WorldWideScience

Sample records for chalk mounds stevns

  1. Late Maastrichtian chalk mounds, Stevns Klint, Denmark

    DEFF Research Database (Denmark)

    Anderskouv, Kresten; Damholt, Tove; Surlyk, Finn

    controlling the depositional thickness variation across a mound and thus mound growth pattern. Relatively long wave-length wavy-bedded chalk shows gentle convex-up geometries and would probably be described as sediment waves if recognized in seismic sections. The chalk waves were deposited under weaker......-member processes: those that were purely physical and related to the interaction between available grain sizes and hydrodynamics, and those that were largely biological and associated with benthic growth and sediment trapping mainly by bryozoans. The succession was deposited on the upper part of the flank of a 3...

  2. Late Maastrichtian chalk mounds, Stevns Klint, Denmark

    DEFF Research Database (Denmark)

    Anderskouv, Kresten; Damholt, Tove; Surlyk, Finn

    2007-01-01

    determine depositional thickness across a mound and thus mound growth pattern. Relatively long wavelength wavy-bedded chalk show gentle convex-up geometries and would probably be described as sediment waves if recognized in seismic sections. The chalk waves were deposited under weaker current velocities...... the depositional architecture indicates a complex and   dynamic environment. The depositional style seems to be controlled by the interplay and relative importance of two end-member processes; those that were purely physical and related to the interaction between available grain sizes and...

  3. Late Maastrichtian chalk mounds, Stevns Klint, Denmark — Combined physical and biogenic structures

    Science.gov (United States)

    Anderskouv, Kresten; Damholt, Tove; Surlyk, Finn

    2007-08-01

    Upper Maastrichtian chalk exposed at the Sigerslev quarry, Stevns Klint, Denmark is characterized by wavy and mound-like bedding geometries outlined by bands of black flint nodules. Four morphological elements are recognized, although bedding geometries are highly variable: southward migrating mounds, eastward migrating mounds, chalk waves and evenly bedded chalk. The mounds are interpreted as having been formed by currents carrying fine-grained suspended sediment which was primarily deposited on the up-current mound flanks. Bryozoans were prolific on the up-current flanks and mound summits, which stabilized the mounds, increased bed roughness and the overall accumulation rate. However, accumulation thicknesses do not correlate consistently with bryozoan density. The bryozoans were therefore important for the formation of the mounds, but the distribution of bryozoans did not solely determine depositional thickness across a mound and thus mound growth pattern. Relatively long wavelength wavy-bedded chalk show gentle convex-up geometries and would probably be described as sediment waves if recognized in seismic sections. The chalk waves were deposited under weaker current velocities than those active during mound formation. The exposed succession is topped by more evenly bedded chalk which was deposited by quiet pelagic fall-out of fine-grained material. The whole succession was deposited on the upper part of the northern flank of a large WNW-ESE trending 3 km wide depositional ridge with an amplitude of 35-40 m formed by contour-parallel WNW-ward flowing bottom currents. The mounds may have been deposited by regional bottom currents, or by spill-over currents from the valley south of the large ridge. The succession was deposited during varying bottom current intensities and the depositional architecture indicates a complex and dynamic environment. The depositional style seems to be controlled by the interplay and relative importance of two end-member processes

  4. Marine macrofossil communities in the uppermost Maastrichtian chalk of Stevns Klint, Denmark

    DEFF Research Database (Denmark)

    Hansen, Thomas; Surlyk, Finn

    2014-01-01

    -erosive bottom currents. It is draped by the upper Sigerslev Member, which was laid down in deeper water than any other chalk known from onshore Denmark. Deposition took place under quiet conditions, apparently not influenced by bottom currents. The sparse level-bottom community lived on a seafloor with low...... similarly mound-bedded lower Sigerslev Member. The number of polychaete species is also greater in the Højerup Member. The faunal differences reflect the shallower-water setting and a higher influx of food during deposition of the latter unit. The final Maastrichtian benthic macrofossil community at Stevns...

  5. Effect of Fluid Dynamic Viscosity on the Strength of Chalk

    DEFF Research Database (Denmark)

    Hedegaard, K.; Fabricius, Ida Lykke

    The mechanical strength of high porosity and weakly cemented chalk is affected by the fluid in the pores. In this study, the effect of the dynamic viscosity of non-polar fluids has been measured on outcrop chalk from Sigerslev Quarry, Stevns, Denmark. The outcome is that the measured strength of...... the chalk decreases with increasing dynamic viscosity. The proposed qualitative explanation is that pressure difference supports and enhances the generation of microscopic shear and tensile failures....

  6. Correlation of carbon isotope events in the Danish Upper Cretaceous chalk

    Energy Technology Data Exchange (ETDEWEB)

    Schovsbo, N.H.; Rasmussen, Susanne L.; Sheldon, E. (Geological Survey of Denmark and Greenland, Copenhagen (Denmark)); Stemmerik, L. (Univ. of Copenhagen, Dept. of Geography and Geology, Copenhagen (Denmark))

    2008-07-15

    A high resolution carbon isotope (delta13C) profile through the upper Campanian to Maastrichtian chalk was recently completed based on material from the Stevns-1 core from the Stevns peninsula, eastern Denmark. The delta13C variation of marine carbonates essentially reflects global perturbations in the carbon cycle, i.e. the burial fluxes of carbonate carbon versus organic carbon. It is widely observed that the delta13C variation broadly tracks the eustatic sea-level curve, and that delta13C curves can be used for stratigraphic correlation. In the Stevns-1 core, a total of 29 notable isotope changes have been identified in the upper Campanian to Maastrichtian succession. In order to evaluate the stratigraphic significance of the isotope changes, the variation in delta13C values of the mid-Maastrichtian chalk from cores in eastern Denmark and the Danish North Sea, and from outcrops at Roerdal, northern Jylland has been examined. The selected interval is characterised by distinct chalk and marl cycles in the Stevns-1 and Karlslunde-1 cores and in the Roerdal quarry, where as a non-cyclic clean chalk is found in the M-10X well from the North Sea. In the Roerdal quarry, the chalk-marl unit spans the upper-lower Maastrichtian boundary in the Boreal brachiopod and belemnite stratigraphies. In Stevns-1 and Karlslunde-1 the chalk-marl unit was deposited during the younger part of nannofossil subzone UC20b. This paper presents preliminary results of a high-resolution study of carbon isotopes, carried out by the Geological Survey of Denmark and Greenland (GEUS) in co-operation with partners from the Department of Geography and Geology at the University of Copenhagen. This paper is a product of the Cretaceous Research Centre (CRC) at Geocenter Denmark. (au)

  7. Dialog mellem kommunen og virksomheder på Stevns

    OpenAIRE

    Høier, Jon Plenge; Jensen, Mikkel Lundemann

    2013-01-01

    This project is concerned with the dialogue between the municipality and the corporations in Stevns. Statistic research has shown that the dialogue between the two is quite poor. In this project we wish to examine what challenges the municipality and the business sector in Stevns face with regards to good dialogue. We will do so by analysing official documents from Stevns while also conducting interviews with five representatively chosen business owners, the deputy chief municipal executive, ...

  8. Biot critical frequency applied as common friction factor for pore collapse and failure of chalk with different pore fluids and temperatures

    DEFF Research Database (Denmark)

    Andreassen, Katrine Alling; Fabricius, Ida Lykke; Foged, Niels Nielsen

    2011-01-01

    A fluid effect toward higher strengths for oil-saturated chalk compared with water-saturated chalk has previously been identified and labeled the "water-weakening phenomenon," but has not been further characterized physically. The hypothesis of this paper is that the Biot critical frequency with ...... present a new test series on Stevns chalk with unconfined compression and Brazilian strength results. Copyright © 2011 Society of Petroleum Engineers....

  9. Stevns Klint - a candidate for the World Heritage list

    OpenAIRE

    Knudsen, Birgitte Bendiks; Looten, Céline

    2013-01-01

    World Heritage is a concept only used for the most outstanding sites in the world. On the World Heritage list were there in 2012 only 962 sites in the entire world, which indicates that it is only the best of the best that can be allowed to enter the list. Stevns Klint, located in Stevns Municipality, in Denmark was nominated in 2010 for the World Heritage list. In this project we will use Stevns Municipality´s plan concerning the tourism aspect as a background for our own analysis, with the ...

  10. The Effect of Bacteria Penetration on Chalk Permeability

    DEFF Research Database (Denmark)

    Halim, Amalia Yunita; Shapiro, Alexander; Nielsen, Sidsel Marie;

    , the spore forming Bacillus licheniformis 421 and the non-spore forming Pseudomonas putida K12, were used. The core plugs were Stevns Klint outcrop with initial permeability at 2-4 mD. The results revealed that bacteria were able to penetrate and to be transported through the chalk. Furthermore, a...... higher number of B. licheniformis was detected on the effluent compared with P. putida. However, in the experiment with B. licheniformis mainly spores were detected in the effluent. The core permeability decreased rapidly during injection of bacteria and a starvation period of 12 days did not allow the...... permeability to return to initial condition....

  11. Managing Injected Water Composition To Improve Oil Recovery: A Case Study of North Sea Chalk Reservoirs

    DEFF Research Database (Denmark)

    Zahid, Adeel; Shapiro, Alexander; Stenby, Erling Halfdan;

    2012-01-01

    with the following injecting fluids: distilled water, brine with and without sulfate, and brine containing only magnesium ions. The total oil recovery, recovery rate, and interaction mechanisms of ions with rock were studied for different injecting fluids at different temperatures and wettability...... only the injection brine composition but also the formation water composition affected the oil recovery at high temperatures from the Stevns Klint chalk rock.......In recent years, many core displacement experiments of oil by seawater performed on chalk rock samples have reported SO42–, Ca2+, and Mg2+ as potential determining ions for improving oil recovery. Most of these studies were carried out with outcrop chalk core plugs. The objective of this study is...

