8. Altersvergleich der Orogenesen und Versuch einer Korrelation des Grundgebirges in verschiedenen Teilen der Erde

Ohne Zusammenfassung     

Versuch einer Analyse der großen Bewegungen der Erdkruste

Ohne Zusammenfassung     

Mixed and Multi-Stock Fisheries

The September 2003 ICES Annual Science Conference was held inTalinn, Estonia, and Theme Session V was "Mixed and multi-stockfisheries – challenges and tools for assessments, prediction,and management." The theme session brought together researchersfrom the salmonid and marine fishery fields to address commonproblems faced when multiple fleets harvest a common stock,     

Holocene excursions of the Northwest European geoid

Computer-assisted analyses of more than 600 radiocarbon-dated sea-level indicators from northwestern Europe, concentrated around the North Sea margin, indicate that vertical crustal movements are more important that eustatic sea-level change in determining the locus of Holocene shoreline positions through time. For the past 14,000 radiocarbon years, the divergence of sea-level data for the northwest European sectors exceeds the maximum estimated sea-level rise by a factor of two or more. Projecting these data to a single meridian demonstrates the remarkable variety of vertical crustal movement in northwestern Europe.Accumulating radiocarbon-dated sea-level indicators into millennial cohorts, we generate isobase maps which begin to specify areas of notable vertical crustal mobility. These isobase maps appear to confirm that eustatic sea-level rise is subordinate to postglacial geoidal excursions in determining the locus of contemporary northwestern European shorelines.     

Stratigraphy of the Neoproterozoic to early Palaeozoic Savory Basin,Western Australia,and correlation with the Amadeus and Officer Basins

The Savory Basin in central Western Australia was recognized in the mid‐1980s during regional mapping of very poorly exposed Proterozoic rocks previously assigned to the Bangemall Basin. All of the sedimentary rock units in the Savory Basin have been included in the Savory Group, which unconformably overlies the Mesoproterozoic Yeneena and Bangemall Groups. Correlation with adjacent basins is impeded by poor outcrop and the lack of subsurface information. Possible correlations have been investigated with the much better known Amadeus Basin to the east, and with the Officer Basin. Two correlations now clarify the age and relationships of the Savory Group. First, the Skates Hills Formation contains distinctive stromatolites previously recorded from the Bitter Springs Formation of the Amadeus Basin. In addition, the Skates Hills and Bitter Springs Formations have many lithological features in common. This correlation is strengthened by comparison with surface and subsurface units in the northern Officer Basin. Second, the intergrading sandstone‐diamictite of the Boondawari Formation is very similar to the intergrading Pioneer Sandstone‐Olympic Formation of the Amadeus Basin, and the overlying siltstone closely resembles the Pertatataka Formation and its correlative the Winnall beds. The stromatolitic and oolitic carbonates at the top of the Boondawari Formation are broadly comparable with those of the Julie Formation (which grades down into the Pertatataka Formation). Support for this set of correlations comes from carbon isotope chemostratigraphy. The stromatolites include two new forms described herein, Eleonora boondawarica and Acaciella savoryensis, together with a third form too poorly preserved to be formally defined. The age of the upper sandstones is unknown. The McFadden Formation seems to have its provenance in the Paterson Orogen. The southeastern extension of this orogen is the Musgrave Block, where compression followed by uplift at about 560–530 Ma (Peterman Ranges Orogeny) led to the formation of large amounts of conglomerate (Mt Currie Conglomerate) and sandstone (Arumbera Sandstone). If tectonic events in the Paterson Orogen were contemporaneous with those in the Musgrave Block, the McFadden Formation would correlate with the Arumbera Sandstone.     

Relating hydrogeomorphic properties to stream buffering chemistry in the Neversink River watershed,New York State,USA

Monitoring the effects of acidic deposition on aquatic ecosystems in the Northeastern US has generally required regular measurements of stream buffering chemistry (i.e. acid‐neutralizing capacity (ANC) and calcium Ca²⁺), which can be expensive and time consuming. The goal of this paper was to develop a simple method for predicting baseflow buffering chemistry based on the hydrogeomorphic properties of ten nested watersheds in the Neversink River basin (2·0–176·0 km²), an acid‐sensitive basin in the Catskill Mountains, New York State. The tributaries and main reach watersheds have strongly contrasting mean baseflow ANC values and Ca²⁺ concentrations, despite rather homogeneous vegetation, bedrock geology, and soils. A stepwise regression was applied to relate 13 hydrogeomorphic properties to the mean baseflow ANC values and Ca²⁺ concentrations. The regression analysis showed that watersheds with lower ANC values had a higher mean ratio of ‘quickflow’ runoff to precipitation during 20 non‐snowmelt runoff events (referred to as mean runoff ratio). The mean runoff ratio could explain at least 80% of the variability in mean baseflow ANC values and Ca²⁺ concentrations among the ten watersheds. Greater mean runoff ratios also correlated with steeper slopes and greater drainage densities, thus allowing the prediction of baseflow ANC values (r² = 0·75) and Ca²⁺ concentrations (r² = 0·77) with widely available spatial data alone. These results indicate that hydrogeomorphic properties can predict a watershed's sensitivity to acid deposition in regions where the spatial sources of stream buffering chemistry from the bedrock mineralogy and soils are fairly uniform. Copyright © 2010 John Wiley & Sons, Ltd.     

Einwände der Geographie gegen die Wegenersche Theorie der Kontinentalverschiebungen

Ohne Zusammenfassung     

Modulation of the inflow into the Caribbean Sea by North Brazil Current rings

A two-year long record from a triangular mooring array between the Lesser Antilles islands Tobago, Barbados, and St. Lucia is used to investigate the inflow into the Caribbean Sea, the amount of South Atlantic Water (SAW) carried with the inflow, and the role of North Brazil Current (NBC) rings in the observed variability. The data set consists of time series from temperature/conductivity recorders and current meters in the moorings, bottom-mounted inverted echo sounders at the Tobago and St. Lucia mooring positions, and supplementary shipboard measurements. The acoustic travel time measurements of the inverted echo sounders and the conductivity/temperature time series are used for continuous estimation of dynamic height profiles and geostrophic currents between the surface and 1000 dbar as well as the amount of SAW found at the mooring positions.The observations show a domination of intraseasonal variability between 0 and 15 Sv, superimposed on the long-term fluctuations. With time scales of one to three months, these represent the signature of the NBC rings. The baroclinic transport time series shows nine periods of increased variability, indicative of the rings interacting with the Lesser Antilles island arc; with the exception of one, these periods were associated with corresponding sea surface height anomalies. No marked seasonality was observed in the transport variability or the ring frequency.The arrival of individual rings leads to a weakening of the inflow into the Caribbean. Nevertheless, the rings carry large amounts of SAW into the area, and the immediate increase of the transport towards the end of a ring event suggests a subsequent flow of this SAW-rich water into the Caribbean. At St. Lucia, rings sometimes cause a short-term decrease of SAW content, indicative of an influx of northern hemispheric water and a blocking situation. The average transport of SAW into the Caribbean south of St. Lucia during the observations amounted to 5.5 Sv, with no significant seasonal cycle, but a small positive trend in SAW fraction as well as in transport of about 15% and 1 Sv, respectively; a corresponding trend in the baroclinic volume transport was not observed.