A call for increased public engagement in geology higher education     

Jane Robb 《Geology Today》2013,29(2):63-67

Rising fees are forcing higher education institutions to think critically about what students are offered for their money. In geology courses there appears to be a lack of guidance for alternative careers in academia or industry, and even a lack of education about wider social, political and economic impacts of the discipline. It is possible to detect a lack of high‐impact geoscience among the popular science communication communities, such as online multidisciplinary blogging platforms. In order to enhance the student experience and the impact of geoscience on the wider public, universities need to look inwards at what they can do to help inspire and educate students to have broader career horizons and bigger public impacts through their research.  相似文献   

Snowmelt variability in Polar Bear Pass,Nunavut, Canada,from QuikSCAT: 2000–2009     

Stephen E. L. Howell  Jane Assini  Kathy L. Young  Anna Abnizova  Chris Derksen 《水文研究》2012,26(23):3477-3488

Snowmelt onset and end date estimates are made from QuikSCAT scatterometer measurements in the Canadian High Arctic wetland of Polar Bear Pass (PBP) and the surrounding region of Bathurst Island, Nunavut. In situ data within PBP is used to validate QuikSCAT snowmelt onset/end date estimates. Results indicate that within PBP from 2000 to 2009, the mean snowmelt onset date was Year Day (YD) 162, the mean snowmelt end date was YD179, and the mean snowmelt duration was 17 days. More interannual variability was apparent in snowmelt end date and duration compared with onset, and only snowmelt end date was significantly correlated with mean June air temperature at ?0.78. Cooler air temperatures in 2004 contributed to a long snowmelt duration of 24 days, and the very short snowmelt duration in 2007 of just 11 days was caused by rapid and sustained increases in air temperature. For snowmelt end date and duration the mean spatial pattern revealed two centres of later snowmelt end date/longer snowmelt duration over Bathurst Island. They were separated by early snowmelt end date/short snowmelt duration in PBP. These patterns are in agreement with the spatial distribution of mean May to July air temperature over Bathurst Island and are likely influenced by the local‐scale topography of Bathurst Island. Given the correlation between air temperature and snowmelt end date, we might expect quicker snowmelt under increased warming. The latter process may have implications for the sustainability of the PBP wetland under a warmer climate. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

The Effects of Salinity on Nitrogen Losses from an Oligohaline Estuarine Sediment   总被引：4，自引：0，他引：4  

Anne E. Giblin  Nathaniel B. Weston  Gary T. Banta  Jane Tucker  Charles S. Hopkinson 《Estuaries and Coasts》2010,33(5):1054-1068

Benthic respiration, sediment–water nutrient fluxes, denitrification and dissimilatory nitrate reduction to ammonium (DNRA) were measured in the upper section of the Parker River Estuary from 1993 to 2006. This site experiences large changes in salinity over both short and long time scales. Sediment respiration ranged from 6 to 52 mmol m⁻² day⁻¹ and was largely controlled by temperature. Nutrient fluxes were dominated by ammonium fluxes, which ranged from a small uptake of −0.3 to an efflux of over 8.2 mmol N m⁻² day⁻¹. Ammonium fluxes were most highly correlated with salinity and laboratory experiments demonstrated that ammonium fluxes increased when salinity increased. The seasonal pattern of DNRA closely followed salinity. DNRA rates were extremely low in March, less than 0.1 mmol m⁻² day⁻¹, but increased to 2.0 mmol m⁻² day⁻¹ in August. In contrast, denitrification rates were inversely related to salinity, ranging from 1 mmol m⁻² day⁻¹ during the spring and fall to less than 0.2 mmol m⁻² day⁻¹ in late summer. Salinity appears to exert a major control on the nitrogen cycle at this site, and partially decouples sediment ammonium fluxes from organic matter decomposition.  相似文献   

Trace element concentrations in the Mexico‐Belize ejecta layer: A link between the Chicxulub impact and the global Cretaceous‐Paleogene boundary     

Jane Wigforss‐Lange  Vivi Vajda  Adriana Ocampo 《Meteoritics & planetary science》2007,42(11):1871-1882

