Grade Upwards Research Articles

Overlapping events in the Acoculco geothermal system, Puebla, Mexico

The Acoculco geothermal system records two major hydrothermal events (prograde skarn overlapped by retrograde/”epithermal” to geothermal stages) in association with pre-calderic to calderic events in the eponymous complex, which belongs to the Trans-Mexican Volcanic Belt. The prograde skarn is associated with a hornblende granite (hereby dated at 1.01 ± 0.01 Ma; U-Pb zircon age), whose apex is found at a ∼1600 m depth, and later andesite dykes and sills. Mineralizing fluids in this stage have salinities of fluid inclusions that range between 9.5 wt.% NaCl equiv. and 33 wt.% NaCl and temperatures of homogenization (Th) up to 470 °C that record various process of mineral formation, such as boiling, depressurization, conductive cooling, isothermal mixing, and dilution. The retrograde stage is represented by early “fossil” brines with salinities 1.4 and 7.3 wt.% NaCl equiv. and Th up to 303 °C, and present-day gasothermal fluids that attain stabilized temperatures up to ∼300 °C at a depth of almost 2000 m. Th of early brines are consistently higher than stabilized temperatures at most of the depths that were surveyed, the isotherms that correspond to 250° and 200 °C dropped ca. 500 m from the early retrograde to the gasothermal stage. These features support the hypothesis that the Acoculco geothermal system has entered its senile stage. Despite that, upon a calculated geothermal gradient at ∼150 °C/km for both Th of the early retrograde stage and stabilized temperatures in the EAC-1 well, it is not foreseen a rapid waning of the thermal anomaly and its ultimate cause.Besides the early Ca-silicate assemblages that constitute the skarn, the architecture of alteration assemblages also records the overlapping of shallow on deep hypogene assemblages. The deep hypogene assemblages respond to alkaline to moderately acidic fluids that correspond to the early retrograde (or “epithermal”) stage: propylitic, phyllic and argillic (kaolinite + nontronite + montmorillonite), from bottom to top. Contrastingly, the shallow hypogene assemblages respond to dominantly acidic fluids, and consist of advanced argillic assemblages that may grade upwards into argillic (kaolinite + illite-smectite) or silicic (vuggy or massive to brecciated silica). The shallow hypogene character of advanced argillic assemblages, as due to steam-heated ground environments (as opposed to deep hypogene or magmatic-hydrothermal assemblages), is deduced from (1) the overall tabular shape of their distribution, (2) the mineralogical association and characteristics of rhombohedral alunite within it, and (3) its relationship with overlying silicic alteration that, in turn, do not possess likely characteristics of sinters. Shallow hypogene advanced argillic assemblages are associated with the present-day gasothermal activity due to sealing that was possibly promoted during the early retrograde/”epithermal” activity.

Stratigraphy, palaeogeography and evolution of the lower Nanaimo Group (Cretaceous), Georgia Basin, Canada

AbstractThe Cretaceous lower Nanaimo Group in the Georgia Basin, Canada comprises multiple depositional phases with distinct depocentres that accumulated in a tectonically active forearc basin setting. Basal coarse‐clastic strata are preserved in paleotopographic depressions and grade upwards into coal‐bearing coastal plains and shallow‐marine deposits. Coal‐bearing and shallow‐marine strata grade laterally into and are overlain by, regionally extensive mudstones and turbidites deposited in deep water. A glauconitic sandstone bed within the deep‐water strata is interpreted as a condensed section and underlies a major disconformity that developed during a pause in the deposition of the lower Nanaimo Group. A second major coarse‐clastic succession occurs hundreds of metres above the glauconite bed in the central Georgia Basin and comprises conglomerate, sandstone, mudstone and coal deposited in continental depositional environments. The shift in sedimentation from the northern Georgia Basin to the central Georgia Basin is interpreted to record the emergence of an island (Nanoose Uplift) in the central Georgia Basin that acted as a major sediment source to the adjacent depocentres. The stratigraphic break between the coal‐bearing coarse‐clastic strata in the northern Georgia Basin and the significantly younger coal‐bearing coarse‐clastic strata in the central Georgia Basin indicates that the lower Nanaimo Group was deposited in distinct depocentres. Between the older, coarse‐clastic strata in the north and younger, coarse‐clastic strata in the central Georgia Basin, we hypothesize that a major deepwater canyon system (Qualicum Canyon) existed and transferred sediment from the semi‐restricted Georgia Basin to the Pacific Ocean to the west. Development of the Qualicum Canyon and exposure of the Nanoose Uplift during deposition of the younger, central coarse‐clastic strata suggests that syntectonic activity drove basin uplift and erosion and this occurred throughout the deposition of the lower Nanaimo Group.

