Titanium and water-rich metamorphic olivine in high-pressure serpentinites from the Voltri Massif (Ligurian Alps, Italy): evidence for deep subduction of high-field strength and fluid-mobile elements

Titanium- and water-rich metamorphic olivine (Fo 86-88) is reported from partially dehydrated serpentinites from the Voltri complex, Ligurian Alps. The rocks are composed of mostly antigorite and olivine in addition to magnetite, chlorite, clinopyroxene and Ti-clinohumite. In situ secondary ion mass spectrometry (SIMS) data show that metamorphic olivine has very high and strongly correlated H2O (up to 0.7 wt%) and TiO2 contents (up to 0.85 wt%). Ti-rich olivine shows colourless to yellow pleochroism. Olivine associated with Ti-clinohumite contains low Ti, suggesting that Ti-rich olivine is not the breakdown product of Ti-clinohumite. Fourier transform infrared spectroscopy (FTIR) absorption spectra show peaks of serpentine, Ti-clinohumite and OH-related Si vacancies. Combining FTIR and SIMS data, we suggest the presence of clustered planar defects or nanoscale exsolutions of Ti-clinohumite in olivine. These defects or exsolutions contain more H2O (x similar to 0.1 in the formula 4Mg(2)SiO(4)center dot(1-x)Mg(OH, F)(2)center dot xTiO(2)) than Ti-clinohumite in the sample matrix (x = 0.34-0.46). In addition to TiO2 and H2O, secondary olivine contains significant Li (2-60 ppm), B (10-20 ppm), F (10-130 ppm) and Zr (0.9-2.1 ppm). It is enriched in B-11 (delta B-11 = +17 to +23 parts per thousand). Our data indicate that secondary olivine may play a significant role in transporting water, high-field strength and fluid-mobile elements into the deeper mantle as well as introduce significant B isotope anomalies. Release of hydrogen from H2O-rich olivine subducted into the deep mantle may result in strongly reduced mantle domains.OAIID:oai:osos.snu.ac.kr:snu2014-01/102/0000043439/1SEQ:1PERF_CD:SNU2014-01EVAL_ITEM_CD:102USER_ID:0000043439ADJUST_YN:YEMP_ID:A076886DEPT_CD:3345CITE_RATE:3.476FILENAME:de hoog et al-14-cmp-titanium- and water-ric.pdfDEPT_NM:지구환경과학부SCOPUS_YN:NCONFIRM:

The Stability of One-Step Schemes for First-Order Two-Point Boundary Value Problems

The stability of a finite difference scheme is related explicitly to the stability of the continuous problem being solved. At times, this gives materially better estimates for the stability constant than those obtained by the standard process of appealing to the stability of the numerical scheme for the associated initial value problem

De boer en de huwelijksmarkt.

Mogelijke oorzaken voor het achterblijven van huwelijkssluitingen door boeren vgl. met de rest van de Nederlandse bevolkin

Boron isotope record of peak metamorphic ultrahigh-pressure and retrograde fluid–rock interaction in white mica (Lago di Cignana, Western Alps)

This study presents boron (B) concentration and isotope data for white mica from (ultra)high-pressure (UHP), subduction-related metamorphic rocks from Lago di Cignana (Western Alps, Italy). These rocks are of specific geological interest, because they comprise the most deeply subducted rocks of oceanic origin worldwide. Boron geochemistry can track fluid–rock interaction during their metamorphic evolution and provide important insights into mass transfer processes in subduction zones. The highest B contents (up to 345 μg/g B) occur in peak metamorphic phengite from a garnet–phengite quartzite. The B isotopic composition is variable (δ11B = − 10.3 to − 3.6%) and correlates positively with B concentrations. Based on similar textures and major element mica composition, neither textural differences, prograde growth zoning, diffusion nor a retrograde overprint can explain this correlation. Modelling shows that B devolatilization during metamorphism can explain the general trend, but fails to account for the wide compositional and isotopic variability in a single, well-equilibrated sample. We, therefore, argue that this trend represents fluid–rock interaction during peak metamorphic conditions. This interpretation is supported by fluid–rock interaction modelling of boron leaching and boron addition that can successfully reproduce the observed spread in δ11B and [B]. Taking into account the local availability of serpentinites as potential source rocks of the fluids, the temperatures reached during peak metamorphism that allow for serpentine dehydration, and the high positive δ11B values (δ11B = 20 ± 5) modelled for the fluids, an influx of serpentinite-derived fluid appears likely. Paragonite in lawsonite pseudomorphs in an eclogite and phengite from a retrogressed metabasite have B contents between 12 and 68 μg/g and δ11B values that cluster around 0% (δ11B = − 5.0 to + 3.5). White mica in both samples is related to distinct stages of retrograde metamorphism during exhumation of the rocks. The variable B geochemistry can be successfully modelled as fluid–rock interaction with low-to-moderate (< 3) fluid/rock ratios, where mica equilibrates with a fluid into which B preferentially partitions, causing leaching of B from the rock. The metamorphic rocks from Lago di Cignana show variable retention of B in white mica during subduction-related metamorphism and exhumation. The variability in the B geochemical signature in white mica is significant and enhances our understanding of metamorphic processes and their role in element transfer in subduction zones

