Early Proterozoic,basaltic andesite tuff-breaccia: downslope,subaqueous mass transport of phreatomagmatically-generated tephra

At Bear Lake, in the Flin Flon-Snow Lake greenstone belt of Manitoba, 400⁺ m of thick-to very thick-bedded, generally ungraded, basaltic andesite tuff-breccia, breccia, and lapilli-tuff are intercalated with pillowed lava flows in the upper part of an early Proterozoic submarine basaltic andesite shield volcano. The fragmental rocks comprise angular, amygdaloidal blocks and lapilli, many with partial chilled selvages, in a matrix of blocky, non-amygdaloidal to highly amygdaloidal vitric basaltic andesite ash and small lapilli. Minor thin-to medium-bedded, commonly normally graded tuff occurs in the upper part of the sequence. Clasts in fragmental beds consistently have higher amygdule contents than intercalated lava flows. Although similar to pillow-fragment breccias, the Bear Lake fragmental rocks were produced by extended surtseyan-type, phreatomagmatic eruptions, with associated fire fountain activity, at a progressively subsiding, shallow water vent. Periodic tephra slumping generated debris flows that transported particles down the uppe, gentle slope of the volcano to a depositional site at a water depth of less than 1 km. Turbidity currents probably carried much fine tephra to deeper water; tuff was deposited in the preserved section only after explosive volcanism ceased.     

Creating a global warming implementation regime

This paper proposes a global warming implementation regime which addresses the issues of equity, flexibility, cost minimization, and population growth. Previously proposed international policy instruments, such as country by country targets, carbon taxes, and tradable permits, face major difficulties as stand alone proposals. The key element of the regime proposed here is to combine annual tradable permits which are allocated based on population in a fixed year with a small carbon tax ($5–10/tonne) on emissions in excess of permits. Both permits and carbon taxes are applied to national level governments, which in turn would use whatever mix of policies desired to reduce national emissions. It is suggested that the initial number of permits correspond to total global emissions in the base year; over time, the number of permits could be reduced and the tax rate increased if improved scientific knowledge so dictates. By allocating permits based on population the equity concerns of developing countries are addressed, while taxing emissions in excess of permit holdings removes the rigidity of a quota system and limits resource transfers by effectively capping the permit trading price, which is a major concern of industrialized countries. To accommodate the difficulties of countries which have not yet achieved the demographic transition, the permit allocation scheme could be subject to a one-time adjustment after 10–15 years based on some weighting of the initial and then-current populations. The proposed scheme is based on the premise that there is a large potential for reducing emissions in developed countries or limiting emission increases in developing countries, and the intention is to create competition between national level governments in implementing cost-effective emission reduction.     

Diet and gill morphology of the East Coast redeye round herring Etrumeus wongratanai off KwaZulu-Natal,South Africa

Stomach content analyses and measurements of gillraker morphology were used to assess the diet and feeding ecology of the East Coast redeye round herring Etrumeus wongratanai and provide data for comparisons with other small pelagic fishes off South Africa. Samples were collected by jigging from a kayak off Scottburgh, KwaZulu-Natal (KZN), over the period July 2013–May 2014. In total, 66 stomachs (containing 4 407 prey items) and 66 gill arches were examined. Stomach content analyses indicated that East Coast redeye round herring, at the time of sampling, fed on large (1 500–2 500?µm) particles, with ～2 500?µm particles making the greatest contribution to dietary carbon. The species feeds on larger particles than do anchovy Engraulis encrasicolus and sardine Sardinops sagax, but on particles of a similar size to those consumed by West Coast redeye round herring Etrumeus whiteheadi. There were significant differences in mean gillraker gaps between East Coast redeye round herring and both sardine and anchovy, but not between East Coast and West Coast redeye round herring. The differences in gillraker gaps between East Coast redeye round herring, sardine and anchovy are indicative of resource partitioning through differential feeding, based on zooplankton size. The data suggest that there is no resource partitioning between East and West coast redeye round herring, indicating that competition is likely to occur between them. However, such competition is minimised by limited spatial overlap between these two species.     

Mass physical properties, sliding and erodibility of experimentally deposited and differently consolidated clayey muds (Approach, equipment, and first results)

On experimentally deposited kaolinite, illite, and Ca-bentonite consolidated under their own load or by additional vertical pressure, the progress of compaction in relation to excess pore water pressure, mass physical properties, gravitational mass movements in a tilted tank, and erodibility under running water in a flume were studied. The very low consolidated sediments near the mud/water interface do not obey the generally used theory in soil mechanics. They show a different, non-linear relationship between void ratio or water content and depth below the sedimentary surface on the one hand, or effective overburden pressure and shear strength on the other. The same is true of other physical properties such as permeability, which changes considerably with depth and time of consolidation. High sedimentation rates on slopes induce shallow sediment flow, whereas at low rates and critical slope angles different types of slope failures including the breaking up of water-rich sediment into sharp boundered blocks are observed. Flume studies on soft clay muds show three different types of erosion: continuously suspending, discontinuous erosion of crumbs or shreds, and wavy deformation of the clay surface with disintegration of particles from the crests. The critical tractive stress depends not only on clay type, void ratio, and shear strength, but significantly also on the ‘geologic history’of the clay (i.e. deposition from thin suspension or dense slurry, fabric, consolidation and swelling generating minute inhomogeneities etc.). The experiments may lead to a better understanding of all mechanical processe's including pore-water flow taking place near or not far below the sediment/ water interface.     

Weathering of surface clasts as an indicator of the relative age of glacial deposits on Jameson Land, East Greenland

The relative age of glacial deposits on Jameson Land was investigated by weathering-based techniques. Two related methods, measurement of rind thickness and of Schmidt hammer rebound values. were added to a dating programme of luminescence-, amino acid- and ¹⁴C-analyses. Rind thicknesses differ significantly between areas which represent three glacial phascs, spanning a time interval from late Saale to Late Weichselian. Rebound values are more susceptible to external factors than the rind values but may, if these external factors are known, serve as a complement to the interpretation of rind development.