  12. Late Cretaceous (late Campanian-Maastrichtian) sea-surface temperature record of the Boreal Chalk Sea

    Science.gov (United States)

    Thibault, Nicolas; Harlou, Rikke; Schovsbo, Niels H.; Stemmerik, Lars; Surlyk, Finn

    2016-02-01

    The last 8 Myr of the Cretaceous greenhouse interval were characterized by a progressive global cooling with superimposed cool/warm fluctuations. The mechanisms responsible for these climatic fluctuations remain a source of debate that can only be resolved through multi-disciplinary studies and better time constraints. For the first time, we present a record of very high-resolution (ca. 4.5 kyr) sea-surface temperature (SST) changes from the Boreal epicontinental Chalk Sea (Stevns-1 core, Denmark), tied to an astronomical timescale of the late Campanian-Maastrichtian (74 to 66 Ma). Well-preserved bulk stable isotope trends and calcareous nannofossil palaeoecological patterns from the fully cored Stevns-1 borehole show marked changes in SSTs. These variations correlate with deep-water records of climate change from the tropical South Atlantic and Pacific oceans but differ greatly from the climate variations of the North Atlantic. We demonstrate that the onset and end of the early Maastrichtian cooling and of the large negative Campanian-Maastrichtian boundary carbon isotope excursion are coincident in the Chalk Sea. The direct link between SSTs and δ13C variations in the Chalk Sea reassesses long-term glacio-eustasy as the potential driver of carbon isotope and climatic variations in the Maastrichtian.

  13. Late Cretaceous (Late Campanian–Maastrichtian sea surface temperature record of the Boreal Chalk Sea

    Directory of Open Access Journals (Sweden)

    N. Thibault

    2015-11-01

    Full Text Available The last 8 Myr of the Cretaceous greenhouse interval were characterized by a progressive global cooling with superimposed cool/warm fluctuations. The mechanisms responsible for these climatic fluctuations remain a source of debate that can only be resolved through multi-disciplinary studies and better time constraints. For the first time, we present a record of very high-resolution (ca. 4.5 kyr sea-surface temperature (SST changes from the Boreal epicontinental Chalk Sea (Stevns-1 core, Denmark, tied to an astronomical time scale of the late Campanian–Maastrichtian (74 to 66 Myr. Well-preserved bulk stable isotope trends and calcareous nannofossil palaeoecological patterns from the fully cored Stevns-1 borehole show marked changes in SSTs. These variations correlate with deep-water records of climate change from the tropical South Atlantic and Pacific oceans but differ greatly from the climate variations of the North Atlantic. We demonstrate that the onset and end of the early Maastrichtian cooling and of the large negative Campanian–Maastrichtian boundary carbon isotope excursion are coincident in the Chalk Sea. The direct link between SSTs and δ13C variations in the Chalk Sea reassesses long-term glacio-eustasy as the potential driver of carbon isotope and climatic variations in the Maastrichtian.

  14. Late Cretaceous (Late Campanian-Maastrichtian) sea surface temperature record of the Boreal Chalk Sea

    Science.gov (United States)

    Thibault, N.; Harlou, R.; Schovsbo, N. H.; Stemmerik, L.; Surlyk, F.

    2015-11-01

    The last 8 Myr of the Cretaceous greenhouse interval were characterized by a progressive global cooling with superimposed cool/warm fluctuations. The mechanisms responsible for these climatic fluctuations remain a source of debate that can only be resolved through multi-disciplinary studies and better time constraints. For the first time, we present a record of very high-resolution (ca. 4.5 kyr) sea-surface temperature (SST) changes from the Boreal epicontinental Chalk Sea (Stevns-1 core, Denmark), tied to an astronomical time scale of the late Campanian-Maastrichtian (74 to 66 Myr). Well-preserved bulk stable isotope trends and calcareous nannofossil palaeoecological patterns from the fully cored Stevns-1 borehole show marked changes in SSTs. These variations correlate with deep-water records of climate change from the tropical South Atlantic and Pacific oceans but differ greatly from the climate variations of the North Atlantic. We demonstrate that the onset and end of the early Maastrichtian cooling and of the large negative Campanian-Maastrichtian boundary carbon isotope excursion are coincident in the Chalk Sea. The direct link between SSTs and δ13C variations in the Chalk Sea reassesses long-term glacio-eustasy as the potential driver of carbon isotope and climatic variations in the Maastrichtian.

  15. Diagenesis of Flint and Porcellanite in the Maastrichtian Chalk at Stevns Klint, Denmark

    DEFF Research Database (Denmark)

    Buus Madsen, Heine; Stemmerik, Lars

    2010-01-01

    more stable and ordered megaquartz in irregular voids indicates that silica gel and/or opal-CT transformed to the -quartz phases, microquartz, lutecite, chalcedony, and megaquartz, through the dissolution–precipitation process (Ostwald ripening). These results motivate a conceptual model in which the...... that precipitation of the flint precursor can be controlled by a combination of an abundant biosiliceous source and high microbial activity in the sediments immediately below the seafloor. Flint is therefore likely to reflect deposition in a narrow interval at relatively shallow depths and therefore...

  16. Chalk as a reservoir

    DEFF Research Database (Denmark)

    Fabricius, Ida Lykke

    chalk intervals are to some extent cemented and cannot compact mechanically at realistic effective stresses and only deform elastically. All chalk intervals though, may react by fracturing to changes in shear stress. So where natural fractures are not prevalent, fractures may be generated hydraulically....... Fractures play a significant role in the production of hydrocarbons from chalk reservoirs....

  17. Seismic architecture of the Chalk Group from onshore reflection data in eastern Denmark

    DEFF Research Database (Denmark)

    Moreau, Julien; Anderskouv, Kresten; Boldreel, Lars Ole;

    The Upper Cretaceous-Danian chalk is well exposed in the 14 km long coastal cliff of Stevns Klint (eastern Denmark). The cliff is a world renowned for its spectacular exposure of the Cretaceous-Palaeogene boundary. Based on regional geological knowledge of the field and cores, the characteristics...... completed with the acquisition of an extensive set of subsurface data. The data include high resolution 2D multichannel seismics onshore and offshore, a seismic refraction profile, two entirely cored boreholes including wireline logs, GPR cross-hole tomography, thermographic analysis, etc. We intend...... to compile and merge the geological and geophysical datasets to investigate the variation of the Chalk Group properties and their signature in the subsurface. In this communication, the seismic reflection data are being analysed. Very high resolution litho-, bio- and cyclostratigraphy can be correlated...

  18. Chalk as a reservoir

    DEFF Research Database (Denmark)

    Fabricius, Ida Lykke

    Reservoir properties of chalk depend on the primary sediment composition as well as on subsequent diagenesis and tectonic events. Chalks of the North Sea almost exclusively have mudstone or wackestone texture. Microfossils may have retained their porosity where degree of diagenesis is low, or be......, and the best reservoir properties are typically found in mudstone intervals. Chalk mudstones vary a lot though. The best mudstones are purely calcitic, well sorted and may have been redeposited by traction currents. Other mudstones are rich in very fine grained silica, which takes up pore space and...... thus reduces porosity at the same time as it increases specific surface and thus cause permeability to be low. In the Central North Sea the silica is quartzitic. Silica rich chalk intervals are typically found in the Ekofisk and Hod formations. In addition to silica, Upper Cretaceous and Palæogene...

  19. Permeability prediction in chalks

    DEFF Research Database (Denmark)

    Alam, Mohammad Monzurul; Fabricius, Ida Lykke; Prasad, Manika

    2011-01-01

    The velocity of elastic waves is the primary datum available for acquiring information about subsurface characteristics such as lithology and porosity. Cheap and quick (spatial coverage, ease of measurement) information of permeability can be achieved, if sonic velocity is used for permeability...... prediction, so we have investigated the use of velocity data to predict permeability. The compressional velocity fromwireline logs and core plugs of the chalk reservoir in the South Arne field, North Sea, has been used for this study. We compared various methods of permeability prediction from velocities....... The relationships between permeability and porosity from core data were first examined using Kozeny’s equation. The data were analyzed for any correlations to the specific surface of the grain, Sg, and to the hydraulic property defined as the flow zone indicator (FZI). These two methods use two...

  20. Stair-stepped Mound

    Science.gov (United States)

    2003-01-01

    MGS MOC Release No. MOC2-429, 22 July 2003This April 2003 Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a stair-stepped mound of sedimentary rock (right of center) on the floor of a large impact crater in western Arabia Terra near 11.0oN, 4.4oW. Sedimentary rock outcrops are common in the craters of this region. The repeated thickness and uniformity of the layers that make up this mound suggest that their depositional environment was one in which cyclic or episodic events occurred over some period of time. The sediments might have been deposited in a lake, or they may have settled directly out of the atmosphere. Most of the layered material was later eroded away, leaving this circular mound and the other nearby mesas and knobs. The image is illuminated by sunlight from the lower left.

  1. Less chalk more action

    Science.gov (United States)

    Mitriceski Andelkovic, Bojana; Jovic, Sladjana

    2016-04-01

    Less chalk more action Education should not be a mechanical system that operates according to the principles of the orders and implementation. Education should respect the basic laws of the develop and progress. Curiosity is the engine of achievement and children spontaneously and happily learn only if they get interested, if teacher wake up and stimulate their creativity and individuality. We would like to present classes that are realized as thematic teaching with several subjects involved: chemistry, geography, math, art and biology. Classes were organized for students at age from 10 to 13 years, every month during autumn and winter 2015. Better students identified themselves as teachers and presented peer education .Teachers were monitoring the process of teaching and help to develop links between younger and older students, where older students were educators to younger students. Also one student with special needs was involved in this activities and was supported by other students during the workshops The benefit from this project will be represented with evaluation marks. Evaluation table shows that group of ten students(age 10 to13 years) which are selected in October as children with lack of motivation for learning, got better marks, at the end of January , then they had it in the beginning of the semester.