Abstract— Four exposures of Chicxulub impact ejecta along the Mexico‐Belize border have been sampled and analyzed for major and trace element abundances. The ejecta deposits consist of a lower spheroid bed, containing clay and dolomite spheroids, and an upper diamictite bed with boulders and clasts of limestone and dolomite. The matrix of both beds is composed of clay and micritic dolomite. The rare earth element (REE) compositions in the matrix of both units show strong similarities in concentrations and pattern. Furthermore, the Zr/TiO₂ scatter plot shows a linear correlation indicating one source. These results indicate that the basal spheroid bed has the same source and was generated during the same event as the overlying diamictite bed, which lends support to a single‐impact scenario for the Albion Formation ejecta deposits. The elevated concentrations of non‐meteoritic elements such as Sb, As, U, and Zn in the matrix of the lower spheroid bed are regarded to have been derived from the sedimentary target rocks at the Chicxulub impact site. The positive Eu and Ce anomalies in clay concretion and in the matrix of the lower part of the spheroid bed in Albion Island quarry is probably related to processes involved in the impact, such as high temperature and oxidizing conditions. Analogous trace element anomalies have been reported from the distal Cretaceous‐Paleogene (K/T) boundary clay layer at different sites. Thus, the trace element signals, reported herein, are regarded to support a genetic link between the Chicxulub impact, the ejecta deposits along the Mexico‐Belize border, and the global K/T boundary layer.  相似文献   

The use of genetic algorithms to model protoplanetary discs     

Annibal Hetem  Jr    Jane Gregorio-Hetem 《Monthly notices of the Royal Astronomical Society》2007,382(4):1707-1718

The protoplanetary discs of T Tauri and Herbig Ae/Be stars have previously been studied using geometric disc models to fit their spectral energy distribution (SED). The simulations provide a means to reproduce the signatures of various circumstellar structures, which are related to different levels of infrared excess. With the aim of improving our previous model, which assumed a simple flat-disc configuration, we adopt here a reprocessing flared-disc model that assumes hydrostatic, radiative equilibrium. We have developed a method to optimize the parameter estimation based on genetic algorithms (GAs). This paper describes the implementation of the new code, which has been applied to Herbig stars from the Pico dos Dias Survey catalogue, in order to illustrate the quality of the fitting for a variety of SED shapes. The star AB Aur was used as a test of the GA parameter estimation, and demonstrates that the new code reproduces successfully a canonical example of the flared-disc model. The GA method gives a good quality of fit, but the range of input parameters must be chosen with caution, as unrealistic disc parameters can be derived. It is confirmed that the flared-disc model fits the flattened SEDs typical of Herbig stars; however, embedded objects (increasing SED slope) and debris discs (steeply decreasing SED slope) are not well fitted with this configuration. Even considering the limitation of the derived parameters, the automatic process of SED fitting provides an interesting tool for the statistical analysis of the circumstellar luminosity of large samples of young stars.  相似文献   

Geoffrey Boulton     

James Rose  Jane K. Hart 《Quaternary Science Reviews》2009,28(7-8):580-583

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Promoting geological heritage through postage stamps     

Jane Dove 《Geology Today》2016,32(2):70-74

Postage stamps are useful in promoting geological heritage. This concept is explored through an analysis of British and New Zealand stamps, which portray a variety of different types of geological heritage. Coastal, glacial, fluvial and limestone scenery all feature, together with volcanic landforms such as the Giant's Causeway. Other stamps celebrate the work of historically significant figures who have contributed to geology, such as Charles Darwin. The field of palaeontology is represented in stamps, for example, featuring dinosaurs. Others portray economic activities and engineering achievements associated with geology such as oil and gas exploration. Industrial heritage is depicted by stamps featuring, for example, abandoned tin mines, while building stones are represented in stamps of ancient monuments, bridges, cathedrals and domestic architecture. Perhaps subjects for future stamp issues in the UK might draw upon the recently published 100 top geosites list.  相似文献   

Carbon dioxide and carbon monoxide photoproduction quantum yields in the Delaware Estuary     

Emily M. White  David J. Kieber  Jane Sherrard  William L. Miller  Kenneth Mopper 《Marine Chemistry》2010,118(1-2):11-21

Photochemical mineralization of dissolved organic matter (DOM) plays an important role in the cycling of carbon in estuarine systems. A key to modeling this process is knowledge of apparent quantum yields (AQYs) for the photochemical products. Here we determined spectral AQYs for carbon dioxide (CO₂) and carbon monoxide (CO), the main products of DOM photomineralization, along the main axis of the Delaware Estuary. Apparent quantum yields for CO₂ photoproduction were determined shipboard using a multi-spectral irradiation system. Carbon monoxide AQYs were determined in stored samples by employing a narrow band spectral irradiation system. A single AQY spectrum described carbon dioxide photochemical production within the estuary whereas CO AQY spectra varied with salinity, suggesting different precursors and mechanisms for the production of these two species. CO₂ AQYs were used along with shipboard measurements of DOM absorbance and solar irradiance to calculate photoproduction rates. Calculated CO₂ photoproduction rates agreed with directly measured rates (2 to 4 μM CO₂ d^? 1) within experimental error, supporting the further development and use of AQYs to calculate regional-scale photochemical fluxes.  相似文献   

