Hydrogen fluence in Genesis collectors: Implications for acceleration of solar wind and for solar metallicity

NASA's Genesis mission was flown to capture samples of the solar wind and return them to the Earth for measurement. The purpose of the mission was to determine the chemical and isotopic composition of the Sun with significantly better precision than known before. Abundance data are now available for noble gases, magnesium, sodium, calcium, potassium, aluminum, chromium, iron, and other elements. Here, we report abundance data for hydrogen in four solar wind regimes collected by the Genesis mission (bulk solar wind, interstream low‐energy wind, coronal hole high‐energy wind, and coronal mass ejections). The mission was not designed to collect hydrogen, and in order to measure it, we had to overcome a variety of technical problems, as described herein. The relative hydrogen fluences among the four regimes should be accurate to better than ±5–6%, and the absolute fluences should be accurate to ±10%. We use the data to investigate elemental fractionations due to the first ionization potential during acceleration of the solar wind. We also use our data, combined with regime data for neon and argon, to estimate the solar neon and argon abundances, elements that cannot be measured spectroscopically in the solar photosphere.     

Exploring Spatially Non-stationary Relationships in the Determinants of Mineralization in 3D Geological Space

Exploring the spatial relationships between various geological features and mineralization is not only conducive to understanding the genesis of ore deposits but can also help to guide mineral exploration by providing predictive mineral maps. However, most current methods assume spatially constant determinants of mineralization and therefore have limited applicability to detecting possible spatially non-stationary relationships between the geological features and the mineralization. In this paper, the spatial variation between the distribution of mineralization and its determining factors is described for a case study in the Dingjiashan Pb–Zn deposit, China. A local regression modeling technique, geological weighted regression (GWR), was leveraged to study the spatial non-stationarity in the 3D geological space. First, ordinary least-squares (OLS) regression was applied, the redundancy and significance of the controlling factors were tested, and the spatial dependency in Zn and Pb ore grade measurements was confirmed. Second, GWR models with different kernel functions in 3D space were applied, and their results were compared to the OLS model. The results show a superior performance of GWR compared with OLS and a significant spatial non-stationarity in the determinants of ore grade. Third, a non-stationarity test was performed. The stationarity index and the Monte Carlo stationarity test demonstrate the non-stationarity of all the variables throughout the area. Finally, the influences of the degree of non-stationary of all controlling factors on mineralization are discussed. The existence of significant non-stationarity of mineral ore determinants in 3D space opens up an exciting avenue for research into the prediction of underground ore bodies.

     

The influence of 70 and 120 kHz tonal signals on the behavior of harbor porpoises (Phocoena phocoena) in a floating pen

Two harbor porpoises in a floating pen were subjected to five pure tone underwater signals of 70 or 120kHz with different signal durations, amplitudes and duty cycles (% of time sound is produced). Some signals were continuous, others were intermittent (duty cycles varied between 8% and 100%). The effect of each signal was judged by comparing the animals' surfacing locations and number of surfacings (i.e. number of respirations) during test periods with those during baseline periods. In all cases, both porpoises moved away from the sound source, but the effect of the signals on respiration rates was negligible. Pulsed 70kHz signals with a source level (SL) of 137dB had a similar effect as a continuous 70kHz signal with an SL of 148dB (re 1muPa, rms). Also, a pulsed 70kHz signal with an SL of 147dB had a much stronger deterring effect than a continuous 70kHz signal with a similar SL. For pulsed 70kHz signals (2s pulse duration, 4s pulse interval, SL 147dB re 1muPa, rms), the avoidance threshold sound pressure level (SPL), in the context of the present study, was estimated to be around 130dB (re 1muPa, rms) for porpoise 064 and around 124dB (re 1muPa, rms) for porpoise 047. This study shows that ultrasonic pingers (70kHz) can deter harbor porpoises. Such ultrasonic pingers have the advantage that they do not have a "dinner bell" effect on pinnipeds, and probably have no, or less, effect on other marine fauna, which are often sensitive to low frequency sounds.     

