronological investigations yield in situ U/Pb zircon ages of 312 ± 4 Ma for the biotite granite and of 292 ± 4 Ma for the rhyodacitic dykes indicating a time gap of ≈ 20 Ma between these two intrusive events. A contemporaneous but geochemically specialized granitic intrusion associated with NW striking “felsitic” dykes occurs about 10 to 20 km to the NW of Arnolz. However, the rhyodacites around Arnolz differ significantly from these felsitic dykes in their geochemistry and alteration phenomena which points to a different magmatic source. This coincides with a change in the orientation of the dykes from a NW direction controlling the geochemically specialized intrusions in the NW to a dominating NNE direction mirrored by the studied rhyodacites at Arnolz.

Evolution history of pelitic gneiss and HP-granulites in the Moldanubian Zone of the southern Bohemian Massif.

Evolution history of pelitic gneiss and HP-granulites in the Moldanubian Zone of the southern Bohemian Massif.

The Blaník Gneiss in the southern Bohemian Massif (Czech Republic): a rare rock composition among the early palaeozoic granites of Variscan Central Europe

Metamorphosed and deformed tourmaline-bearing leucogranites with a Cambro-Ordovician formation age are widespread in the Monotonous Group of the Variscan southern Bohemian Massif, Czech Republic. The rocks, known locally as Blanik gneiss, are strongly peraluminous and classify as phosphorus-rich low-T, S-type granite. The magma formed from a metapelitic source, most likely through muscovite dehydration melting. With respect to its low-T origin and the abundance of tourmaline, the Blanik gneiss is exotic within the spectrum of Early Palaeozoic granites of the Variscan fold belt of Central Europe. Coeval granitic gneisses in the neighbouring Gfohl unit of the Bohemian Massif can be classified as higher T S-type granites and were probably generated through biotite dehydration melting. The geochemical differences between the Early Palaeozoic granitic magmatism in the Gfohl unit and the Monotonous Group support models claiming that these two geological units belonged to independent peri-Gondwana terranes before the Variscan collision. It is suggested here, that the Gfohl unit and the Monotonous Group represent zones of higher and lower heat flow within the Early Palaeozoic northern Gondwana margin, respectively. The geochemical data presented in this study could be helpful for terrane correlations and palaeogeographic reconstructions.

Fluid evolution history in pelitic gneiss in the Moldanubian Zone of the southern Bohemian Massif.

Fluid evolution history in pelitic gneiss in the Moldanubian Zone of the southern Bohemian Massif.

How well do pseudosection calculations reproduce simple experiments using natural rocks: an example from high-P high-T granulites of the Bohemian Massif

This study represents a comparison between thermodynamic calculations (pseudosections) and the results of the experimental investigation of high-P/high-T granulites from the Bohemian Massif by Tropper et al. (2005). The experiments were conducted at 7501000°C at 1.6 GPa, 950°C, 1.4 GPa and 800-900°C at 1.2 GPa in order to model the high-P/high-T evolution of the south Bohemian granulites. Tropper et al. (2005) used granitic gneiss as starting material whose chemical composition almost perfectly matched the main granulite type of the Southern Bohemian Massif. To test the validity of the experiments pseudosection calculations using the programs THERIAK-DOMINO and PERPLEX were performed in the chemical system K O-Na O-CaO-FeO-MgO-MnO-Al O -TiO -SiO 2 2 2 3 2 2 H O (KNCFMMnTiASH). The calculations revealed that the experimentally obtained phase assemblages could very well be reprodu2 ced despite the use of different activity models for solid solutions, compositional trends of garnet and feldspars good to satisfactorily. The calculations revealed two major inconsistencies: 1.) the stability of biotite is underestimated in the experiments by ca. 50-100°C and 2.) the amount of melt generated in the experiments is much larger than in the calculations. The reasons for these inconsistencies can be explained by: 1.) electron microprobe analysis of micas from the run products which revealed high F-contents not analyzed previously by Tropper et al. (2005), which is not accounted for in relevant biotite activity models, and by: 2.) the nature of the experimental set-up (lack of eqilibrium in the subsolidus region and fast reaction overstep) which is responsible for generation of abnormously high amounts of melts. Nonetheless the combination of experimental and thermodynamic investigations and its comparison to natural rocks allows gathering deeper insights into the metamorphic evolution of these high-P/high-T granulites.