  2. Integrated seismic analysis of the Chalk Group in eastern Denmark—Implications for estimates of maximum palaeo-burial in southwest Scandinavia

    DEFF Research Database (Denmark)

    Nielsen, Lars; Boldreel, Lars Ole; Hansen, Thomas Mejer; Lykke-Andersen, Holger; Stemmerik, Lars; Surlyk, Finn; Thybo, Hans

    . The burial anomaly will be over-estimated by ~150–200m if the analysis is based on the average Chalk Group velocity and clay content is disregarded. Burial anomaly values of ~450–600m result if the strongest velocity contrast at ~600–650m depth is interpreted to be a result of diagenetic effects......The origin of the topography of southwest Scandinavia is subject to discussion. Analysis of borehole seismic velocity has formed the basis for interpretation of several hundred metres of Neogene uplift in parts of Denmark.Here, refraction seismic data constrain a 7.5km long P-wave velocity model of...... the Chalk Group below the Stevns peninsula, eastern part of the Danish Basin. The model contains four layers in the ~860m thick Chalk Group with mean velocities of 2.2km/s, 2.4km/s, 3.1km/s, and 3.9–4.3km/s. Sonic and gamma wireline log data from two cored boreholes represent the upper ~450m of the...

  3. Mound publications for 1991

    Energy Technology Data Exchange (ETDEWEB)

    Nowka, Stephen L. [ed.

    1992-05-01

    This document is a compilation of all Mound formal technical publications and oral presentations for calendar year 1991. It is intended to serve as an aid to personnel in obtaining or referring to specific publications by giving the proper complete reference for each information item published during the year. Some items, such as proceedings publications, may have issue dates or periods of coverage prior to 1991; however, they were formally published during 1991.

  4. Mound facility physical characterization

    Energy Technology Data Exchange (ETDEWEB)

    Tonne, W.R.; Alexander, B.M.; Cage, M.R.; Hase, E.H.; Schmidt, M.J.; Schneider, J.E.; Slusher, W.; Todd, J.E.

    1993-12-01

    The purpose of this report is to provide a baseline physical characterization of Mound`s facilities as of September 1993. The baseline characterizations are to be used in the development of long-term future use strategy development for the Mound site. This document describes the current missions and alternative future use scenarios for each building. Current mission descriptions cover facility capabilities, physical resources required to support operations, current safety envelope and current status of facilities. Future use scenarios identify potential alternative future uses, facility modifications required for likely use, facility modifications of other uses, changes to safety envelope for the likely use, cleanup criteria for each future use scenario, and disposition of surplus equipment. This Introductory Chapter includes an Executive Summary that contains narrative on the Functional Unit Material Condition, Current Facility Status, Listing of Buildings, Space Plans, Summary of Maintenance Program and Repair Backlog, Environmental Restoration, and Decontamination and Decommissioning Programs. Under Section B, Site Description, is a brief listing of the Site PS Development, as well as Current Utility Sources. Section C contains Site Assumptions. A Maintenance Program Overview, as well as Current Deficiencies, is contained within the Maintenance Program Chapter.

  5. Permeability of Rubble Mound Material

    DEFF Research Database (Denmark)

    Williams, A.F.; Burcharth, H. F.; Adel, H. den;

    The flow of water through the pores of rubble mound breakwaters has two effects upon breakwater performance. The pore pressures generated within the rubble material will effect the stability of the mound. The flow of water in and out of the pores plays a critical part in the dissipation of wave e...

  6. Ecologically acceptable flows in Chalk rivers

    OpenAIRE

    Acreman, Mike; Dunbar, Michael

    2010-01-01

    The term ‘Chalk rivers’ is used to describe all those water courses dominated by groundwater discharge from Chalk geology. Natural conditions and historical modification have generated an ecosystem, with rich and unique assemblages and with high value to society (e.g. SACs, SSSIs, visual amenity and fisheries. Chalk rivers are considered to be sensitive to hydrological and morphological change and there is concern that flood defence and land drainage schemes, catchment agriculture, urbanisati...

  7. Self Compacting Concrete with Chalk Filler

    DEFF Research Database (Denmark)

    Sørensen, Eigil V.

    2007-01-01

    Utilisation of Danish chalk filler has been investigated as a means to produce self compacting concrete (SCC) at lower strength levels for service in non aggressive environments. Stable SCC mixtures were prepared at chalk filler contents up to 60% by volume of binder to yield compressive strengths...

  8. Decommissioning Experience: Chalk River, Canada

    International Nuclear Information System (INIS)

    Full text: Atomic Energy of Canada Limited has reported that work has continued on the decommissioning of old structures on the Chalk River laboratory site. An environmental assessment was approved in 2006 for the decommissioning of the NRX reactor fuel bays (A and B). The regulator approved two work packages for the removal of water and the wooden structure over the bays. The A bays were cleaned as far as possible and were emptied in 2007. Decontamination work will continue. Sections of the B bays were filled with sand and other parts filled with water. NRX is currently in storage (i.e. a dormant state) with surveillance. (author)

  9. Elastic behaviour of North Sea chalk

    DEFF Research Database (Denmark)

    Gommesen, Lars; Fabricius, Ida Lykke; Mukerji, T.;

    2007-01-01

    We present two different elastic models for, respectively, cemented and uncemented North Sea chalk well-log data. We find that low Biot coefficients correlate with anomalously low cementation factors from resistivity measurements at low porosity and we interpret this as an indication of cementation......-saturated North Sea reservoir chalk. In the acoustic impedance–Poisson's ratio plane, we forecast variations in porosity and hydrocarbon saturation from their influence on the elastic behaviour of the chalk. The Gassmann model and the self-consistent approximation give roughly similar predictions of the effect of...... filtrate. The amplitude-versus-angle (AVA) response for the general North Sea sequence of shale overlying chalk is predicted as a function of porosity and pore-fill. The AVA response of both cemented and uncemented chalk generally shows a declining reflectivity coefficient versus offset and a decreasing...

  10. Geochemistry of the Cretaceous-Tertiary boundary (Fish Clay at Stevns Klint (Denmark: Ir, Ni and Zn in kerogen

    Directory of Open Access Journals (Sweden)

    PAVLE I. PREMOVIC

    2006-07-01

    Full Text Available Geochemical analyses of trace metals (Ir, Ni and Zn in the kerogen of the black marl of the Cretaceous-Tertiary boundary succession (Fish Clay at Stevns Klint (Hjerup Church were undertaken. The data for this kerogen were in accordance with a previous hypothesis that this (insoluble geoorganic polymer was derived from humic substances (mainly humic acids of a nearshore soil. Substantial proportions of Ir, Ni and Zn within the kerogen structure were probably contained in these substances arriving at the sedimentary site. It is proposed that these humics were probably transported by acid surface waters (induced by the KT asteroid impact into the shallow marine basin of Stevns Klint. It is also suggested that local leaching/weathering of the asteroidal impact fallout on the land near these waters played an important role in providing Ir, Ni and Zn for these substances. Apparently, Ir, Ni and Zn of the kerogen were created by the chondritic component of the impact ejecta fallout.

  11. Brief historical background of Miamisburg Indian Mound

    Energy Technology Data Exchange (ETDEWEB)

    Russell, Lorraine M. [comp.

    1960-01-01

    The construction of Mound Laboratory was completed in 1948. The name Mound Laboratory was chosen for this installation because of the major Indian Mound which is immediately adjacent to the Plant site. Frequent inquiries of visitors to Mound Lab concerning the Indian Mounds in general and specifically Miamisburg's Indian Mound has indicated an area of "outside interest". We, therefore, thought it would be appropriate to furnish this brief historical background to all of the attendees at the Twentieth Meeting of the Mechanical Equipment Management Subgroup.

  12. Understanding heterogeneity in UK Chalk catchments and its influence on groundwater flooding

    Science.gov (United States)

    Peach, D. W.; Vounaki, T.; Jackson, C. R.; Hughes, A. G.; Wheater, H. S.

    2008-12-01

    The numerical simulation of groundwater flooding is increasingly necessary as this problem is gaining recognition from government and regulators and climate change may bring more extreme events. The Natural Environment Research Council of the UK is funding the British Geological Survey, Imperial College, and the Centre for Ecology and Hydrology to examine the problem of groundwater flooding in the Cretaceous Chalk of Berkshire, 50 kilometres west of London. Typically regional resource issues can be examined using traditional groundwater models that do not consider in detail the influence of flow in the unsaturated zone, but the delays in recharge transmission through this zone to the water table may be very significant in terms of flood timing and prediction. The position of ground elevation relative to water table is clearly important but not often considered in groundwater resource modelling. Groundwater level and stream (and flood) flow responses are important data that may be hard to gather from typical groundwater monitoring systems. These problems have been examined in a Chalk catchment in Berkshire where good records of the 2000-1 and 2003 flooding events have been collected, including flooded extent, rainfall, groundwater levels, river and spring flows. From this analysis, it appears that two groundwater mounds develop in the upper part of the Pang and Lambourn catchments. These mounds intersect dry valleys, which flowed for several months, the consequent flooding causing considerably disruption. Modelling of these events is providing new insight into the heterogeneity of Chalk transmissivity and storage parameters, enhanced knowledge of its dual permeability and porosity and demonstrating the importance of understanding the post-depositional hydrogeological history of the aquifer.

