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During the Variscan orogeny in Central Europe, partial melting in the lower continental crust formed granitic magmas, which intruded into the upper crust and left compounds of Ca (plus [Eu.sup.2+]), Mg, etc. in the lower crust. From the late Paleozoic decomposition of the tonalitic upper crust, sedimentary graywackes were produced reflecting the composition of this crust. The repeated reworking of the sedimentary cover caused the formation of sands. Sandstones as their products of consolidation contain increasing fractions of quartz and decreasing feldspar from Carboniferous and Triassic to Cretaceous age. A distinct negative Eu anomaly characterizes the majority of these rocks. The latter is imprinted by the Variscan magmatism. Quartz as used for numerous Medieval wood ash glasses is marked for its Central European origin by a distinct negative Eu anomaly in contrast to many soda glasses produced outside Germany mostly with a small or none Eu anomaly. Keywords Graywackes * Sandstones * Quartz * Rare earth elements * Medieval glass, We have investigated quartz-bearing coarse-grained sedimentary rocks as originally being formed from tectonic and weathering detritus of the Variscan orogenic mountains in Germany. This orogeny occurred from about 380 to [...]

Byline: Roland Stalder (1,2), Andreas Kronz (1), Klaus Simon (1) Keywords: Enstatite; Hydrogen incorporation; Water activity; Sodium; Chlorine Abstract: The incorporation of hydrogen in enstatite in a hydrous system containing various amounts of NaCl was investigated at 25 kbar. The hydrogen content in enstatite shows a clear negative correlation to the NaCl-concentration in the system. The most favourable explanation is the reduction of water fugacity due to dilution. Other reasons for the limited hydrogen incorporation at high NaCl levels, such as a significant influence of Na.sup.+ on the defect chemistry or an exchange between OH.sup.- and [Cl.sup.-]in enstatite, appear much less important. A partition coefficient D .sub.Na .sup.En/Fluid = 0.0013 could be determined, demonstrating that Na is less incompatible in enstatite than H. The new results support the idea that dissolved components have to be considered when the total hydrogen storage capacity in nominally anhydrous minerals is estimated, especially in geological settings with high levels of halogens, such as subduction zones. Author Affiliation: (1) Geowissenschaftliches Zentrum der Universitat Gottingen, Goldschmidtstrasse 1, 37077, Gottingen, Germany (2) Institut fur Mineralogie und Petrographie, Universitat Innsbruck, Innrain 52, 6020, Innsbruck, Austria Article History: Registration Date: 04/04/2008 Received Date: 01/02/2008 Accepted Date: 04/04/2008 Online Date: 16/04/2008 Article note: Communicated by J. Hoefs.

Byline: Birgit Scheibner (1,2), Gerhard Worner (1), Lucia Civetta (3), Heinz-Gunter Stosch (4), Klaus Simon (1), Andreas Kronz (1) Keywords: Grandite; Ca-rich garnets; Andradite; Rare earth elements; Mt. Somma-Vesuvius; Fractionation; Partition coefficient; Skarn; Hydrothermal; Magma chamber; Phonolite Abstract: Igneous garnets have the potential to strongly fractionate rare earth elements (REE). Yet informations on partition coefficients are very scant, and criteria for distinguishing between hydrothermal and magmatic garnets are ambiguous. To fill this gap, we present trace element and isotopic data for two types of Ca-rich garnets from phonolites (Mt. Somma-Vesuvius). Both Ca-garnet populations are different in their style and dynamics of fractionation: one population is progressively strongly depleted in HREE from core to rim, reflecting REE fractionation in the host phonolite via earlier-crystallized garnets. Such examples for extreme changes in HREE in garnets are only known for hydrothermal grandites by REE-bearing fluids. The second garnet population is homogeneous and formed in a closed system. Near-flat patterns between Sm and Lu confirm experimental data indicating lower D(Sm)/D(Lu) for Ca-rich garnets than for e.g. pyrope-rich garnets. It follows: D .sup.Grt/PhMelt for La = 0.5, Sm = 48 and Yb = 110. Author Affiliation: (1) Geowissenschaftliches Zentrum Gottingen (GZG)--Geochemie, Universitat Gottingen, Goldschmidtstr. 1, 37077, Gottingen, Germany (2) Forschungszentrum Julich, Neue Materialien und Chemie, Wilhelm-Johnen-Strasse 12, 52428, Julich, Germany (3) Instituto Nazionale di Geofisica e Vulcanologia, Osservatorio Vesuviano and Department Scienze Fisiche, Universita di Napoli Federico II, Via Diocleziano 328, 80124, Naples, Italy (4) Institut fur Mineralogie und Geochemie, Universitat Karlsruhe (TH), Fritz-Haber-Weg 2, D-76131, Karlsruhe, Germany Article History: Registration Date: 29/12/2006 Received Date: 30/06/2006 Accepted Date: 19/12/2006 Online Date: 23/02/2007 Article note: Communicated by T. L. Grove.

