Improved time control on Cretaceous coastal deposits: new results from Sr isotope measurements using laser ablation     

Stefan Burla  Felix Oberli  Ulrich Heimhofer  Uwe Wiechert  Helmut Weissert 《地学学报》2009,21(5):401-409

Sr-isotope measurements of unaltered oyster shell calcite using laser-ablation multi-collector ICPMS techniques represent a powerful tool capable of establishing a chronostratigraphic framework for fossil near-shore deposits. This approach is tested on two shoal-water successions from the Portuguese Algarve and Lusitanian basins covering Late Barremian to Albian strata. ⁸⁷Sr/⁸⁶Sr values derived from low-Mg calcite of oyster shells fluctuate between 0.70717 ± 0.00001 and 0.70746 ± 0.00002; absolute values as well as stratigraphic trends match well with the global open-marine seawater signal. The new Sr-isotope results in combination with existing bio- and chemostratigraphic records allow for identification of an Early Aptian biocalcification crisis at both studied localities and show that this event has severely affected coastal environments along the evolving Atlantic. Siliciclastic intervals in the Algarve section are interpreted as near-shore equivalents of enhanced detrital shedding into shelf and deep-sea environments as a consequence of increased chemical weathering rates during humid climate episodes.  相似文献   

The Arctic Coastal Dynamics Database: A New Classification Scheme and Statistics on Arctic Permafrost Coastlines     

Hugues Lantuit  Pier Paul Overduin  Nicole Couture  Sebastian Wetterich  Felix Aré  David Atkinson  Jerry Brown  Georgy Cherkashov  Dmitry Drozdov  Donald Lawrence Forbes  Allison Graves-Gaylord  Mikhail Grigoriev  Hans-Wolfgang Hubberten  James Jordan  Torre Jorgenson  Rune Strand ?deg?rd  Stanislav Ogorodov  Wayne H. Pollard  Volker Rachold  Sergey Sedenko  Steve Solomon  Frits Steenhuisen  Irina Streletskaya  Alexander Vasiliev 《Estuaries and Coasts》2012,35(2):383-400

Arctic permafrost coasts are sensitive to changing climate. The lengthening open water season and the increasing open water area are likely to induce greater erosion and threaten community and industry infrastructure as well as dramatically change nutrient pathways in the near-shore zone. The shallow, mediterranean Arctic Ocean is likely to be strongly affected by changes in currently poorly observed arctic coastal dynamics. We present a geomorphological classification scheme for the arctic coast, with 101,447?km of coastline in 1,315 segments. The average rate of erosion for the arctic coast is 0.5?m? year^?1 with high local and regional variability. Highest rates are observed in the Laptev, East Siberian, and Beaufort Seas. Strong spatial variability in associated database bluff height, ground carbon and ice content, and coastline movement highlights the need to estimate the relative importance of shifting coastal fluxes to the Arctic Ocean at multiple spatial scales.  相似文献   

Rossberg landslide history and flood chronology as recorded in Lake Lauerz sediments (Central Switzerland)     

Felix Bussmann  Flavio S. Anselmetti 《Swiss Journal of Geoscience》2010,103(1):43-59

The southern slopes of Rossberg mountain, Central Switzerland, on which one of the largest historic landslides of the Alpine region was released in 1806 ad (Goldauer Bergsturz), are prone to large-scale mass wasting processes. This has led to numerous sliding events, which are well-recognizable in the modern topography but lack accurate dating. In order to provide new insights into the timing and the processes associated with past landslides as well as into the frequency of exceptional flood events, long sediment cores were retrieved from the subsurface of Lake Lauerz that lies in the pathway of these landslides and that records strong runoff events with typical flood layers. Analyses of the recovered cores display a sedimentologic succession with variable fingerprints of past landslides and flood events, depending on the coring location within the lake. The landslide signature can be calibrated using the 1806 ad event: An organic-rich peaty unit, which is found in two cores located close to the rockmass impact, points towards a sudden, gravity spreading-induced lateral displacement of the swampy plain where parts of the rock mass were accumulating. This rapid lateral mobilization of soft sediments, and not the rock masses, acted as ultimate trigger for the reported ~15 m-high impulse waves on the lake. In the more distal areas, the 1806 ad event led to the deposition of a thick, organic-rich redeposited layer. The 10 m-long core from the distal basin covers a radiocarbon-dated ~2,000 years sedimentation history and contains a highly similar event layer that was deposited in 810 ± 60 ad. This layer is most likely the product of a major historic landslide, known as Röthener Bergsturz, which, based on scarce historical reports, was commonly dated to 1222 ad. In the 2,000 years record, we identify three periods with enhanced occurrence of flood turbidites dated to 580–850 ad, 990–1420 ad, and 1630–1940 ad. Among the 54 detected flood layers, 6 probably mark exceptionally heavy rainfall events that are dated to ~610, ~1160, ~1290, ~1660, ~1850, and ~1876 ad, the latter being associated to one of the most intense rainfall events ever recorded instrumentally in the region.  相似文献   

