Reconstruction of Indian Ocean summer monsoon dynamicsat Nam Co using lipid biomarkers since 24 cal ka BP

Abstract HKT-ISTP 2013 B

Rock Glacier Characteristics Under Semiarid Climate Conditions in the Western Nyainqêntanglha Range, Tibetan Plateau

Abstract Rock glaciers are receiving increased attention as a potential source of water and indicator of climate change in periglacial landscapes. They consist of an ice‐debris mixture, which creeps downslope. Although rock glaciers are a wide‐spread feature on the Tibetan Plateau, characteristics such as its ice fraction are unknown as a superficial debris layer inhibits remote assessments. We investigate one rock glacier in the semiarid western Nyainqêntanglha range (WNR) with a multi‐method approach, which combines geophysical, geological and geomorphological field investigations with remote sensing techniques. Long‐term kinematics of the rock glacier are detected by 4‐year InSAR time series analysis. The ice content and the active layer are examined by electrical resistivity tomography, ground penetrating radar, and environmental seismology. Short‐term activity (11‐days) is captured by a seismic network. Clast analysis shows a sorting of the rock glacier's debris. The rock glacier has three zones, which are defined by the following characteristics: (a) Two predominant lithology types are preserved separately in the superficial debris patterns, (b) heterogeneous kinematics and seismic activity, and (c) distinct ice fractions. Conceptually, the studied rock glacier is discussed as an endmember of the glacier—debris‐covered glacier—rock glacier continuum. This, in turn, can be linked to its location on the semiarid lee‐side of the mountain range against the Indian summer monsoon. Geologically preconditioned and glacially overprinted, the studied rock glacier is suggested to be a recurring example for similar rock glaciers in the WNR. This study highlights how geology, topography and climate influence rock glacier characteristics and development.Plain Language Summary Climate change has begun to impact all regions of our planet. In cold regions, such as high‐mountain areas, rising temperatures lead to massive melting of glaciers. Besides this evident loss of ice, permafrost, a long‐term ice resource hidden in the subsurface, has started to thaw. Rock glaciers as visible permafrost‐related landforms consist of an ice‐debris mixture, which makes them creep downslope. Due to this movement and their recognizable shape, rock glaciers are permafrost indicators in high‐mountain areas. We investigate one rock glacier in the western Nyaingêntanglha Range (Tibetan Plateau) using field and remote sensing methods to understand its development and to know the current state of its ice core. Our main outcome is, that the heterogeneous creeping behavior, the properties of the debris cover as well as the internal distribution of ice are the results of a continuous development from a glacier into today's rock glacier. In particular, the high ice content in particular sections points to such a glacial precondition. The debris layer covering the internal ice attenuates the effect of climate warming. This makes the rock glacier and similar rock glaciers found in the northern part of the mountain range important future water resources for the semiarid region.Key Points Geophysical and remote sensing methods in concert reveal the morphostructure, ice fraction, and kinematics of the studied rock glacier Rock glacier characteristics are controlled by geology, topography and climate on the Tibetan Plateau The studied rock glacier is conceptually interpreted as the endmember of a glacier—debris‐covered glacier—rock glacier continuu