Noble gases in E-chondrites     

Jane Crabb  Edward Anders 《Geochimica et cosmochimica acta》1981,45(12):2443-2464

Noble gas data are reported for 12 E-chondrites. Combined with literature data, they show that K-Ar ages are >4 Æ for 14 out of 18 meteorites, yet U, Th-He ages are often shorter, perhaps due to late, mild reheating. Cosmic-ray exposure ages differ systematically between types 4 and 6, with E4's mostly below 16 Myr and E6's above 30 Myr. This may mean that the E-chondrite parent body contains predominantly a single petrologic type on the (~ 1 km) scale of individual impacts, in contrast to the more thoroughly mixed parent bodies of the ordinary chondrites.The heavy noble gases consist of at least two primordial components: the usual planetary component (${}^{36}\text{Ar}{}^{132}\text{Xe}\text{~ 80}$) and a less fractionated, ‘subsolar’ component ($\text{2700 ≤}{}^{36}\text{Ar}{}^{132}\text{Xe}\text{≤ 3800}$). The latter is found in highest concentration in the E4 chondrite South Oman (³⁶Ar = 760 × 10^?8cc/g, ${}^{36}\text{Ar}{}^{132}\text{Xe}\text{= 2700}$). The isotopic compositions of both components are similar to typical planetary values, indicating that some factor other than mass controlled the noble gas elemental ratios. The heavy Xe isotopes occasionally show some of the lowest ${}^{134}\text{Xe}{}^{132}\text{Xe}$ and ${}^{136}\text{Xe}{}^{132}\text{Xe}$ ratios measured in bulk chondrites, suggestive of nearly fission-free Xe (e.g. ${}^{136}\text{Xe}{}^{132}\text{Xe}\text{= 0.3095 ± 0.0020}$). Amounts of planetary gas in E4 E6 chondrites fall in the range for ordinary chondrites of types 4–6, but, in contrast to the ordinary chondrites. fail to correlate with petrologic type or volatile trace element contents. Another unusual feature of E-chondrites is that primordial Ne is present even in most 4's and 5's (²⁰Ne_p ~ 1 to 7 × 10^?8cc/g). with an isotopic composition consistent with planetary Ne.Analyses of mineral separates show that the planetary gases are concentrated in an HF- and HCl-insoluble mineral similar to phase Q, the poorly characterized, HNO₃-soluble carrier of primordial gases in carbonaceous and ordinary chondrites. The subsolar gases, on the other hand, are located in an HCl- and HNO₃-resistant phase, possibly enstatite or a minor phase included in enstatite. Much of the ¹²⁹Xe_r (50% for E4's, > 70% for E6's) is in HCl-resistant but HF-soluble sites, suggestive of a silicate.A similar subsolar component may be responsible for the high ${}^{36}\text{Ar}{}^{132}\text{Xe}$ ratios of some C3's, unequilibrated ordinary chondrites, and the unique aubrite Shallowater. The planet Venus also has a high $\text{Ar}\text{Kr}$ ratio, well above the planetary range, and hence may have acquired its noble gases from an E-chondrite-like material, similar to South Oman.  相似文献   

Bicyclic sesquiterpenoids and diterpenoids in Australian crude oils     

R. Paul Philp  Trevor D. Gilbert  Jane Friedrich 《Geochimica et cosmochimica acta》1981,45(7):1173-1180

Bicyclanes previously reported only in heavily biodegraded Texas Gulf Coast crudes have been found to be ubiquitous in Australian crude oils of non-marine origin from four different basins. The compounds are present in oils, thought to be derived from the same or similar sources, that have undergone varying degrees of biodegradation. They are also found to be present in oils of different geological age. In addition a series of tricyclic diterpenoid hydrocarbons was common to four oils from the Gippsland Basin. Four of these compounds had the molecular formula C₂₀H₃₄ and mass spectral fragmentation patterns suggested they were mono-unsaturated diterpenoids. The presence of unsaturated diterpenoids in crude oils appears to be a unique observation. It is proposed that the diterpenoids may be the source of the bicyclanes also observed in these oils.  相似文献