New interglacial deposits from Copenhagen,Denmark: marine Isotope Stage 7     

Ole Bennike  Lars Hedens  Kirsty High  Joakim S. Korshj  Geoffrey Lemdahl  Kirsty Penkman  Richard C. Preece  Knud Rosenlund  Finn A. Viehberg 《Boreas: An International Journal of Quaternary Research》2019,48(1):107-118

During a pre‐site survey and construction of a new metro route and station in Copenhagen, fossiliferous organic‐rich sediments were encountered. This paper reports on multidisciplinary investigations of these organic sediments, which occurred beneath a sediment succession with a lower till, glacifluvial sand and gravel, an upper till and glacifluvial sand. The organic sediments were underlain by glacifluvial sand and gravel. The organic‐rich sediments, which were up to 0.5 m thick, accumulated in a low‐energy environment, possibly an oxbow lake. They were rich in plant fossils, which included warmth‐demanding trees and other species, such as Najas minor, indicating slightly higher summer temperatures than at present. Freshwater shells were also frequent. Bithynia opercula allowed the sediments to be put into an aminostratigraphical framework. The amino acid racemization (AAR) ratios indicate that the organic sediments formed during Marine Isotope Stage 7 (MIS 7), which is consistent with optically stimulated luminescence dating that gave ages of 206 and 248 ka from the underlying minerogenic deposit. The assemblages from Trianglen are similar to interglacial deposits from the former Free Port (1.4 km away) in Copenhagen, except that Corbicula and Pisidium clessini were not found at Trianglen. The presence of these bivalves at the Free Port and the ostracod Scottia tumida at Trianglen indicates a pre‐Eemian age. AAR data from archived Bithynia opercula from the Free Port were almost identical to those from Trianglen, indicating that the two sites are contemporary. We suggest the Trianglen interglacial be used as a local name for the MIS 7 interglacial deposits in Copenhagen. MIS 7 deposits have rarely been documented from the region, but MIS 7 deposits may have been mistaken for other ages. The use of AAR ratios in Bithynia opercula has a great potential for correlation of interglacial non‐marine deposits in mainland northern Europe.  相似文献   

Shapes on a plane: evaluating the impact of projection distortion on spatial binning   总被引：1，自引：0，他引：1  

Sarah E. Battersby  Daniel “daan” Strebe  Michael P. Finn 《制图学和地理信息科学》2017,44(5):410-421

ABSTRACT

One method for working with large, dense sets of spatial point data is to aggregate the measure of the data into polygonal containers, such as political boundaries, or into regular spatial bins such as triangles, squares, or hexagons. When mapping these aggregations, the map projection must inevitably distort relationships. This distortion can impact the reader’s ability to compare count and density measures across the map. Spatial binning, particularly via hexagons, is becoming a popular technique for displaying aggregate measures of point data sets. Increasingly, we see questionable use of the technique without attendant discussion of its hazards. In this work, we discuss when and why spatial binning works and how mapmakers can better understand the limitations caused by distortion from projecting to the plane. We introduce equations for evaluating distortion’s impact on one common projection (Web Mercator) and discuss how the methods used generalize to other projections. While we focus on hexagonal binning, these same considerations affect spatial bins of any shape, and more generally, any analysis of geographic data performed in planar space.  相似文献   

Vik,Marte Lange. 2015. Landskapsdemokrati som metafor og materialitet: Eksempler på landskapspraksiser i møte med den europeiske landskapskonvensjonen     

Finn Arler  Marie Stenseke 《Norsk geografisk tidsskrift. Norwegian journal of geography》2016,70(2):128-130

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Food Diaries to Measure Food Access: A Case Study from Rural Cuba     

Federica Bono  John C. Finn 《The Professional geographer》2017,69(1):59-69

This article aims to make a contribution to current debates in the literature on food access by describing a mixed-methods approach to study the access to food in one rural community in Cuba. Each of the forty households in our study was asked to complete a detailed food diary in which they indicated what they ate and where they acquired each of the ingredients that they used for a full week. Although in Cuba the state plays a central role in organizing the distribution of food items, this method revealed a much more complex web of rural food access. By addressing alternative networks of food access and informal social relations, we aim to show how the use of food diaries, in combination with qualitative data from interviews and participant observation, can provide detailed insights in the complex processes and networks of food access.  相似文献   

The Mesozoic of Western Scandinavia and East Greenland     

Arvid NФttvedt Erik P. Johannessen Finn Surlyk 《《幕》》2008,31(1):59-65

Thick Mesozoic sediments are found offshore Norway and Denmark, and Mesozoic rocks are present and well exposed in Denmark, along the coast of East Greenland and on the arctic islands of Svalbard.
During the Mesozoic, Scandinavia and Greenland were subject to major extension in the Late Permian-Early Triassic and Late Jurassic-Early Cretaceous, prior to Cenozoic opening of the North Atlantic. Deep basins developed along the rift zones of the North Sea and between East Greenland and Norwa）; and were .filled with sediments derived from mainland Scandinavia and Greenland. The marginal areas bordering the rift zones suffered less subsidence, as did the epicontinental Barents Sea.  相似文献   

Relocation of Wyoming Mine Production Blasts Using Calibration Explosions     

C.A. Finn  G.D. Kraft  M.S. Sibol  R.L. Jones  M.E. Pulaski 《Pure and Applied Geophysics》2001,158(1-2):105-116