Neue Ergebnisse über das Jungquartär im Neckarschwemmfächer bei Heidelberg

Am Beispiel eines repräsentativen Aufschlusses nordwestlich Mannheim-Wallstadt wird aufgezeigt, wie sich mit Hilfe paläontologischer Methoden (Konchylien, 14C-Daten, Pollen- und Holzartenbestimmung) sowie Sediment- und Strukturmerkmalen (Korngröße, Schichtung, Kryoturbationserscheinungen etc.) das Jungquartär des Neckarschwemmfächers stratigraphisch, paläoklimatisch und genetisch gliedern läßt. Das Riß-Würm-Interglazial, bisher im nördlichen Oberrheingraben nur sedimentologisch erfaßt, kann im Neckarschwemmfächer auf Grund von Eichenholzfunden und warmzeitlichen Konchylien — in wesentlich geringerer Tiefe als bisher angenommen — nachgewiesen werden. Mittels Holzartenbestimmung läßt sich von etwa 50 000 bis ca. 42 500 J.v.h. ein kühl-atlantisches und von ca. 42 500 bis etwa 27 000 J.v.h. ein kühl-kontinentales Klima rekonstruieren. Für ein sehr kaltes Klima von 43 000—39 000 J.v.h., wie es in den Niederlanden von Zagwijn und Paepe (1968) festgestellt wurde, ergeben sich keine Anhaltspunkte. Das Würm-Hochglazial (oberes Pleniglazial) ist entweder nur relativ geringmächtig oder nur indirekt (durch intensive Kryoturbationserscheinungen etc.) nachweisbar.researc

Die Verwendbarkeit der geomorphologischen Karte 1:25000 (GMK 25) der Bundesrepublik Deutschland für Nachbarwissenschaften und Planung

In der vorliegenden Arbeit wurde die Verwendbarkeit der im Rahmen des DFG-Schwerpunktprogramms „Geomorphologische Detailkartierung in der Bundesrepublik Deutschland” entwickelten Karten im Maßstab 1 : 25 000 (GMK 25) für nicht-geomorphologische Nutzer diskutiert. Ausgehend von dem in der theoretischen Kartographie entwickelten Kommunikationsmodell (UCAR 1979) konnten die folgenden beiden Gruppen in Bezug auf die Informationsübermittlung unterschieden werden: - Nutzer, die die in der GMK 25 enthaltenen Informationen direkt verwenden können und - Nutzer, denen die Informationen nur zugänglich sind, wenn sie übersetzt sind oder eine Übersetzungsanleitung vorliegt. Zusätzlich erörtert wurde im Rahmen dieser theoretischen Diskussion die Frage, inwieweit mit der vorgegebenen Legende eine redundanzfreie Informationsübermittlung überhaupt möglich ist. Um die direkte Verwendbarkeit zu demonstrieren, wurden im zweiten Teil (Kap. 4) die in der GMK 25 enthaltenen Informationen mit sechs Beispielen aus verschiedenen nicht-geomorphologischen Fachbereichen (Bodenkunde, Geologie, Ingenieurgeologie) verglichen. Bei allen ausgeführten Beispielen ergab dieser Vergleich eine sehr weitgehende Übereinstimmung mit der GMK 25-Legende. Für die zweite Nutzergruppe wurde im dritten Teil (Kap. 5) eine Übersetzungsanleitung, auf der Basis der GMK-Legende, erstellt. Zusätzlich wurden, ausgehend von den übersetzten Informationen, Karten erarbeitet, die die anwendungsbezogenen Informationen, wie z.B. Gesamteignung für Landwirtschaft, Gesamteignung für Abfallwirtschaft, direkt enthalten. Auch in diesen Fällen ergab der Vergleich mit Beispielen aus dem nicht-geomorphologischen Bereich, insbesondere der Planung, sehr weitgehende Übereinstimmung.researchDFG, SUB Göttinge

PSV for the past 16 ka cal BP from Lake Tangra Yumco, Tibetan Plateau

Paleomagnetic data including inclination, declination, MAD values and MDF are given on an event correct composite depth (ECCD) and age for the composite lacustrine record TAN12-2 from Lake Tangra Yumco, Tibetan Plateau

Une reconstruction multi-proxy et comparaison des changements de paléomilieux de l’Holocène des estuaires d’Alvor et d’Alcantarilha (Portugal du sud)