Development of a Middle–Late Holocene subaqueous clinoform in the northern Jiangsu coastal zone, western South Yellow Sea

The northern Jiangsu coastal zone (NJCZ) is part of the western coast of the South Yellow Sea and is located between the mouths of the Yellow and Yangtze rivers. The two rivers and the Huaihe River have discharged into the NJCZ at various times during the Holocene. As a result, multi-stage deltas and clinoforms have developed in the NJCZ, including the old Yellow River delta (OYRD) (1128–1855 CE). An old clinoform has recently been identified just below the OYRD, but its age and origin are uncertain because of limited data. In this study, integrated analyses of a new borehole core SYS-1601 penetrating the clinoform were conducted to document the evolution of the NJCZ and to provide a study case for other coastal regions influenced by major river systems and complex hydrodynamic conditions. Analyses included accelerator mass spectrometry (AMS) 14C and optically stimulated luminescence (OSL) dating, measurements of grain size and Sr-Nd isotopes, and identification of benthic foraminifera and ostracoda. Results show that the evolution of the subaqueous clinoform prior to the development of the OYRD in the western South Yellow Sea was concurrent with and genetically linked to the formation of the Huaihe delta on the NJCZ. The clinoform started to form at the same time as the Middle Holocene maximum flooding of the NJCZ at ∼7.0 ka. Cross-shelf progradation of the clinoform was coeval with progradation of the Huaihe delta and terminated at 1128 CE, when the Yellow River changed course and started to discharge off the Jiangsu coast to form the OYRD. The clinoform exhibits an overall coarsening-upward succession, comprising clayey silt and silt in the lower part grading upwards into silt and sandy silt, and its sediment was sourced largely from the Huaihe and Yangtze rivers. During the development of the clinoform from ∼7.0 ka to 1128 CE, the Yellow River did not flow into the South Yellow Sea through the Jiangsu coast for a sufficiently long time to contribute a substantial amount of sediment to the formation of the clinoform. The initiation and evolution of the clinoform were controlled mainly by complex interactions of dynamic processes, geomorphological conditions, and sediment supply into the western South Yellow Sea during the Middle–Late Holocene.

Litologie a paleopůdy klikovského souvrství ve vrtu 2140 01T1 Dunajovice, třebonská pánev

The 2140 01T1 borehole sampling the Late Cretaceous non-marine strata of the Klikov Formation in the central part of the Třeboň Basin in southern Bohemia provided ~ 70 m thick alluvial succession composed of alternating sandstone and mudstone intervals that overlays deeply weathered crystalline basement. The mudstone interval in the lower part of the Klikov Formation is separated by sandy layers into several 2–4 m thick fining-upward units. The sharp-based sandy layers with fusain, carbonized stems and rip-up clasts of underlying mudstone are interpreted as avulsion deposits. They grade upwards into heterolithic sand-silt sequence and mottled massive mudstone with burrows, rhizohalos and variably developed pedogenic features. Such cyclic arrangement probably reflects autogenic processes on distal floodplain with episodic deposition and upward increasing subaerial exposition and pedogenic overprint. In the middle to upper parts of the Klikov Formation up to 6 m thick channel sandbodies with sharp erosional bases cutting into the underlying laminated sand-silt heteroliths of channel levee deposits occur. The thickness of the single-storey sandbodies corresponds usually to c. 2 m which suggests up to 3 m deep channels during bankfull discharge. The thicker multi-storey sandbodies record channel amalgamation on the alluvial ridge or shallow paleovalley fillings. The sandbodies grade upwards to massive mudstones of abandoned channel fills and floodplain deposits. These floodplain units are up to 8 m thick and consist of variegated massive mudstones interrupted by discrete up to 1 m thick fining upward layers of rippled sandstone representing crevasse splay deposits. Depositional context including preserved levee deposits, abandoned channel fillings and floodplain finegrained deposits suggests rather higher sinuosity of the formative rivers. Palaeosol profiles represent pedogenically modified floodplain fines with gradational bases and sharp erosive top surfaces. At least 10 palaeosols were identified in the measured section, forming mostly discrete profiles up to 2 m thick consisting of several B-horizons that differ in the degree of the soil structure development, colour, mottling, grain size, presence of clay hypocoatings and bioturbation index. The most common Bw horizons form lower parts of the profiles and have no or only a weakly developed angular blocky structure (ABS). The typical mottling is caused by a hierarchical system of vermicular greenish-grey reduction rhizohalos, that may be filled by silt to sand or illuviated clay hypocoatings and probably follow the original plant root system. Some patches have diffuse orange rims of iron oxides, probably represented by goethite. Mudstone of Bsst horizons displays well-developed ABS with rare wedge-shaped peds and contains a number of illuviated clay skins and redox depletions. Vertic features like fine cracks filled by sand are common, and slickensides with clay hypocoatings occur rarely. Mudstones of Bt horizons contain a number of illuviated clay hypocoatings filling root channels or interpedal cracks, while the Bss horizons exhibit well-developed ABS with slickensides and contain a number of vertical cracks filled by sandy grains. Palaeosol profiles represent mainly argillisols and vertic argillisols with transitions to argillic vertisols. Poorly developed argillic to vertic protosols are also common. Palaeosol profiles differ mainly in the degree of structural development/maturity, which is given by various lengths of exposition to similar climatic conditions. Vertical distribution of palaeosols reflects their position in the alluvial landscape with locally specific hydromorphic conditions rather than a distinct climatic trend. Most of palaeosols exhibits downprofile translocation of clay (illuviation) leading to the formation of argillic horizon, which typically develop on stabilized landscape in humid climate with seasonal moisture deficit.

