Sedimentpetrographische und geochemische Untersuchungen an Karbonatgesteinen des Zechsteins

Introduction and methods applied: some new DTA-methods (quantitative determination of gypsum, determination of grain-size of carbonates, analysis of small amounts of iron in the dolomite lattice and of magnesium in calcite) and improved DTA-data on some minerals (clay minerals, Fe- and Al-hydroxides, pyrite, quartz, fluorite), occuring in the residue of carbonate rocks and not admitting solution by acids, are given.

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Meinem verehrten Lehrer, Herrn Prof. Dr. Dr. h. c. C. W. Correns, danke ich sehr für die Überlassung des Themas. Für viele Hinweise und Diskussionen bin ich weiterhin Frau Dr. P. Schneiderhöhn, Herrn Prof. Dr. K. H. Wedepohl und Herrn Dr. H. E. Usdowski zu Dank verpflichtet.     

Rebuttal to “The case of the Biscayne Bay and aquifer near Miami,Florida: density-driven flow of seawater or gravitationally driven discharge of deep saline groundwater?” by Weyer (Environ Earth Sci 2018, 77:1–16)

A recent paper by Weyer (Environ Earth Sci 2018, 77:1–16) challenges the widely accepted interpretation of groundwater heads and salinities in the coastal Biscayne aquifer near Miami, Florida, USA. Weyer (2018) suggests that the body of saltwater that underlies fresh groundwater just inland of the coast is not a recirculating wedge of seawater, but results instead from upward migration of deep saline groundwater driven by regional flow. Perhaps more significantly, Weyer (2018) also asserts that established hydrologic theory is fundamentally incorrect with respect to buoyancy. Instead of acting along the direction of gravity (that is, vertically), Weyer (2018) claims, buoyancy acts instead along the direction of the pressure gradient. As a result, Weyer (2018) considers currently available density-dependent groundwater flow and transport modeling codes, and the analyses based on them, to be in error. In this rebuttal, we clarify the inaccuracies in the main points of Weyer’s (2018) paper. First, we explain that Weyer (2018) has misinterpreted observed equivalent freshwater heads in the Biscayne aquifer and that his alternative hypothesis concerning the source of the saltwater does not explain the observed salinities. Then, we review the established theory of buoyancy to identify the problem with Weyer’s (2018) alternative theory. Finally, we present theory and cite successful benchmark simulations to affirm the suitability of currently available codes for modeling density-dependent groundwater flow and transport.     

LA-ICPMS analyses of silicate melt inclusions in co-precipitated minerals: Quantification, data analysis and mineral/melt partitioning

We present a new approach to determine the composition of silicate melt inclusions (SMI) using LA-ICPMS. In this study, we take advantage of the occurrence of SMI in co-precipitated mineral phases to quantify their composition without depending on additional sources of information. Quantitative SMI analyses are obtained by assuming that the ratio of selected elements in SMI trapped in different phases are identical. In addition Fe/Mg exchange equilibrium between olivine and melt was successfully used to quantify LA-ICPMS analyses of SMI in olivine. Results show that compositions of SMI from the different host minerals are identical within their uncertainty. Thus (1) the quantification approach is valid; (2) analyses are not affected by the composition of the host phase; (3) the derived melt compositions are representative of the original melt, excluding significant syn- or postentrapment modification such as boundary layer effects or diffusive reequilibration with the host mineral. With this data we established a large dataset of mineral/melt partition coefficients for the investigated mineral phases in hydrous calc-alkaline basaltic-andesitic melts. The clinopyroxene/melt and plagioclase/melt partition coefficients are consistent with the lattice strain model of Blundy and Wood [Blundy, J., Wood B., 1994. Prediction of crystal-melt partition-coefficients from elastic-moduli. Nature372, 452-454].     

Evolution of Mafic Alkaline Melts Crystallized in the Uppermost Lithospheric Mantle: a Melt Inclusion Study of Olivine-Clinopyroxenite Xenoliths, Northern Hungary

Olivine-clinopyroxenite xenoliths exhumed in alkali basalts(sensu lato) in the Nógrád–GömörVolcanic Field (NGVF), northern Hungary, contain abundant silicatemelt inclusions. Geothermobarometric calculations indicate thatthese xenoliths crystallized as cumulates in the upper mantlenear the Moho. These cumulate xenoliths are considered to representa period of Moho underplating by mafic alkaline magmas priorto the onset of Late Tertiary alkaline volcanism in the Carpathian–Pannonianregion. The major and trace element compositions of silicatemelt inclusions in olivine display an evolutionary trend characterizedby a strong decrease in CaO/Al₂O₃. The parental melt of thecumulates was a basanite formed by low-degree ( 2%) partialmelting of a garnet peridotite source. The compositional trendof the silicate melt inclusions, textural features, and modellingwith pMELTS show that the parental melt evolved by major clinopyroxeneand minor olivine crystallization followed by the appearanceof amphibole simultaneously with significant resorption of theearlier clinopyroxene and olivine. The resulting residual meltwas highly enriched in Al₂O₃, alkalis and most incompatibletrace elements. This type of melt is likely to infiltrate andreact with surrounding mantle peridotite as a metasomatic agent.It might also form high-pressure pegmatite-like bodies in themantle that might be the source of the amphibole and sanidinemegacrysts also found in the alkali basalts of the NGVF. Preferentialremelting of the later-formed (i.e. lower temperature) mineralassemblage (amphibole, sanidine, residual glass) might havesignificantly contaminated the host alkaline mafic lavas, increasingtheir Al₂O₃ and total alkali contents and, therefore, reducingtheir MgO, FeO and CaO content. KEY WORDS: silicate melt inclusions; geochemistry; petrogenesis; Nógrád–Gömör Volcanic Field; Pannonian Basin     

