Latest Miocene and Pleistocene ages of faulting, determined by ⁴⁰Ar/³⁹Ar single-crystal dating of airfall tuff and silicic extrusives of the Erciyes Basin, central Turkey: evidence for intraplate deformation related to the tectonic escape of Anatolia     

Noah Jaffey  Alastair Robertson  Malcolm Pringle 《地学学报》2004,16(2):45-53

The Ericiyes Basin is a trans‐tensional basin situated 20 km north of the regional Ecemi? Fault Zone. Recently it has been hypothesized that faulting within the Erciyes Basin links with the Ecemi? Fault Zone further south as part of a regional Central Anatolian Fault Zone. New ⁴⁰Ar/³⁹Ar dating of volcanic and volcaniclastic rocks adjacent to faults, both along the margins and in the centre of the Erciyes Basin, constrains the timing of basin inception and later faulting. Extensional faulting occurred along the eastern and western margins of the basin during the Early Messinian (latest Miocene). Sinistral and minor normal faulting were active along the axis of the basin during the early Pleistocene. These fault timings are similar to those inferred for the Ecemi? Fault Zone further south, and support the hypothesis that faulting within the Erciyes Basin and the Ecemi? Fault Zone are indeed linked.  相似文献   

Handling uncertainty in extreme or unrepeatable hydrological processes—the need for an alternative paradigm     

Jim Hall  Malcolm Anderson 《水文研究》2002,16(9):1867-1870

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Quantitative shape analysis: A review     

Malcolm W. Clark 《Mathematical Geology》1981,13(4):303-320

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Comment on 'Generalized thin sheet analysis in magnetotellurics: an extension of Price's analysis'     

R. P. Ranganayaki  T. R. Madden  Malcolm J. Drury 《Geophysical Journal International》1981,65(1):237-238

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Geochemistry of coral from Papua New Guinea as a proxy for ENSO ocean–atmosphere interactions in the Pacific Warm Pool     

Linda K. Ayliffe  Michael I. Bird  Michael K. Gagan  Peter J. Isdale  Heather Scott-Gagan  Bruce Parker  David Griffin  Michael Nongkas  Malcolm T. McCulloch 《Continental Shelf Research》2004,24(19):2343-2356

A Porites sp. coral growing offshore from the Sepik and Ramu Rivers in equatorial northern Papua New Guinea has yielded an accurate 20-year history (1977–1996) of sea surface temperature (SST), river discharge, and wind-induced mixing of the upper water column. Depressions in average SSTs of about 0.5–1.0 °C (indicated by coral Sr/Ca) and markedly diminished freshwater runoff to the coastal ocean (indicated by coral δ¹⁸O, δ¹³C and UV fluorescence) are evident during the El Niño – Southern Oscillation (ENSO) events of 1982–1983, 1987 and 1991-1993. The perturbations recorded by the coral are in good agreement with changes in instrumental SST and river discharge/precipitation records, which are known to be diagnostic of the response of the Pacific Warm Pool ocean–atmosphere system to El Niño. Consideration of coastal ocean dynamics indicates that the establishment of northwest monsoon winds promotes mixing of near-surface waters to greater depths in the first quarter of most years, making the coral record sensitive to changes in the Asian–Australian monsoon cycle. Sudden cooling of SSTs by 1°C following westerly wind episodes, as indicated by the coral Sr/Ca, is consistent with greater mixing in the upper water column at these times. Furthermore, the coral UV fluorescence and oxygen isotope data indicate minimal contribution of river runoff to surface ocean waters at the beginning of most years, during the time of maximum discharge. This abrupt shift in flood-plume behaviour appears to reflect the duration and magnitude of northwest monsoon winds, which tend to disperse flood plume waters to a greater extent in the water column when wind-mixing is enhanced. Our results suggest that a multi-proxy geochemical approach to the production of long coral records should provide comprehensive reconstructions of tropical paleoclimate processes operating on interannual timescales.  相似文献   

