Holocene evolution of mud depocentres on a high-energy, low-accumulation shelf (NW Iberia)     

Hendrik Lantzsch  Till J.J. Hanebuth  Vera B. Bender 《Quaternary Research》2009,72(3):325-336

The high-energy, low-accumulation NW Iberian shelf features three confined Holocene mud depocentres. Here, we show that the evolution of such depocentres follows successive steps. The flooding of inner shelf zones and river catchment areas by the late deglacial sea-level rise provided the precondition for shelf mud deposition. Following this, the Holocene deceleration of the sea-level rise caused a rapid refill of the accommodation space within river valleys. Subsequently, the export of major amounts of fines was initiated. The initial onset and loci of shelf mud deposition were related to deposition-favouring conditions in mid-shelf position or to the presence of morphological highs, which act as sediment traps by providing protection against stronger hydrodynamic energy. The detailed reconstruction of the Holocene depocentre evolution shows for the first time that the expansion of such shelf mud deposits cannot only occur by linear growth off the associated sediment source. Rather, they might develop around centres that are fully disconnected from the source of original sediment supply, and expand later into specific directions. Based on these differences and on the connection of the individual mud depocentres to the material source we propose a conceptual subdivision of the group “mid-shelf mud depocentres”.  相似文献   

Near-future changes in storm surges along the Atlantic Iberian coast     

Fortunato  André B.  Meredith  Edmund P.  Rodrigues  Marta  Freire  Paula  Feldmann  Hendrik 《Natural Hazards》2019,98(3):1003-1020

Natural Hazards - Decadal predictions bridge the gap between the short-term weather/seasonal forecasts and the long-term climate projections. They target the reproduction of large-scale weather...  相似文献   

Book reviews     

Eckard Kleine  Hendrik M. van Aken 《Ocean Dynamics》1996,48(1):109-113

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Isotopen-geochemische Untersuchungen an Mollusken-Schalen verschiedener Seen Mitteleuropas     

Dr. E. Linz  Prof. Dr. German Müller 《Mineralogy and Petrology》1981,29(1):55-65

Zusammenfassung Die Schalen limnischer Gastropoden und Pelecypoden aus verschiedenen mitteleuropäischen Seen zeigen neben der zu erwartenden, von marinen Mollusken grundsätzlich abweichenden Isotopenzusammensetzung beim¹⁸O, ortsspezifische Unterschiede, die auf unterschiedlich isotopisch zusammengesetzte Wässer in den einzelnen Seen zurückzuführen sind.So spiegeln die Mollusken des Bodensees die isotopische Zusammensetzung des schmelzwasserführenden Alpenrheins wider und sind entsprechend arm an¹⁸O, während beim sehr flachen Neusiedler See durch starke Evaporation das¹⁸O/¹⁶O-Verhältnis in Richtung des schwereren Isotops verschoben ist.

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Isotope geochemistry of mollusc shells from central European lakes

Summary Carbonate shells of limnic gastropods and pelecypods from various lakes of central Europe have an isotopic composition which is principally asimilar—as to be expected—to the composition of marine molluscs.Differences in the¹⁸O concentration can be related to the specific isotopic composition of the water in which the molluscs live. The low¹⁸O concentration of-for example-Lake Constance molluscs reflects the isotopic composition of the Rhine Rive, which carries abundant melting water from the Alps with a correspondingly low¹⁸O concentration. In the Neusiedler See, strong evaporation leads to an enrichment in the heavy isotope¹⁸O in the water of the very shallow lake and consequently in the mollusc shells.

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Mit 2 Abbildungen  相似文献   

Measuring surface-wave overtone phase velocities using a mode-branch stripping technique     

Hendrik Jan van  Heijst John Woodhouse 《Geophysical Journal International》1997,131(2):209-230

We present a method for the retrieval of the phase velocities of surface-wave overtones. The 'single-station' method is successful for several Love and Rayleigh overtone branches (up to at least four) in mode-specific period ranges between 40 and 200 s. It uses mode-branch cross-correlation functions and relies on adjusting the phase and amplitude of the mode branches one at a time. A standard statistical optimization technique is used. We discuss in detail the a priori information that is added to stabilize the retrieval procedure. In addition, we present a technique to estimate the reliability of individual phase and amplitude measurements. The retrieval method and the technique to estimate reliabilities can be used together in a highly automated way, making the methods especially suited for studying the large volume of digital data now available.
We include several applications to synthetic and recorded waveforms. We will discuss in detail an experiment with 90 waveforms that have travelled along very similar paths from Vanuatu to California. For this path, we will present average overtone phase velocities and an average 1-D velocity structure.  相似文献   

Late Triassic sauropodomorph and Middle Jurassic theropod tracks from the Xichang Basin,Sichuan Province,southwestern China:First report of the ichnogenus Carmelopodus     

Li-Da Xing  Jin Ba  Martin G.Lockley  Hendrik Klein  Sheng-Wu Yan  Anthony Romilio  Chun-Yong Chou  W.Scott Persons IV 《古地理学报》2018,(1)