Partnerselectie bij huwelijkssluiting in Nederland

In this study the matter of mate selection at marriage in the Netherlands has been raised. Apart from a literature study this study has been based on two field surveys carried out in March and April 1976. The problem dealt with in this report has been formulated as follows: has a change appeared in successing generations in the Netherlands in the complex of factors and/or the power of relations within the complex of factors which influence mate selection and what are the consequences of this eventual change for the theory building about mate selection. Within this framework 21 hypotheses have been put to the test. These hypotheses are partly based on existing literature.In the first chapter the most important concepts emerging from literature about mate selection have been treated. The central idea has been formed by homogamy. In this chapter homogamy has been related to geographic propinquity, racial and ethnic background, religious denomination, level of education and social class. Moreover the incest-taboo and a number of psychological theories have briefly been treated. Also some general theories concerning mate selection have been dealt with. In the final part of this chapter mating and dating behaviour and the first meeting have been discussed. With regard to mating and dating behaviour the matter of marriage bureaus (in 1981: about 9.000 candidates registered at bona fide bureaus) has also been investigated and so has the phenomenon of marriage advertisements. With regard to the first meeting, the geographic propinquity has been treated next to the cause of this meeting.On setting up the inquiry (chapter 2) three conditions had to be fulfilled:a. questioning of the marriage partners has to happen in such a way that mutual influencing was avoided as much as possible; b. couples from the marriage cohorts 1972, 1973, 1974 and 1975 had to be questioned (field survey March 1976);c. questioning of the parents of the marriage partners who had been asked in the first place, had to be possible (field survey April 1976).All this resulted in two field surveys: the mate selection re search of people married in the period 1972-1975 and the research of their parents. Regarding the population first mentioned, representativeness has been pursued. It will be clear that this could not be the case with regard to the population of the parents and the parents-in-law (effects of demographic drop out, etc.). Concerning the people married in the period 1972-1975 740 persons were questioned (370 couples). Though the number of refusals etc. was rather high (35%) this population appeared to be representative for the period 1972-1975. These married people were asked to give the addresses of their parents. Altogether 493 addresses were given. In all 746 of the parents (373 couples) were questioned. For this population the percentage of refusals was 24. The population of the parents consisted of the following part populations: parents and parents-in-law 204; parents of man only 88; parents of women only 80 (one interview could not be used). The possibility existed to connect the population of the parents directly with the population of the children. From the trial-interviews it ap peared that the questions put to the children could not entirely be repeated with regard to the parents. It appeared that the factor time caused disturbances here.In the third, fourth and fifth chapter a description respectively a test of the hypotheses of mate selection has been dealt with. The most important conclusions can be summarized as follows.In the seventies young people started to meet each other in a more informal way. In many fields the separation of the sexes had come to an end. The classical meeting places (fair, public ball, carnival, parties and family festivities) became less important. The youngsters did not need to wait for a special occasion. It became part of the youth culture to visit dancing halls or a pop-concert together with boy- and girl-friends and that they spent their leisure time together. Therefore it was no wonder that 60% could not mention a direct setting for their first meeting. During the past decades integration took place in a number of fields. Because of means of transport of their own the young people have become more mobile. Next to that the level of consumption has also played a part at mate selection. We have been able to determine that mate-selection has taken place within the leisure setting. In former days it was no ex ception that one had to save up for months to join the carni val of fair successfully. It now appeared to be possible to take part in the extensive "recreation culture" without saving up.With regard to the mating and dating behaviour of those que tioned the following could be concluded:- the youngest generation has not been educated separately according to sex;- in the recreational field the youngest generation has strongly mixed with each other (according to age and sex);- in financial respect the youngest generation has become more independant.From the comparison between the generations it appeared that both had to do with rules, orders and prohibitions of their parents. The degree to which, however, differed strongly. The parents were raised very strictly by their parents. For that matter, girls were tethered by a shorter rope than boys. Also the younger generation had to do with rules. Their parents too were stricter for their daughters than for their sons. One should not consider the setting of rules and changes of them an isolated phenomenon. Here too more general trends are under discussion, such as developments within the family, the grea ter independence, also in the economic field, and the indivi dualized understanding of marriage in society.Also with regard to the degree to which homogamy occurred, differences between the generations can be mentioned. The generation of the parents more often married equals with regard to educational level than the young couples did. From the Dutch pattern of nuptiality it appeared that, regarding the age of marriage, an adaption to the West European pattern of nuptiality has taken place (people marry at a younger age). It also appeared that the differences in age between men and women have decreased.With regard to religious denomination changes have been considerable. Secularization and backsliding have also had a great influence on the field of mate selection. With the younger couples homogamy after religious denomination occurred less frequently than with their parents. From the research it has become clear that, apart from the members of the reformed churches, all communions have lost members, not in particular because of mixed marriages but because of mass secularization. From testing the hypotheses (see annexe) it appeared that, in general, men were more active than women during the period of mate selection. Homogamy still appeared to be characteristic. However, from comparing the generations it appeared that homogamy occurred more frequently with the older generation.This could partly be ascribed to demographic factors (duration of marriage, mortality, divorces) but also to social developments which had found an echo within the families (family and marriage being based on economic agreements less than in former days, the authority of parents with respect to children has decreased). Apart from differences between men and women there appeared to be resemblances too. In general it appeared that boys did not differ from girls with regard to their conduct towards their parents at conflicts etc. and concerning liberties they thought they could permit themselves. This may point to the influence of the emancipation movement on female youngsters in the Netherlands. Ultimately it appeared that the presence of homogamy or not, did not cause problems between parents and children. This may mean that pluriformity and mobility are generally accepted in Dutch society. However, a different explanation is also possible. Between parents and children conflicts are evaded or got round. As for that it is characteristic of many young couples who were married in church (this perhaps being one of the most important reasons that the parents were satisfied) that they withdrew from their religious duties afterwards.The most important recommendation towards policy is that in the near future policy makers have to reckon with demographic and family effects of their decisions.</p

