Editors’ message: Online re-publication of legacy articles on the occasion of Hydrogeology Journal’s 20th anniversary, 1992–2012     

Clifford I. Voss  Sue M. Duncan 《Hydrogeology Journal》2012,20(8):1433-1439

  相似文献   

Dynamite fishing in northern Tanzania - pervasive, problematic and yet preventable     

Sue Wells 《Marine pollution bulletin》2009,58(1):20-23

Dynamite fishing, although illegal, has resurfaced in recent years as a major threat to the reefs of northern Tanzania. This is despite the fact that institutional arrangements for co-management of the inshore fisheries by local communities and the district governments have been put in place and, through a 12-year donor-funded programme, numerous activities undertaken to build capacity for effective fisheries management. The use of dynamite is having widespread negative impacts, including damage to the reefs and their long-term productivity, deterrence of tourism investors, and potential threat to the large population of coelacanths in the area. The dynamite fishers are able to continue, even though enforcement efforts have been stepped up, because they are members of influential families or otherwise well-connected. Previous similar cases in Tanzania, and examples from elsewhere in the world, suggest that a major initiative is now needed to develop a zero-tolerance approach on the part of fishers and local and national leaders, that will shame the dynamiters through peer pressure, promote full implementation of sanctions and penalties by the judiciary, and lead to public recognition of and support for the work of the enforcement agencies.  相似文献   

Climate change impacts on environmental geosciences: Introduction     

Lawal Billa  Sue Walker 《地学前缘(英文版)》2019,10(2):361-362

正Climate change and its impacts have become topical issues of global news, scientific research and conferences. Environmental Geosciences incorporate the various disciplines of geosciences and their multifaceted interactions with life. Research discussions on the interaction of climate change, geosciences and environment may often be blur, and Schmidt-Thoméet al.(2010) stated that"Often past climate changes that can be deduced from geological records may help in understanding the speed of potential climate change effects, i.e. how quickly have sea levels changed, how drastic has nature reacted to ups and downs in temperature, etc. These analyses of past events help in giving outlooks on potential changes in our living environment. It is also of important to understand the magnitude and potential effects of extreme events, such as droughts and floods".  相似文献   

Reconciling late faulting over the whole Alpine belt: from structural analysis to geochronological constrains     

Audrey Bertrand  Christian Sue 《Swiss Journal of Geoscience》2017,110(2):565-580

The significance of late-stage fracturing in the European Alps in a large geodynamic context is reappraised by studying brittle deformations over the entire belt. In the internal Western Alps, paleostress datasets display a major occurrence of orogen-parallel extension resulting in normal faulting and associated strike-slip mode. There the direction of subhorizontal extension rotates with the bending of the Alpine belt. In the Central Alps, paleostress tensors also indicate orogen-parallel extensional regimes, both in the Bergell area and the Lepontine Dome, where the brittle structures are associated with ductile structures related to the formation of large-scale upright folds that accommodate most of the collisional shortening due to the north-directed component of the movement of the South-Alpine indenter. This brittle deformation phase is of Miocene age and is coeval with the propagation of the Alpine front toward the external Alpine domains. In the Eastern Alps, brittle deformation of the Tauern Window displays an overwhelming occurrence of orogen-parallel normal faulting and associated strike-slip regimes again, which is inferred to be driven by lateral extrusion of the orogenic wedge toward the Pannonian basin, partly due to indentation on the Dolomites indenter. The major orogen-parallel extensional signal of the brittle Cenozoic deformations appears remarkably stable all over the internal Alps. Extensional brittle structures are part of a late phase of collisional deformation, during which the propagation of the Alpine front of the Western Alps and the northward movement of the Southern Alpine and the Dolomites indenters in the Central and Eastern Alps were accommodated by orogen-parallel extension in the inner zones, at the scale of the entire chain.  相似文献   