Upper Triassic and Middle Jurassic strata of the Xichang Basin in Sichuan Province, southwestern China, yielded important dinosaur ichnofossils. From the Xujiahe Formation of the Yiguojiao tracksite, we report a Late Triassic footprint assemblage in China and the first discovery of diagnostic Triassic sauropodomorph tracks in this region. The tracks share a number of features in common with the ichnogenera Eosauropus(Late Triassic) and Liujianpus(Early Jurassic). The neighboring Bingtu tracksite is stratigraphically younger(Shaximiao Formation, Middle Jurassic) and preserves small tridactyl theropod tracks that represent the first occurrence of the ichnotaxon Carmelopodus in China and Asia. While these tracks are morphologically comparable to those from the Middle Jurassic type locality in North America, the specimens from China show the proximal margin of the digit IV impression in a more cranial position, which may indicate a trackmaker with a relatively short metatarsal IV. In addition to the skeletal record, the Carmelopodus footprints document the presence of small theropods in the dinosaur fauna of the Middle Jurassic Shaximiao Formation.  相似文献   

Unusual dinosaur trackway preservation as clues to paleo-landscape and behavior from the Lower Cretaceous Luohe Formation,Shaanxi Province,China     

Lida Xing  Martin G.Lockley  Yongzhong Tang  Hendrik Klein  W.Scott Persons IV  Miaoyan Wang  Xingwen Li  Hao Wu 《地学前缘(英文版)》2021,12(2):737-745

Poorly preserved tracks have limited ichnotaxonomic or biotaxon utility,but may reveal useful information about the paleoenvironment,behavior and track taphonomy.Eight mostly parallel to sub parallel trackway segments(T1–T8)were registered on a truncation surface in the Lower Cretaceous Luohe Formation of Shaanxi Province.These attest to the passage of several bipeds,probably all theropods,in a paleo-contour-parallel,south-north direction in an arid setting.Quality of preservation in these trackways is poor,but notably superior in two additional trackways(T9–T10)on a foreset surface.Trackway T9 indicates a didactyl trackmaker,probably a deinonychosaurian,heading north to south.This is the 13th report of deinonychosaurian tracks from the Lower Cretaceous of China.If any or all the eight south-north oriented trackway segments represent continuations of other segments in the same trackways,the total number of individual trackmakers heading in this direction may have been as lowas three.Although the trackway pattern and sedimentological evidence could indicate a physically controlled pathway influencing the direction taken by these trackmakers,the possibility that the trackways also represented small social or gregarious group cannot be ruled out.  相似文献   

Vertical gradient of nutrients in two dimictic lakes – influence of phototrophic sulfur bacteria on nutrient balance     

Uwe?SeligEmail author  Thomas?Hübener  Reinhard?Heerkloss  Hendrik?Schubert 《Aquatic Sciences - Research Across Boundaries》2004,66(3):247-256

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Numerical modeling of wind waves generated by tropical cyclones using moving grids   总被引：1，自引：0，他引：1  

Hendrik L. Tolman  Jose-Henrique G.M. Alves 《Ocean Modelling》2005,9(4):305-323

A version of the WAVEWATCH III wave model featuring a continuously moving spatial grid is presented. The new model option/version is intended for research into wind waves generated by tropical cyclones in deep water away from the coast. The main advantage of such an approach is that the cyclones can be modeled with spatial grids that cover much smaller areas than conventional fixed grids, making model runs with high spatial resolution more economically feasible. The model modifications necessary are fairly trivial. Most complications occur due to the Garden Sprinkler effect (GSE) and methods used to mitigate it. The basic testing of the model is performed using idealized wind fields consisting of a Rankine vortex. The model is also applied to hurricane Lili in the Gulf of Mexico in October 2002. The latter application shows that the moving grid approach provides a natural way to deal with hurricane wind fields that have a high-resolution in space, but a low resolution in time. Although the new model version is originally intended for tropical cyclones, it is suitable for high-resolution modeling of waves due to any moving weather pattern.  相似文献   

The role of porous matrix in water flow regulation within a karst unsaturated zone: an integrated hydrogeophysical approach     

Simon D. Carrière  Konstantinos Chalikakis  Charles Danquigny  Hendrik Davi  Naomi Mazzilli  Chloé Ollivier  Christophe Emblanch 《Hydrogeology Journal》2016,24(7):1905-1918

Some portions of the porous rock matrix in the karst unsaturated zone (UZ) can contain large volumes of water and play a major role in water flow regulation. The essential results are presented of a local-scale study conducted in 2011 and 2012 above the Low Noise Underground Laboratory (LSBB – Laboratoire Souterrain à Bas Bruit) at Rustrel, southeastern France. Previous research revealed the geological structure and water-related features of the study site and illustrated the feasibility of specific hydrogeophysical measurements. In this study, the focus is on hydrodynamics at the seasonal and event timescales. Magnetic resonance sounding (MRS) measured a high water content (more than 10 %) in a large volume of rock. This large volume of water cannot be stored in fractures and conduits within the UZ. MRS was also used to measure the seasonal variation of water stored in the karst UZ. A process-based model was developed to simulate the effect of vegetation on groundwater recharge dynamics. In addition, electrical resistivity tomography (ERT) monitoring was used to assess preferential water pathways during a rain event. This study demonstrates the major influence of water flow within the porous rock matrix on the UZ hydrogeological functioning at both the local (LSBB) and regional (Fontaine de Vaucluse) scales. By taking into account the role of the porous matrix in water flow regulation, these findings may significantly improve karst groundwater hydrodynamic modelling, exploitation, and sustainable management.  相似文献