Analysis of ADCP data above a bottom observatory

A 300-kHz ADCP was set on GEOSTAR, a six-m3 deep-sea observatory. It was operated with cells of 80 cm during a three-week test experiment at 42-m water depth in the northern Adriatic sub-basin. Although it provided valuable data about the horizontal current field over most of the water column, it also allowed specifying the wake disturbances induced by the observatory. These disturbances are characterised by vertical velocities that are significant up to ~20 m above seafloor (echo intensity data suggest that the wake can even reach the surface), and by inclinations of the bottom nepheloïd layer (as deduced from differences in echo intensities from beam to beam). Our analysis is validated by consistent relationships between the horizontal current direction and speed on one side and the characteristics of both dynamical (vertical velocity) and non-dynamical (echo intensity) parameters on the other side. It is in good agreement with the simulations from a numerical model, and hence specifies the sensitivity (especially with respect to echo intensity) and accuracy of an instrument usually operated within fields of current and scatterers not disturbed by the device supporting it. In addition, the error velocity parameter displays specific characteristics that easily allow specifying the thickness of the layer disturbed by the observatory, thus providing a technique to validate the quality of data acquired in similar conditions

Biodiversity of the genus Cladophialophora

Cladophialophora is a genus of black yeast-like fungi comprising a number of clinically highly significant species in addition to environmental taxa. The genus has previously been characterized by branched chains of ellipsoidal to fusiform conidia. However, this character was shown to have evolved several times independently in the order Chaetothyriales. On the basis of a multigene phylogeny (nucLSU, nucSSU, RPB1), most of the species of Cladophialophora (including its generic type C. carrionii) belong to a monophyletic group comprising two main clades (carrionii- and bantiana-clades). The genus includes species causing chromoblastomycosis and other skin infections, as well as disseminated and cerebral infections, often in immunocompetent individuals. In the present study, multilocus phylogenetic analyses were combined to a morphological study to characterize phenetically similar Cladophialophora strains. Sequences of the ITS region, partial Translation Elongation Factor 1-α and β-Tubulin genes were analysed for a set of 48 strains. Four novel species were discovered, originating from soft drinks, alkylbenzene-polluted soil, and infected patients. Membership of the both carrionii and bantiana clades might be indicative of potential virulence to humans