Multi-angle backscatter classification and sub-bottom profiling for improved seafloor characterization

This study applies three classification methods exploiting the angular dependence of acoustic seafloor backscatter along with high resolution sub-bottom profiling for seafloor sediment characterization in the Eckernförde Bay, Baltic Sea Germany. This area is well suited for acoustic backscatter studies due to its shallowness, its smooth bathymetry and the presence of a wide range of sediment types. Backscatter data were acquired using a Seabeam1180 (180 kHz) multibeam echosounder and sub-bottom profiler data were recorded using a SES-2000 parametric sonar transmitting 6 and 12 kHz. The high density of seafloor soundings allowed extracting backscatter layers for five beam angles over a large part of the surveyed area. A Bayesian probability method was employed for sediment classification based on the backscatter variability at a single incidence angle, whereas Maximum Likelihood Classification (MLC) and Principal Components Analysis (PCA) were applied to the multi-angle layers. The Bayesian approach was used for identifying the optimum number of acoustic classes because cluster validation is carried out prior to class assignment and class outputs are ordinal categorical values. The method is based on the principle that backscatter values from a single incidence angle express a normal distribution for a particular sediment type. The resulting Bayesian classes were well correlated to median grain sizes and the percentage of coarse material. The MLC method uses angular response information from five layers of training areas extracted from the Bayesian classification map. The subsequent PCA analysis is based on the transformation of these five layers into two principal components that comprise most of the data variability. These principal components were clustered in five classes after running an external cluster validation test. In general both methods MLC and PCA, separated the various sediment types effectively, showing good agreement (kappa >0.7) with the Bayesian approach which also correlates well with ground truth data (r²?>?0.7). In addition, sub-bottom data were used in conjunction with the Bayesian classification results to characterize acoustic classes with respect to their geological and stratigraphic interpretation. The joined interpretation of seafloor and sub-seafloor data sets proved to be an efficient approach for a better understanding of seafloor backscatter patchiness and to discriminate acoustically similar classes in different geological/bathymetric settings.     

Positions of extragalactic objects in the vicinity of M3 and M31 (5C3 radio field) and in the 5C1 radio field

We have determined the positions of 65 compact extragalactic objects with magnitudes between 16^m and 21^m.7. The mean error of one position is about 0″.3 in α cos δ and in δ. Some hitherto unpublished redshifts are also listed.     

Cumulate gabbros from the Southwest Indian Ridge, 54°S-7° 16′ E: implications for magmatic processes at a slow spreading ridge

A diverse volcanic and plutonic rock suite was recovered from the center of the 80 km long ridge segment of the Southwest Indian Ridge (54°S, 7°16 E) between the Islas Orcadas and Shaka Fracture Zones. The cumulus nature of the gabbroic rocks in the suite is indicated by phase, modal and cryptic layering, igneous lamination, and low incompatible element abundances. We present a mass-balance model for calculating the proportions and compositions of cumulus phases and crystallized intercumulus liquid from bulk-rock major element compositions. The model is based on the ability to define a compositional array of basaltic liquids and on the assumption that cumulus minerals are initially in equilibrium with trapped liquid. Calculated proportions of trapped liquid range from 3%–15%; values that are characteristic of adcumulates to mesocumulates. Models of postcumulus crystallization indicate significant enrichments of incompatible elements and buffering of compatible elements in residual trapped liquids, thus explaining the high TiO₂ contents observed in magnesian clinopyroxenes. Cumulus phase assemblages and compositions suggest solidification in shallow level magma chambers, but disequilibrium plagioclase compositions suggest some crystallization at greater depth. Furthermore, basalt compositions projected onto the olivine-clinopyroxenequartz pseudoternary suggest magma generation over a range of pressures (from less than 10 to greater than 20 kb) as well as polybaric fractional crystallization. We suggest that the Southwest Indian Ridge is characterized by low magma supply with small batches of melt that either ascend directly to the surface having undergone limited polybaric crystallization or are trapped in shallow crustal magma chambers where they evolve and solidify to form cumulate gabbros. The adcumulus nature of the gabbros investigated here suggests slow cooling rates typical of large intrusions implying relatively large, but ephemeral magma chambers below segments of the Southwest Indian Ridge.     