Catering situation at Austrian schools

Abstract Background Due to the increase in all-day compulsory schools in Austria, it is important that students receive health-promoting meals throughout the day. The aim of the analysis was a nationwide evaluation of the current situation concerning catering at schools. Methods Using a nationwide representative sample of schools from the 5th grade upwards, a questionnaire was conducted as a telephone interview with 331 randomly chosen schools. In addition, 56 schools in Vienna from the 5th grade onwards were randomly selected in order to analyze the current offer at school cafeterias in detail. Results Lunch was offered at 72% of all schools, a school cafeteria was available at 81%, a cold drink vending machine at 66%, a hot drink vending machine at 41% and a snack vending machine at 23%. With regard to the health promoting composition of the catering offer, 18% of all schools already had a certified lunch menu, 22% a certified school cafeteria, 14% a certified cold drink vending machine and 5% a certified snack vending machine. In 79% of schools there is direct competition for school catering (93% supermarkets, 45% bakeries, 33% snack stands, 8% fast food restaurants). The results of the detailed analysis in Vienna showed that only 35% of all school cafeterias are certified. All of these locations are advised externally. Conclusions The majority of the schools offer catering during breaks and at lunchtime. Without external advice, the majority of the offers must be classified as not health promoting. Key messages The food offered at schools is an important component in the nutrition of students in Austria. Cafeteria operators in schools often need external advice in order to be able to offer a healthy selection of food and beverages.

A middle Eocene treefall pit and its filling: a microenvironmental study from the onset of a forest mire in the Geiseltal (Germany)

The treefall pit of a large tree at the base of the middle Eocene Mittelkohle has been studied in the former open-cast mine Neumark Nord of the Geiseltal Mining District. Above a light clastic soil, the sedimentation in the pit started with backfall and downwashed material grading upwards into pond deposits that filled the pit. This represents a high-resolution section equivalent in time to the initial peat-forming environment. Palynology revealed a striking difference between a fern-dominated herbaceous plant community below the pit and a pulse of washed-in fagaceous pollen (Tricolpopollenites liblarensis) at the base of the pit. This is overlain by an assemblage of woody taxa typical of a peat swamp forest associated with a number of tropical elements. Comparison with a nearby but undisturbed transition from underlying sediments to the seam confirms the ecotonal character of the parent plant of T. liblarensis, and suggests that Cupressaceae s.l., Nyssaceae and Myricaceae especially benefited from moisture and light in the clearing of the treefall pit. The transition from the underlying sediment to the lignite represents a sharp break in the sedimentary regime from clastic to purely organic material with a bounding surface colonised by large trees, most of them preserved as individual stumps, but including some fallen logs.

Moral Competence and Public Value

Moral competence and public value are closely related. The core public value is democracy, which is actually a bundle of the four moral principles: freedom, justice, truth, and cooperation. Moral competence is the ability to apply these principles, that is, the ability to solve conflicts and problems inevitably resulting from applying these principles to real-life decision-making. As empirical and experimental evidence show, the moral principles of democracy are shared by most, if not all, people. However, most people do not have the opportunity to develop a minimum moral competence. Thus they cannot behave according to their moral principles without requiring (expensive) external control. Therefore, society must spend much money on their control. If society would foster the moral competence of all citizens, it could save much expenditure. Today, we can foster moral competence very effectively with methods like the Konstanz Method of Dilemma-Discussion (KMDD). The KMDD can be used with almost all age groups (3rd grade upwards). It is not only very effective but requires little time and money and no change of the curriculum. However, it is only effective if it is used by well trained and certified KMDD-Teachers. In my presentation I will explain in detail the new concept of moral competence, how it can be made visible through the experimentally designed Moral Competence Test (MCT), how relevant moral competence is for various kinds of behavior, and how it can be effectively fostered by the KMDD, which is used in various educational settings like grade school, secondary school, university, professional training, army academy, prison, and theater. </br></br> Key Words: Moral-democratic competence, moral orientations, Experimental Questionnaires, moral-democratic education, teacher training

A 571 million-year-old alkaline volcanic lake photosynthesizing microbial community, the Anti-atlas, Morocco.