—?An important requirement for a comprehensive seismic monitoring system is the capability to accurately locate small seismic events worldwide. Accurate event location can improve the probability of determining whether or not a small event, recorded predominantly by local and regional stations, is a nuclear explosion. For those portions of the earth where crustal velocities are not well established, reference event calibration techniques offer a method of increased locational accuracy and reduced locational bias.¶In this study, data from a set of mining events with good ground-truth data in the Powder River Basin region of eastern Wyoming are used to investigate the potential of event calibration techniques in the area. Results of this study are compared with locations published in the prototype International Data Center's Reviewed Event Bulletin (REB). A Joint Hypocenter Determination (JHD) method was applied to a s et of 23 events. Four of those events with superior ground-truth control (mining company report or Global Positioning System data) were used as JHD reference events. Nineteen (83%) of the solutions converged and the resulting set of station-phase travel-time corrections from the JHD results was then tested. When those travel-time corrections were applied individually to the four events with good ground-truth control, the average locational error reduced the original REB location error from 16.1?km to 5.7?km (65% improvement). The JHD locations indicated reduced locational bias and all of the individual error ellipses enclosed the actual known event locations.¶Given a set of well-recorded calibration events, it appears that the JHD methodology is a viable technique for improving locational accuracy of future small events where the location depends on arrival times from predominantly local and/or regional stations. In this specific case, the International Associ ation of Seismology and the Physics of the Earth's Interior (IASPEI) travel-time tables, coupled with JHD-derived travel-time corrections, may obviate the need for an accurately known regional velocity structure in the Powder River Basin region.  相似文献   

A finite element method for the diffusion-convection equation with constant coefficients     

E. VaroG&#x;lu  W.D.L. Finn 《Advances in water resources》1978,1(6):337-343

Existing numerical methods for the solution of the diffusion-convection equation are unsatisfactory for convection dominated flow problems. A new finite element method incorporating the method of characteristics for the solution of the diffusion-convection equation with constant coefficients in one spatial dimensions is derived. This method is capable of solving diffusion-convection equation without any of the difficulties encountered in the existing numerical methods for the whole spectrum of dispersion from pure diffusion, through mixed dispersion, to pure convection. Several examples for the one-dimensional case are solved and results are compared with the exact solutions. The generalization of the method to variable coefficients and to the diffusion-convection equation in two space dimensions are discussed.  相似文献   

Geospatial data resampling and resolution effects on watershed modeling: A case study using the agricultural non-point source pollution model   总被引：4，自引：0，他引：4  

E. Lynn?UseryEmail author  Michael P.?Finn  Douglas J.?Scheidt  Sheila?Ruhl  Thomas?Beard  Morgan?Bearden 《Journal of Geographical Systems》2004,6(3):289-306

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Ellipsoidal vertical deflections and ellipsoidal gravity disturbance: Case studies     

E. W. Grafarend  G. Finn  A. A. Ardalan 《Studia Geophysica et Geodaetica》2006,50(1):1-57

First, we present three different definitions of the vertical which relate to (i) astronomical longitude and astronomical latitude as spherical coordinates in gravity space, (ii) Gauss surface normal coordinates (also called geodetic coordinates) of type ellipsoidal longitude and ellipsoidal latitude and (iii) Jacobi ellipsoidal coordinates of type spheroidal longitude and spheroidal latitude in geometry space. Up to terms of second order those vertical deflections agree to each other. Vertical deflections and gravity disturbances relate to a reference gravity potential. In order to refer the horizontal and vertical components of the disturbing gravity field to a reference gravity field, which is physically meaningful, we have chosen the Somigliana-Pizzetti gravity potential as well as its gradient. Second, we give a new closed-form representation of Somigliana-Pizzetti gravity, accurate to the sub Nano Gal level. Third, we represent the gravitational disturbing potential in terms of Jacobi ellipsoidal harmonics. As soon as we take reference to a normal potential of Somigliana-Pizzetti type, the ellipsoidal harmonics of degree/order (0,0), (1,0), (1, − 1), (1,1) and (2,0) are eliminated from the gravitational disturbing potential. Fourth, we compute in all detail the gradient of the gravitational disturbing potential, in particular in orthonormal ellipsoidal vector harmonics. Proper weighting functions for orthonormality on the International Reference Ellipsoid are constructed and tabulated. In this way, we finally arrive at an ellipsoidal harmonic representation of vertical deflections and gravity disturbances. Fifth, for an ellipsoidal harmonic Gravity Earth Model (SEGEN: http://www.uni-stuttgart.de/gi/research/paper/coefficients/coefficients.zip) up to degree/order 360/360 we compute the global maps of ellipsoidal vertical deflections and ellipsoidal gravity disturbances which transfer a great amount of geophysical information in a properly chosen equiareal ellipsoidal map projection.  相似文献   

A new and simple method for qualitative sampling of meiobenthos-communities     

Finn Andreas Viehberg   《Limnologica》2002,32(4):350-351

The introduced collecting method is based on a common entomologist exhauster, which is specified for the fieldwork in aquatic systems with a sieve-inset and a bottom-lid. The living organisms are collected visually from the sampled debris and no further extraction is needed. The apparatus is designed for qualitative sampling of microcrustaceans (e.g. Cladocera, Copepoda, Ostracoda) and minimises disturbance at the sampling site.  相似文献