The present study investigates the history of two estuaries on the Algarve coast, southern Portugal, through a multi-proxy approach that links sedimentology, geochemistry, palynology, microfaunal analyses and radiocarbon dating. These analyses provide an overview of the development of these estuaries over the last ∼7500 years. Palynological data reveal climate-driven vegetational shifts over the whole period. Microfauna, which is composed predominantly of foraminifers and ostracods, provides evidence for periods of marine and brackish water conditions, observed in both estuaries. Whereas the sediment record from the Alvor estuary shows a clear, nearly continuous silting-up sequence, the development of the Alcantarilha estuary is characterised by fluvial sedimentation, replaced by a marine environment at about 7300 yr calBP. Marine transgression is indicated by marine-brackish foraminifera and ostracod assemblages, while upper-marsh pollen decreased and wetland communities increased at the same time. A continuous shallowing of the estuaries followed between ∼6700 yr calBP and ∼5700 yr calBP in Alvor and 4500 yr calBP in Alcantarilha. This was interrupted by a distinct high-energy event, possibly a storm or tsunami, between 6400 and 5800 yr cal BP in Alvor; the event was not recorded in the Alcantarilha estuary. Afterwards, the silting-up restarted with clear similarities to the pre-event situation and continued until ∼3500/2000 yr calBP. This process wasinfluenced by the build-up ofsand barriersin front of the estuaries. Thisis also documented by a higher percentage of upper-marsh vegetation. The core from Alcantarilha estuary shows another layer of high-energy deposits, with mainly marine foraminifers and ostracods after 4500 yr calBP. The youngest parts of the two records are characterised by decreasing tidal influence and increasing anthropogenic impact, indicated by increasing values of cultivated plants and other human-induced changes of vegetation cover.Nous étudions l’histoire de deux estuaires de la côte d’Algarve (sud du Portugal) en utilisant des reconstructions multi-proxy (sédimentologie, géochimie, palynologie, micropaléontologie et datation au carbone 14). Basé sur ces derniers ∼7500 ans. Les données palynologiques décrivent des transformations florales que nous expliquons par des changements climatiques. L’évolution de la microfaune (foraminifères et ostracodes) est le reflet de l’alternance des environnements marins et saumâtres dans les deux carottes étudiées. La carotte d’Alvor montre clairement une séquence régressive. La carotte d’Alcantarilha est caractérisée par une sédimentation fluviatile à laquelle succède, vers 7300 ans calBP, une sédimentation marine littorale. La transgression est indiquée par des foraminifères et des ostracodes vivant dans des eaux saumâtres à marines. Pendant cette transgression, la proportion des pollens de l’étage supralittoral recule et celle de la zone humide augmente. Entre ∼6700 ans calBP et ∼5700 ans calBP à Alvor et 4500 ans calBP à Alcantarilha, la profondeur de la lagune diminue progressivement. Un évènement de haute énergie (tempête ou tsunami) est enregistré entre 6400 et 5800 ans cal BP sur le site d’Alvor mais pas celui d’Alcantarilha. Après cet évènement, la profondeur de la lagune régresse de nouveau jusqu’à 3500/2000 ans calBP. L’évolution de cette régression est soulignée par la formation d’un cordon littoral sur le front de l’estuaire, indiqué par l’augmentation de la proportion de la végétation de l’étage supralittoral. La carotte d’Alcantarilha montre une autre couche de sédiments, déposés en milieu de haute énergie, mise en évidence par les foraminifères et les ostracodes marins après 4500 ans calBP. La partie la plus jeune des carottes est marquée par la diminution de l’influence de la marée et une augmentation de l’impact anthropique (changement général de la végétation et accroissement des proportions des pollens des plantes cultivées).German Research Foundation (DFG; MA 1308/09)info:eu-repo/semantics/publishedVersio

Investigações geo-arqueológicas sobre a configuração do litoral algarvio durante o Holoceno