The Ediacaran period coincides with the emergence of ancestral animal lineages and cyanobacteria capable of thriving in nutrient deficient oceans which together with photosynthetic eukaryotic dominance, culminated in the rapid oxygenation of the Ediacaran atmosphere. However, ecological evidence for the colonization of the Ediacaran terrestrial biosphere by photosynthetic communities and their contribution to the oxygenation of the biosphere at this time is very sparse. Here, we expand the repertoire of Ediacaran habitable environments to a specific microbial community that thrived in an extreme alkaline volcanic lake 571Myr ago in the Anti-atlas of Morocco. The microbial fabrics preserve evidence of primary growth structures, comprised of two main microbialitic units, with the lower section consisting of irregular and patchy thrombolytic mesoclots associated with composite microbialitic domes. Calcirudite interbeds, dominated by wave-rippled sandy calcarenites and stromatoclasts, fill the interdome troughs and seal the dome tops. A meter-thick epiclastic stromatolite bed grading upwards from a dominantly flat to wavy laminated base, transitions into low convex laminae consisting of decimeter to meter-thick dome-shaped stromatolitic columns, overlies the thrombolitic and composite microbialitic facies. Microbialitic beds constructed during periods of limited clastic input, and underlain by coarse-grained microbialite-derived clasts and by the wave-rippled calcarenites, suggest high-energy events associated with lake expansion. High-resolution microscopy revealed spherulitic aggregates and structures reminiscent of coccoidal microbial cell casts and mineralized extra-polymeric substances (EPS). The primary fabrics and multistage diagenetic features, represented by active carbonate production, photosynthesizing microbial communities, photosynthetic gas bubbles, gas escape structures, and tufted mats, suggest specialized oxygenic photosynthesizers thriving in alkaline volcanic lakes, contributed toward oxygen variability in the Ediacaran terrestrial biosphere.

Raně středověké říční koryto v blízkosti fortifikačního systému velkomoravského hradiska Pohansko u Břeclavi

Geophysical, sedimentological, palynological, absolute-age dating and archeological techniques were used to study the deposits of the Early Medieval fluvial channel in the area of the Great Moravia Empire agglomeration Pohansko near Břeclav. Artificial profile situated on the base of ERT profiles and the archeological results led to opening of the fluvial channel. Newly documented fluvial channel erosively cut the complex of flood loams. Gravel lag covers the bottom of the channel and grade upwards into sandy channel infill with fining upward trend. Fluvial sandy dunes forming the most characteristic architectural element of the infill are represented mostly by trough cross-stratified medium-grained sands. These sands were penetrated by the piece of oak wood. Both the OSL dating of the sandy deposits and the dating of the oak wood (C14 and dendrochronology) point to the 9th century A.D. when the Great Moravia Empire was on its peak expansion. Active fluvial channel was probably used as a part of the fortification system and a possible wood bridge existed here in the front of the proposed Western Gate of the Pohansko agglomeration. Palynological studies reveal some fragmentation of the landscape and agricultural activities in the close surroundings. Deposits of the studied fluvial channel were covered by the beds of the younger flood loams.

Ordovician ironstone of the Iberian margin: Coastal upwelling, ocean anoxia and Palaeozoic biodiversity

AbstractMiddle to Upper Ordovician ironstone and associated sedimentary rocks of the West Asturian‐Leonese and Cantabrian tectonostratigraphic zones, Spain, provide new information regarding the Palaeozoic Fe cycle and the palaeoceanography of the Rheic Ocean. Examination of drill cores and outcrops indicates the southeastern margin of this narrow seaway was a dynamic continental shelf where upwelling of ferruginous seawater and storm currents controlled lithofacies character. Parasequence composition and stacking relationships suggest ironstone accumulated during marine transgression as accommodation increased from lowstand conditions. Proximal parasequences record aggradation from deep subtidal to shoreface environments. Hummocky cross‐stratified sandstone and organic‐rich siltstone grade upwards into swaley cross‐stratified sandstone and granular Fe‐silicate‐rich ironstone capped by a flooding surface. Distal parasequences were deposited below storm wave base on the distal shelf and are composed of variably bioturbated organic‐rich siltstone with thin Fe‐chlorite and phosphorite layers. These differences in parasequence character define two different ironstone factories where Fe was concentrated and precipitated in sediment. Lithofacies associations support an emerging model for ironstone deposition where coastal upwelling delivered and stimulated the precipitation of Fe within shelf sediment. This notion provides further evidence for the development of intermittent anoxic water masses in an Ordovician ocean that was near the threshold of becoming fully ventilated. This style of Fe delivery probably represents a tipping point in the oxygenation history of the Phanerozoic oceans and is a throwback to the Precambrian when widespread anoxia allowed hydrothermal Fe to concentrate in the global ocean. New data suggest that minor extinction events punctuating the Great Ordovician Biodiversification Event may be traced to these anoxic waters, which in addition to Fe, were also enriched in biologically toxic, redox sensitive trace elements. Conversely, precipitation of upwelling‐related ironstone may have helped sequester these trace elements, providing a negative feedback response that would aid post‐extinction recovery.