Thermal and mechanical behaviour of the orogenic middle crust during the syn‐ to late‐orogenic evolution of the Variscan root zone, Bohemian Massif

AbstractWe combine structural observations, petrological data and 40Ar–39Ar ages for a stack of amphibolite facies metasedimentary units that rims high‐P (HP) granulite facies felsic bodies exposed in the southern Bohemian Massif. The partly migmatitic Varied and Monotonous units, and the underlying Kaplice unit, show a continuity of structures that are also observed in the adjacent Blanský les HP granulite body. They all exhibit an earlier NE−SW striking and steeply NW‐dipping foliation (S3), which is transposed into a moderately NW‐dipping foliation (S4). In both the Varied and Monotonous units, the S3 and S4 foliations are characterized by a Sil–Bt–Pl–Kfs–Qtz–Ilm±Grt assemblage, with occurrences of post‐D4 andalusite, cordierite and muscovite. In the Monotonous unit, minute inclusions of garnet, kyanite, sillimanite and biotite are additionally found in plagioclase from a probable leucosome parallel to S3. The Kaplice unit shows rare staurolite and kyanite relicts, a Sil–Ms–Bt–Pl–Qtz±Grt assemblage associated with S3, retrogressed garnet−staurolite aggregates during the development of S4, and post‐D4 andalusite, cordierite and secondary muscovite. Mineral equilibria modelling for representative samples indicates that the Varied unit records conditions higher than ~7 kbar at 725 °C during the transition from S3 to S4, followed by a P−T decrease from ~5.5 kbar/750 °C to ~4.5 kbar/700 °C. The Monotonous unit shows evidence of partial melting in the S3 fabric at P−T above ~8 kbar at 740–830 °C and a subsequent P−T decrease to 4.5–5 kbar/700 °C. The Kaplice unit preserves an initial medium‐P prograde path associated with the development of S3 reaching peak P−T of ~6.5 kbar/640 °C. The subsequent retrograde path records 4.5 kbar/660 °C during the development of S4. 40Ar–39Ar geochronology shows that amphibole and biotite ages cluster at c. 340 Ma close to the HP granulite, whereas adjacent metasedimentary rocks preserve c. 340 Ma amphibole ages, but biotite and muscovite ages range between c. 318 and c. 300 Ma. The P−T conditions associated with S3 imply an overturned section of the orogenic middle crust. The shared structural evolution indicates that all mid‐crustal units are involved in the large‐scale folding cored by HP granulites. The retrograde P–T paths associated with S4 are interpreted as a result of a ductile thinning of the orogenic crust at a mid‐crustal level. The 40Ar–39Ar ages overlap with U–Pb zircon ages in and around the HP granulite bodies, suggesting a short duration for the ductile thinning event. The post‐ductile thinning late‐orogenic emplacement of the South Bohemian plutonic complex is responsible for a re‐heating of the stacked units, reopening of argon system in mica and a tilting of the S4 foliation to its present‐day orientation.

Improved calibrations for Raman-spectroscopic determinations of CO2 in cordierite using three excitation wavelengths (488, 515 and 633 nm)

Ten natural cordierite single crystals with X Fe in the range 0.044–0.76 and 0.12 to 1.97 wt% CO 2 were investigated with Raman microspectroscopy using three different wavelengths. Improved calibration diagrams for CO 2 determinations in single crystals and thin sections for the 488, 515 and 633 nm laser excitation wavelengths show significantly lower standard deviations for CO 2 determinations (±0.04 to 0.07 wt%) compared to an earlier study done solely at 633 nm. The diagrams are based on the linear relationship between CO 2 in wt.% and the ratios of the Raman peak of CO 2 to two Si-O-stretching vibrations. The consideration of orientation dependencies and the improvement of background corrections and spectra fitting procedures also contributed to the significantly higher precision. Because Fe-incorporation in cordierite leads to structural changes that result in Raman peak shifts and peak broadening, including peaks considered in this investigation, a correction was introduced for precise CO 2 determination on Fe-bearing samples. This improved CO 2 determination method was then applied on a 2D spatial scale to two cordierite grains in a thin section of a granulite-facies metapelite from Kosseldorf in the Sauwald area (southern Bohemian Massif, Upper Austria), which yielded CO 2 contents of 0.27–0.31 ±0.07 wt%.

