Post-Svecokarelian andinotype evolution in central Sweden

Granitoids and associated volcanics, postorogenic in relation to the Svecokarelian orogeny, constitute a belt in central Sweden. Evidence presented in this paper suggest that the belt originated in an Andinotype orogenic environment. The inferred development of the belt was characterized by fracture-controlled high-level emplacement of batholiths in an ensialic setting. Voluminous venting of ignimbrites and formation of grabens through cauldron subsidence accompanied the recurrent intrusive activity. Block movements and episodes of burial metamorphism appear to have been prominent features throughout the history of the post-Svecokarelian belt.

---

Zusammenfassung Granitoide Plutonite und verwandte Vulkanite, post-orogen im Verhältnis zur Svekokarelischen Orogenese, bilden einen Gürtel in Mittelschweden. Es wird gezeigt, daß der Gürtel in einer andinotypen Orogenese gebildet wurde. Die vorgeschlagene Entwicklung des Gürtels ist geprägt durch spaltentektonisch kontrollierte Platznahme von Batholithen in einem seichten Niveau der Kruste in ensialischem Mileau. Umfangreiche Eruptionen von Ignimbriten sowie die Bildung von Grabenbrüchen durch Kalderen-Einstürzungen begleiten die erneute intrusive Tätigkeit. Blockbewegungen und episodische Versenkungsmetamorphosen sind charakteristisch während der gesamten Entwicklungsgeschichte des post-svekokarelischen Gürtels.

---

Résumé Des granitoïdes et des volcanites associées, postorogéniques par rapport à l'orogénese svécokarélienne, forment une ceinture en Suède centrale. La présente étude suggère que la mise en place de ces roches s'est effectuée dans un environment orogénique Andinotype. L'évolution de la ceinture c'est caractérisée par la mise en place; contrée par des fractures, de batholites peu profonds, en milieu ensialique. Des volumineuses éruptions d'ignimbrites et la formation de grabens par «cauldron subsidence» ont accompagné la mise en place des batholites. Des mouvements verticaux de blocs, ainsi que des épisodes de métamorphisme d'enfouissement («burial metamorphism») semblent être des faits dominants du développement historique de la ceinture post-svécokarélienne.

---

, , , - . , . . - .

     

The Ordovician chondrite from Brunflo, central Sweden: III. Geochemistry of terrestrial alteration

The fossil H chondrite Brunflo, found in a slab of Ordovician limestone from central Sweden, is pervasively altered to an assemblage dominated by calcite and barite. The meteorite is surrounded by a 15–20 cm wide zone of lighter colors than the unaffected limestone due to dissolution of hematite. Here we present detailed geochemical analyses of two meteorite samples, 14 limestone samples at distances from 0 to 29 cm along two profiles from the meteorite, and a reference sample of Brunflo limestone. Element concentrations in Brunflo and surrounding bleached limestone have been strongly disturbed during two stages of alteration (early oxygenated and deep burial). In the meteorite, the Ni/Co ratio has changed from an initial value of 20 to 0.8 and redox sensitive elements like V, As, Mo, Re and U are strongly enriched. The sulfur isotope composition of barite from Brunflo (δ³⁴S=+35‰) indicates initial loss of meteoritic sulfide, followed by later accumulation of sea water sulfate as barite. During deep burial under more reducing conditions, reduction processes supported by an externally derived reductant possibly derived from alum shale underlying the limestone, were largely responsible for the observed redox phenomena. In spite of massive redistribution of many elements, concentrations of Pt, Ir and Au remain at chondritic levels. The geochemistry and mineralogy of alteration determined for Brunflo are similar to those in “reduction spots” in red beds, where accumulation of a similar suite of elements (except Mo, Re) occurred as a result of isolated reduction activity.     