As part of a research project funded by the German Science Foundation (DFG. Deutsche Forschungsgemeinschaft), which took place from 2006 until 2010, traditional archaeological and modern geo-archaeological methods were used to study the changes taking place during the Holocene within the estuaries on the south coast of Portugal, the Algarve. Priority was placed on ascertaining if the development of the coastline between the Neolithic Period and the Middle Ages was more the result of natural causes (transgression, high energy events and climate) or human impact (settlement, land-use, erosion). A clear starting point was provided by the previously undertaken geomorphic research done at the Cerro da Vila (Vilamoura), where it has been possible to reconstruct the living conditions in and around the Roman harbour village once located there. Building on the results of this “on site” investigation, the first point of research was to analyse the influence of the hinterland (“off site”) on the hydrology of the coastal areas. Meanwhile the situation in selected estuaries neighbouring the Cerro da Vila and the related drainage areas was studied in order to identify the fundamental developments of the entire western Algarve coast (Barlavento). By comparing the different effected geo-archaeological archives in the Algarve it should become possible to differentiate erosional phases caused by changes in climate or high energy events from mostly local factors, which are induced by anthropogenic land-use; therein lies the hypothesis. The palynological studies were especially useful here in determining the human influence on the land use of the Algarve coast. The aim of the accompanying archaeological study was to draw chronologically differentiated distribution maps showing the development of human settlement between the Neolithic Period and the Middle Ages. The results of this interdisciplinary study show that the silting of the large estuaries on the southern coast of Portugal can be seen as a result of anthropogenic erosion that had already begun in the Bronze Age and reached its peak during the Roman Period. Furthermore geo-archaeological investigation shows a very strong impact, with several effects on the settlement patterns of the region (harbours, fishing-villages, murex-production, etc.), during the time of the Roman Empire.Integrado num projecto financiado pela Deutsche Forschungsgemeinschaft (DFG, Fundação Alemã de Investigação), foram investigados entre 2005 e 2010, com os métodos da arqueologia tradicional e da geo-arqueologia interdisciplinar, a evolução e a colmatação de diversos estuários e lagunas na actual costa sul de Portugal, no Algarve, durante o Holoceno recente (7000–1000 BP). O principal objectivo deste estudo foi o de esclarecer qual o impacto que as influências antropogénicas e climáticas tiveram sobre a evolução da costa, desde o Neolítico até à Época Medieval. O ponto de partida baseou-se nos estudos geomorfológicos anteriormente realizados nos arredores do sítio arqueológico do Cerro da Vila (Vilamoura), com o objectivo de obter uma reconstituição das condições ambientais desta estação portuária romana. Tendo por base estas primeiras informações “on site”, a prioridade foi analisar a influência das mudanças ocorridas durante o holoceno-recente na rede hidrográfica costeira (rios, ribeiras, etc.). Ao mesmo tempo, alguns estuários vizinhos do Cerro da Vila e suas redes — todos na zona ocidental do Algarve (Barlavento) — foram alvos de estudo, com o objectivo de identificar e definir melhor a configuração da costa sul de Portugal. Foi a hipótese base deste projecto que, com a análise comparativa dos diversos arquivos geo-arqueológicos identificados na zona do Algarve, possibilitou a individualização dos efeitos sub-regionais (climáticos, subida do nível do mar) dos efeitos locais (uso do solo) referentes à erosão do solo. Em especial, as investigações palinológicas possibilitaram a obtenção de excelentes resultados em relação à reconstituição da influência humana e da agricultura no litoral algarvio no passado. Os trabalhos arqueológicos que se realizaram em paralelo com estes estudos das geociências, tiveram o objectivo de elaborar diversos mapas de distribuição da ocupação humana do Algarve para as várias etapas da Pré-História e História, entre o Neolítico e a Época Medieval, especialmente nas zonas mais afectadas pelas mudanças na erosão e na colmatação dos estuários e lagunas. O resultado deste estudo possibilitou um melhor conhecimento sobre o processo de colmatação dos estuários do Sul de Portugal como principal evidência do notável impacto humano nesta zona, desde a Idade do Bronze e com um clímax na Época Romana. Estas alteraçőes do paleo-ambiente tiveram, evidentemente efeitos muito profundos no padrão de assentamento durante esta última fase de ocupação roman