REINTRODUCTION AND RANGE EXPANSION OF EASTERN WILD TURKEYS IN MINNESOTA*     

MARTIN D. MITCHELL  RICHARD O. KIMMEL  JENNIFER SNYDERS 《Geographical review》2011,101(2):269-284

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Discussion: “Were the Ediacaran siliciclastics of South Australia coastal or deep marine?” by Retallack et al., Sedimentology, 59, 1208–1236     

RICHARD H. T. CALLOW  MARTIN D. BRASIER  DUNCAN MCILROY 《Sedimentology》2013,60(2):624-627

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Capturing and modelling metre‐scale spatial facies heterogeneity in a Jurassic ramp setting (Central High Atlas,Morocco)     

FRÉDÉRIC AMOUR  MARIA MUTTI  NICOLAS CHRIST  ADRIAN IMMENHAUSER  SUSAN M. AGAR  GREGORY S. BENSON  SARA TOMÁS  ROBERT ALWAY  LACHEN KABIRI 《Sedimentology》2012,59(4):1158-1189

Each simulation algorithm, including Truncated Gaussian Simulation, Sequential Indicator Simulation and Indicator Kriging is characterized by different operating modes, which variably influence the facies proportion, distribution and association of digital outcrop models, as shown in clastic sediments. A detailed study of carbonate heterogeneity is then crucial to understanding these differences and providing rules for carbonate modelling. Through a continuous exposure of Bajocian carbonate strata, a study window (320 m long, 190 m wide and 30 m thick) was investigated and metre‐scale lithofacies heterogeneity was captured and modelled using closely‐spaced sections. Ten lithofacies, deposited in a shallow‐water carbonate‐dominated ramp, were recognized and their dimensions and associations were documented. Field data, including height sections, were georeferenced and input into the model. Four models were built in the present study. Model A used all sections and Truncated Gaussian Simulation during the stochastic simulation. For the three other models, Model B was generated using Truncated Gaussian Simulation as for Model A, Model C was generated using Sequential Indicator Simulation and Model D was generated using Indicator Kriging. These three additional models were built by removing two out of eight sections from data input. The removal of sections allows direct insights on geological uncertainties at inter‐well spacings by comparing modelled and described sections. Other quantitative and qualitative comparisons were carried out between models to understand the advantages/disadvantages of each algorithm. Model A is used as the base case. Indicator Kriging (Model D) simplifies the facies distribution by assigning continuous geological bodies of the most abundant lithofacies to each zone. Sequential Indicator Simulation (Model C) is confident to conserve facies proportion when geological heterogeneity is complex. The use of trend with Truncated Gaussian Simulation is a powerful tool for modelling well‐defined spatial facies relationships. However, in shallow‐water carbonate, facies can coexist and their association can change through time and space. The present study shows that the scale of modelling (depositional environment or lithofacies) involves specific simulation constraints on shallow‐water carbonate modelling methods.  相似文献   

Magnetic mineral transport and sorting in the swash‐zone: northern Lake Erie,Canada     

ERIC GALLAWAY  ALAN S. TRENHAILE  MARIA T. CIOPPA  ROBERT G. HATFIELD 《Sedimentology》2012,59(6):1718-1734

A combined field and laboratory study in northern Lake Erie has provided new insights into the origin and dynamics of heavy mineral placer deposits on beaches consisting primarily of non‐magnetic sediment. Work was conducted on the cross‐shore and longshore transport of heavy magnetic minerals using magnetic susceptibility and fluorescent paints to trace the movement, in the field, of samples of magnetic (magnetite) and non‐magnetic (quartz and calcite) grains, respectively. Laboratory experiments examined how the burial of small, dense magnetic minerals is affected by the grain size of the non‐magnetic host material, and how grain burial affects magnetic susceptibility measurements at the surface. The field experiments demonstrated that the magnetic mineral tracers were buried rapidly beneath coarser, non‐magnetic grains under low to moderate wave conditions, and subsequently were unable to move in the longshore or cross‐shore directions. The laboratory experiments showed that the magnetic susceptibility rapidly decreased with the rate and depth of burial of the magnetic minerals, and that magnetic grain burial was most effective beneath coarser rather than finer non‐magnetic sand and, for the latter sediments, under less rather than more energetic conditions. The results imply that magnetic mineral concentrations develop in this area through magnetic grain burial under fairly mild conditions, and subsequent settling, exposure and concentration in the upper swash zone during more energetic periods, when the non‐magnetic grains are eroded. It is probably during these erosional periods, when the magnetic minerals are exposed in fairly homogeneous deposits, that longshore and cross‐shore transport takes place.  相似文献   

Barite in the ocean – occurrence,geochemistry and palaeoceanographic applications     

