A simple and inexpensive chromium-reducible sulfur method for acid-sulfate soils   总被引：2，自引：0，他引：2  

Edward D. Burton  Leigh A. SullivanRichard T. Bush  Scott G. JohnstonAnnabelle F. Keene 《Applied Geochemistry》2008

A new chromium-reducible sulfur (CRS) method suitable for the quantification of reduced inorganic S (RIS) in acid-sulfate soils is presented. The new method utilises the reduction of RIS by an acidic Cr(II) solution within a sealed reaction chamber and diffusion of the produced H₂S_(g) into an alkaline Zn solution. It offers rapid sample processing times, without the need for large volumes of high-purity N_2(g) or for specialized, expensive glassware. Examination of pyrite-talc mixtures containing up to 11.8% pyrite, revealed that the method achieves 95–98% recovery of RIS. A comparison between CRS measured by the new diffusion-based method and that measured by a standard purge-and-trap method for 25 pyritic soil samples shows a very strong (r² = 0.996) linear relationship with a slope of 0.995. The ability of the new diffusion-based CRS method to achieve accurate and precise quantification of RIS in acid-sulfate soils is demonstrated.  相似文献   

Corrigendum     

G. R. Holdgate  M. W. Wallace  S. J. Gallagher  A. J. Smith  J. B. Keene  D. Moore 《Australian Journal of Earth Sciences》2013,60(4)

  相似文献   

A celebration of women in astronomy     

Jocelyn Bell Burnell 《Astronomy& Geophysics》2004,45(6):6.10-6.14

Jocelyn Bell Burnell ponders the achievements and status of women in astronomy, past, present and future.  相似文献   

Numerical prediction of an intense convective system associated with the July 1987 montreal flood. part I: Gravity waves and the squall line     

Stéphane Bélair  Da‐Lin Zhang  Jocelyn Mailhot 《大气与海洋》2013,51(3):447-473

Abstract

In this study, a 24‐h high‐resolution numerical prediction of a prefrontal squall line associated with the 14 July 1987 Montreal flood is employed to investigate the origin and role of mesoscale gravity waves in the development of the squall system. The 24‐h integration using an improved mesoscale version of the Canadian regional finite‐element model is first validated against available observations; then non‐observable features are diagnosed to reveal the relationship between deep convection and gravity wave events. It is shown that the model reproduces well many aspects of the squall line, such as the propagation and organization of the convective system, as well as its associated precipitation. It is found that gravity waves are first excited near Lake Erie, following the initiation of early convective activity. Then, these waves propagate eastward and northeastward at speeds of 20 and 35 m s^‐1, respectively. As the waves propagate downstream, deep convection radiates rapidly behind the wave trough axis, forming a long line of squall convection. Because the squall line moves with the gravity waves in a “phase‐locked” manner, deep convection has a significant influence on the structure and amplitude of the gravity waves. The sensitivity of the wave‐squall prediction to various parameters in convective parameterization is also examined.  相似文献   

Iron geochemical zonation in a tidally inundated acid sulfate soil wetland     

Scott G. Johnston  Annabelle F. Keene  Richard T. Bush  Edward D. Burton  Leigh A. Sullivan  Lloyd Isaacson  Angus E. McElnea  Col R. Ahern  C. Douglas Smith  Bernard Powell 《Chemical Geology》2011,280(3-4):257-270

Tidal inundation is a new technique for remediating coastal acid sulfate soils (CASS). Here, we examine the effects of this technique on the geochemical zonation and cycling of Fe across a tidally inundated CASS toposequence, by investigating toposequence hydrology, in situ porewater geochemistry, solid-phase Fe fractions and Fe mineralogy. Interactions between topography and tides exerted a fundamental hydrological control on the geochemical zonation, redistribution and subsequent mineralogical transformations of Fe within the landscape. Reductive dissolution of Fe(III) minerals, including jarosite (KFe₃(SO₄)₂(OH)₆), resulted in elevated concentrations of porewater Fe²⁺ (> 30 mmol L^?1) in former sulfuric horizons in the upper-intertidal zone. Tidal forcing generated oscillating hydraulic gradients, driving upward advection of this Fe²⁺-enriched porewater along the intertidal slope. Subsequent oxidation of Fe²⁺ led to substantial accumulation of reactive Fe(III) fractions (up to 8000 μmol g^?1) in redox-interfacial, tidal zone sediments. These Fe(III)-precipitates were poorly crystalline and displayed a distinct mineralisation sequence related to tidal zonation. Schwertmannite (Fe₈O₈(OH)₆SO₄) was the dominant Fe mineral phase in the upper-intertidal zone at mainly low pH (3–4). This was followed by increasing lepidocrocite (γ-FeOOH) and goethite (α-FeOOH) at circumneutral pH within lower-intertidal and subtidal zones. Relationships were evident between Fe fractions and topography. There was increasing precipitation of Fe-sulfide minerals and non-sulfidic solid-phase Fe(II) in the lower intertidal and subtidal zones. Precipitation of Fe-sulfide minerals was spatially co-incident with decreases in porewater Fe²⁺. A conceptual model is presented to explain the observed landscape-scale patterns of Fe mineralisation and hydro-geochemical zonation. This study provides valuable insights into the hydro-geochemical processes caused by saline tidal inundation of low lying CASS landscapes, regardless of whether inundation is an intentional strategy or due to sea-level rise.  相似文献   