Byline: Zeming Zhang (1), Yilin Xiao (2), Jochen Hoefs (2), J. G. Liou (3), Klaus Simon (2) Abstract: The main hole (MH) of the Chinese Continental Scientific Drilling Project (CCSD) in southern Sulu has penetrated into an ultrahigh-pressure (UHP) metamorphic rock slice which consists of orthogneiss, paragneiss, eclogite, ultramafic rock and minor schist. Recovered eclogites have a UHP metamorphic mineral assemblage of garnet + omphacite + rutile +- phengite +- kyanite +- coesite +- epidote. Ultramafic rocks contain garnet + olivine + clinopyroxene + orthopyroxene +- Ti-clinohumite +- phlogopite. Gneisses and schists contain an amphibolite-facies paragenesis, but their zircons have coesite, garnet, omphacite (or jadeite) and phengite inclusions, indicating that eclogites and gneisses have been subjected to in situ UHP metamorphism. Using available geothermobarometers, P--T estimates of 3.1--4.4 GPa and 678--816degC for eclogites were obtained. If surface outcrops and neighboring shallow drill holes are considered together, we suggest that a huge supracrustal rock slab (> 50 km long x 100 km wide x 5 km deep) was subducted to a depth > 100 km and then exhumed to the surface. The depth interval (0--2,050 m) of the CCSD-MH can be divided into six lithological units. Unit 1 consists of alternating layers of quartz-rich and rutile-rich eclogites, with thin interlayers of gneiss and schist. Eclogites of unit 1 are characterized by Nb, Ta, Sr and Ti depletions, low Mg number and general LREE enrichment. Unit 2 comprises rutile- and ilmenite-rich eclogite and minor 'normal' eclogite and is characterized by high TiO.sub.2, total Fe, V, Co and Sr, and very low SiO.sub.2, alkali, Zr, Ba, Nb, Ta and total REE contents, and LREE-depleted REE patterns with slightly positive Eu anomalies. Unit 3 contains ultramafic rock and minor MgO-rich eclogite. Protoliths of UHP rocks from units 1, 2 and 3 represent a layered mafic to ultramafic intrusion at crustal depth. Units 4 and 6 consist of interlayered eclogite and paragneiss the eclogites are characterized by Th, U, Nb, Ta and Ti depletion and K enrichment and LREE-enriched REE patterns. Paragneisses show Nb, Ta, Sr and Ti depletions and LREE-enriched REE patterns occasionally with slightly negative Eu anomalies, indicating that their protoliths represent metamorphic supracrustal series. Unit 5 consists mainly of orthogneisses, showing distinct Nb, Ta, Sr and Ti depletions, and LREE-enriched REE patterns with pronounced negative Eu anomalies, suggesting granitic protoliths. In conclusion it is proposed that the southern Sulu UHP belt consists of a series of meta-supracrustal rocks, a layered mafic--ultramafic complex and granites. Author Affiliation: (1) Institute of Geology, Chinese Academy of Geological Sciences, 26 Baiwanzhuang Road, Beijing, 100037, China (2) Geowissenschaftliches Zentrum der Universitat Gottingen, Goldschmittstrasse 1, 37077, Gottingen, Germany (3) Department of Geological and Environmental Sciences, Stanford University, Stanford, CA, 94305, USA Article History: Registration Date: 16/06/2006 Received Date: 05/05/2006 Accepted Date: 26/05/2006 Online Date: 18/07/2006 Article note: Communicated by T. L. Grove