  13. Analysis of Rubble Mound Breakwaters

    DEFF Research Database (Denmark)

    Mettam, J.D.; Allsop, N.W.H.; Bonafous, P.;

    Working Group 12 was set up to consider the analysis of rubble mound breakwaters with a view to achieving a better understanding of safety aspects. The working group decided to develop the practical application of risk analysis in the design of rubble mound breakwaters by using partial coefficients....... Six subgroups, A-F, were established to carry out different aspects of the study. The reports of these subgroups are available in full at the General Secretariat of PIANC. The Main Report summarises the subgroup reports and presents the overall view of the results of the working group. A new system...... of design for rubble mound breakwaters has been developed whereby partial coefficients can be derived for any chosen probability of failure within the specified service life of the structures. Due to lack of general failure formulae, partial coefficients could only be determined for conventional multi...

  14. Reactor loops at Chalk River

    International Nuclear Information System (INIS)

    This report describes broadly the nine in-reactor loops, and their components, located in and around the NRX and NRU reactors at Chalk River. First an introduction and general description is given of the loops and their function, supplemented with a table outlining some loop specifications and nine simplified flow sheets, one for each individual loop. The report then proceeds to classify each loop into two categories, the 'main loop circuit' and the 'auxiliary circuit', and descriptions are given of each circuit's components in turn. These components, in part, are comprised of the main loop pumps, the test section, loop heaters, loop coolers, delayed-neutron monitors, surge tank, Dowtherm coolers, loop piping. Here again photographs, drawings and tables are included to provide a clearer understanding of the descriptive literature and to include, in tables, some specifications of the more important components in each loop. (author)

  15. Rubble Mound Breakwater Failure Modes

    DEFF Research Database (Denmark)

    Burcharth, H. F.; Z., Liu

    1995-01-01

    The RMBFM-Project (Rubble Mound Breakwater Failure Modes) is sponsored by the Directorate General XII of the Commission of the European Communities under the Contract MAS-CT92- 0042, with the objective of contributing to the development of rational methods for the design of rubble mound breakwaters....... 11 institutes from the European Union participate in the project. The paper presents an overview of the project background, the research objective, the research methodology and the research results of the project. The outcome of the project is a large amount of formulae describing important failure...

  16. The North Sea reservoir chalk characterization

    OpenAIRE

    Kallesten, Emanuela

    2015-01-01

    A significant amount of the hydrocarbon production in the North Sea is related to chalk reservoirs. Since 1969, the chalk play remains one of the most important oil sources in Norway. With the initial expected recovery factor 17%, development in technologies and methods contributed to a substantial increase in oil recovery to an approximately 40%. Much of the reserves in place are yet to be extracted, and secondary and tertiary recovery methods need to advance in order to mobilize the remaini...

  17. Chalk: composition, diagenesis and physical properties

    OpenAIRE

    Fabricius, Ida Lykke

    2007-01-01

    Chalk is a sedimentary rock of unusually high homogeneity on the scale where physical properties are measured, but the properties fall in wide ranges. Chalk may thus be seen as the ideal starting point for a physical understanding of rocks in general. Properties as porosity, permeability, capillary entry pressure, and elastic moduli are consequences of primary sediment composition and ofsubsequent diagenetic history as caused by microbial action, burial stress, temperature, and pore pressure....

  18. Subsidence and capillary effects in chalks

    OpenAIRE

    Delage, Pierre; Schroeder, Christian; Cui, Yu-Jun

    1996-01-01

    Based on the concepts of the mechanics of unsaturated soils where capillary phenomena arise between the wetting fluid (water) and the non-wetting one (air), the subsidence of chalks containing oil (non-wetting fluid) during water injection (wetting fluid) is analysed. It is shown that the collapse phenomenon of unsaturated soils under wetting provides a physical explanation and a satisfactory prediction of the order of magnitude of the subsidence of the chalk. The use of a well established co...

  19. Impact of diagenesis on carbonate mound formation

    NARCIS (Netherlands)

    van der Land, C.

    2011-01-01

    This thesis is devoted to define the parameters influencing cold-water coral growth and therefore carbonate mound development with a focus on the impact of diagenesis on mound sediments. The first part of this thesis (Chapters 2 to 4) discusses the distributionand growth history of carbonate mounds,

  20. Biometric analysis of the Arkhangelskiella group in the upper Campanian-Maastrichtian of the stevns-1 borehole, Denmark

    DEFF Research Database (Denmark)

    Thibault, Nicolas Rudolph

    2010-01-01

    The taxonomy of the calcareous nannofossil Arkhangelskiella is revised using the results of a biometric analysis performed on 599 specimens from various stratigraphic levels throughout the upper Campanian-Maastrichtian of the Stevns-1 borehole, Denmark. Combined qualitative labelling and biometric...... measurements suggest that this genus comprises at least three distinct morphogroups in this stratigraphic interval, with possibly one additional morphotype. The results show that the descriptions formerly used for the erection of these groups as distinct species do not fit to their observed range in the...... coccolith length and in the rim width, and that the central opening is an important additional parameter allowing distinction between the different morphogroups. Biometric analysis shows, however, that the morphogroups are strongly overlapping on all measured parameters. Therefore, the three distinct...

  1. Design of Rubble Mound Breakwaters

    DEFF Research Database (Denmark)

    Burcharth, H. F.

    1994-01-01

    Rubble mound breakwaters require availability of often very large quantities of rock materials of various gradings and qualities. Because natural stones are seldom available in sufficient quantities and sizes the materials must in most cases be supplied from quarries. The output from a quarry in...

  2. Adsorption of hydrocarbons in chalk reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Madsen, L.

    1996-12-31

    The present work is a study on the wettability of hydrocarbon bearing chalk reservoirs. Wettability is a major factor that influences flow, location and distribution of oil and water in the reservoir. The wettability of the hydrocarbon reservoirs depends on how and to what extent the organic compounds are adsorbed onto the surfaces of calcite, quartz and clay. Organic compounds such as carboxylic acids are found in formation waters from various hydrocarbon reservoirs and in crude oils. In the present investigation the wetting behaviour of chalk is studied by the adsorption of the carboxylic acids onto synthetic calcite, kaolinite, quartz, {alpha}-alumina, and chalk dispersed in an aqueous phase and an organic phase. In the aqueous phase the results clearly demonstrate the differences between the adsorption behaviour of benzoic acid and hexanoic acid onto the surfaces of oxide minerals and carbonates. With NaCl concentration of 0.1 M and with pH {approx_equal} 6 the maximum adsorption of benzoic acid decreases in the order: quartz, {alpha}-alumina, kaolinite. For synthetic calcite and chalk no detectable adsorption was obtaind. In the organic phase the order is reversed. The maximum adsorption of benzoic acid onto the different surfaces decreases in the order: synthetic calcite, chalk, kaolinite and quartz. Also a marked difference in adsorption behaviour between probes with different functional groups onto synthetic calcite from organic phase is observed. The maximum adsorption decreases in the order: benzoic acid, benzyl alcohol and benzylamine. (au) 54 refs.

  3. Diagenesis of silica-rich mounded chalk, the Coniacian Arnager Limestone, Denmark

    DEFF Research Database (Denmark)

    Buus Madsen, Heine; Stemmerik, Lars; Surlyk, Finn

    precipitation of opal-CT. The opal-CT formed at temperatures around 17°C, the precipitation lowered the silica activity and the Si/Al ratio of the pore water, resulting in precipitation of clinoptilolite, feldspar and smectite. Calcite formed synchronouslywith the latest clinoptilolite.Minoramounts of quartz...... precipitated in pore water with low silica activity during maximum burial, probably to depths of 200-250 m. The dissolution of sponge spicules and decomposition of the sponge tissue also resulted in the release of Ba2+, Sr2+,Mg2+, Ca2+ and CO3 2-, facilitating precipitation of barite and dolomite...... consist of twomicrofacies, spiculiticwackestone and bioturbated spiculitic wackestone, containing 10-22% and 7-12% moulds after spicules, respectively. Subsequent to deposition and shallow burial, dissolution of siliceous sponge spicules increased the silica activity of the pore water and initiated...

  4. Mound Plant Environmental Monitoring Plan

    International Nuclear Information System (INIS)

    The purpose of this Environmental Monitoring Plan (EMP) is to describe the environmental monitoring and surveillance programs in place at Mound. The Plan is required by DOE Order 5400.1 (DOE, 1990). The programs described in the EMP are required by the DOE 5400 Order series and by the Environmental Regulatory Guide for Radiological Effluent Monitoring and Environment Surveillance (DOE 1991a), referred to as the Regulatory Guide throughout this Plan

  5. Chalk Formations as Natural Barriers towards Radionuclide Migration

    DEFF Research Database (Denmark)

    Pedersen, Walther Batsberg; Carlsen, Lars; Jensen, Bror Skytte

    1985-01-01

    A series of chalk samples from the cretaceous formation overlying the Erslev salt dome have been studied in order to establish permeabilities, porosities, dispersion-, diffusion-, and sorption characteristics of the chalk. The chalk was found to be porous (∊≈0.4), however, of rather low permeabil...

  6. Microdeformation and subcritical cracking in chalk

    Science.gov (United States)

    Bergsaker, Anne; Dysthe, Dag Kristian

    2016-04-01

    Deformation processes in chalks, both in relation to changing pore fluids and stress conditions has been of great interest as chalk is an important reservoir rock for both hydrocarbons and ground water. Lately it has also gained interest as a potential reservoir rock for captured CO2. Chalks are composed of large amounts of biogenic calcite grains, the skeletal debris of marine microorganisms. Its deformation is highly time and stress dependent, and governed by a transition from distributed to localized deformation at the onset of yield, affected by mechanisms such as subcritical crack growth and pore collapse. We present a microdeformation rig which makes use of thermal expansion as a means of subjecting small samples to strictly controlled tensile stresses. High resolution imaging provides resolutions down to 0.5 micrometers, enabling study of pore scale processes during slow deformation. Examples of localized and distributed deformation are presented.