Morphology and formation of spreading cracks on pillow lavas at Cape Grim, northwestern Tasmania, Australia     

Yoshihiko Goto  Jocelyn McPhie 《Bulletin of Volcanology》2012,74(7):1611-1619

Tertiary basaltic pillow lobes at Cape Grim, northwestern Tasmania, Australia display well-preserved spreading cracks in the glassy crust. The spreading cracks are lens-shaped or rectangular in plan view. In cross section, they consist of a graben-like depression with a broad floor bounded by steep scarps. The floor of spreading crack contains an axial crack and a number of ridges that are arranged symmetrically with respect to the axial crack. The ridges within spreading cracks are inferred to have formed by the regular, repeated production and splitting of new crust at the centre of the spreading crack. This new interpretation of ridges in spreading cracks differs from the previous interpretation in which they are regarded as elongate normal fault blocks. Our interpretation provides new insight into the propagation mechanisms of pillow lavas.  相似文献   

Submarine eruption-fed and resedimented pumice-rich facies: the Dogashima Formation (Izu Peninsula,Japan)     

Martin Jutzeler  Jocelyn McPhie  Sharon R. Allen 《Bulletin of Volcanology》2014,76(10):1-29

In the Izu Peninsula (Japan), the Pliocene pumice-rich Dogashima Formation (4.55?±?0.87 Ma) displays exceptional preservation of volcaniclastic facies that were erupted and deposited in a below wave-base marine setting. It includes high-concentration density current deposits that contain clasts that were emplaced hot, indicating an eruption-fed origin. The lower part of the Dogashima 2 unit consists of a very thick sequence (<12 m) of massive grey andesite breccia restricted to the base of a submarine channel, gradationally overlain by pumice breccia, which is widespread but much thinner and finer in the overbank setting. These two breccias share similar mineralogy and crystal composition and are considered to be co-magmatic and derived from the destruction of a submarine dome by an explosive, pumice-forming eruption. The two breccias were deposited from a single, explosive eruption-fed, sustained, sea floor-hugging, water-supported, high-concentration density current in which the clasts were sorted according to their density. At the rim of the channel, localised good hydraulic sorting of clasts and stratification in the pumice breccia are interpreted to reflect local current expansion and unsteadiness rather than to be the result of hydraulic sorting of clasts during fall from a submarine eruption column and/or umbrella plume. A bimodal coarse (>1 m) pumice- and ash-rich bed overlying the breccias may be derived from delayed settling of pyroclasts from suspension. In Dogashima 1 and 2, thick cross- and planar-bedded facies composed of sub-rounded pumice clasts are intercalated with eruption-fed facies, implying inter-eruptive mass-wasting on the flank of a submarine volcano, and reworking and resedimentation by high-energy tractional currents in a below wave-base environment.  相似文献   

Mid-Mountain Clouds at Whistler During the Vancouver 2010 Winter Olympics and Paralympics     

Ruping Mo  Paul Joe  George A. Isaac  Ismail Gultepe  Roy Rasmussen  Jason Milbrandt  Ron McTaggart-Cowan  Jocelyn Mailhot  Melinda Brugman  Trevor Smith  Bill Scott 《Pure and Applied Geophysics》2014,171(1-2):157-183

A comprehensive study of mid-mountain clouds and their impacts on the Vancouver 2010 Winter Olympics and Paralympics is presented. Mid-mountain clouds were frequently present on the Whistler alpine venue, as identified in an extensive archive of webcam images over a 45-day period from February 5 to March 21, 2010. These clouds posed serious forecast challenges and had significant impacts on some Olympic and Paralympic alpine skiing competitions. Under fair weather conditions, a diurnal upslope (anabatic) flow can work in concert with a diurnal temperature inversion aloft to produce a localized phenomenon known as “Harvey’s Cloud” at Whistler. Two detailed case studies in this paper suggest that mid-mountain clouds can also develop in the area as a result of a moist valley flow interacting with a downslope flow descending from the mountaintop. A southerly inflow through the Sea-to-Sky corridor can be channeled by the local topography into a westerly upslope flow toward Whistler Mountain, resulting in orographic clouds on the alpine venue. Under favorable circumstances, these clouds are trapped to the mid-mountain zone by the leeward subsidence of an elevated southerly flow. The presence of the downslope subsidence was manifested by a distinguished dry layer observed on the top of the mid-mountain clouds in both cases. It is the subsidence-induced adiabatic warming that imposes a strong buoyant suppression to trap the mid-mountain cloud. On the other hand, the subsidence-induced dry layer has the potential to trigger evaporative instability to periodically breakup the mid-mountain cloud.  相似文献   

Past major tsunamis and the level of tsunami risk on the Aitape coast of Papua New Guinea     

Davies  Hugh L.  Simeon  Oliver B.  Hope  Geoffrey  Petchey  Fiona  Davies  Jocelyn M. 《Natural Hazards》2019,96(3):1019-1040

Natural Hazards - This paper reports the results of an investigation into past major tsunamis on the Aitape coast of Papua New Guinea. The investigation was mounted to gather information to help...  相似文献   

What it takes to make a planet     

Iwan Williams  Prof.  Jocelyn Bell 《Astronomy& Geophysics》2006,47(5):5.16-5.17

What lay behind the decision to reclassify Pluto as a "dwarf planet" at August's IAU General Assembly in Prague?  相似文献