Ferrobasalts from the Spiess Ridge segment of the Southwest Indian Ridge

Highly vesicular, microporphyritic basaltic rocks have been dredged from the slow-spreading Spiess Ridge segment of the Southwest Indian Ridge. All the samples recovered are hyalocrystalline with plagioclase, clinopyroxene and olivine as phenocryst and microphenocryst phases. Titanomagnetite occurs as euhedral microphenocrysts in some of the more evolved samples. In terms of bulk rock and quench glass chemistry the lavas are characterised by highly evolved compositions(e.g. FeO*=10.3−14.2%;TiO₂=2.0−3.4%;K₂O=0.50−1.1%;MgO=6.0−3.5%;Zr=160−274ppm;Nb=14−32ppm) and can be classified as ferrobasalts. Isotopic and incompatible element ratios of the lavas(e.g.⁸⁷Sr/⁸⁶Sr=0.70325−0.70333;Zr/Nb=8.4−11.3;Y/Nb=2.3−1.4) indicate their strongly “enriched” nature (see also Dickey et al. [6]).

Quantitative major and trace element modelling indicates that most of the compositional variations observed can be attributed to low-pressure fractional crystallisation of plagioclase, clinopyroxene and minor olivine and titanomagnetite. The range in composition can be accounted for by up to 65% fractional crystallisation.

We suggest that the extreme differentiation of the Spiess Ridge lavas is related not to spreading rate, but to rate of magma supply. The basaltic melts appear to have evolved in a newly established zone of magmatic activity, associated with the most recent northward jump of the Bouvet triple junction, where they were effectively isolated from significant admixture of primitive magmas.     

Pervasive melt percolation reactions in ultra-depleted refractory harzburgites at the Mid-Atlantic Ridge, 15° 20′N: ODP Hole 1274A

ODP Leg 209 Site 1274 mantle peridotites are highly refractory in terms of lack of residual clinopyroxene, olivine Mg# (up to 0.92) and spinel Cr# (∼0.5), suggesting high degree of partial melting (>20%). Detailed studies of their microstructures show that they have extensively reacted with a pervading intergranular melt prior to cooling in the lithosphere, leading to crystallization of olivine, clinopyroxene and spinel at the expense of orthopyroxene. The least reacted harzburgites are too rich in orthopyroxene to be simple residues of low-pressure (spinel field) partial melting. Cu-rich sulfides that precipitated with the clinopyroxenes indicate that the intergranular melt was generated by no more than 12% melting of a MORB mantle or by more extensive melting of a clinopyroxene-rich lithology. Rare olivine-rich lherzolitic domains, characterized by relics of coarse clinopyroxenes intergrown with magmatic sulfides, support the second interpretation. Further, coarse and intergranular clinopyroxenes are highly depleted in REE, Zr and Ti. A two-stage partial melting/melt–rock reaction history is proposed, in which initial mantle underwent depletion and refertilization after an earlier high pressure (garnet field) melting event before upwelling and remelting beneath the present-day ridge. The ultra-depleted compositions were acquired through melt re-equilibration with residual harzburgites. Electronic supplementary material Supplementary material is available in the online version of this article at and is accessible for authorized users.     

A Note on Extension Variances in IR2

Matheron (1971) proposed an approximation of the extension variance in IR. We propose in this note an extension of this formula in IR ² , based on a MacLaurin formula. Its application is shown in an example, the estimation of the maximum depressional storage of a soil surface.