  7. Elastic behaviour of North Sea chalk

    DEFF Research Database (Denmark)

    Gommesen, Lars; Fabricius, Ida Lykke; Mukerji, T.;

    2007-01-01

    We present two different elastic models for, respectively, cemented and uncemented North Sea chalk well-log data. We find that low Biot coefficients correlate with anomalously low cementation factors from resistivity measurements at low porosity and we interpret this as an indication of cementation...... self-consistent approximation, which here represents the unrelaxed scenario where the pore spaces of the rock are assumed to be isolated, and the Gassmann theory, which assumes that pore spaces are connected, as tools for predicting the effect of hydrocarbons from the elastic properties of brine......-saturated North Sea reservoir chalk. In the acoustic impedance–Poisson's ratio plane, we forecast variations in porosity and hydrocarbon saturation from their influence on the elastic behaviour of the chalk. The Gassmann model and the self-consistent approximation give roughly similar predictions of the effect of...

  8. Adsorption Properties of Chalk Reservoir Materials

    DEFF Research Database (Denmark)

    Okhrimenko, Denis

    Understanding adsorption energetics and wetting properties of calcium carbonate surfaces is essential for developing remediation strategies for aquifers, improving oil recovery, minimising risk in CO2 storage and optimising industrial processes. This PhD was focussed on comparing the vapour....../gas adsorption properties of synthetic calcium carbonate phases (calcite, vaterite and aragonite) with chalk, which is composed of biogenic calcite (>98%). In combination with data from nanotechniques, the results demonstrate the complexity of chalk behavior and the role of nanoscale clay particles. The results...

  9. Aquifer properties of the Chalk of England

    OpenAIRE

    MacDonald, Alan M.; Allen, David J

    2001-01-01

    Aquifer properties data from 2100 pumping tests carried out in the Chalk aquifer have been collated as part of a joint British Geological Survey/Environment Agency project. The dataset is highly biased: most pumping tests have been undertaken in valley areas where the yield of the Chalk is highest. Transmissivity values from measured sites give the appearance of log-normality, but are not truly log-normal. The median of available data is 540 m2/d and the 25th and 75th percentiles 190 m2/d and...

  10. Simulated Mima mounds emerge from small interactions

    CERN Document Server

    Lewis, Chloë Peregrine Hunt

    2011-01-01

    The Mima-mound-and-vernal-pool topography of California is rich in endemic plant and invertebrate species, but we do not know how this unusual environment is created or maintained. Burrowing rodents have been observed to move soil upwards at annual rates sufficient to maintain the mounds despite erosion, but there is no tested explanation of this behavior. We propose that the mounds are an emergent effect of small-scale (10 cm, 1 day) interactions between topography, hydrology, plant growth, and rodent burrowing. A cellular automata simulation of these processes both generates and maintains mound-pool topography with minimal dependence on initial conditions, and can also describe mound morphogenesis on slopes, where observed mound geometry is distinct from that on level ground.

  11. Chalk aquifer study : permeability and fractures in the English Chalk : a review of hydrogeological literature

    OpenAIRE

    Allen, D J

    1995-01-01

    The purpose of this report is to provide a review of the hydrogeological literature concerning the hydraulically significant fractures in the Chalk aquifer in England. The review discusses only the effect of the fractures on the permeability of the aquifer; it does not address the question of storage, nor the properties of the matrix. The report charts the evolution of ideas regarding the nature, occurrence and causes of hydraulically significant fractures in the Chalk and atte...

  12. Poroelasticity of high porosity chalk under depletion

    DEFF Research Database (Denmark)

    Andreassen, Katrine Alling; Fabricius, Ida Lykke

    2013-01-01

    The theory of poroelasticity for the elastic region below pore collapse by means of three different loading paths gives the possibility to compare the static and dynami-cally determined Biot coefficient for a set of experimental data with uniaxial loading on outcrop chalk performed with different...

  13. Slope failure of chalk channel margins

    DEFF Research Database (Denmark)

    Gale, A.; Anderskouv, Kresten; Surlyk, Finn;

    2015-01-01

    The importance of mass transport and bottom currents is now widely recognized in the Upper Cretaceous Chalk Group of Northern Europe. The detailed dynamics and interaction of the two phenomena are difficult to study as most evidence is based on seismic data and drill core. Here, field observations...

  14. Nickel adsorption on chalk and calcite

    DEFF Research Database (Denmark)

    Belova, Dina Alexandrovna; Lakshtanov, Leonid; Carneiro, J.F.;

    2014-01-01

    Nickel uptake from solution by two types of chalk and calcite was investigated in batch sorption studies. The goal was to understand the difference in sorption behavior between synthetic and biogenic calcite. Experiments at atmospheric partial pressure of CO2, in solutions equilibrated with calcite...

  15. Design of Rubble Mound Breakwaters

    DEFF Research Database (Denmark)

    Burcharth, H. F.

    1992-01-01

    Rubble mound breakwaters require availability of often very large quantities of rock materials of various gradings and qualities. Because natural stones are seldom available in sufficient quantities and sizes the materials must in most cases be supplied from quarries. The output from a quarry in...... construction stage. Anyway, it is seldom that a fair amount of rocks of mass larger than 10-15 t can be produced, even in good quality quarries. If heavier blocks are needed concrete armour units or vertical structures must be considered....

  16. Sulphur Extraction at Bryan Mound

    Energy Technology Data Exchange (ETDEWEB)

    Kirby, Carolyn L [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Lord, Anna C. Snider [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-08-01

    The Bryan Mound caprock was subjected to extens ive sulphur mining prior to the development of the Strategic Petroleum Reserve. Undoubtedl y, the mining has modified the caprock integrity. Cavern wells at Bryan Mound have been subject to a host of well integr ity concerns with many likely compromised by the cavernous capro ck, surrounding corrosive environment (H 2 SO 4 ), and associated elevated residual temperatures al l of which are a product of the mining activities. The intent of this study was to understand the sulphur mining process and how the mining has affected the stability of the caprock and how the compromised caprock has influenced the integrity of the cavern wells. After an extensiv e search to collect pert inent information through state agencies, literature sear ches, and the Sandia SPR librar y, a better understanding of the caprock can be inferred from the knowledge gaine d. Specifically, the discovery of the original ore reserve map goes a long way towards modeling caprock stability. In addition the gained knowledge of sulphur mining - subs idence, superheated corrosive wa ters, and caprock collapse - helps to better predict the post mi ning effects on wellbore integrity. This page intentionally left blank

  17. COCARDE: new view on old mounds - an international network of carbonate mound research

    Science.gov (United States)

    Rüggeberg, A.; Foubert, A.; Vertino, A.; van Rooij, D.; Spezzaferri, S.; Henriet, J.-P.; Dullo, W.-C.; Cocarde Science Community

    2012-04-01

    Carbonate mounds are important contributors of life in different settings, from warm-water to cold-water environments, and throughout geological history. Research on modern cold-water coral carbonate mounds over the last decades made a major contribution to our overall understanding of these particular sedimentary systems. By looking to the modern carbonate mound community with cold-water corals as main framework builders, some fundamental questions could be addressed, until now not yet explored in fossil mound settings. The international network COCARDE (http://www.cocarde.eu) is a platform for exploring new insights in carbonate mound research of recent and ancient mound systems. The aim of the COCARDE network is to bring together scientific communities, studying Recent carbonate mounds in midslope environments in the present ocean and investigating fossil mounds spanning the whole Phanerozoic time, respectively. Scientific challenges in modern and ancient carbonate mound research got well defined during the ESF Magellan Workshop COCARDE in Fribourg, Switzerland (21.-24.01.2009). The Special Volume Cold-water Carbonate Reservoir systems in Deep Environments - COCARDE (Marine Geology, Vol. 282) was the major outcome of this meeting and highlights the diversity of Recent carbonate mound studies. The following first joint Workshop and Field Seminar held in Oviedo, Spain (16.-20.09.2009) highlighted ongoing research from both Recent and fossil academic groups integrating the message from the industry. The field seminar focused on mounds from the Carboniferous platform of Asturias and Cantabria, already intensively visited by industrial and academic researchers. However, by comparing ancient, mixed carbonate-siliciclastic mound systems of Cantabria with the Recent ones in the Porcupine Seabight, striking similarities in their genesis and processes in mound development asked for an integrated drilling campaign to understand better the 3D internal mound build-up. The

  18. Competitive sorption of organic contaminants in chalk

    Science.gov (United States)

    Graber, E. R.; Borisover, M.