Influence of wave and sediment dynamics on cordgrass (<Emphasis Type="Italic">Spartina anglica</Emphasis>) growth and sediment accumulation on an exposed intertidal flat     

Andrew?SwalesEmail author  Iain?T.?MacDonald  Malcolm?O.?Green 《Estuaries and Coasts》2004,27(2):225-243

Isolated patches ofSpartina anglica (cordgrass) at two sites on a wave-exposed mid-intertidal flat of the 340 km² Manukau Harbor (Auckland, New Zealand) have developed very differently since being planted in the mid-1970s. Although the two sites are only 0.5 km apart and at the same intertidal elevation,Spartina patches at the easternmost site (site 1) have as much as an order of magnitude higher biomass and accumulated sediment volume thanSpartina patches at site 2. A field experiment was conducted to characterize waves and associated sediment dynamics at each site, which might explain whySpartina patches at the two sites have developed so differently over the past 25 yr or so. Suspended sediments were measured and wave characteristics were inferred from subsurface pressure data measured for 5 wk at bothSpartina sites and at an intermediate location. Bed-orbital speeds and frictional wave-energy dissipation were consistently lower at the easternmost site with the largerSpartina patches. The west-to-east reduction in wave energy is due to the spatial arrangement of theSpartina sites relative to the predominant wind fetches. The wave-energy gradient is maintained by tidal-cycle variations in fetch and bed friction and results in a west-to-east reduction in sand suspension. Silt, which is largely resuspended under southwest winds, is redeposited in the low wave-energy conditions in and around the larger site 1Spartina patches. Shell accumulation bySpartina patches at site 1 occurs infrequently, during southwest winds >10 m s⁻¹ and water depths >0.7 m, when waves are least attenuated by bed friction. Large between-site differences in the growth of and sediment accumulation by theSpartina patch are consistent with the observed wave-energy gradient. The resulting spatial patterns of silt, sand, and shell resuspension and deposition directly influence the rate of sediment accumulation bySpartina patches and the composition of accumulated sediment on this wave-exposed intertidal flat.  相似文献   

The ECOMAN project: A novel approach to defining sustainable ecosystem function     

Galloway TS  Brown RJ  Browne MA  Dissanayake A  Lowe D  Depledge MH  Jones MB 《Marine pollution bulletin》2006,53(1-4):186-194

The ECOMAN was initiated in 2001 by the University of Plymouth, UK, Plymouth Marine Laboratory and the Department of the Environment, Fisheries and Rural Affairs (DEFRA) to address the need for more pragmatic assessment techniques linking environmental degradation with its causes. The primary aim of the project was to develop an evidence-based approach in which suites of easy-to-use, cost-effective and environmentally valid biological responses (biomarkers) could be used together to assess the health of coastal systems through the general condition of individuals. A range of sub-lethal endpoints, chosen to reflect successive levels of biological organisation (molecular, cellular, physiological), was evaluated in common coastal organisms showing different feeding types (filter feeding, grazing, predation) and habitat requirements (estuary, rocky shore). Initially, the suite of biomarkers was used in laboratory studies to determine the relative sensitivities of key species within different functional groups to common contaminants. These results were then validated in field studies performed in a range of ecosystems exhibiting different degrees/signatures of contamination. Here, an example is provided of a field study in the Humber Estuary, UK, which illustrates how multivariate statistical analysis can be used to identify patterns of response to discriminate between contaminated and clean sites. The use of a holistic, integrated approach of this kind is advocated as a practical means of assessing the impact of chemical contamination on organismal health and of ranking the status of marine ecosystems.  相似文献   

Vulnerability of Aboriginal health systems in Canada to climate change   总被引：1，自引：0，他引：1  

James D. Ford  Lea Berrang-Ford  Malcolm King  Chris Furgal   《Global Environmental Change》2010,20(4):668-680