The Miller Range 090340 and 090206 meteorites: Identification of new brachinite‐like achondrites with implications for the diversity and petrogenesis of the brachinite clan          下载免费PDF全文

Cyrena Anne Goodrich  Noriko T. Kita  Stephen R. Sutton  Sue Wirick  Juliane Gross 《Meteoritics & planetary science》2017,52(5):949-978

Miller Range (MIL) 090340 and MIL 090206 are olivine‐rich achondrites originally classified as ureilites. We investigate their petrography, mineral compositions, olivine Cr valences, equilibration temperatures, and (for MIL 090340) oxygen isotope compositions, and compare them with ureilites and other olivine‐rich achondrites. We conclude that they are brachinite‐like achondrites that provide new insights into the petrogenesis of brachinite clan meteorites. MIL 090340,6 has a granoblastic texture and consists of ~97 modal % by area olivine (Fo = molar Mg/[Mg+Fe] = 71.3 ± 0.6). It also contains minor to trace augite, chromite, chlorapatite, orthopyroxene, metal, troilite, and terrestrial Fe‐oxides. Approximately 80% by area of MIL 090206,5 has a granoblastic texture of olivine (Fo 72.3 ± 0.1) plus minor augite and chromite, similar to MIL 090340 but also containing minor plagioclase. The rest of the section consists of a single crystal of orthopyroxene (~11 × 3 mm), poikilitically enclosing rounded grains of olivine (Fo = 76.1 ± 0.6), augite, chromite, metal, and sulfide. Equilibration temperatures for MIL 090340 and MIL 090206, calculated from olivine‐spinel, olivine‐augite, and two‐pyroxene thermometry range from ~800 to 930 °C. In both samples, symplectic intergrowths of Ca‐poor orthopyroxene + opaque phases (Fe‐oxides, sulfide, metal) occur as rims on and veins/patches within olivine. Before terrestrial weathering, the opaques were probably mostly sulfide, with minor metal. All petrologic properties of MIL 090340 and MIL 090206 are consistent with those of brachinite clan meteorites, and largely distinct from those of ureilites. Oxygen isotope compositions of olivine in MIL 090340 (δ¹⁸O = 5.08 ± 0.30‰, δ¹⁷O = 2.44 ± 0.21‰, and Δ¹⁷O = ?0.20 ± 0.12‰) are also within the range of brachinite clan meteorites, and well distinguished from ureilites. Olivine Cr valences in MIL 090340 and the granoblastic area of MIL 090206 are 2.57 ± 0.06 and 2.59 ± 0.07, respectively, similar to those of three brachinites also analyzed here (Brachina, Hughes 026, Nova 003). They are higher than those of olivine in ureilites, even those containing chromite. The valence systematics of MIL 090340, MIL 090206, and the three analyzed brachinites (lower Fo = more oxidized Cr) are consistent with previous evidence that brachinite‐like parent bodies were inherently more oxidized than the ureilite parent body. The symplectic orthopyroxene + sulfide/metal assemblages in MIL 090340, MIL 090206, and many brachinite clan meteorites have superficial similarities to characteristic “reduction rims” in ureilites. However, they differ significantly in detail. They likely formed by reaction of olivine with S‐rich fluids, with only minor reduction. MIL 090340 and the granoblastic area of MIL 090206 are similar in modal mineralogy and texture to most brachinites, but have higher Fo values typical of brachinite‐like achondrites. The poikilitic pyroxene area of MIL 090206 is more typical of brachinite‐like achondrites. The majority of their properties suggest that MIL 090340 and MIL 090206 are residues of low‐degree partial melting. The poikilitic area of MIL 090206 could be a result of limited melt migration, with trapping and recrystallization of a small volume of melt in the residual matrix. These two samples are so similar in mineral compositions, Cr valence, and cosmic ray exposure ages that they could be derived from the same lithologic unit on a common parent body.  相似文献   

