Tephrochronology and the late Holocene volcanic and flood history of Eyjafjallajökull,Iceland     

ANDREW J. DUGMORE  ANTHONY J. NEWTON  KATE T. SMITH  KERRY‐ANN MAIRS 《第四纪科学杂志》2013,28(3):237-247

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Estimating tectonic uplift of the Cape Fear Arch (south‐eastern United States) using reconstructions of Holocene relative sea level          下载免费PDF全文

ALEX J. WRIGHT  BENJAMIN P. HORTON  SIMON E. ENGELHART  ANDREW C. KEMP  DAVID MALLINSON  ROBERT E. KOPP 《第四纪科学杂志》2014,29(8):749-759

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Global oceanic and land biotic carbon sinks from the Scripps atmospheric oxygen flask sampling network   总被引：1，自引：1，他引：0  

ANDREW C. MANNING †  RALPH F. KEELING 《Tellus. Series B, Chemical and physical meteorology》2006,58(2):95-116

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WEATHER,GEOGRAPHY, AND VEHICLE‐RELATED HYPERTHERMIA IN CHILDREN*     

ANDREW GRUNDSTEIN  JAN NULL  VERNON MEENTEMEYER 《Geographical review》2011,101(3):353-370

Vehicle‐related hyperthermia is an unfortunate tragedy that leads to the accidental deaths of children each year. This research utilizes the most extensive dataset of child vehicle‐related hyperthermia deaths in the United States, including 414 deaths between 1998 and 2008. Deaths follow a seasonal pattern, with a peak in July and no deaths in December or January. Also, deaths occurred over a wide range of temperature and radiation levels and across virtually all regions, although most of them took place across the southern United States. In particular, the Phoenix, Houston, Dallas, and Las Vegas metropolitan areas had the greatest number of deaths. We utilize our vehicle hyperthermia index (vhi ) to compare expected deaths versus actual deaths in a metropolitan area, based on the number of children in the area who are under the age of five and on the frequency of hot days in the area. The vhi indicates that the Memphis, West Palm Beach‐Boca Raton, and Las Vegas metropolitan areas are the most dangerous places for vehicle‐related hyperthermia. We conclude by discussing several recommendations with public health policy implications.  相似文献   

Asteroid impact and mass extinction at the K–T boundary: an extinct red herring     

ANDREW C. KERR 《Geology Today》1997,13(4):157-159

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Late Neanderthal occupation in North‐West Europe: rediscovery,investigation and dating of a last glacial sediment sequence at the site of La Cotte de Saint Brelade,Jersey     

MARTIN BATES  MATTHEW POPE  ANDREW SHAW  BECCY SCOTT  JEAN‐LUC SCHWENNINGER 《第四纪科学杂志》2013,28(7):647-652

In 2011, a programme of field research was undertaken to effect the stabilization of an unstable section in the West Ravine at the key Neanderthal occupation site of La Cotte de St Brelade on the Channel Island of Jersey. As part of this essential remedial work the threatened section was analysed to characterize its archaeological and palaeoenvironmental potential as well provide optically stimulated luminescence (OSL) dates. The work determined, through two concordant OSL dating programmes, that the section formed part of an extensive sequence of sedimentation spanning >105 to <48 ka. Furthermore, reanalysis of the archive determined that the sediment sequence examined contained the stratigraphic equivalent of deposits lying below those that have previously produced Neanderthal fossils. Through our work, we can now constrain these younger sediments to being younger than 48 ka. The combined results suggest that this sequence now represents the recovery of an extensive dataset, thought lost to science through complete excavation, which holds the potential to throw light on the disappearance of Neanderthal populations from the Atlantic‐edge outpost on the north‐west frontier of their world.  相似文献   

Representation of 3-D elevation in terrain databases using hierarchical triangulated irregular networks: a comparative analysis     

MAHDI ABDELGUERFI  CHRIS WYNNE  EDGAR COOPER  LADNER ROY 《International journal of geographical information science》2013,27(8):853-873