ELIZABETH M. GRIFFITH  ADINA PAYTAN 《Sedimentology》2012,59(6):1817-1835

The mineral barite (BaSO₄) can precipitate in a variety of oceanic settings: in the water column, on the sea floor and within marine sediments. The geological setting where barite forms ultimately determines the geochemistry of the precipitated mineral and its usefulness for various applications. Specifically, the isotopic and elemental composition of major and trace elements in barite carry information about the solution(s) from which it precipitated. Barite precipitated in the water column (marine or pelagic barite) can be used as a recorder of changes in sea water chemistry through time. Barite formed within sediments or at the sea floor from pore water fluids (diagenetic or cold seeps barite) can aid in understanding fluid flow and sedimentary redox processes, and barite formed in association with hydrothermal activity (hydrothermal barite) provides information about conditions of crust alteration around hydrothermal vents. The accumulation rate of marine barite in oxic‐pelagic sediments can also be used to reconstruct past changes in ocean productivity. Some key areas for future work on the occurrence and origin of barite include: fully characterizing the mechanisms of precipitation of marine barite in the water column; understanding the role and potential significance of bacteria in barite precipitation; quantifying parameters controlling barite preservation in sediments; determining the influence of diagenesis on barite geochemistry; and investigating the utility of additional trace components in barite.  相似文献   

AREAL RAINFALL EVALUATION USING TWO SURFACE FITTING TECHNIQUES     

ELIZABETH M. SHAW  P. P. LYNN 《水文科学杂志》2013,58(4):419-433

ABSTRACT

Two trend surface fitting techniques, the use of bi-cubic splines and multiquadric analysis, have been applied to the determination of areal rainfall. On two mathematically defined test surfaces, the methods were applied using gridded data; the bi-cubic splines gave the better results. For non-gridded data, selected and random points, the multiquadric analysis gives satisfactory values. With real catchment and storm data, multiquadric analysis is shown to be a potentially very useful and flexible method for determining areal rainfall.  相似文献   

Building a prototype Geographical Correlates Exploration Machine     

STAN OPENSHAW  ANNA CROSS  MARTIN CHARLTON 《International journal of geographical information science》2013,27(3):297-311

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Palaeowind directions recorded in the youngest loess in Poland and western Ukraine as derived from anisotropy of magnetic susceptibility measurements     

JERZY NAWROCKI  OLGA POLECHOSKA  REJ BOGUCKIJ  MARIA &#;ANCZONT 《Boreas: An International Journal of Quaternary Research》2006,35(2):266-271

Studies of the anisotropy of magnetic susceptibility (AMS) were carried out in order to define the directions and strength of palaeowind during the sedimentation of the youngest loesses in Poland and western Ukraine. These sediments, like the Chinese and Alaskan loesses, appear suitable for application of the AMS method. The inclined mean minimum axes were considered as reflecting the prevailing palaeowind direction at the time of loess sedimentation. The majority of the sections studied indicate a palaeowind direction from W-SW to E-NE, with a mean azimuth of 258°. This direction corresponds to the strike of the Weichselian ice-sheet margin and is parallel to the axis of the lowland between the ice-sheet margin to the north and the Carpathian Mountains and the Podole Upland to the south. Further AMS studies of the oldest parts of loess sequences in Poland and western Ukraine may help in reconstruction of the atmospheric circulation in this part of Europe since c. 900 kyr BP.  相似文献   

A first-order analysis of the potential rôle of CO₂ fertilization to affect the global carbon budget: a comparison of four terrestrial biosphere models     

DAVID W. KICKLIGHTER  MICHELE BRUNO  SILKE DÖNGES  GERD ESSER  MARTIN HEIMANN  JOHN HELFRICH  FRANK IFT  FORTUNAT JOOS  JÖRG KADUK  GUNDOLF H. KOHLMAIER  A. DAVID McGUIRE  JERRY M. MELILLO  ROBERT MEYER  BERRIEN MOORE III  REAS NADLER  I. COLIN PRENTICE  WALTER SAUF  ANNETTE L. SCHLOSS  STEPHEN SITCH  UWE WITTENBERG  GUDRUN WÜRTH 《Tellus. Series B, Chemical and physical meteorology》1999,51(2):343-366

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A regionalized IO-model to value seasonal recreational ecosystem services in a mountain National Park in Spain     

Víctor MARTIN BARROSO  Mónica de CASTRO-PARDO  Pascual FERNNDEZ MARTNEZ  Joo C.AZEVEDO 《山地科学学报》2022,(1):211-227

Recreational Ecosystem Services (RES) are among the most frequently evaluated ecosystem services.RES are seen as a major opportunity for sustainable development...  相似文献