A semi-probabilistic procedure for developing societal risk function

Among the coastal districts of mega city Istanbul, Bakirkoy is one of the most critical one with the importance of air and marine transportation and presence of many other coastal facilities and structures that are prone to suffer from marine hazards. In the history, the Sea of Marmara has experienced numerous earthquake and landslide events and associated tsunamis. Therefore, tsunami risk assessment is essential for all coastal districts of Istanbul, including Bakirkoy district. In this study, a further developed methodology for tsunami human vulnerability and risk assessment Metropolitan Tsunami Human Vulnerability Assessment (MeTHuVA) is applied for Bakirkoy district of Istanbul, considering earthquake generated tsunamis. High-resolution tsunami hazard analysis is performed with the integration of coastal inundation computation with tsunami numerical tool NAMI DANCE and tsunami human vulnerability assessment with GIS-based multi-criteria decision analysis methods (MCDA). Using analytical hierarchy process method of MCDA, a hierarchical structure is established, composed of two main elements of tsunami human vulnerability: Vulnerability at Location and Evacuation Resilience. Tsunami risk assessment for Bakirkoy district is calculated by integrating result of hazard and vulnerability assessments with a risk relation that includes a parameter (n), which represents the preparedness and awareness level of the community. Tsunami simulations revealed that the maximum inundation distance is over 350 m on land and water penetrates almost 1700 m along Ayamama stream. Inundation is observed in eleven neighborhoods of Bakirkoy district. In the inundation zone, maximum flow depth is found to be over 5.7 m. The inundated area forms 4.2% of whole Bakirkoy district, and 62 buildings are located in the inundation zone. Hazard, vulnerability and risk assessment results for different neighborhoods of Bakirkoy district are presented and discussed.     

Redshift and velocity dispersion of the cluster of galaxies around NGC 326

Redshifts of several galaxies thought to be associated with NGC 326 are determined. The results confirm the presence of a cluster and find a mean redshift of     and a line-of-sight velocity dispersion σ _z =599 (+230,−110) km s⁻¹. The velocity dispersion and previously measured X-ray gas temperature of kT ≃1.9 keV are consistent with the cluster σ _z kT relation, and NGC 326 is seen to be a slowly moving member of the cluster.     

Bias of Apparent Tracer Ages in Heterogeneous Environments

The interpretation of apparent ages often assumes that a water sample is composed of a single age. In heterogeneous aquifers, apparent ages estimated with environmental tracer methods do not reflect mean water ages because of the mixing of waters from many flow paths with different ages. This is due to nonlinear variations in atmospheric concentrations of the tracer with time resulting in biases of mixed concentrations used to determine apparent ages. The bias of these methods is rarely reported and has not been systematically evaluated in heterogeneous settings. We simulate residence time distributions (RTDs) and environmental tracers CFCs, SF₆, ⁸⁵Kr, and ³⁹Ar in synthetic heterogeneous confined aquifers and compare apparent ages to mean ages. Heterogeneity was simulated as both K‐field variance (σ²) and structure. We demonstrate that an increase in heterogeneity (increase in σ² or structure) results in an increase in the width of the RTD. In low heterogeneity cases, widths were generally on the order of 10 years and biases generally less than 10%. In high heterogeneity cases, widths can reach 100 s of years and biases can reach up to 100%. In cases where the temporal variations of atmospheric concentration of individual tracers vary, different patterns of bias are observed for the same mean age. We show that CFC‐12 and CFC‐113 ages may be used to correct for the mean age if analytical errors are small.     

Influence of Boundary Condition Types on Unstable Density‐Dependent Flow

Boundary conditions are required to close the mathematical formulation of unstable density‐dependent flow systems. Proper implementation of boundary conditions, for both flow and transport equations, in numerical simulation are critical. In this paper, numerical simulations using the FEFLOW model are employed to study the influence of the different boundary conditions for unstable density‐dependent flow systems. A similar set up to the Elder problem is studied. It is well known that the numerical simulation results of the standard Elder problem are strongly dependent on spatial discretization. This work shows that for the cases where a solute mass flux boundary condition is employed instead of a specified concentration boundary condition at the solute source, the numerical simulation results do not vary between different convective solution modes (i.e., plume configurations) due to the spatial discretization. Also, the influence of various boundary condition types for nonsource boundaries was studied. It is shown that in addition to other factors such as spatial and temporal discretization, the forms of the solute transport equation such as divergent and convective forms as well as the type of boundary condition employed in the nonsource boundary conditions influence the convective solution mode in coarser meshes. On basis of the numerical experiments performed here, higher sensitivities regarding the numerical solution stability are observed for the Adams‐Bashford/Backward Trapezoidal time integration approach in comparison to the Euler‐Backward/Euler‐Forward time marching approach. The results of this study emphasize the significant consequences of boundary condition choice in the numerical modeling of unstable density‐dependent flow.     

First Detection of 4He in a Sample of Interstellar Neutral Gas Collected Onboard Mir Station

For the first time, the method of collecting impinging atoms in pretreated foil surfaces during exposure from a spacecraft allowed to detect in the laboratory, after retrieval of the foils,⁴He gas of interstellar origin in the expected concentration. This revised version was published online in July 2006 with corrections to the Cover Date.