Unravelling the D1 event: evidence for early granite-up, greenstone-down tectonics in the Eastern Goldfields, Western Australia

The early tectonic history of the Eastern Goldfields Terrane (EGT) is poorly understood, but in places ca 2800 Ma mafic–ultramafic sequences are conformably overlain by ca 2720–2670 Ma sequences (e.g. Leonora and Laverton districts), suggesting minimal early deformation. The first significant angular unconformities occur at the base of the ca 2670–2655 Ma late basins and indicate that deformation was contemporaneous with deposition of the late basins. These basins mark the end of the volcano-sedimentary record in the EGT and typically grade upwards from polymictic mafic-dominated conglomerates to more siliciclastic compositions with abundant granitic clasts. The clastic sequences record the uplift and exhumation of granite-cored domes. There is a distinct lack of clasts with internal deformation fabrics (e.g. schist or gneiss). The timing of late basin formation overlaps with the ca 2672–2660 Ma D1 event, which has been variously described as extensional or compressional. D1 structures comprise a bedding-parallel S1 that is axial planar to F1 folds. The late basins and early D1 fabrics are overprinted by upright north-trending F2 folds and a sub-vertical S2. A period of crustal thickening was achieved by autochthonous processes with deposition of greenstone sequences into local basins between ca 2720 and 2670 Ma. Partial convective overturn (or granite-up, greenstone-down tectonics) developed as a result of gravitational instability. As the large granite–gneiss bodies rose, solid-state extensional D1 shears developed around the granites with a radial pattern of L1 extension lineations. Areas of compression developed within the sinking greenstone sequences. A final phase of subsidence in the central parts of the greenstone belts produced depocentres (late basins). A shift from dominantly vertical tectonics to horizontal tectonics at ca 2655–2650 Ma is marked by the onset of east–west D2 compression and the change in granite compositions from high-Ca to low-Ca granites. KEY POINTS Older ca 2800 Ma mafic–ultramafic sequences are conformably overlain by ca 2720–2670 Ma sequences suggesting minimal early deformation in the EGT. The first significant angular unconformities are at the base of the ca 2665 Ma late basin sequences. Late basin sequences record the uplift and exhumation of granite-cored domes and sedimentation is contemporaneous with the regional ca 2672–2660 Ma D1 event. The D1 event represents granite-up, greenstone-down tectonics (D1 event) that developed as a result of gravitational instability arising from autochthonous crustal thickening from ca 2720–2670 Ma. Granite-up, greenstone-down tectonics precludes an accretionary model for the development of the EGT.

Development of REE mineralization in the giant Maoniuping deposit (Sichuan, China): insights from mineralogy, fluid inclusions, and trace-element geochemistry

Rare-earth deposits associated with intrusive carbonatite complexes are the world’s most important source of these elements (REE). One of the largest deposits of this type is Maoniuping in the Mianning-Dechang metallogenic belt of eastern Tibet (Sichuan, China). In the currently mined central part of the deposit (Dagudao section), REE mineralization is hosted by a structurally and mineralogically complex Late Oligocene (26.4 ± 1.2 Ma, 40Ar/39Ar age of fluorphlogopite associated with bastnasite) hydrothermal vein system developed in a coeval syenite intrusion. Low-grade stockworks of multiple veinlets and breccias in the lower part of the orebody grade upwards into progressively thicker veins (up to 12 m in width) that are typically zoned and comprise ferromagnesian micas (biotite to fluorphlogopite), sodium clinopyroxenes (aegirine to aegirine-augite), sodium amphiboles (magnesio-arfvedsonite to fluororichterite), K-feldspar, fluorite, barite, calcite, and bastnasite. The latter four minerals are most common in the uppermost 80 m of the Dagudao section and represent the climax of hydrothermal activity. Systematic variations in the fluid inclusion data indicate a continuous hydrothermal evolution from about 230–400 °C (fluid inclusions in feldspar, clinopyroxene, and amphibole) to 140–240 °C (fluid inclusions in bastnasite, fluorite, calcite). Hydrothermal REE transport was probably controlled by F−, (SO4)2−, Cl−, and (CO3)2− as complexing ligands. We propose that at Dagudao, silicate magmas produced orthomagmatic fluids that explored and expanded a fissure system generated by strike-slip faulting. Initially, the fluids had appreciable capacity to transport REE and, consequently, no major mineralization developed. The earliest minerals to precipitate were alkali- and Fe-rich silicates containing low levels of F, which caused progressive enrichment of the fluid in Ca, Mg, F, Cl, REE, (SO4)2−, and (CO3)2−, leading to the crystallization of aegirine-augite, fluororichterite, fluorphlogopite, fluorite, barite, calcite, and bastnasite gradually. Barite, fluorite, calcite, and bastnasite are the most common minerals in typical ores, and bastnasite generally postdates these gangue minerals. Thus, it is very probable that fluid cooling and formation of large amount of fluorite, barite, and calcite triggered bastnasite precipitation in the waning stage of hydrothermal activity.