Climate change has been identified as potentially the biggest health threat of the 21st century. Canada in general has a well developed public health system and low burden of health which will moderate vulnerability. However, there is significant heterogeneity in health outcomes, and health inequality is particularly pronounced among Aboriginal Canadians. Intervention is needed to prevent, prepare for, and manage climate change effects on Aboriginal health but is constrained by a limited understanding of vulnerability and its determinants. Despite limited research on climate change and Aboriginal health, however, there is a well established literature on Aboriginal health outcomes, determinants, and trends in Canada; characteristics that will determine vulnerability to climate change. In this paper we systematically review this literature, using a vulnerability framework to identify the broad level factors constraining adaptive capacity and increasing sensitivity to climate change. Determinants identified include: poverty, technological capacity constraints, socio-political values and inequality, institutional capacity challenges, and information deficit. The magnitude and nature of these determinants will be distributed unevenly within and between Aboriginal populations necessitating place-based and regional level studies to examine how these broad factors will affect vulnerability at lower levels. The study also supports the need for collaboration across all sectors and levels of government, open and meaningful dialogue between policy makers, scientists, health professionals, and Aboriginal communities, and capacity building at a local level, to plan for climate change. Ultimately, however, efforts to reduce the vulnerability of Aboriginal Canadians to climate change and intervene to prevent, reduce, and manage climate-sensitive health outcomes, will fail unless the broader determinants of socio-economic and health inequality are addressed.  相似文献   

History of astronomical discoveries     

Malcolm Longair 《Experimental Astronomy》2009,25(1-3):241-259

The wide diversity of routes to astronomical, astrophysical and cosmological discovery is discussed through a number of historical case studies. Prime ingredients for success include new technology, precision observation, extensive databases, capitalising upon discoveries in cognate disciplines, imagination and luck. Being in the right place at the right time is a huge advantage. The changing perspectives on the essential tools for tackling frontier problems and astronomical advance are discussed.  相似文献   

Expanding the application of the Eu‐oxybarometer to the lherzolitic shergottites and nakhlites: Implications for the oxidation state heterogeneity of the Martian interior     

Molly C. McCANTA  Linda ELKINS‐TANTON  Malcolm J. RUTHERFORD 《Meteoritics & planetary science》2009,44(5):725-745

Abstract— Experimentally rehomogenized melt inclusions from the nakhlite Miller Range 03346 (MIL 03346) and the lherzolitic shergottite Allan Hills 77005 (ALH 77005) have been analyzed for their rare earth element (REE) concentrations in order to characterize the early melt compositions of these Martian meteorites and to calculate the oxygen fugacity conditions they crystallized under. D(Eu/Sm)_{pyroxene/melt} values were measured at 0.77 and 1.05 for ALH 77005 and MIL 03346, respectively. These melts and their associated whole rock compositions have similar REE patterns, suggesting that whole rock REE values are representative of those of the early melts and can be used as input into the pyroxene Eu‐oxybarometer for the nakhlites and lherzolitic shergottites. Crystallization fO₂ values of IW + 1.1 (ALH 77005) and IW + 3.2 (MIL 03346) were calculated. Whole rock data from other nakhlites and lherzolitic shergottites was input into the Eu‐oxybarometer to determine their crystallization fO₂ values. The lherzolitic shergottites and nakhlites have fO₂ values that range from IW + 0.4 to 1.6 and from IW + 1.1 to 3.2, respectively. These values are consistent with some previously determined fO₂ estimates and expand the known range of fO₂ values of the Martian interior to four orders of magnitude. The origins of this range are not well constrained. Possible mechanisms for producing this spread in fO₂ values include mineral/melt fractionation, assimilation, shock effects, and magma ocean crystallization processes. Mineral/melt partitioning can result in changes in fO₂ from the start to the finish of crystallization of 2 orders of magnitude. In addition, crystallization of a Martian magma ocean with reasonable initial water content results in oxidized, water‐rich, late‐stage cumulates. Sampling of these oxidized cumulates or interactions between reduced melts and the oxidized material can potentially account for the range of fO₂ values observed in the Martian meteorites.  相似文献