Apatite fission-track dating and low-temperature history of the Bavarian Forest (southern Bohemian Massif)

Apatite fission-track (AFT) dating applied to uplifted Variscan basement blocks of the Bavarian Forest is employed to unravel the low-temperature history of this segment of the Bohemian Massif. Twenty samples were dated and confined track lengths of four samples were measured. Most samples define Cretaceous APT ages between 110 and 82 Ma (Albian to Campanian) and three samples give older ~148–140 Ma (Jurassic–Cretaceous boundary) ages. No discernible regional age variations exist between the areas north-east and south-west of the Pfahl shear zone, but >500 m post-Jurassic and post-Cretaceous vertical offsets along this and other faults can be inferred from elevation profile analyses. The AFT ages clearly postdate the Variscan exhumation history of the Bavarian Forest. Thermal modeling reveals that the ages are best explained by a slight reheating of the basement rocks to temperatures within the apatite partial annealing zone during the middle and late Jurassic and/or by late Cretaceous marine transgression causing burial heating, which affected marginal low-lying areas of the Bohemian Massif and the Bavarian Forest. Late Jurassic period was followed by enhanced cooling through the 120–60 °C temperature interval during the subsequent exhumation phase for which denudation rates of ~100 m myr−1 were calculated. On a regional scale, Jurassic–Cretaceous AFT ages are ubiquitous in marginal structural blocks of the Bohemian Massif and seem to reflect the exhumation of these zones more distinctly compared to central parts.

Upper-mantle structure beneath the southern Bohemian Massif and its surroundings imaged by high-resolution tomography

Upper-mantle structure beneath the southern Bohemian Massif and its surroundings imaged by high-resolution tomography

Morphometric analysis of a reactivated Variscan fault in the southern Bohemian Massif (Budějovice basin, Czech Republic)

Quantitative geomorphic parameters are used to assess active vertical displacements at the NW–SE striking Hluboká fault and the NNE–SSW striking Rudolfov fault in the southern Bohemian Massif. The faults are part of a late Variscan fault system that was repeatedly reactivated in Mesozoic, Miocene, and Pliocene times forming the margins of the Budějovice basin. This basin is filled with up to 340-m-thick Cretaceous to Quaternary sediments and forms morphological lowland surrounded by hill country.We compared the basin-facing hillslopes along the faults with other slopes that are not fault-controlled. All creeks and drainage basins share similar geological and hydrological settings and the common base level of the Vltava River. Morphological differences in valley shapes, stream profiles, and drainage basin geometry therefore are likely to reflect different uplift of the crystalline basement with respect to the Budějovice basin.All calculated geomorphic parameters characterise the hillslope along the Hluboká fault as a very straight mountain–piedmont junction with a morphology that is influenced by uplift along the fault. Differential uplift is indicated by extremely low values of mountain front sinuosity (Smf 1.01 to 1.06), high stream length gradients (SL up to 200), and very low valley floor width to height ratios (Vf 0.05 to 0.26). The values are clearly distinct from the values observed at the other hillslopes. Streams showing convex-up thalweg sections with marked single knickpoints close to the Hluboká fault and previously published geodetic data (Vyskočil, 1973) support the interpretation of active vertical fault displacement. Values observed at the Hillslope crossing the Rudolfov fault (Smf 1.17 to 2.20, SL up to 130, Vf 0.29 to 2.5) and convex-up stream profiles of creeks crossing the fault may classify the slope along the Rudolfov fault as moderately active. The interpretation is again corroborated by published geodetic data.The analysed part of the margin of the Budějovice basin that is not fault controlled revealed geomorphic parameters that are not indicative for differential vertical displacements (Smf 1.30 to 4,16, SL up to 57, Vf 2.10 to 4.80). Concave-up stream profiles of creeks draining into the basin are characteristic for equilibrated streams.

Supercooled melt inclusions in lower-crustal granulites as a consequence of rapid exhumation by channel flow

Here we report on the unexpected occurrence of felsic (granitic) inclusions with quench textures such as spherulite and dendrite (hereafter referred to as “felsite inclusions”), similar to some volcanic rocks, within garnet in presumably “slowly cooled” lower-crustal granulites of various geologic ages ranging from Early Proterozoic to Middle Paleozoic and wide global distribution (the Limpopo Belt, the Grenville Province, the Lützow-Holm Complex of East Antarctica, the Highland Complex of Sri Lanka, and the southern Bohemian Massif). The well-preserved textures of felsite inclusions are indicative of melts formed by anatexis during high-pressure and high-temperature metamorphism, crystallization under far-from-equilibrium conditions (at >50°C undercooling) and subsequent rapid cooling. The occurrence of felsite inclusions in granulites in restricted tectonostratigraphic zones in Sri Lanka, among other examples, may be the first geologic evidence for fast exhumation of lower-crustal rocks to andalusite-stable upper-crustal conditions by channel flow in a continental collision orogen. We hypothesize that granulites ascend episodically along discrete high-strain zones and cool as fast as some felsic magmas. This conclusion sheds new light on the debate regarding the deep crustal processes and necessitates changes to fundamental beliefs about exhumation rates based on rates of plate convergence (1–10cm/year).

