108 research outputs found
Efficient geomorphological mapping based on geographic information systems and remote sensing data : an example from Jena, Germany
We present a detailed geomorphological map (1:5000-scale) of a middle mountainous area in Jena, Germany. To overcome limitations and to extend the possibility of manually digital mapping in a structural way, we propose an approach using geographic information systems (GIS) and high-resolution digital data. The geomorphological map features were extracted by manually interpreting and analyzing the combination of different data sources using light detection and ranging (LiDAR) data. A combination of topographic and geological maps, digital orthophotos (DOPs), Google Earth images, field investigations, and derivatives from digital terrain models (DTMs) revealed that it is possible to generate the geomorphologic features involved in classical mapping approaches. LiDAR-DTM and land surface parameters (LSPs) can provide better results when incorporating the visual interpretation of multidirectional hillshade and LSP composite maps.Findings enabled us to systematically delineate landforms and geomorphological process domains. We suggest that further use of digital data should be undertaken to support analysis and applications
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 NyainqĂȘntanglha 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 iceâdebris mixture, which creeps downslope. Although rock glaciers are a wideâspread 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 NyainqĂȘntanglha range (WNR) with a multiâmethod approach, which combines geophysical, geological and geomorphological field investigations with remote sensing techniques. Longâterm kinematics of the rock glacier are detected by 4âyear InSAR time series analysis. The ice content and the active layer are examined by electrical resistivity tomography, ground penetrating radar, and environmental seismology. Shortâterm activity (11âdays) 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 glacierâdebrisâcovered glacierârock glacier continuum. This, in turn, can be linked to its location on the semiarid leeâside 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 highâmountain areas, rising temperatures lead to massive melting of glaciers. Besides this evident loss of ice, permafrost, a longâterm ice resource hidden in the subsurface, has started to thaw. Rock glaciers as visible permafrostârelated landforms consist of an iceâdebris mixture, which makes them creep downslope. Due to this movement and their recognizable shape, rock glaciers are permafrost indicators in highâmountain areas. We investigate one rock glacier in the western NyaingĂȘntanglha 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 glacierâdebrisâcovered glacierârock glacier continuu
Neue Ergebnisse ĂŒber das JungquartĂ€r im NeckarschwemmfĂ€cher bei Heidelberg
Am Beispiel eines reprĂ€sentativen Aufschlusses nordwestlich Mannheim-Wallstadt wird aufgezeigt, wie sich mit Hilfe palĂ€ontologischer Methoden (Konchylien, 14C-Daten, Pollen- und Holzartenbestimmung) sowie Sediment- und Strukturmerkmalen (KorngröĂe, Schichtung, Kryoturbationserscheinungen etc.) das JungquartĂ€r des NeckarschwemmfĂ€chers stratigraphisch, palĂ€oklimatisch und genetisch gliedern lĂ€Ăt. Das RiĂ-WĂŒrm-Interglazial, bisher im nördlichen Oberrheingraben nur sedimentologisch erfaĂt, kann im NeckarschwemmfĂ€cher auf Grund von Eichenholzfunden und warmzeitlichen Konchylien â in wesentlich geringerer Tiefe als bisher angenommen â nachgewiesen werden. Mittels Holzartenbestimmung lĂ€Ăt sich von etwa 50 000 bis ca. 42 500 J.v.h. ein kĂŒhl-atlantisches und von ca. 42 500 bis etwa 27 000 J.v.h. ein kĂŒhl-kontinentales Klima rekonstruieren. FĂŒr ein sehr kaltes Klima von 43 000â39 000 J.v.h., wie es in den Niederlanden von Zagwijn und Paepe (1968) festgestellt wurde, ergeben sich keine Anhaltspunkte. Das WĂŒrm-Hochglazial (oberes Pleniglazial) ist entweder nur relativ geringmĂ€chtig oder nur indirekt (durch intensive Kryoturbationserscheinungen etc.) nachweisbar.researc
Die Verwendbarkeit der geomorphologischen Karte 1:25000 (GMK 25) der Bundesrepublik Deutschland fĂŒr Nachbarwissenschaften und Planung
In der vorliegenden Arbeit wurde die Verwendbarkeit der im Rahmen des DFG-Schwerpunktprogramms âGeomorphologische Detailkartierung in der Bundesrepublik Deutschlandâ entwickelten Karten im MaĂstab 1 : 25 000 (GMK 25) fĂŒr nicht-geomorphologische Nutzer diskutiert.