A new palaeoenvironmental model for the evolution of the Byzovaya Palaeolithic site,northern Russia

Recently, the sediment stratigraphy and geochronology of the well‐known Palaeolithic site Byzovaya in northern Russia were investigated. New technological analyses of the artefacts suggest a Middle Palaeolithic Mousterian culture, and occupation by Neanderthals, not Modern humans as previously thought. We present here a new and detailed documentation of the stratigraphy, including the geological context of the artefacts and faunal remains. From sedimentological criteria we confidently interpret the find‐bearing strata as debris‐flow deposits, covered by aeolian sediments. The chronology is based on radiocarbon and luminescence (OSL) dates from the find‐bearing and overlying strata. The results are utilized to reconstruct the geological history at the excavation area. The stratigraphy varies considerably across the excavation area. The most intact and undisturbed part of the sequence was found inside the most recent Excavation II. In this part the artefacts and bones appear to have been permanently sealed and protected by aeolian sand. The older Excavation I shows a more complicated stratigraphy, as the finds may have been temporarily exposed during the early Holocene owing to ravine incision and slumping activity. The individual radiocarbon dates that were collected from different parts of the site and from various stratigraphic positions are re‐investigated in this study. By using Bayesian statistics the conclusion is that the site was occupied during a restricted period around 30.6–34.7 ka. A series of partly unpublished OSL dates of coversand from different sites demonstrates a regional aeolian signal during the Lateglacial in northern Russia, 15–14 ka.     

High-speed photography of the bubble generated by an airgun1

High-speed photography has been used visually to study the shape, surface, turbulence and behaviour of an underwater oscillating bubble generated by an airgun. The source was a BOLT airgun with a chamber volume of 1.6cu.in., placed in a 0.85m³ tank at 0.5m depth. Near-field signatures were also recorded in order to compare the instant photographs of the oscillating bubble with the pressure field recorded about 25 cm from the gun. Estimations of the bubble-wall velocity and bubble radius estimated from high-speed film sequences are also presented, and are compared with modelled results. The deviation between the modelled and measured bubble radii was at most 9%. In order to check the capacity for transmission of light through the bubble, a concentrated laser beam was used as illumination. We found that the air bubble is a strong scattering medium of laser light, hence the bubble is opaque.     

Kinetic energy–rainfall intensity relationship for Central Cebu, Philippines for soil erosion studies

In the study of soil erosion, specifically on detachment of soil particles by raindrop impact, kinetic energy is a commonly suggested indicator of the raindrop's ability to detach soil particles from the soil mass. Since direct measurement of kinetic energy requires sophisticated and costly instruments, the alternative approach is to estimate it from rainfall intensity. The present study aims at establishing a relationship between rainfall intensity and kinetic energy for rainfalls in Central Cebu, Philippines as a preface of a wider regional investigation.

Drop size distributions of rainfalls were measured using the disdrometer RD-80. There are two forms of kinetic energy considered here. One is kinetic energy per unit area per unit time (KE_R, J m⁻² h⁻¹) and the other is kinetic energy per unit area per unit depth (KE, J m⁻² mm⁻¹). Relationships between kinetic energy per unit area per unit time (KE_R) and rainfall intensity (I) were obtained using linear and power relations. The exponential model and the logarithmic model were fitted to the KE–I data to obtain corresponding relationships between kinetic energy per unit area per unit depth of rainfall (KE) and rainfall intensity (I). The equation obtained from the exponential model produced smaller standard error of estimates than the logarithmic model.     

Daily Weather Observations in Sixteenth-Century Europe

Thirty-two weather diaries written in astronomical calendars in central Europe in the late fifteenth and sixteenth centuries are presented and discussed. Systematic weather observations were promoted by the rise of planetary astronomy and its application in astro-meteorology. The practice of keeping weather diaries spread from Cracow (Poland) to Ingolstadt (Germany) and from there to other universities. The data obtained from these sources provided the backbone for setting up series of precipitation indices for Poland, Germany and Switzerland. Monthly statistics of days with precipitation, snowfall and frost were computed by counting the relevant entries in the most important diaries. The results were compared with either those obtained from instrumental measurements in the same place or with those from modern instrumental measurements in a neighbouring place. The final results show that autumn was considerably colder in the early sixteenth century. April was considerably drier and July was wetter during the period 1508-1531 than during 1901-1960. In order to highlight the impact of weather patterns on grain prices in a year of crisis, the timing of wet and dry spells in southern Poland and southern Germany is compared for the year 1529. Winters became 1.7°C colder from 1564 to 1576 and the month of July tended to be wetter than in 1901-1960. Details noted in the diaries kept between 1585 and 1600 by the astronomers Brahe (near Copenhagen) and Fabricius (in the Ostfriesland region of northwestern Germany) closely agree. It rained more often in June and July and temperatures dropped. The winter months were more frequently dominated by winds from easterly directions, the frequency of snowfall was higher and a deficit occurred in precipitation. This points to a higher frequency of high pressure in the Fennoscandian area with cold air advection from the east or northeast.     