    2003-12-01

    In the Negev desert, Israel, a chemical industrial complex is located over fractured Eocene chalk formations where transfer of water and solutes between fracture voids and matrix pores affects migration of contaminants in the fractures due to diffusion into the chalk matrix. This study tests sorption and sorption competition between contaminants in the chalk matrix to make it possible to evaluate the potential for contaminant attenuation during transport in fractures. Single solute sorption isotherms on chalk matrix material for five common contaminants ( m-xylene, ametryn, 1,2-dichloroethane, phenanthrene, and 2,4,6-tribromophenol) were found to be nonlinear, as confirmed in plots of Kd versus initial solution concentration. Over the studied concentration ranges, m-xylene Kd varied by more than a factor of 100, ametryn Kd by a factor of 4, 1,2-dichloroethane Kd by more than a factor of 3, phenanthrene Kd by about a factor of 2, and 2,4,6-tribromophenol Kd by a factor of 10. It was earlier found that sorption is to the organic matter component of the chalk matrix and not to the mineral phases (Chemosphere 44 (2001) 1121). Nonlinear sorption isotherms indicate that there is at least some finite sorption domain. Bi-solute competition experiments with 2,4,6-tribromophenol as the competitor were designed to explore the nature of the finite sorption domain. All of the isotherms in the bi-solute experiments are more linear than in the single solute experiments, as confirmed by smaller variations in Kd as a function of initial solution concentration. For both m-xylene and ametryn, there is a small nonlinear component or domain that was apparently not susceptible to competition by 2,4,6-tribromophenol. The nonlinear sorption domain(s) is best expressed at low solution concentrations. Inert-solvent-normalized single and bi-solute sorption isotherms demonstrate that ametryn undergoes specific force interactions with the chalk sorbent. The volume percent of phenanthrene

  19. Water in chalk reservoirs: 'friend or foe?'

    International Nuclear Information System (INIS)

    Most of the petroleum fields in the Norwegian sector of the North Sea are sandstone reservoirs; the oil and gas are trapped in different species of sandstone. But the Ekofisk Field is a chalk reservoir, which really challenges the operator companies. When oil is produced from chalk reservoirs, water usually gets in and the reservoir subsides. The subsidence may be expensive for the oil companies or be used to advantage by increasing the recovery rate. Since 60 per cent of the world's petroleum reserves are located in carbonate reservoirs, it is important to understand what happens as oil and gas are pumped out. Comprehensive studies at the Department of Petroleum Technology and Applied Geophysics at Stavanger University College in Norway show that the mechanical properties of chalk are considerably altered when the pores in the rock become saturated with oil/gas or water under different stress conditions. The processes are extremely complex. The article also maintains that the effects of injecting carbon dioxide from gas power plants into petroleum reservoirs should be carefully studied before this is done extensively

  20. Groundwater Mounding Beneath Stormwater Infiltration Basins

    Science.gov (United States)

    Nimmer, M.; Thompson, A. M.; Misra, D.

    2007-12-01

    An accurate understanding of groundwater mound formation is important in the proper design of stormwater infiltration basins since these basins are often required to recharge a portion of pre-development infiltration volume. Mound formation due to localized recharge may reduce the infiltration rate of the basin and the ability of the soil to filter pollutants. The goal of this research was to understand groundwater mounding and the potential for contaminant transport resulting from recharge beneath stormwater infiltration basins. A 0.10 ha infiltration basin serving a 9.4 ha residential subdivision in Oconomowoc, Wisconsin was used in this study. Subsurface conditions included sand and gravel material and a groundwater table at 2.3 m below grade. Three storm events, 4.9 cm, 2.8 cm, and 4.3 cm, between August 2006 and April 2007 were modeled using the two-dimensional numerical model HYDRUS. The calibrated model was used to evaluate hypothetical basin operation scenarios for various basin sizes, soil types, ponding depths, and water table depths. The groundwater mound intersected the basin floor in most scenarios with loamy sand and sandy loam soils, an unsaturated thickness of 1.52 m, and a ponding depth of 0.61 m. No groundwater table response was observed with ponding depths less than 0.31 m with an unsaturated zone thickness of 6.09 m. The mound height was most sensitive to hydraulic conductivity and unsaturated zone thickness. A 7.6 cm sediment layer delayed the time to reach maximum mound height, but had a minimal effect on the magnitude of the mound. Mound heights increased as infiltration basin size increased.

  1. Environmental changes and growth history of a cold-water carbonate mound (Propeller Mound, Porcupine Seabight)

    Science.gov (United States)

    Rüggeberg, Andres; Dullo, Christian; Dorschel, Boris; Hebbeln, Dierk

    2007-02-01

    On- and off-mound sediment cores from Propeller Mound (Hovland Mound province, Porcupine Seabight) were analysed to understand better the evolution of a carbonate mound. The evaluation of benthic foraminiferal assemblages from the off-mound position helps to determine the changes of the environmental controls on Propeller Mound in glacial and interglacial times. Two different assemblages describe the Holocene and Marine Isotope Stage (MIS) 2 and late MIS 3 (˜31 kyr BP). The different assemblages are related to changes in oceanographic conditions, surface productivity and the waxing and waning of the British Irish Ice Sheet (BIIS) during the last glacial stages. The interglacial assemblage is related to a higher supply of organic material and stronger current intensities in water depth of recent coral growth. During the last glaciation the benthic faunas showed high abundances of cassidulinid species, implying cold bottom waters and a reduced availability of organic matter. High sedimentation rates and the domination of Elphidium excavatum point to shelf erosion related to sea-level lowering (˜50 m) and the progradation of the BIIS onto the shelf. A different assemblage described for the on-mound core is dominated by Discanomalina coronata, Gavelinopsis translucens, Planulina ariminensis, Cibicides lobatulus and to a lower degree by Hyrrokkin sarcophaga. These species are only found or show significantly higher relative abundances in on-mound samples and their maximum contribution in the lower part of the record indicates a higher coral growth density on Propeller Mound in an earlier period. They are less abundant during the Holocene, however. This dataset portrays the boundary conditions of the habitable range for the cold-water coral Lophelia pertusa, which dominates the deep-water reefal ecosystem on the upper flanks of Propeller Mound. The growth of this ecosystem occurs during interglacial and interstadial periods, whereas a retreat of corals is documented in

  2. Compaction of microfossil and clay-rich chalk sediments

    DEFF Research Database (Denmark)

    Fabricius, Ida Lykke

    2001-01-01

    The aim of this study was to evaluate the role of microfossils and clay in the compaction of chalk facies sediments. To meet this aim, chalk sediments with varying micro texture were studied. The sediments have been tested uniaxially confined in a stainless-steel compaction cell. The sediments ar...

  3. Compaction of North-sea chalk

    Science.gov (United States)

    Keszthelyi, Dániel; Dysthe, Dag Kristian; Jamtveit, Bjørn

    2014-05-01

    The Ekofisk field is the largest petroleum field in the Norwegian North Sea territory where oil is produced from chalk formations. Early stage of oil production caused considerable changes in pore fluid pressure which led to a reservoir compaction. Pore collapse mechanism caused by the dramatic increase of effective stress, which in turn was caused by the pressure reduction by hydrocarbon depletion, was early identified as a principal reason for the reservoir compaction (Sulak et al. 1991). There have been several attempts to model this compaction. They performed with variable success on predicting the Ekofisk subsidence. However, the most of these models are based on empirical relations and do not investigate in detail the phenomena involved in the compaction. In sake of predicting the Ekofisk subsidence while using only independently measurable variables we used a chalk compaction model valid on geological time-scales (Japsen et al. 2011) assuming plastic pore-collapse mechanism at a threshold effective stress level. We identified the phenomena involved in the pore collapse. By putting them in a sequential order we created a simple statistical analytical model. We also investigated the time-dependence of the phenomena involved and by assuming that one of the phenomena is rate-limiting we could make estimations of the compaction rate at smaller length-scales. By carefully investigating the nature of pressure propagation we could upscale our model to reservoir scale. We found that the predicted compaction rates are close enough to the measured rates. We believe that we could further increase accuracy by refining our model. Sulak, R. M., Thomas, L. K., Boade R. R. (1991) 3D reservoir simulation of Ekofisk compaction drive. Journal of Petroleum Technology, 43(10):1272-1278, 1991. Japsen, P., Dysthe, D. K., Hartz, E. H., Stipp, S. L. S., Yarushina, V. M., Jamtveit. (2011) A compaction front in North Sea chalk. Journal of Geophysical Research: Solid Earth (1978

  4. Chalk effect on PVC cross-linking under irradiation

    International Nuclear Information System (INIS)

    Effect of nonmodified and modified chalk on curing degree of polymer matrix was studied under-irradiation of PVC-compositions. Films of the compositions (100 mass part 7 PVC, 0-100 mas.part of chalk, 2.5 - lead sulfate, 1.5 - lead stearate and 0.3 - glycerin) were irradiated up to absorbed dose 0.1 MGy in an inert medium. Content of gel-fraction after boiling in THF was determined with use of IR spectroscopy. It was established, that intensive dehydrochlorination and polymer curing took place on chalk particle surface. Network fixed strongly chalk particles. However, chalk inhibited processes of dehydrochlorination and PVC curing, increasing amount of noncured PVC in polymer matrix

  5. Design and construction of mound breakwaters

    Directory of Open Access Journals (Sweden)

    Josep R. Medina

    2014-08-01

    Full Text Available This paper describes the evolution of design techniques applied to mound breakwaters as well as some key tools, equipment and construction techniques. The influence of the theoretical and laboratory research is analyzed in detail, from the pioneering research by Iribarren eighty years ago to the construction of single-layer armored breakwaters in recent decades. The economic optimization and the new embodied energy and carbon concepts associated to the construction of mound breakwaters are studied. New concepts as well as the invention of new armor units are examined as is their impact based on the observations from small-scale physical experiments and the relevance of the equipment and logistic constraints to explain the evolution of the way mound breakwaters have been designed and built over time.

