The compressibility of silicate liquids containing Fe2O3 and the effect of composition,temperature, oxygen fugacity and pressure on their redox states

Ultrasonic longitudinal acoustic velocities in oxidized silicate liquids indicate that the pressure derivative of the partial-molar volume of Fe₂O₃ is the same in iron-rich alkali-, alkaline earth- and natural silicate melt compositions at 1 bar. The dV/dP for multicomponent silicate liquids can be expressed as a linear combination of partial-molar constants plus a positive excess term for Na₂O−Al₂O₃ mixing. Partial-molar properties for FeO and Fe₂O₃ components allow extension of the empirical expression of Sack et al. (1980) to permit the calculation of Fe-redox equilibrium in a natural silicate liquid as a function of composition, temperature, fo₂ and pressure; a more formal thermodynamic expression is presented in the Appendix. The predicted equilibrium fo₂ of natural silicate melts, of fixed oxygen content, closely parallels that defined by the metastable assemblage fayalite+magnetite+β-quartz (FMQ), in pressure-temperature space. A silicate melt initially equilibrated at 3 GPa and FMQ, will remain within approximately 0.5 log₁₀ units of FMQ during its closed-system ascent. Thus, for magmas closed to oxygen, iron-redox equilibrium in crystal-poor pristine glassy lavas represents an excellent probe of the relative oxidation state of their source regions.     

用超速CT机检测99例无症状香港中国人降低钙指数

回顾分析Ｍａｔｉｌｄａ医院超速ＣＴ室筛选首批病人中９９例中国人资料，很明显从通常采用１３０－１００Ｈｏｕｎｓｆｉｅｌｄ单位作为检出冠状血管钙化的基数应用至中国人身上其阈值数目需要降低，同时，我们也发现如果病人年龄按每１０年范围分组（２１－３０，３０－４０，４１－５０，５１－６０）而计算其超速ＣＴ的钙化指数会较随机男女一起按平均计算更易区分其差异．进一步分析显示，男性中年时候超速ＣＴ指数已达最高值，而女性则晚１０年方达最高值，因此，为了更易探测冠脉循环内钙化倾向应作出超速ＣＴ检出钙化的指数数目．这些实践经验对动脉粥样硬化过程的预测或预防有实际意义．     

Optimization of determining the additional constant of an electronic distance meter

Summary The optimization of the method of determining the addition constant of an EDM is discussed. The advantages of the optimization procedure from the point of view of efficiency and improvement of accuracy are reported.

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The annual cycle of kiel bight plankton: A long-term analysis

Over the past decade, the annual cycle of the major pelagic processes in relation to environmental factors and species composition of the plankton has been studied intensively at a fixed station in Kiel Bight. A series of sequential phases, differentiated according to characteristic properties, succeed each other in a recurring pattern each year. The following phases have been differentiated: the spring diatom bloom, the late spring copepod maximum, the summer stratification, the fall blooms and the winter dormancy. Each phase represents a particular pattern of biogenous element cycling, both within the pelagic system and between the pelagic and benthic systems. Each phase is also characterized by a spectrum of dominant species, many of which do not recur each year. Greatest variation is found amongst bloom diatoms, whereas large, slow-growing species such as the Ceratia and most metazooplankton are highly recurrent. Variation in species composition is not related to long-term trends since the past century, in spite of the considerable increase in anthropogenic nutrient input to the Bight. Short-term events appear to determine occurrence of fast-growing species, many of which have benthic resting stages in their life histories. It is concluded that more attention should be paid to life history strategies of species if the mechanisms of seasonal succession are to be elucidated. Long-term observations on appearance or absence of the various species in relation to environmental properties can provide clues as to the nature of these life history strategies.     

Effect of waves in the redistribution of sediments along the Konkan coast

From the wave refraction diagrams it is delineated that the Jaigad Head and Warori Bluff are the zones of wave energy convergence and the Narvan and Ambwah bays the areas of wave energy divergence. The presence of two distinct mineral phases noticed at the Jaigad, Ambwah and Varvade bays shows that there are two different circulations of sediment movements. The presence of natural barriers restricts the movement of sediment along the coast. The sand bar at the mouth of the Jaigad Bay has different orientations during the monsoon and non-monsoon periods causing obstruction to navigation during the former period.     

Eduard Suess' relations to the Pre-1950 schools of thought in global tectonics

Two main schools of thought in global tectonics are recognized during the first half of the XXth century on the basis of their proponents' attitude towards the principle of uniformitarianism and their belief in an inherent order and regularity vs. disorder and irregularity in tectonics. One group, here called the Wegener-Argand school, had a unifomitarian approach to global tectonics and believed in an inherently irregular Nature, in which probability rather than determinism was believed to be a realistic approach. The other, here called the Kober-Stille school, was largely non-uniformitarian (neocatastrophist) and believed in an orderly, regular Nature. These two schools correspond to Argand's mobilists and fixists respectively. In this paper I show that Eduard Suess was a convinced uniformitarian as far as his views on global tectonics are concerned and denied any inherent regularity in tectonic phenomena, temporal or spatial. In his interpretations of the causes and nature of orogeny, nature of geosynclines, and causes and nature of stabilisation, Suess appears to be the predecessor of the Wegener-Argandians, i. e. of the mobilists and not of the Kober-Stilleans as hitherto assumed. Although he remained a fixist and contractionist to the end Suess seems to have paved the way for the mobilists much as he did for the nappists during the last quarter of the XIX^th century.