Pleistocene terraces of the Vltava River in the Budějovice basin (Southern Bohemian Massif): New insights into sedimentary history constrained by luminescence data

We studied Quaternary sediments from the Budějovice basin in southern Bohemia, now being able to reconstruct the landscape formation of this area during the late Pleistocene. The main objective of this study was to map fluvial terraces of the rivers Vltava and Malše in the basin and to constrain their ages by luminescence dating. Topographic data from a high-resolution DEM in combination with lithological profiles of more than 1000 boreholes allowed identifying five terrace levels (BB 1 to BB 5) with bases ranging from 7m below to 26m above the recent mean water level of the Vltava River. For the lowermost terrace level BB 1, a consistent stratigraphy with ages ranging between 84.5±9.0ka and 7.9±0.8ka was constrained. Additionally, we obtained luminescence ages of alluvial fan and colluvial deposits, which allow us to better constrain the late Pleistocene sedimentation history of the study area. Based on the spatial distribution of derived ages, the terrace level BB 1 represents a complex sediment body incorporating more distinct packages of river aggradation. The presence of stacked fluvial deposits of Pleistocene age underneath the recent floodplain points to an ongoing subsidence or relative tectonic stability of the Budějovice basin during the late Pleistocene.

Accessory minerals in igneous and metamorphic rocks

This issue is devoted to papers on accessory minerals contributed to the Accessory Minerals Session at the 20th General Meeting of the International Mineralogical Association held in Budapest 21–27 August 2010. The themes included in this special issue not only cover many aspects of the mineralogy and crystal chemistry of zircon, monazite, magnetite, beryl, sphene, columbite, and Nb-Ta oxides but also utilize these accessory minerals as a tool for solving a series of very complex geological problems. Overall the session and this issue cover accessory minerals from a wide range of magmatic and metamorphic rocks. Novak et al. describe the behaviour of beryl during metamorphic induced hydrothermal activity. Here euhedral, gem quality, large, blue beryl crystals, up to 2 cm in diameter, formed in syntectonic, quartz-calcite veins in lowgrade, metamorphic, Fe-rich host rocks, which are primarily enriched in Be and Li, and where CO2 was the major agent for Be mobility. In Chudik et al. complex Nb-Ta(-Sn) mineral assemblages from a granite, beryl-rich pegmatite are described. Comparison is made with similar mineral assemblages in other pegmatite bodies from the Western Carpathians in order to link mineralizing potentials between the various occurrences in this region. Colombini et al. deal mainly with sphene stability and saturation in rhyolites from southern Nevada, USA, where they estimate sphene/ melt partition coefficients in conjunction with co-existing zircon saturation and zircon/melt partition coefficients. The results from this study have implications regarding the petrogenesis and geochemical modelling of felsic igneous systems. Krenn et al. present results from monazite dating which they use to constrain the timing of ore mineralization in the eastern Tauern Window, Austria. The results indicate that monazite can occasionally take in large amounts of S and common Pb, with the latter constituting an appreciable peril for EMPA dating. In Friedl et al. new constraints on Variscan HP-HT metamorphism are determined for granulite facies rocks from the southern Bohemian massif, based on zircon zoning patters. The metamorphic overgrowths of these zircons originated in two evolutionary stages consisting of an inner shell with higher U and an outer shell with lower U. Fluorapatite megacrysts, from the Gloserheia pegmatite, S Norway, which contain xenotime and monazite inclusions are described by Harlov. Formation of these inclusions is interpreted as being due to fluid-aided coupled dissolution-reprecipitation processes sometime during late subsolidus cooling of the pegmatite. Later, fluid-aided Ostwald ripening of these inclusions within the fluorapatite resulted in a scattering of a few large inclusions in areas of the fluorapatite devoid of numerous small inclusions. Broska and Petrik utilize Fe-Ti oxides for the mapping of I-type granite suites. Including pre-mixing and post-mixing Fe-Ti-oxides and their oxidation products in granitoids, this paper demonstrates assimilation processes in granites via common Fe-Ti-oxide, fluorapatite, and titanite assemblages. Burda and Klotzli present cathodoluminescence images and LA-ICP-MS U-Pb analyses of zircons from orthogneiss F. Finger (*) Department of Materials Engineering and Physics, University of Salzburg, 5020 Salzburg, Austria e-mail: Friedrich.Finger@sbg.ac.at