Distribution of heavy minerals in sediment cores from the Laptev Sea continental margin and the central Arctic Ocean

Focussing on heavy-mineral associations in the Laptev-Sea continental margin area and the eastern Arctic Ocean, 129 surface sediment samples, two short and four long gravity cores have been studied. By means of the accessory components, heavy-mineral associations of surface sediment samples from the Laptev-See continental slope allowed the distinction into two different mineralogical provinces, each influenced by fluvial input of the Siberian river Systems. Transport pathways via sea ice from the shallow shelf areas into the Arctic Ocean up to the final ablation areas of the Fram Strait can be reconstructed by heavy-mineral data of surface sediments from the central Arctic Ocean. The shallow shelf of the Laptev Sea seems to be the most important source area for terrigenous material, as indicated by the abundant occurence of amphiboles and clinopyroxenes. Underneath the mixing Zone of the two dominating surface circulation Systems, the Beaufort- Gyre and Transpolar-Drift system, the imprint of the Amerasian shelf regions up to the Fram Strait is detectable because of a characteristical heavy-mineral association dominated by detrital carbonate and opaque minerals. Based On heavy-mineral characteristics of the potential circum-Arctic source areas, sea-ice drift, origin and distribution of ice-rafted material can be reconstructed during the past climatic cycles. Different factors controlling the transport of terrigenous material into the Arctic Ocean. The entrainment of particulate matter is triggered by the sea level, which flooded during highs and lows different regions resulting in the incorporation of sediment from different source areas into the sea ice. Additionally, the fluvial input even at low stands of sea level is responsible for the delivery of material of distinct sources for entrainment into the sea ice. Glacials and interglacials of climate cycles of the last 780 000 years left a characteristical signal in the central Arctic Ocean sediments caused by the ice- rafted material from different sources in the circum-Arctic regions and its change through time. Changes in the heavy-mineral association from an amphibole-dominated into a garnet-epidote-assemblage can be related to climate-related changes in source areas and directions of geostrophic winds, the dominating drive of the sea-ice drift. During Marine Isotope Stage (MIS) 6, the central Arctic Ocean is marked by an heavy-mineral signal, which occurs in recent sediments of the eastern Kara Sea. Its characteristics are high amounts of epidote, garnet and apatite. On the other hand, during the Same time interval a continuous record of Laptev Sea sediments is documented with high contents of amphiboles on the Lomonosov Ridge near the Laptev Sea continental slope. A nearly similar Pattern was detected in MIS 5 and 4. Small-scale glaciations in the Putorana-mountains and the Anabar-shield may have caused changes in the drainage area of the rivers and therefore a change in fluvial input. During MIS 3, the heavy-mineral association of central Arctic sediments show similar patterns than the Holocene mineral assemblage which consists of amphiboles, ortho- and clinopyroxenes with a Laptev Sea source. These minerals are indicating a stable Transpolar-Drift system similar to recent conditions. An extended influence of the Beaufort Gyre is only recognized, when sediment material from the Amerasian shelf areas reached the core location PS2757-718 during Termination Ib. Based On heavy-mineral data from Laptev-Sea continental slope Core PS2458-4 the paleo-sea-ice drift in the Laptev Sea during 14.000 years was reconstructed. During Holocene sea-level rise, the bathymetrically deeper parts of the Western shelf were flooded first. At the beginning of the Atlantic stage, nearly the entire shelf was marine influenced by fully marine conditions and the recent surface circulation was established.

Literary Studies in the Border Zone : International Students Studying American Fiction in Dalarna

Det amerikanska subjektets rekonstruktion: en studie av prisbelönad amerikansk skönlitterär prosa från 1990-talet

Planung des Lernfeldunterrichtes im Spannungsfeld von Geschäftsprozessorientierung und lernfeldübergreifender Kompetenzentwicklung. Das Hamburger Konzept kooperativer curricularer Entwicklungsarbeit

Der Hamburger Schulversuch EARA (Erprobung neu strukturierter Ausbildungsformen im Rahmen des Ausbildungskonsenses 2007-2010“) wurde durch in Konsortium der Universität Hamburg evaluiert und wissenschaftlich begleitet. Die Schulversuchsevaluation gliederte sich in einen summativen und einen formativen Teil (vgl. EARA 2012, 11 f.). Im Rahmen der formativen Evaluation wurden intensive curriculare Entwicklungsarbeiten geleistet, die durch eine enge Kooperation von wissenschaftlicher Begleitung und Projektschulen geprägt waren. Dieser Beitrag stellt die theoretischen Grundlagen der gemeinsamen Curriculumentwicklung im Schulversuch EARA dar. Diese sind umfassend in der Kooperation mit der beruflichen Schule für Büro und Personalmanagement Bergedorf für das Berufsbild Kaufleute für Bürokommunikation umgesetzt worden. In diesem Beitrag werden zunächst zentrale Herausforderungen der schulnahen Curriculumentwicklung im Kontext des Lernfeldansatzes dargestellt, um dann im zweiten Abschnitt die im Schulversuch EARA zum Tragen gekommenen Lösungsansätze zu beschreiben. Die spezifischen Herausforderungen waren (1) eine veränderte curriculare Entwicklungslogik, (2) die notwendige curriculare Rekonstruktion von Lernfeldern, (3) die Schwierigkeiten prozessübergreifender Kompetenzentwicklung und (4) die geforderte Verknüpfung von Prozess- und Systemperspektive in den Lernsituationen. Die Lösungsvorschläge für diese Herausforderungen münden im Konzept der Hamburger Kompetenzmatrix und werden am Beispiel von Ergebnissen aus dem Projekt EARA dargestellt. Der Beitrag endet mit der Bilanzierung von Erfolgen und Desideraten.