The main hole (MH) of the Chinese Continental Scientific Drilling Project (CCSD) in southern Sulu has penetrated into an ultrahigh-pressure (UHP) metamorphic rock slice which consists of orthogneiss, paragneiss, eclogite, ultramafic rock and minor schist. Recovered eclogites have a UHP metamorphic mineral assemblage of garnet + omphacite + rutile [+ or -] phengite [+ or -] kyanite [+ or -] coesite [+ or -] epidote. Ultramafic rocks contain garnet + olivine + clinopyroxene + orthopyroxene [+ or -] Ti-clinohumite [+ or -] phlogopite. Gneisses and schists contain an amphibolite-facies paragenesis, but their zircons have coesite, garnet, omphacite (or jadeite) and phengite inclusions, indicating that eclogites and gneisses have been subjected to in situ UHP metamorphism. Using available geothermobarometers, P-T estimates of 3.1-4.4 GPa and 678-816[degrees]C for eclogites were obtained. If surface outcrops and neighboring shallow drill holes are considered together, we suggest that a huge supracrustal rock slab (> 50 km long x 100 km wide x 5 km deep) was subducted to a depth > 100 km and then exhumed to the surface. The depth interval (0-2,050 m) of the CCSD-MH can be divided into six lithological units. Unit 1 consists of alternating layers of quartz-rich and rutile-rich eclogites, with thin interlayers of gneiss and schist. Eclogites of unit i are characterized by Nb, Ta, Sr and Ti depletions, low Mg number and general LREE enrichment. Unit 2 comprises rutile- and ilmenite-rich eclogite and minor 'normal' eclogite and is characterized by high Ti[O.sub.2], total Fe, V, Co and Sr, and very low Si[O.sub.2], alkali, Zr, Ba, Nb, Ta and total REE contents, and LREE-depleted REE patterns with slightly positive Eu anomalies. Unit 3 contains ultramafic rock and minor MgO-rich eclogite. Protoliths of UHP rocks from units 1,2 and 3 represent a layered mafic to ultramafic intrusion at crustal depth. Units 4 and 6 consist of interlayered eclogite and paragneiss; the eclogites are characterized by Th, U, Nb, Ta and Ti depletion and K enrichment and LREE-enriched REE patterns. Paragneisses show Nb, Ta, Sr and Ti depletions and LREE-enriched REE patterns occasionally with slightly negative Eu anomalies, indicating that their protoliths represent metamorphic supracrustal series. Unit 5 consists mainly of orthogneisses, showing distinct Nb, Ta, Sr and Ti depletions, and LREE-enriched REE patterns with pronounced negative Eu anomalies, suggesting granitic protoliths. In conclusion it is proposed that the southern Sulu UHP belt consists of a series of meta-supracrustal rocks, a layered mafic-ultramafic complex and granites.

Glassy orthopyroxene granodiorite-tonalite (named pincinite after type locality) was described from basaltic lapilli tuffs of the Pliocene maar near Pincina village in the Slovakian part of the Pannonian Basin. Two pincinite types exhibit a qualitatively similar mineral composition (quartz, [An.sub.20-55] plagioclase, intergranular silicic glass with orthopyroxene and ilmenite, [+ or -] K-feldspar), but strongly different redox potential and formation PT conditions. Peraluminous pincinite is reduced (6-7% of total iron as [Fe.sup.3+] in corundum-normative intergranular dacitic glass) and contains ilmenite with 8-10 mol% [Fe.sub.2][O.sub.3] and orthopyroxene dominated by ferrosilite. High-density (up to 0.85 g/ [cm.sup.3]) primary C[O.sub.2] inclusions with minor [H.sub.2], C[H.sub.4], [H.sub.2]S, CO and [N.sub.2] (< 2 mol% total) are present in Qtz and Plg. Equilibrium PT conditions inferred from the intergranular Opx-Ilm-Glass assemblage and fluid density correspond to 1,170 [+ or -] 50[degrees]C, 5.6 [+ or -] 0.4 kbar, respectively. Metaluminous pincinite is more oxidised (25-27% of total iron as [Fe.sup.3+] in diopside-normative intergranular glass of rhyolite-trachyte-dacite composition) and contains [Fe.sub.2][O.sub.3]-rich ilmenite (17-29 mol%) associated with enstatite. Fluid inclusions are composed of C[O.sub.2]-[H.sub.2]O mixtures with up to 38 mol% [H.sub.2]O. Raman spectroscopy revealed [H.sub.2]S along with dominant C[O.sub.2] in the carbonic phase. Equilibrium PT parameters for the intergranular Opx-Ilm-Glass assemblage correspond to 740 [+ or -] 15[degrees]C, 2.8 [+ or -] 0.1 kbar, respectively. Reducing gas species ( 0.705-0.706, [[delta].sup.18]O > 9% V-SMOW) around alkali basalt reservoir in depths between 17 and 20 km, and around late stage derivatives of the basalt fractionation, intruding the crust up to depths of 10-11 km. Low water activity in the pincinite parental melt was caused by C[O.sub.2]-flux from the Tertiary basaltic reservoirs and intrusions. The anatexis leads to generation of a melt-depleted granulitic crust beneath the Pannonian Basin, and the pincinites are interpreted as equivalents of igneous charnockites and enderbites quenched at temperatures above solidus and unaffected by sub-solidus re-equilibration and metamorphic overprint.