Estimates of Roughness Parameters for Arrays of Obstacles

Some methods are evaluated and extended to estimate roughness length and zero plane displacement height for atmospheric flow over arrays of obstacles, typically buildings. It appears that the method proposed by Bottema, with an extension to account for low density obstacle arrays, performs best. Procedures are proposed to represent irregular obstacle arrangements by a representative regular array to which Bottema's method can be applied. It is shown that this can be done without loss of accuracy, in general, roughness length can be predicted within a factor of two in more than 74% of the cases (95% reliability estimate). The methods proposed by Lettau and Raupach have been included in the evaluation. Lettau's model, which only requires input on the frontal area density, predicts roughness length unbiassed for frontal area densities up to 0.3, but predictions will be within a factor of two in more than 59% of the cases only (95% reliability estimate).     

Initial uncertainties in ‘nuclear winter’: A proposed test based on the dresden firestorm

Conclusions An extinction optical depth of 20 is necessary for total darkness (NAS, 1985), although a considerably lower value than that can produce near-total darkness because scattered light does not generate shadows and contrast. It can be seen that the Dresden firestorm smoke cloud, calculated under the conditions usually assumed in nuclear winter calculations, should have resulted in total darkness over a vast area.Using the 500 mb chart, it can be retrodicted that the smoke plume, as part of the counterclockwise circulation about the low over southern Sweden, was over central Poland as dawn broke on the 14th. Indeed, at 9 AM (Table I), smoke from what had been Dresden should have been passing over what had been Warsaw. Depending upon the specific size of the plume at the time, anywhere from a few hundred thousand to over ten million people should have been plunged into darkness.It appears unlikely that such extensive darkening could have gone unreported (especially in the light of the heightened awareness resulting from wartime conditions, and the proximity of the Soviet/German front). This has direct implications for the aforementioned initial uncertainties in nuclear winter. Possible explanations include: (a) Very low smoke emission factors - perhaps even lower than 0.001 (Broyles, 1985); (b) Substantial removal of smoke in the black rain that followed the firestorm (Irving, 1963, p. 175). Values for prompt smoke removal reaching 90% are not out of the realm of possibility (Schneider et al., 1986; Penner, 1986).The present author is of the opinion that more effort should be expended by students of the nuclear winter phenomenon to learn from WWII mass urban fires. Many eyewitnesses to these events must still be living, and there must be at least some scientifically-useable material in archives. For example, there is a 122-m, 10-min motion film of the Dresden firestorm (Irving, 1963, p. 159). It is in the film archives of the Imperial War Museum. Perhaps some new details of firestorm genesis, spread, etc. could be learned from it. There must be other log books, such as the one of Kraus (1986), which could well yield scientificallyvaluable information.     

Vulnerable or Resilient? A Multi-Scale Assessment of Climate Impacts and Vulnerability in Norway

This paper explores the issue of climate vulnerability in Norway, an affluent country that is generally considered to be resilient to the impacts of climate change. In presenting a multi-scale assessment of climate change impacts and vulnerability in Norway, we show that the concept of vulnerability depends on the scale of analysis. Both exposure and the distribution of climate sensitive sectors vary greatly across scale. So do the underlying social and economic conditions that influence adaptive capacity. These findings question the common notion that climate change may be beneficial for Norway, and that the country can readily adapt to climate change. As scale differences are brought into consideration, vulnerability emerges within some regions, localities, and social groups. To cope with actual and potential changes in climate and climate variability, it will be necessary to acknowledge climate vulnerabilities at the regional and local levels, and to address them accordingly. This multi-scale assessment of impacts and vulnerability in Norway reinforces the importance of scale in global change research.