Defining diagnostic criteria to describe the role of rift inheritance in collisional orogens: the case of the Err-Platta nappes (Switzerland)

It is commonly accepted that collisional orogens involve the reactivation of former rifted margins. While it remains debated how rift inheritance can be identified and how it controls the architecture of orogens this case study analyses the importance of rift-inheritance during reactivation of a passive margin. The study analyses complex, non-layer cake rift structures within the well-exposed Err and Platta nappes (SE Switzerland), representing the former distal Adriatic margin of the Alpine Tethys. Diagnostic criteria for rift inheritance include: (1) typical fault rocks with a mantle derived fluid signature, and (2) tectono-sedimentary breccias made of reworked exhumed basement and grading upwards into late syn- and post-rift sediments. Based on the study of “recognisable” features, a methodology is etablished, which enables to (1) map rift-related detachment faults and (2) to analyse their role during reactivation and formation of a thrust stack. First, second and third order thrust systems are defined. First order thrust systems juxtapose different rift domains (proximal, necking, and distal). Second order systems are dominantly made up of basement sheets sampling the former footwall of an extensional detachment fault. Third order systems mainly consist of the former hanging wall of an extensional detachment fault. A major result of this study is that thrust faults commonly reactivate former extensional detachment faults, especially in the exhumed mantle domain (Platta nappe), while in the hyperextended domain (Err nappe) reactivation of rift-inherited structures is more complex and often incomplete. The results of this study may help to better identify remnants of former distal margins and to define and analyse their complex stacking patterns observed in many internal parts of collisional orogens.

Crystal accumulation in a tilted arc batholith

![][1] The Wooley Creek batholith is a Late Jurassic, arc-related, calc-alkaline plutonic complex in the Klamath Mountain province of California. Post-emplacement tilting and erosion have exposed ~12 km of structural relief. The complex consists of an older (~159.1 Ma) lower zone (pyroxenite to tonalite) assembled by piecemeal emplacement of many magma batches, a younger (~158.2 Ma) upper zone (quartz diorite to granite), and a transitional central zone. In the lower zone, pyroxenes are too Fe rich to be in equilibrium with a melt whose composition was that of the host rock. Mass-balance calculations and simulations using rhyolite-MELTS indicate that these rocks are cumulates of pyroxenes and plagioclase ± olivine and accessory apatite and oxides. Percentages of interstitial melt varied from ~7.5–83%. The plagioclase/pyroxene ratios of cumulates vary considerably among the most mafic rocks, but are relatively uniform among quartz diorite to tonalite. This near-constant ratio results in compositional trends that mimic a liquid line of descent. In the upper zone, bulk-rock compositional trends are consistent with differentiation of andesitic parental magmas. Upward gradation from quartz dioritic to granitic compositions, modeled via mass-balance calculations and rhyolite-MELTS simulations, indicate that structurally lower parts of the upper zone are cumulates of hornblende and plagioclase ± biotite and accessory minerals, with 37–80% trapped melt. In contrast, the structurally higher part of the upper zone represents differentiated magma that escaped the subjacent cumulates, representing differentiated melt fractions remaining from 92–54%. The ratio of cumulate plagioclase/(plagioclase + mafic minerals) ~0.48 among upper-zone cumulates, mimicking a liquid line of descent. The results suggest that compositional variation in many calc-alkaline plutons may be at least as representative of crystal accumulation as of fractional crystallization. If so, then the assumption that arc plutons geochemically resemble frozen liquids is dubious and should be tested on a case-by-case basis. Moreover, comparisons of plutonic rock compositions with those of potentially comagmatic volcanic rocks will commonly yield spurious results unless accumulation in the plutons is accounted for. [1]: /embed/graphic-1.gif