Ausgehend von dem in der theoretischen Kartographie entwickelten Kommunikationsmodell (UCAR 1979) konnten die folgenden beiden Gruppen in Bezug auf die InformationsĂŒbermittlung unterschieden werden:
- Nutzer, die die in der GMK 25 enthaltenen Informationen direkt verwenden können und
- Nutzer, denen die Informationen nur zugĂ€nglich sind, wenn sie ĂŒbersetzt sind oder eine Ăbersetzungsanleitung vorliegt.
ZusĂ€tzlich erörtert wurde im Rahmen dieser theoretischen Diskussion die Frage, inwieweit mit der vorgegebenen Legende eine redundanzfreie InformationsĂŒbermittlung ĂŒberhaupt 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 ausgefĂŒhrten Beispielen ergab dieser Vergleich eine sehr weitgehende Ăbereinstimmung mit der GMK 25-Legende.
FĂŒr die zweite Nutzergruppe wurde im dritten Teil (Kap. 5) eine Ăbersetzungsanleitung, auf der Basis der GMK-Legende, erstellt. ZusĂ€tzlich wurden, ausgehend von den ĂŒbersetzten Informationen, Karten erarbeitet, die die anwendungsbezogenen Informationen, wie z.B. Gesamteignung fĂŒr Landwirtschaft, Gesamteignung fĂŒr Abfallwirtschaft, direkt enthalten. Auch in diesen FĂ€llen ergab der Vergleich mit Beispielen aus dem nicht-geomorphologischen Bereich, insbesondere der Planung, sehr weitgehende Ăbereinstimmung.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 palĂ©omilieux de lâHolocĂšne des estuaires dâAlvor et dâAlcantarilha (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 âŒ7500 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 âŒ6700 yr calBP and âŒ5700 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 âŒ3500/2000 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 Ă©tudions lâhistoire de deux estuaires de la cĂŽte dâAlgarve (sud du Portugal) en utilisant des reconstructions multi-proxy (sĂ©dimentologie, gĂ©ochimie, palynologie, micropalĂ©ontologie et datation au carbone 14). BasĂ© sur ces derniers âŒ7500 ans. Les donnĂ©es palynologiques
dĂ©crivent des transformations florales que nous expliquons par des changements climatiques. LâĂ©volution de la microfaune (foraminifĂšres
et ostracodes) est le reflet de lâalternance des environnements marins et saumĂątres dans les deux carottes Ă©tudiĂ©es. La carotte dâAlvor
montre clairement une sĂ©quence rĂ©gressive. La carotte dâAlcantarilha est caractĂ©risĂ©e par une sĂ©dimentation fluviatile Ă laquelle succĂšde, vers 7300 ans calBP, une sĂ©dimentation marine littorale. La transgression est indiquĂ©e par des foraminifĂšres et des ostracodes
vivant dans des eaux saumĂątres Ă marines. Pendant cette transgression, la proportion des pollens de lâĂ©tage supralittoral recule et celle de la zone humide augmente. Entre âŒ6700 ans calBP et âŒ5700 ans calBP Ă Alvor et 4500 ans calBP Ă Alcantarilha, la profondeur de la lagune diminue progressivement. Un Ă©vĂšnement de haute Ă©nergie (tempĂȘte ou tsunami) est enregistrĂ© entre 6400 et 5800 ans cal BP sur le
site dâAlvor mais pas celui dâAlcantarilha. AprĂšs cet Ă©vĂšnement, la profondeur de la lagune rĂ©gresse de nouveau jusquâĂ 3500/2000 ans calBP.