  6. Kolmanda aastatuhande piraadid / kommenteerinud Peter Chalk ja Gordan Van Hook

    Index Scriptorium Estoniae

    2009-01-01

    Piraatlusest Somaalia piirkonnas ja rahvusvahelistest dokumentidest piraatluse vastu võitlemiseks 21. sajandil. Kommenteerivad uurimiskeskuse RAND Corporation vanempoliitanalüütik Peter Chalk ja transpordikompanii Maersk Line innovatsiooni ja arenduse vanemdirektor Gordan Van Hook

  7. The Cretaceous-Tertiary boundary Fiskeler at Stevns Klint, Denmark: the geochemistry of the major trace metals

    Directory of Open Access Journals (Sweden)

    SALVADOR LOMONACO

    2001-10-01

    Full Text Available Trace metals in the four discrete layers of the Cretaceous-Tertiary boundary (Fiskeler at Stevns Klint (Denmark are relatively well studied, yet much remains to be learned about them. Therefore, an integrated study of the trace (meteoritic Ir, partly meteoritic Cr/Ni/Co/Au and terrestrial Zn/Cu/La/Ce/Nd/Sm/Eu/Tb/Yb/Ta/Th metals in the basal black marl of Fiskeler and in its (carbonate, HCl-soluble, smectite, HCl-insoluble, silicate and kerogen fractions was undertaken. The mineralogy of the marl is comparatively simple, authigenic calcite (mainly derived from planktonic marine algae: coccoliths, detrital Mg-smectite and quartz being the principal components, with lesser amounts of kerogen, Fe3+-oxides, pyrite, ilite and feldspar. Selective leaching procedures were used to establish geochemical associations and specific mineralogical locations of the trace metals. The results identified the main locations of the major trace metals (Cr/Ni/Co/Zn/Cu/Ir/Au. They occur mainly in the smectite and, to a lesser extent, in the biogenic calcite (Ni/Co/Zn and kerogen (Ir/Au. The trace metal data are in accordance with the hypothesis that substantial proportions of Cr/Ni/Co/Zn/Cu/Ir/Au were probably contained in the detrital smectite arriving at the site of the deposition. In a general discussion of the results, a geochemical model describing the incorporation of trace metals in the smectite is presented, based on the weathering/trasport of the clay by (impact-induced acid surface waters and the adsorption of trace metal ions by the smectite particles/colloids in the acidic solution of nearby oxic soil. The distribution/enrichment patterns of Cr/Ni/Co/Zn of the basal black marl and higher Fiskeler layers indicate, on the other hand, that notable proportions of these metals were incorporated into the smectite structure during the formation of the clay. The trace metal data are also considered in light of previously published paleoecological and geochemical

  8. Toe rock stability for rubble mound breakwaters

    NARCIS (Netherlands)

    Baart, S.; Ebbens, R.; Nammuni-Krohn, J.; Verhagen, H.J.

    2010-01-01

    Present design tools, as found in the Rock Manual or Coastal Engineering Manual, for the determination of toe rock size for rubble mound breakwaters are based on test data with a large spread: data is relatively dispersed around the centre and descriptive equations have limited applicability ranges.

  9. Stochastic Design of Rubble Mound Breakwaters

    DEFF Research Database (Denmark)

    Nielsen, Søren R.K.; Burcharth, Hans F.

    The paper presents a level III reliability method from which the armour layer of rubble mound breakwaters can be designed, so that the total costs of construction price and expected maintaince expenses are minimized. Since the physics of the wave-structure interaction are not yet fully understood...

  10. Hydraulic Response of Rubble Mound Breakwaters

    DEFF Research Database (Denmark)

    Andersen, Thomas Lykke

    Rubble mound breakwaters have been extensively investigated in the last decades. Nevertheless, there still exists some white spots where only little knowledge and only poor design rules are available. Some of these white spots are due to new types of structures developed in recent years. In this ...

  11. Radioactive disequilibrium in mound spring deposits

    International Nuclear Information System (INIS)

    The problem to be resolved was the age of the mound spring sediments on the margin of the Great Artesian Basin to the south and southwest of Lake Eyre. Nine samples from six springs and two from neighbouring dune fields were collected. The parent and daughter nuclides for the uranium and thorium decay chains have been comprehensively measured by a variety of techniques: DNA, thick-source alpha particle counting, field scintillometry, high resolution gamma spectrometry and high resolution alpha spectrometry. Gross radioactive disequilibrium in the uranium chain is found for the spring samples. The activity, in Bq kg-1, for the uranium chain at and below radium, compared with the parent uranium and its immediate daughters, ranges from an excess factor of two to a factor of six, depending on the age of the spring mound deposit. This is interpreted as evidence that radium is being carried up into the springs with artesian groundwater and deposited in the spring mound sediments. There is also evidence for a small excess of thorium. The ages of the spring mound deposits have been successfully found by thermoluminescence. They range from about 20 ka to 500 ka. The disequilibrium suggests why attempts to use uranium series dating have not been successful

  12. Independent technical review of the Mound Plant

    Energy Technology Data Exchange (ETDEWEB)

    1994-06-01

    This report documents an Independent Technical Review (ITR) of the facilities, organizations, plans, and activities required to transition particular elements of the Mound Plant from Defense Program (DP) funded operation as appropriate either to community developed reuse or safe deactivation leading to decontamination and decommissioning (D&D). The review was conducted at the request of the Dr. Willis Bixby, Deputy Assistant Secretary, U.S. Department of Energy EM-60, Office of Facility Transition and Management and is a consensus of the nine member ITR Team. Information for the review was drawn from documents provided to the ITR Team by the Miamisburg Area Office (MB) of the DOE, EG&G, the City of Miamisburg, and others; and from presentations, discussions, interviews, and facility inspections at the Mound Plant during the weeks of March 14 and March 28, 1994. During the week of April 25, 1994, the ITR Team met at Los Alamos, New Mexico to develop consensus recommendations. A presentation of the core recommendations was made at the Mound Plant on May 5, 1994. This is an independent assessment of information available to, and used by, the Mound Plant personnel. Repetition of the information is not meant to imply discovery by the ITR Team. Team members, however, acting as independent reviewers, frequently assess the information from a perspective that differs significantly from that of the Mound Plant personnel. The report is based on information obtained and conditions observed during the March 1994 review interval. The ITR process and normal site work often initiate rapid, beneficial changes in understanding and organization immediately following the review. These changes frequently alter conditions observed during the review, but the report does not address changes subsequent to the review interval.

  13. The invertebrate ecology of the Chalk aquifer in England (UK)

    Science.gov (United States)

    Maurice, L.; Robertson, A. R.; White, D.; Knight, L.; Johns, T.; Edwards, F.; Arietti, M.; Sorensen, J. P. R.; Weitowitz, D.; Marchant, B. P.; Bloomfield, J. P.

    2016-03-01

    The Chalk is an important water supply aquifer, yet ecosystems within it remain poorly understood. Boreholes (198) in seven areas of England (UK) were sampled to determine the importance of the Chalk aquifer as a habitat, and to improve understanding of how species are distributed. Stygobitic macro-invertebrates were remarkably common, and were recorded in 67 % of boreholes in unconcealed Chalk, although they were not recorded in Chalk that is concealed by low-permeability strata and thus likely to be confined. Most species were found in shallow boreholes (50 m) water tables, indicating that the habitat is vertically extensive. Stygobites were present in more boreholes in southern England than northern England (77 % compared to 38 %). Only two species were found in northern England compared to six in southern England, but overall seven of the eight stygobitic macro-invertebrate species found in England were detected in the Chalk. Two species are common in southern England, but absent from northern England despite the presence of a continuous habitat prior to the Devensian glaciation. This suggests that either they did not survive glaciations in the north where glaciers were more extensive, or dispersal rates are slow and they have never colonised northern England. Subsurface ecosystems comprising aquatic macro-invertebrates and meiofauna, as well as the microbial organisms they interact with, are likely to be widespread in the Chalk aquifer. They represent an important contribution to biodiversity, and may influence biogeochemical cycles and provide other ecosystem services.

  14. The Chalk River Tritium Extraction Plant

    International Nuclear Information System (INIS)

    The Chalk River Tritium Extraction Plant for removal of tritium from heavy water is described. Tritium is present in the heavy water from research reactors in the form of DTO at a concentration in the range of 1-35 Ci/kg. It is removed by a combination of catalytic exchange to transfer the tritium from DTO to DT, followed by cryogenic distillation to separate and concentrate the tritium to T2. The tritium product is reacted with titanium and packaged for transportation and storage as titanium tritide. The plant processes heavy water at a rate of 25 kg/h and removes 80% of the tritium and 90% of the protium per pass. Catalytic exchange is carried out in the liquid phase using a proprietary wetproofed catalyst. The plant serves two roles in the Canadian fusion program: it produces pure tritium for use in fusion research and development, and it demonstrates on an industrial scale many of the tritium technologies that are common to the tritium systems in fusion reactors (author)

  15. Mound site environmental monitoring report for calendar year 1993

    International Nuclear Information System (INIS)

    The purpose of this report is to inform the public about the impact of Mound operations on the population and the environment. Mound is a government-owned facility operated by EG ampersand G Mound Applied Technologies for the U.S. Department of Energy (DOE). This integrated production, development, and research site performs work in support of DOE's weapon and energy related programs, with emphasis on explosive, nuclear and energy technologies. The Mound Plant, named after the Miamisburg Indian Mound adjacent to the site, comprises 120 buildings on 124 hectares (306 acres) of land in Miamisburg, Ohio, approximately 16 km (10 mi) southwest of Dayton. The Great Miami River, which flows through the city of Miamisburg, dominates the landscape of the five-county region surrounding Mound. The river valley is highly industrialized. The rest of the region is predominately farm land dotted with light industry and small communities. The climate is moderate. The geologic record preserved in the rocks underlying Mound indicates that the area has been relatively stable since the beginning of the Paleozoic Era more than 500 million years ago. No buildings at Mound are located in a floodplain or in areas considered wetlands. Included in the report are the following: perspective on radiation; radionuclide releases from Mound; Dose limites; doses from Mound Operations; Results of the environmental Monitoring Program; Ground water monitoring program; environmental restoration program; quality assurance for environmental data

  16. The Magellan mound province in the Porcupine Basin

    Science.gov (United States)

    Huvenne, V. A. I.; Bailey, W. R.; Shannon, P. M.; Naeth, J.; di Primio, R.; Henriet, J. P.; Horsfield, B.; de Haas, H.; Wheeler, A.; Olu-Le Roy, K.

