Adjustment of a Formulated Sediment for Sediment Testing with Caenorhabditis elegans (Nematoda)

The OECD soil, which is standardised for use in the sediment toxicity with the midge Chironomus riparius revealed inhibition of the nematode Caenorhabditis elegans in body growth length and egg production of 41.0% and 84%, respectively. 18 formulated sediments were tested to optimise the sediment composition for growth and reproduction of C. elegans. Their components were chosen to simulate native sediments, whereby different quantities and different clay minerals were tested. The mixture that we found to be optimal in our experiments consisted of 5% sphagnum peat, 70% calcitic sand, 0.5% dolomite limestone, 4.5% iron(III) oxide, and a clay combination of 1.5% chlorite and 18.5% aluminium(III) oxide. When applying this mixture to C. riparius, the new formulated sediment improved also growth in comparison to the OECD sediment.     

Konvergenzerscheinungen der Mineralbildung einiger sedimentärer deutscher Eisenerze

Zusammenfassung Sedimentäre Eisenerze können durch Ausflocken von Fe⁺⁺⁺haltigen Solen und durch Ausfällen von Fe⁺⁺haltigen Lösungen gebildet werden. Aus Solen gebildete Erze werden als Begleitelemente Kieselsäure und Aluminium anreichern, während aus Lösungen gebildete Erze manganreicher sind und Kieselsäure und Aluminium zurücktreten.     

Die Rotsedimentation im Saar-Pfälzischen Rotliegenden

Ohne Zusammenfassung     

Über den Verwitterungszustand des Granitgruses vom Fliegenberg,westlich Thiersheim (Fichtelgebirge) mit besonderer Berücksichtigung der Schwerminerale

Zusammenfassung Es werden der qualitative Mineralbestand und die Korngrößen verteilung im Verwitterungsgrus des Granites vom Fliegenberg, westlich Thiersheim, angegeben. Während der mechanische Zerfall des Gesteins als relativ stark erkannt worden ist, sind keine nennenswerten chemischen Mineralumwandlungen festzustellen. Dadurch wird die vorteilhafte Untersuchung der Schwerminerale ermöglicht. Eine hervorragende Stellung nimmt der Apatit ein. Dieser ist nahezu frisch. Da er sick an anderer Stelle (Grus des Brockengranits) unter ähnlichen Verwitterungen als chemisch instabil erwiesen hat, wird die Verwitterung des Fliegenberggranites noch jüngeren rezenten Verwitterungseinflüssen zugeschrieben. Die restliche Schwermineralassoziation wird in dieWellssche Gruppe der pneumatolytischen Bildungen eingeordnet. Die Beobachtungen deuten auf eine geringe Tiefenstufe des hier aufgeschlossenen Teils vom Granitkörper und die besondere Anlage zu einer Grusbildung hin.Herrn Professor Dr.Carl W. Correns zum 60. Geburtstag gewidmet.     

Numerical prognosis for salinity profiles of future lakes in the opencast mine Merseburg-Ost

Salt-laden groundwater inflows have formed monimolimnia in developing lakes of the abandoned opencast lignite mine Merseburg-Ost, Central Germany. Water-levels are still rising. To predict the future status of the lakes, two numerical models were developed. One was designed to predict groundwater flows, the second included limnophysical processes. The models were run in parallel and data exchange between them was performed every 1 to 10 years of model time. A trial of a 100-years prognosis was done. The results of surface salinity, mixing depth, and salinity profile are given. A sensitivity analysis yielded indications for the accuracy of the prediction.     

Amorphous copper and zinc sulfides in the metalliferous sediments of the Red Sea

Detailed studies on the copper and zinc distribution in metalliferous sediments from the Atlantis II Deep (Red Sea) demonstrate that beside chalcopyrite and sphalerite appreciable amounts of copper and zinc are found in X-ray amorphous copper and zinc sulfides not previously described. Only low contents of copper and zinc are present in nontronites, hydroxides and carbonates.     

Earthquake strong motion simulated by stress drop models

Shallow strike slip earthquakes on vertical faults are modelled as two-dimensional antiplane strain ruptures in a uniformly prestressed homogeneous halfspace. Behind the rupture front, which is specified, the stress drops to a lower value. The elastodynamic boundary value problem is solved with a finite difference method. Several cases are studied, which include symmetric and one-directional rupture propagation, surface faulting, multiple events, variable rupture velocity, sticking and rebreaking of the fault plane. The time function of displacement, velocity and acceleration are interpreted as signals generated by events in the focus, namely starting, stopping and breaking through the surface of the rupture. The model explains peak velocity and peak acceleration in the near field of M5.5–6 earthquakes; which are typically about 0.2 m/s and 5 m/s² at 10 km epicentral distance, if the rupture velocity is close to the shear wave velocity. Sticking of the fault does not alter the accelerograms significantly, but it increases the seismic moment in simple events and decreases it in multiple events.Contribution No. 226, Geophysical Institute, University of Karlsruhe.