Dispersed quartz veinlets in Proterozolc enderbitic charnockite from Tromoy, Bamble sector (southern Norway), with Ti-concentrations of mostly 80-180 ppm, produce bright blue cathodoluminescence (CL), against contrasting micro-textures of secondary pure quartz with low CL intensity. The textures comprise grain boundary alteration, healed micro-fractures, patches of secondary quartz, and euhedral quartz nuclei. The secondary quartz locally makes up 50% of the total quartz. Trace element analysis has been done by electronprobe micro-analysis (EPMA), laser-induced coupled plasma mass spectrometry (LA-ICPMS), and additional electron-paramagnetic resonance (EPR) spectroscopy. These studies testify systematic trace element reduction and extensive quartz recovery during retrograde metamorphism. We assume healing of a part of the aqueous fluid inclusions during a late thermal event, possible correlated with Paleozoic magmatic activity in the Oslo-Rift. During final cooling, aqueous fluids were largely retrapped in patches of secondary quartz associated with healed fractures, whereas carbonic inclusions (without secondary quartz) may have survived retrograde metamorphism. The variable but generally high salinity of fluid inclusions is assumed to be in part the result of quartz recovery by which ion concentrations were increased in the percentage range.

An alkali feldspar megacryst from a protomylonite has been studied using laser ablation-ICP-mass spectrometry combined with cathodoluminescence imaging, Raman spectroscopy, and electron probe microanalysis. The aim was to determine the original (magmatic) geochemical pattern of the crystal and the changes introduced by protomylonitization. Digital concentration-distribution models, derivative gradient models, and fractal statistics, e.g., Hurst-exponent values are used in a novel way to reveal subtle changes in the trace-element composition of the feldspar. Formation of the crystal is reflected in a slightly chaotic trace-element (Ba, Sr, and Rb) distribution pattern that is more or less characterized by continuous development from a fairly homogeneous environment. Derivative gradient models demonstrate a microdomain pattern. Fractal statistics show that element behavior was changeable, with Ba and Sr always more persistent (continuing) and Rb always less persistent, with the latter showing a tendency to migrate. The variations in the Hurst exponent are, however, too large to be explained by magmatic differentiation alone. The observed element behavior may be explained by structural changes revealed by Raman spectroscopy and CL. In high-strain domains, T-O-T modes become stronger for Si-O-Al than Al-O-Al linkages. Increasing amounts of Al-O-Al defects are demonstrated by cathodoluminescence. Both may result from small-distance diffusion creep, making the crystal geochemical pattern slightly patchy. In turn, the marginal part of the megacryst has a mosaic of randomly orientated, newly crystallized K-feldspars. The re-growth is confirmed by trace-element distribution patterns and fractal statistics which identify an abrupt change in the transformation environment. The novel set of tools used in this study reveals a complicated history of megacryst formation and transformation that otherwise would be difficult to unravel and decipher. Keywords Alkali feldspar megacryst, Geochemistry, Raman spectroscopy, Fractal statistics, 3D depiction, Protomylonite, Introduction The imprint of a variety of petrogenetic processes is typically recorded in the composition and structure of mylonitized granitoids. Such rocks formed during a multistage process will reflect the [...]

Analyses of igneous xenoliths containing high-iron-oxide melt (HIM) indicated that they resulted from crystal fractionation in a deep-crustal chamber of alkali basalt magma. HIM represented a primary magmatic phase. These findings were observed in globules of oxide melts dominated by iron and titanium. Fluid inclusion and mineral composition data showed immiscible separation of the HIM at magmatic temperatures. The HIM separation occurred during clinopyroxene accumulation in an alkali trachybasalt and continued during crystallization of amphibole and K-feldspar.