LâĂ©volution de cette rĂ©gression est soulignĂ©e par la formation dâun cordon littoral sur le front de lâestuaire, indiquĂ© par lâaugmentation de la
proportion de la vĂ©gĂ©tation de lâĂ©tage supralittoral. La carotte dâAlcantarilha montre une autre couche de sĂ©diments, dĂ©posĂ©s en milieu de haute
Ă©nergie, mise en Ă©vidence par les foraminifĂšres et les ostracodes marins aprĂšs 4500 ans calBP. La partie la plus jeune des carottes est marquĂ©e par la diminution de lâinfluence de la marĂ©e et une augmentation de lâimpact anthropique (changement gĂ©nĂ©ral de la vĂ©gĂ©tation et accroissement des proportions des pollens des plantes cultivĂ©es).German Research Foundation (DFG; MA 1308/09)info:eu-repo/semantics/publishedVersio
InvestigaçÔes 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 âon siteâ investigation, the first point of research was to analyse the
influence of the hinterland (âoff siteâ) 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 estuårios e lagunas na
actual costa sul de Portugal, no Algarve, durante o Holoceno recente (7000â1000 BP). O principal
objectivo deste estudo foi o de esclarecer qual o impacto que as influĂȘncias antropogĂ©nicas e climĂĄticas
tiveram sobre a evolução da costa, desde o NeolĂtico atĂ© Ă Ăpoca Medieval. O ponto de partida
baseou-se nos estudos geomorfolĂłgicos anteriormente realizados nos arredores do sĂtio arqueolĂłgico
do Cerro da Vila (Vilamoura), com o objectivo de obter uma reconstituição das condiçÔes ambientais
desta estação portuåria romana.
Tendo por base estas primeiras informaçÔes âon siteâ, a prioridade foi analisar a influĂȘncia das mudanças
ocorridas durante o holoceno-recente na rede hidrogrĂĄfica costeira (rios, ribeiras, etc.). Ao mesmo
tempo, alguns estuĂĄrios vizinhos do Cerro da Vila e suas redes â todos na zona ocidental do Algarve
(Barlavento) â foram alvos de estudo, com o objectivo de identificar e definir melhor a configuração da
costa sul de Portugal. Foi a hipĂłtese base deste projecto que, com a anĂĄlise comparativa dos diversos
arquivos geo-arqueológicos identificados na zona do Algarve, possibilitou a individualização dos efeitos
sub-regionais (climĂĄticos, subida do nĂvel do mar) dos efeitos locais (uso do solo) referentes Ă erosĂŁo
do solo. Em especial, as investigaçÔes palinológicas possibilitaram a obtenção de excelentes resultados
em relação Ă reconstituição da influĂȘncia humana e da agricultura no litoral algarvio no passado.
Os trabalhos arqueolĂłgicos que se realizaram em paralelo com estes estudos das geociĂȘncias, tiveram
o objectivo de elaborar diversos mapas de distribuição da ocupação humana do Algarve para
as vĂĄrias etapas da PrĂ©-HistĂłria e HistĂłria, entre o NeolĂtico e a Ăpoca Medieval, especialmente
nas zonas mais afectadas pelas mudanças na erosão e na colmatação dos estuårios e lagunas.
O resultado deste estudo possibilitou um melhor conhecimento sobre o processo de colmatação
dos estuĂĄrios do Sul de Portugal como principal evidĂȘncia do notĂĄvel impacto humano nesta zona,
desde a Idade do Bronze e com um clĂmax na Ăpoca Romana. Estas alteraçĆes do paleo-ambiente
tiveram, evidentemente efeitos muito profundos no padrĂŁo de assentamento durante esta Ășltima
fase de ocupação roman
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