Ergänzung und Berichtigung zu “Zurückführung des Großwetters auf solare Erscheinungen”

Ohne Zusammenfassung     

Can silicon monoxide grains be responsible for the interstellar 9.7 micrometer absorption band?

In this paper results of an experimental investigation of the spectra of submicrometersized silicon monoxide grains are presented. The grains manufactured from commercial SiO were prepared according to the Jena IR spectroscopy program for particulates of cosmic importance. The comparison of the laboratory spectra with those derived by means of Mie calculations using published refractive indices of bulk SiO revealed a fundamental discrepancy concerning the number and the positions of the bands. Therefore, the experimental SiO grains are suggested to change their internal structural state by the heating connected with the pressing of the KBr pellets, where the grains are embedded in. This sensitivity against heating by some hundred K rules out that SiO grains can be responsible for the 9.7 m circumstellar as well as interstellar spectral feature.     

Krypton and xenon from the solar wind and solar energetic particles in two lunar ilmenites of different antiquity

Abstract We present Kr and Xe isotope data obtained by closed system stepped etching of ilmenite separates from two lunar samples exposed to the solar corpuscular radiation at different epochs. Helium, neon, and argon in the same samples were reported to consist of two components: isotopically unfractionated solar wind (SW) released in the first steps, and an isotopically heavier component (SEP) released later and, thus, sited at larger depth. The same release characteristic is now observed for the heavy noble gases. We also conclude that solar Kr and Xe consist of two isotopically different components, implanted with different energies. The SW-Kr in a recently irradiated soil has a composition very close to atmospheric Kr, which agrees with other newly reported data from stepped etch- and combustion runs. No clear evidence for temporally variable SW-Kr or SW-Xe spectra was found. “Surface correlated” Kr and Xe components “SUCOR” and “BEOC 12001” are a mixture of SW and SEP. The isotopic fractionation factors relating SW and SEP are close to the square of the mass ratios for all five noble gases. We infer that the measured Kr/Xe ratio in ilmenite is essentially identical to this ratio in the solar corpuscular radiation.     

The interstellar 217 nm band: a third catalogue of equivalent widths

Using the data obtained with the ultraviolet photometer in the Astronomical Netherlands Satellite the equivalent widths of the interstellar 217 nm band as well as other parameters characterizing the behaviour of the continuous interstellar extinction in the wavelength region of the band have been derived for 790 O, B stars with colour excesses E(B - V) ≥ 0·4 mag.     

Basin modeling meets rift analysis – A numerical modeling study from the Jeanne d'Arc basin,offshore Newfoundland,Canada

The Jeanne d'Arc basin, on the Grand Banks offshore Newfoundland, is a confined, failed-rift basin. Its initial development and burial history were controlled by crustal stretching and thinning. This study provides a detailed analysis of the heat flow-, tectonic subsidence-, stretching factor-, maturation- and temperature history, based on 44 1D models- and one full 4D (space and time) model.     

The current performance of the in situ 14C extraction line at ETH

We present the new ¹⁴C extraction line at ETH Zürich. This system is designed to extract in situ-produced cosmogenic ¹⁴C from terrestrial quartz samples, and to obtain pure CO₂ gas for analysis with a gas ion source Accelerator Mass Spectrometry (AMS) system. Samples are degassed at 1550–1600 °C without the use of a fluxing agent. Gas purification is achieved by a series of cryogenic traps and passage through hot Ag and Cu wool/mesh. Graphitization and, thus, sample dilution is not required. Tests to determine the CO₂ recovery after gas extraction and cleaning yielded consistently good recovery rates of >99.8% (n = 7). The ¹⁴C blank contribution from the all-metal tubing system is negligible. Our preliminary procedural blank estimate – deriving mostly from the hot extraction furnace – is <5 × 10^{5 14}C atoms. Extraction tests on two quartz samples by stepped-heating show a quantitative separation of atmospheric ¹⁴C at ≤500 °C from the in situ component above 1200 °C. Based on these data, we estimate to achieve a complete ¹⁴C extraction from a quartz sample.     

Electric currents along earthquake faults and the magnetization of pseudotachylite veins

Pseudotachylites occur in the form of thin glassy veins quenched from frictional melts along the fault planes of major earthquakes. They contain finely grained magnetite and often exhibit a high natural remanent magnetization (NRM). High NRM values imply strong local electric currents. These currents must persist for some time, while the pseudotachylite veins cool through the Curie temperature of magnetite around 580 °C. There is no generally accepted theory explaining how such powerful, persistent currents may be generated along the fault plane. Data presented here suggest the activation of electronic charge carriers, which are present in igneous rocks in a dormant, inactive form. These charge carriers can be “awakened” by the application of stress. They are electrons and defect electrons, also known as positive holes or p-holes for short. While p-holes are capable of spreading out of the stressed rock volume into adjacent p-type conductive unstressed rocks, electrons require a connection to the hot, n-type conductive lower crust. However, as long as the (downward) electron flow is not connected, the circuit is not closed. Hence, with the outflow of p-holes impeded, no current can be sustained. This situation is comparable to that of a charged battery where one pole remains unconnected. The friction melt that forms coseismically during rupture, provides a conductive path downward, which closes the circuit. This allows a current to flow along the fault plane. Extrapolating from laboratory data, every km³ of stressed igneous rocks adjacent to the fault plane can deliver 10³–10⁵ A. Hence, the current along the fault plane will not be limited by the number of charge carriers but more likely by the (electronic) conductivity of the cooling pseudotachylite vein. The sheet current will produce a magnetic field, whose vectors will lie in the fault plane and perpendicular to the flow direction.     

Density structure and tritium-helium age of deep hypolimnetic water in the northern basin of Lake Lugano

Long-term stratification of the deep hypolimnetic waters of the northern basin of Lake Lugano (Lago di Lugano) has resulted in a lack of deep-water renewal which has persisted for decades. Tritium-helium age measurements reveal that deep water has not been in contact with the atmosphere since the 1960s. Higher primary production associated with the significant increase in phosphorus concentration which occurred at this time resulted in greater autochthonous gross sedimentation rates, increasing the rate of mineralization and, consequently, the rate of release of dissolved solids (mainly HCO ₃ ^- and Ca²⁺) into the deep hypolimnion. This gave rise to an intensification of the stratification and to a consequent reduction in the vertical exchange of hypolimnetic water layers. Today, the density stabilizing effect of ion release due to mineralization in the deep water is four to five times greater than the destabilizing effect of the geothermal heat flux from the earth's interior. It is known from laboratory experiments that such small density gradient ratios are likely to give rise to double-diffusive instabilities. However, even rudimentary mass balance calculations of biogeochemical components indicate that shear-induced turbulence, most likely generated by bottom currents, mixes far more efficiently than double diffusion. In the future, the biogenic density stratification is likely to persist in the deep water, unless the upward ion flux, driven by primary production, decreases by a factor of four to five.