Vegetation history of the English chalklands: a mid‐Holocene pollen sequence from the Caburn,East Sussex     

Martyn P. Waller  Sue Hamilton 《第四纪科学杂志》2000,15(3):253-272

A pollen diagram has been produced from the base of the Caburn (East Sussex) that provides a temporally and spatially precise record of vegetation change on the English chalklands during the mid‐Holocene (ca. 7100 to ca. 3800 cal. yr BP). During this period the slopes above the site appear to have been well‐wooded, with vegetation analogous to modern Fraxinus–Acer–Mercurialis communities in which Tilia was also a prominent constituent. However, scrub and grassland taxa such as Juniperus communis, Cornus sanguinea and Plantago lanceolata are also regularly recorded along with, from ca. 6000 cal. yr BP onwards, species specific to Chalk grassland (e.g. Sanguisorba minor). This supports suggestions that elements of Chalk grassland persisted in lowland England through the Holocene. Such communities are most likely to have occupied the steepest slopes, although the processes that maintained them are unclear. Human interference with vegetation close to the site may have begun as early as ca. 6350 cal. yr BP and initially involved a woodland management practice such as coppicing. From the primary Ulmus decline (ca. 5700 cal. yr BP) onwards, phases of limited clearance accompanied by cereal cultivation occurred. Taxus baccata was an important component of the woodland which regenerated between these phases. Copyright © 2000 John Wiley & Sons, Ltd.  相似文献   

Agroclimatological suitability mapping for dryland maize production in Lesotho   总被引：1，自引：0，他引：1  

Mokhele Edmond Moeletsi  Sue Walker 《Theoretical and Applied Climatology》2013,114(1-2):227-236

The climatic potential of maize under dryland farming in Lesotho, southern Africa, was investigated using five suitability indices comprising probability of accumulating heat units of greater than 1,500 growing degree days, probability of a frost-free growing season, probability of seasonal rainfall of more than 500 mm, probability of drought during the flowering to grain-filling stages and the slope of an area. A geographic information system layer was prepared for each of these parameters and the layers overlaid using different weights for each of the climatic suitability indices to obtain an agroclimatic maize suitability map for Lesotho. This analysis yielded different suitability classes. This variability points to prevalence of climatic constraints that need to be acknowledged when attempting to identify management strategies that can optimize the rain-fed maize production in climatically variable environments.  相似文献   

Sediment yield prediction and modelling     

Sue White 《水文研究》2005,19(15):3053-3057

  相似文献   

Brittle deformation in the inner NW Alps: from early orogen-parallel extrusion to late orogen-perpendicular collapse     

Jean-Daniel Champagnac  Christian Sue  Bastien Delacou  Martin Burkhard 《地学学报》2004,16(4):232-242

Internal parts of the Alps have undergone widespread extensional deformation in the course of their Neogene exhumation history. Palaeostress inversion methods are used to map the prevailing stress fields and their evolution through time. Here we present new data from 100 sites with a total of about 2000 faults/striae couples, covering a large portion of the inner north‐western Alps. Palaeostress tensors are mostly extensional, although one‐third of them are transcurrent. The dominant direction of minimum horizontal stress axes (σ3) is in an orogen‐parallel (N30° to N70°) orientation around the bend of the north‐west alpine arc. A comparison between this older (Neogene, post‐metamorphic) stress field with the current stress and strain field determined from seismotectonics and geodesy indicates a change in deformation mode from early orogen‐parallel extrusion to a late and ongoing orogen‐perpendicular spreading.  相似文献   

Erratum: Editors’ Message: Online re-publication of legacy articles on the occasion of Hydrogeology Journal’s 20th anniversary, 1992–2012, and Editors’ Message: Eminent hydrogeologists profiled in 20 years of Hydrogeology Journal (1992–2012)     

Clifford I. Voss  Sue M. Duncan 《Hydrogeology Journal》2013,21(7):1683-1685

  相似文献