3-D terrain representation plays an important role in a number of terrain database applications. Hierarchical Triangulated Irregular Networks (TINs) provide a variable-resolution terrain representation that is based on a nested triangulation of the terrain. This paper compares and analyzes existing hierarchical triangulation techniques. The comparative analysis takes into account how aesthetically appealing and accurate the resulting terrain representation is. Parameters, such as adjacency, slivers, and streaks, are used to provide a measure on how aesthetically appealing the terrain representation is. Slivers occur when the triangulation produces thin and slivery triangles. Streaks appear when there are too many triangulations done at a given vertex. Simple mathematical expressions are derived for these parameters, thereby providing a fairer and a more easily duplicated comparison. In addition to meeting the adjacency requirement, an aesthetically pleasant hierarchical TINs generation algorithm is expected to reduce both slivers and streaks while maintaining accuracy. A comparative analysis of a number of existing approaches shows that a variant of a method originally proposed by Scarlatos exhibits better overall performance.  相似文献   

IDENTIFYING MORAINE SURFACES WITH SIMILAR HISTORIES USING LICHEN SIZE DISTRIBUTIONS AND THE U² STATISTIC, SOUTHEAST ICELAND     

JOHN F. ORWIN  KRISTA M. MCKINZEY  MICHAEL A. STEPHENS  ANDREW J. DUGMORE 《Geografiska Annaler: Series A, Physical Geography》2008,90(2):151-164

Moraine ridges are commonly used to identify past glacier ice margins and so infer glacier mass balance changes in response to climatic variability. However, differences in the form of past ice margins and post-depositional modification of moraine surfaces can complicate these geomorphic records. As a result, simple relationships, such as distance from current ice margin, or linear alignments, may not necessarily indicate moraines deposited contemporaneously. These disturbances can also modify the size distribution of lichen populations, providing a distinctive signature for surfaces with similar histories and a means of identifying contemporaneous moraine surfaces. In this paper, statistical analysis of lichen size distributions is used to identify moraine surfaces with similar histories from complex suites of Little Ice Age moraine fragments in the proglacial areas of Skálafellsjökull (including Sultartungnajökull) and Heinabergsjökull, southeast Iceland. The analysis is based on a novel use of the goodness-of-fit statistic, Watson's U² which provides a measure of 'closeness' between two sample distributions. Moraine fragments with similar histories are identified using cluster analysis of the U² closeness values. The spatial pattern of the clustered moraines suggests three distinct phases of moraine deposition at Skálafellsjökull and Heinabergsjökull, four phases at Sultartungnajökull and a digitate planform margin at Heinabergsjökull. These spatial patterns are corroborated with tephrochronology. The success of the U² statistical analysis in identifying surfaces with similar histories using lichen size distributions suggests that the technique may be useful in augmenting lichenometric surface dating as well as differentiating between other surfaces that support lichen populations, such as rock avalanche deposits.  相似文献   

Stromatolites in the Late Ordovician Eureka Quartzite: implications for microbial growth and preservation in siliciclastic settings     

PETER A. DRUSCHKE  GANQING JIANG  THOMAS B. ANDERSON†  ANDREW D. HANSON 《Sedimentology》2009,56(5):1275-1291

Well-preserved siliciclastic domal stromatolites, up to 2 m wide and 1·5 m high, are found in a 10 to 15 m thick interval within the Late Ordovician Eureka Quartzite of Southern Nevada and Eastern California, USA. These stromatolites appear as either isolated features or patchy clusters that contain more than 70% by volume quartz grains; their association with planar, trough and herringbone cross-bedding suggests that they were formed in an upper shoreface environment with high hydraulic energy. In this environment, sand bars or dunes may have provided localized shelter for initial microbial mat colonization. Biostabilization and early lithification of microbial mats effectively prevented erosion during tidal flushing and storm surges, and the prevalence of translucent quartz sand grains permitted light penetration into the sediment, leading to thick microbial mat accretion and the formation of domal stromatolites. Decimetre-scale to metre-scale stromatolite domes may have served as localized shelter and nucleation sites for further microbial mat colonization, forming patchy stromatolite clusters. Enrichment of iron minerals, including pyrite and hematite, within dark internal laminae of the stromatolites indicates anaerobic mineralization of microbial mats. The occurrence of stromatolites in the Eureka Quartzite provides an example of microbial growth in highly stressed, siliciclastic sedimentary environments, in which microbial communities may have been able to create microenvironments promoting early cementation/lithification essential for the growth and preservation of siliciclastic stromatolites.  相似文献   

Remarks on the deuterium excess in precipitation in cold regions   总被引：1，自引：0，他引：1  

DAVID ANDREW FISHER 《Tellus. Series B, Chemical and physical meteorology》1991,43(5):401-407

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