Gas cooling in simulations of the formation of the galaxy population     

Naoki Yoshida  Felix Stoehr  Volker Springel  Simon D. M. White 《Monthly notices of the Royal Astronomical Society》2002,335(3):762-772

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Monitoring vegetation condition from NOAA operational polar-orbiting satellites over Indian region     

Ramesh P Singh  Felix Kogan 《Journal of the Indian Society of Remote Sensing》2002,30(3):117-118

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The slow rotation of 253 Mathilde     

Stefano Mottola  William D. Sears  Anders Erikson  Alan W. Harris  Jim W. Young  Gerhard Hahn  Mats Dahlgren  Beatrice E. A. Mueller  Bill Owen  Ricardo Gil-Hutton  Javier Licandro  M. Antonietta Barucci  Claudia Angeli  Gerhard Neukum  Claes-Ingvar Lagerkvist  J. Felix Lahulla 《Planetary and Space Science》1995,43(12)

CCD photometry of the NEAR mission fly-by target 253 Mathilde is presented. Measurements taken during 52 nights of observations, from February to June 1995, allow a rotation period of 17.406±0.010 days and a lightcurve amplitude of 0.45±0.02 mag to be determined. A B-V color index of 0.67±0.02 and a V-R of 0.35±0.02 are measured, which are compatible with C-type membership. The determination of the phase relation results in H = 10.28±0.03 and G = 0.12±0.06. Indications that the lightcurve is not strictly singly-periodic are found. A power-spectrum analysis detects a secondary frequency f₂ = 0.0322±0.0010 d⁻¹, which is interpreted as evidence for a complex rotation state.  相似文献   

Industrial relocation of Hong Kong manufacturing firms: towards an expanding industrial space beyond the Pearl river delta   总被引：2，自引：0，他引：2  

Haifeng Felix Liao  Roger C. K. Chan 《GeoJournal》2011,76(6):623-639

This paper explores the recent industrial relocation of Hong Kong manufacturing firms in the Pearl River Delta. Based on a combination of recent surveys, four in-depth case studies and nearly 20 firm interviews through the end of 2008, the paper argues that in response to a dynamic business environment in the region, some Hong Kong manufacturing firms in the PRD are forced to design new spatial strategies. The paper also identifies the different relocation strategies adopted by Hong Kong manufacturing firms, namely, total relocation, stratified relocation and “pseudo relocation”. The industrial space of Hong Kong manufacturing firms will be expanded beyond the PRD. In addition, the new round of relocation of Hong Kong manufacturers is a response to the initiative ushered in by the provincial and local governments in order to achieve the objectives of industrial upgrading, sustainable environment and regional balanced development.  相似文献   

Erratum: Klein–Nishina effects in the spectra of non-thermal sources immersed in external radiation fields     

Rafa&#; Moderski  Marek Sikora  Paolo S. Coppi  Felix Aharonian 《Monthly notices of the Royal Astronomical Society》2005,364(4):1488-1488

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Elaia,Pergamon's maritime satellite: the rise and fall of an ancient harbour city shaped by shoreline migration     

Martin Seeliger  Anna Pint  Stefan Feuser  Svenja Riedesel  Nick Marriner  Peter Frenzel  Felix Pirson  Andreas Bolten  Helmut Brückner 《第四纪科学杂志》2019,34(3):228-244

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Dimensionality‐reduced estimation of primaries by sparse inversion     

Bander Jumah  Felix J. Herrmann 《Geophysical Prospecting》2014,62(5):972-993

Wave‐equation based methods, such as the estimation of primaries by sparse inversion, have been successful in the mitigation of the adverse effects of surface‐related multiples on seismic imaging and migration‐velocity analysis. However, the reliance of these methods on multidimensional convolutions with fully sampled data exposes the ‘curse of dimensionality’, which leads to disproportional growth in computational and storage demands when moving to realistic 3D field data. To remove this fundamental impediment, we propose a dimensionality‐reduction technique where the ‘data matrix’ is approximated adaptively by a randomized low‐rank factorization. Compared to conventional methods, which need for each iteration passage through all data possibly requiring on‐the‐fly interpolation, our randomized approach has the advantage that the total number of passes is reduced to only one to three. In addition, the low‐rank matrix factorization leads to considerable reductions in storage and computational costs of the matrix multiplies required by the sparse inversion. Application of the proposed method to two‐dimensional synthetic and real data shows that significant performance improvements in speed and memory use are achievable at a low computational up‐front cost required by the low‐rank factorization.  相似文献