Bildungssprachliche Kompetenzen bei Schulbeginn: Modellierung–Operationalisierung–Ergebnisse

Bildungssprache (Academic Language) is a necessary prerequisite for success at school. However, only recently has the need for its systematic teaching been recognised. Presently the concept of »Sprache im Fach«, i. E. the teaching of (academic) language in every subject, seems to adequately address the didactic needs, originating in the institutional requirements. Within different research perspectives, various models of Bildungssprache have been set up, most of them conceiving it as a multidimensional construct. Currently influential research perspectives on Bildungssprache study it in the context of migration-related second language acquisition and success at school, within the development of literacy, or with regard to its role for cognition, its being considered a resource with a value of its own. However, most studies only focus on children from 3rd grade upwards.

Inside Mid-Triassic fluvial deposits: a legacy of mining sediment-hosted ore bodies in Cheshire, UK

In the Cheshire Basin the Mid-Triassic Helsby Sandstone Formation includes deposits of fluvial and aeolian origin. Sedimentological details of these deposits are commonly obscured in weathered outcrops but can be studied in unweathered sections in disused mines at the Alderley Edge Geological Site of Special Scientific Interest in northeast Cheshire. Fining-upward cycles seen in the fluvial units comprise channel-fill deposits that rest on an erosion surface, grade upwards from conglomerate to fine sandstone and are overlain by mudstones that underwent erosion at the initiation of the next cycle. The mudstone components of some cycles remain in parts of the mines but others were eroded completely and are now represented by concentrations of intraclasts in the succeeding cycle. Mudstone beds and those containing intraclasts formed complete and partial barriers to fluid movement respectively. Their effect on the migration and accumulation of intrastratal fluids is reflected by the form and disposition of voids left by the mining of ore bodies hosted by this facies. A corollary is that if the voids are interpreted as representing hydrocarbon accumulations, rather than ore bodies, reservoir situations analogous to those in the Helsby Sandstone in comparable structures in the East Irish Sea Basin may be viewed from a unique internal perspective.

Estuarine infill and formation of Deltaic Plains, Shoalhaven River.

The Shoalhaven River is an example of a mature, infilled estuary on a wave-dominated coast. The river presently flows between prominent levees towards the coast, periodically exiting at Shoalhaven Heads, but having much of its flow artificially diverted to exit at Crookhaven Heads. The alluvial plains east of Nowra are the result of estuarine infilling behind a sand barrier, represented by Comerong Island, a southern continuation of the Seven Mile Beach beach-ridge plain. Drilli has revealed marine sands adjacent to this eastern sand barrier, and extensive muds deposited in a barrier estuary beneath most of the plains. The molluscan composition of these sediments indicates deposition in brackish water conditions, with Notospisula trigonella especially widespread. Estuarine infill occurred progressively around deltaic channels, isolating smaller basins which accreted subsequently. Most of the estuarine sedimentation occurred 5500 – 3500 radiocarbon years BP. Brackish-water muds grade upwards into fresh-water alluvial muds deposited from fluvial overbank flows, and the transition is indicated from analysis of the diatoms within sediments in an augerhole near Jaspers Brush. Levees overlie these estuarine sediments in places and indicate natural changes in river channel location. There is an extensive potential acid sulphate soil hazard throughout the plains as a result of the occurrence of pyrite-rich estuarine muds up to an elevation close to mean sea level beneath most of the plains.

Middle Devonian olistostromes in the Rheno-Hercynian zone (Rheinisches Schiefergebirge) — An indication of back arc rifting on the southern shelf of Laurussia

The Rheinisches Schiefergebirge in the Rheno-Hercynian zone of the mid-European Variscides was geographically situated on Laurussia's southern shelf during the Devonian. In its eastern part (Lahn–Dill area), Givetian coarse clastic sediments, formerly misinterpreted as transgressional conglomerates, are recognised as olistostrome deposits intercalated in basinal sediments that document a phase of rifting on the southern shelf of Laurussia. The clastic components, redeposited as olistolithes and rounded boulders, are locally derived rocks of Emsian and Givetian age. The olistostromes show facies patterns comparable with other syn-rift deposits. The proximal facies is characterised by olistolithes and slideflow debrites, overlain by debrites and intercalated with turbidites. The distal facies is represented by intercalation of debrites and turbidites. Both grade upwards into basinal sedimentation. Based on conodont stratigraphy, the redeposition lasted from the Middle varcus Zone to the disparilis Zone. During the Middle varcus Zone footwall uplift raised the sedimentary column of the source area by about 500 m above, which brought it above sea level. Rifting of the Laurussian shelf as a result of hinterland transtension and extension caused by the oblique collision of Peri-Gondwana with Laurussia provides the most plausible explanation for the development of the olistostromes, olistolithes and slideflow debrites in the eastern Rheinisches Schiefergebirge.