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Zusammenfassung Während der ersten Hälfte des XX. Jahrhunderts kann man zwei globaltektonische Denkungsweisen oder Großschulen unterscheiden, die gekennzeichnet sind durch ihre Stellungnahme zum aktualistischen Prinzip in der Tektonik und ob sie an eine ordentliche und regelmäßige Natur glaubten oder nicht. Die erste, hier die Wegener-Argand-Schule genannt, hatte die Gültigkeit des aktualistischen Prinzips in der Tektonik anerkannt und die Natur, im Grunde genommen, als unordentlich und unregelmäßig betrachtet. Die Anhänger dieser Denkweise glaubten, daß probablistische Lösungen tektonischer Probleme realistischer seien als deterministische. Die andere Großschule, hier die Kober-Stille-Schule genannt, war im Grunde genommen anti-aktualistisch (Neo-Katastrophistisch) und glaubte, daß die Natur ordentlich und regelmäßig sei. Diese zwei Schulen entsprechen Argands' Einteilung in Mobilisten und Fixisten. In diesem Artikel zeige ich, daß E. Suess ein überzeugter Aktualist in bezug auf seine tektonischen Ansichten war, und daß er jede Regelmäßigkeit, zeitlicher oder räumlicher Art, der tektonischen Ereignisse ablehnte. In seinen Interpretationen der Ursachen und der Art der Orogenese, der Art der Geosynklinalen und der Ursache und der Art der Erstarrung, erscheint Suess als ein Vorgänger der Wegener-Argand-Schule, d. h. der Mobilisten, deren Gedankengänge er viel näher stand als dem der Kober-Stille-Schule. Obwohl Suess selbst bis zuletzt ein Fixist und Kontraktionist blieb, bereitete er eigentlich den Weg für die Mobilisten, wie er es früher auch für die Nappisten getan hatte.

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Résumé Durant la première moitié du XX^e siêcle, on peut distinguer deux principales écoles de pensée en tectonique globale, selon l'attitude de ses adhérents envers le principe de l'actualisme et selon leur croyance ou non à un ordre et une régularité intrinsèques en tectonique. Le premier groupe, ici appelé l'école de Wegener-Argand, suivit une voie actualiste et crût la Nature essentiellement irrégulière, de telle sorte qu'un traitement probabiliste fût considéré plus réaliste qu'un traitement déterministe. L'autre, appelé ici l'école de Kober-Stille, était essentiellement non-actualiste (néo-catastrophiste) et crût à une Nature ordonnée, régulière. Ces deux écoles correspondent aux mobilistes et aux fixistes d'Argand. Dans cet article, je montre que E. Suess, fût un actualiste convaincu, du moins en ce qui concerne ses opinions sur la tectonique globale, et qu'il rejetta toute notion de régularité dans les phénomènes tectoniques, autant spatiaux que temporaux. Dans ses interprétations des causes et de la nature de l'orogenèse, de la nature des géosynclinaux, et des causes et de la nature de la «stabilisation», Suess est un des précurseurs des «Wegener-Argandiens», c'est à dire des mobilistes. Bien qui'il fût demeuré, jusqu'à la fin de sa vie, fixiste et un avocat de la contraction, il semble que Suess ait préparé la voie aux mobilistes, de la mème façon qu'il l'avait fait pour les nappistes pendant le derier quart du XIX^e siècle.

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Subtidal distribution of barnacles (Cirripedia: Balanidae) in Chesapeake Bay,Maryland

From 1977 to 1980, samples of barnacles were collected (as opportunities arose) from 61 subtidal locations (mostly oyster beds) around Chesapeake Bay, Maryland. Three species were identified from the area.Balanus improvisus dominated, comprising 83% of the 8,231 barnacles identified, and was collected at all locations but one. It occurred over a collection salinity range of 0.8‰ to 17.9‰.Balanus subalbidus (14% of the barnacles identified) was collected over the same salinity range, but mainly in lower salinity waters.Balanus eburneus was scarce (2% of the barnacles identified) and was collected at higher salinities (8.5‰ to 17.1‰).     

Neotectonics of the Pontides: implications for ‘incompatible’ structures along the North Anatolian fault

Data for the post-Serravallian, ‘neotectonic’ evolution of the Pontides in northern Turkey indicate predominant ENE-WSW shortening with complementary NNW-SSE extension. We present a new fault plane solution for the Bartin earthquake (3 September 1968) and compare its mechanism with the movement picture of other neotectonic faults in the Pontides and northern Greece together with that of the Thessaloniki earthquake (20 May 1978). The general strain pattern exhibited by these structures agrees remarkably well with that inferred from early Tortonian-early Pleistocene structures reported from within the North Anatolian fault zone, which have been interpreted as indicating a possible reversal of the sense of movement along the North Anatolian transform fault. Here, we argue that such ‘incompatible’ structures may be related to the overall E-W shortening of Anatolia and the southern parts of the Black Sea resulting from the sideways continental escape from around the African and the Arabian promontories, rather than to hypothetical reversal of motion along the North Anatolian fault, for which there is no evidence other than the above-mentioned ‘incompatible’ structures. This new model also has important implications for seismicity and earthquake risk in regions contained within the southern part of the Black Sea plate.     

Nonlinear plasma wave processes observed in the polar cusp

We present observations of electric and magnetic field variations from proton (about few Hz) to electron cyclotron frequencies (about few kHz) obtained by STAFF instrument on Cluster satellites during two cusp crossings, at ∼6 R _E altitude, in September 2002. The cusp was identified by the presence of intensive fluxes of counter streaming electrons with low energies and broadband wave activity which is typical for this region. Special attention is given for the interval of measurements when the waveform of the magnetic field fluctuations was taken in this region by CLUSTER satellites. The wave has been processed using the wavelet and bispectral analysis. Results showing the cascade of turbulence and wave-wave interactions are presented in this paper. A three wave process can be responsible for the broadening of the wave spectra in the polar cusp.