New data on Mesozoic Radiolaria of Serbia and Bosnia, and implications for the age and evolution of oceanic volcanic rocks in the Central and Northern Balkans

The Dinaridic Ophiolite Belt (DOB) includes Middle Triassic cherty limestones, Upper Triassic radiolarian cherts associated with basaltic lavas and volcaniclastic sediments, and also Jurassic continental slope sequences. Sedimentary sequences grade upwards into Cretaceous red limestones with planktonic foraminifers of the Genus Hedbergella. Many of the Late Triassic to Late Jurassic cherts probably accumulated in an oceanic setting, and now crop out as blocks in olistostromal deposits. Jurassic radiolarite sequences of the margin of the Dinaride Ophiolite Belt are represented by Aalenian, Upper Bajocian–Lower Bathonian and Upper Bathonian–Lower Callovian, Middle Callovian–Oxfordian, Upper Callovian–Upper Oxfordian and Kimmeridgian–Tithonian-aged strata. These are overlain by Upper Tithonian–Valanginian sedimentary sequences with spongolite–radiolarites, volcaniclastic sediments and other continental slope deposits. The oldest units outcropping in the DOB are Mid-Triassic (Ladinian) red cherts and limestones. These are associated with alkaline and tholeiitic basalts in the Bistrica area, and with tholeiitic basalts in the Visoka area. In contrast, in the Vardar Zone Western Belt the oldest basalt–radiolarite formation is represented by cherts associated with tholeiitic basalt in the Ovčar Banja area. Upper Triassic red radiolarites of the Čačak area lie in direct stratigraphical contact with MORB-type pillow lavas and contain a Carnian–Norian radiolarian assemblage. The youngest radiolarian-bearing units are in the Upper Cretaceous part of the Vardar Zone Western Belt, in the Struganik area, where Coniacian–Santonian radiolarians occur in chert–clay–tuff sediments. In addition, cherty limestones from the northern slope of Kozara Mt. contain a Campanian radiolarian assemblage, together with Campanian–Maastrichtian planktonic foraminifers. Volcanic units associated with the siliceous sediments of Dinaride Ophiolite Belt and the Vardar Zone Western Belt are of MOR- and SSZ types, respectively. The ocean-related basalts of the Dinaride Ophiolite Belt and the Vardar Zone Western Belt show some geochemical differences, irrespective of age. Compared to those of the Dinaride Ophiolite Belt, the basalts of the Vardar Zone Western Belt are more variable chemically and exhibit much higher LREE/HREE and Th/REE ratios. Finally, possible paleo-reconstructions of the radiolarian sediments and the volcanic rocks are proposed.

Magmatic evolution of the Mantos Blancos copper deposit, Coastal Range of northern Chile: insight from Sr–Nd isotope, geochemical data and silicate melt inclusions

AbstractThe Mantos Blancos copper deposit (500 Mt at 1.0% Cu) was affected by two superimposed hydrothermal events: (i) phyllic alteration related to a rhyolitic dome emplacement and brecciation at ca 155 Ma; and (ii) potassic, sodic and propylitic alteration at ca 142 Ma, coeval with stocks and sills emplacement of dioritic and granodioritic porphyries, that locally grade upwards into polymictic magmatic hydrothermal breccias. Major hypogene copper sulfide mineralization is related to the second event. A late‐ore mafic dike swarm cross‐cuts all rocks in the deposit. Two types of granodioritic porphyries can be distinguished from petrographic observations and geochemical data: granodiorite porphyry I (GP I) and granodiorite porphyry II (GP II), which resulted from two different trends of magmatic evolution. The concave shape of the rare earth element (REE) distribution pattern together with the weak or absence of negative Eu anomalies in mafic dikes, dioritic and GP I porphyries, suggest hornblende‐dominated fractionation for this magmatic suite. In contrast, distinct negative Eu anomalies and the flat REE patterns suggest plagioclase‐dominated fractionation, at low oxygen fugacity, for the GP II porphyry suite. But shallow mixing and mingling between silicic and dioritic melts are also likely for the formation of the GP II and polymictic breccias, respectively. Sr‐Nd isotopic compositions suggest that the rhyolitic dome rocks were generated from a dominantly crustal source, while the GP I has mantle affinity. The composition of melt inclusions (MI) in quartz crystals from the rhyolitic dome is similar to the bulk composition of their host rock. The MI analyzed in quartz from GP II and in the polymictic magmatic hydrothermal breccia of the deposit are compositionally more evolved than their host rocks. Field, geochemical and petrographic data provided here point to dioritic and siliceous melt interaction as an inducing mechanism for the release of hydrothermal fluids to form the Cu mineralization.