    2007-02-01

    The Magellan mound province is one of the three known provinces of carbonate mounds or cold-water coral banks in the Porcupine Seabight, west of Ireland. It has been studied in detail using a large and varied data set: 2D and 3D seismic data, sidescan sonar imagery and video data collected during ROV deployment have been used to describe the mounds in terms of origin, growth processes and burial. The aim of this paper is to present the Magellan mounds and their setting in an integrated, holistic way. More than 1,000 densely spaced and mainly buried mounds have been identified in the area. They all seem to be rooted on one seismic reflection, suggesting a sudden mound start-up. Their size and spatial distribution characteristics are presented, together with the present-day appearance of the few mounds that reach the seabed. The underlying geology has been studied by means of fault analysis and numerical basin modelling in an attempt to identify possible hydrocarbon migration pathways below or in the surroundings of the Magellan mounds. Although conclusive evidence concerning the processes of mound initiation proves to be elusive, the results of both fault analysis and 2D numerical modelling failed to identify, with confidence, any direct pathways for focused hydrocarbon flow to the Magellan province. Diffuse seepage however may have taken place, as drainage area modelling suggests a possible link between mound position and structural features in the Hovland-Magellan area. During mound development and growth, the interplay of currents and sedimentation seems to have been the most important control. Mounds which could not keep pace with the sedimentation rates were buried, and on the few mounds which maintained growth, only a few corals survive at present.

  17. Toe rock stability for rubble mound breakwaters

    OpenAIRE

    Baart, S.; Ebbens, R.; Nammuni-Krohn, J.; Verhagen, H.J.

    2010-01-01

    Present design tools, as found in the Rock Manual or Coastal Engineering Manual, for the determination of toe rock size for rubble mound breakwaters are based on test data with a large spread: data is relatively dispersed around the centre and descriptive equations have limited applicability ranges. New research has been undertaken to contribute to a more accurate description of toe rock stability. Flume tests have lead to an empirical design criterion for toe bunds in very shallow water base...

  18. Cartografical And Geodetical Aspects Of The Krakus Mound In Cracow

    Science.gov (United States)

    Banasik, Piotr

    2015-12-01

    In this work the fate of the Krakus Mound, the oldest of all existing Krakow's mounds, has been presented. The work was carried out based on selected iconographic, cartographic and geodetic documents. Using as an example old views, panoramas of the city and maps, various functions that the Krakus Mound was fulfilling over its long history were shown. An attempt was made to document the military significance of this mound and the surrounding hills. The particular astro-geodetic importance of the Krakus Mound on the scale of the city and southern Poland region was widely discussed. The Krakus Mound also inscribed itself in the history of the use of GPS technology as well as research on the local determination of the geoid in the area of Krakow.

  19. Environmental control on cold-water carbonate mounds development

    Science.gov (United States)

    Rüggeberg, A.; Liebetrau, V.; Raddatz, J.; Flögel, S.; Dullo, W.-Chr.; Exp. 307 Scientific Party, Iodp

    2009-04-01

    Cold-water coral reefs are very abundant along the European continental margin in intermediate water depths and are able to build up large mound structures. These carbonate mounds particularly occur in distinct mound provinces on the Irish and British continental margins. Previous investigations resulted in a better understanding of the cold-water coral ecology and the development of conceptual models to explain carbonate mound build-up. Two different hypotheses were evoked to explain the origin and development of carbonate mounds, external versus internal control (e.g., Freiwald et al. 2004 versus e.g. Hovland 1990). Several short sediment cores have been obtained from Propeller Mound, Northern Porcupine Seabight, indicating that cold-water corals grew during interglacial and warm interstadial periods of the Late Pleistocene controlled by environmental and climatic variability supporting the external control hypothesis (e.g. Dorschel et al. 2005, R

  20. Mound site environmental report for calendar year 1992

    Energy Technology Data Exchange (ETDEWEB)

    Bauer, L.R.

    1993-07-01

    The purpose of this report is to inform the public about the impact of Mound operations on the population and the environment. Mound is a government-owned facility operated by EG&G Mound Applied Technologies for the US Department of Energy (DOE). This integrated production, development, and research site performs work in support of DOE`s weapon and energy related programs, with emphasis on explosive, nuclear and energy technologies.

  1. Temporal Evolution of A Carbonate Mound In The NE Atlantic

    Science.gov (United States)

    Dorschel, B.; Rüggeberg, A.; Hebbeln, D.; Dullo, C.; Freiwald, A.

    Even though carbonate mounds are quite common structures along the northeast At- lantic margin their history remains largely unknown. Besides the main question, what causes the initial development of these mounds; also their latest evolution in response to changing environmental conditions receives more and more interest. Here, this question has been tackled by new sets of stable isotope data, which provide informa- tion about the growth and accumulation pattern of these mounds for the last 100 ka. The investigated Propeller Mound (52r09'N/12r46'W) is part of the Hovland Mound Province located in the northern Porcupine Seabight. Its base is located in 800 m wa- ter depth and it expands 2 km in N-S direction and 0.7 km in E-W direction. Its top rises up to 150 m above the surrounding seafloor. In September 2000 eight gravity cores have been collected from the Propeller Mound and the surrounding area. Four cores taken from the mound contain cold-water corals and coral fragments in a matrix of silt and clay. The other cores collected from a moat around the mound and from a drift body in the northeast contain mainly sandy silty clays. All off-mound cores are easy to correlate using proxies like Ca ore Fe content. Inter-core correlations with on- mound cores turned out to be difficult. Fragments of the cold-water corals Lophelia pertusa and Madrepora occulata overprint the hemipelagic background signal. Here we use stable isotope data from benthic foraminifers for an inter-core correlation. In combination with 14C ages these data provide information about the evolutionof the mounds in relation to the off-mound area with respect to climate variations during the last 100 ka.

  2. Mound site environmental report for calendar year 1992

    International Nuclear Information System (INIS)

    The purpose of this report is to inform the public about the impact of Mound operations on the population and the environment. Mound is a government-owned facility operated by EG ampersand G Mound Applied Technologies for the US Department of Energy (DOE). This integrated production, development, and research site performs work in support of DOE's weapon and energy related programs, with emphasis on explosive, nuclear and energy technologies

  3. Inverse modeling of Chalk River block

    International Nuclear Information System (INIS)

    Within the framework of the international project HYDROCOIN, a block of fractured monzonitic gneiss within the facilities of Chalk River National Laboratories, Canada, was selected as a test case to study and develop strategies for the calibration and validation of groundwater flow models. Adopting a quasi-three dimensional formulation, the fractures were simulated by two-dimensional finite elements and the rock mass was simulated by strings of line elements. The models were calibrated using, first, steady-state data and, second, transient data. Model calibration involved both identification of model parameters and model structure. Model parameters were obtained by automatic estimation based on measures of the model response and prior information about the model parameters. Excellent agreement between measured and computed heads was obtained for the transient runs. However, such match was only fair in steady-state. Model Structures Identification criteria were used to rank the performance of several model structures. In the steady state the model structure identification criteria did not strongly support increasing the model complexity. However, it is also believed that the information content of the steady state data was quite poor. In contrast, the transient data being both more numerous and more informative than steady-state data, allowed the model structure identification criteria to suggest more complex models. The validation runs were performed on data corresponding to interference pump tests different from the ones used for calibration. The prediction errors in these runs were relatively small and consistent with the calibration uncertainty. Furthermore, the ranking of the models performances during validation runs was the same as the one obtained at the calibration stage, using Model Structure Identification Criteria. (author) 26 figs., 17 tabs., 39 refs

  4. Burial diagenesis of deep sea chalk as reflected in Biot's coefficient

    DEFF Research Database (Denmark)

    Fabricius, Ida Lykke; Alam, Mohammad Monzurul

    2013-01-01

    Burial diagenesis of chalk has been widely studied, but little agreement has been reached on by which mechanism porosity declines, and on how to calculate the deforming stress in the most informative way. Data from Ocean Drilling Program show that calcareous ooze transforms to chalk and chalk to ...

  5. Biot Critical Frequency Applied as Common Friction Factor for Chalk with Different Pore Fluids and Temperatures

    DEFF Research Database (Denmark)

    Andreassen, Katrine Alling; Fabricius, Ida Lykke

    2010-01-01

    Injection of water into chalk hydrocarbon reservoirs has lead to mechanical yield and failure. Laboratory experiments on chalk samples correspondingly show that the mechanical properties of porous chalk depend on pore fluid and temperature. Water has a significant softening effect on elastic...... highly influenced by temperature....

  6. Influence of effective stress coefficient on mechanical failure of chalk

    DEFF Research Database (Denmark)

    Alam, Mohammad Monzurul; Fabricius, Ida Lykke; Hjuler, M.L.;

    2012-01-01

    The Effective stress coefficient is a measure of how chalk grains are connected with each other. The stiffness of chalk may decrease if the amount of contact cements between the grains decreases, which may lead to an increase of the effective stress coefficient. We performed CO2 injection in chalk......, as this process could affect the grain contact cement. If this happens, the effective stress at the grain contacts in a reservoir will change according to the effective stress principle of Biot. In a p′-q space for failure analysis, we observed that a higher effective stress coefficient reduces the...... elastic region and vice versa. However, as the effective stress working on the rock decreases with increased effective stress coefficient, the reduction of elastic region will have less effect on pore collapse strength if we consider the change in the effective stress coefficient. This finding will help...

  7. Chemical and Mechanical processes during burial diagenesis of chalk

    DEFF Research Database (Denmark)

    Borre, Mai Kirstine; Lind, Ida

    1998-01-01

    equal or larger influence on the textural development. In the chalk interval below, compaction is not the only porosity reducing agent but it has a larger influence on texture than concurrent recrystallization. Below 850 m grain-bridging cementation becomes important resulting in a lithified limestone......Burial diagenesis of chalk is a combination of mechanical compaction and chemical recrystallization as well as cementation. We have predicted the characteristic trends in specific surface resulting from these processes. The specific surface is normally measured by nitrogen adsorption but is here...... the Pacific, where a > 1 km thick package of chalk facies sediments accumulated from the Cretaceous to the present. In the upper 200-300 m the sediment is unconsolidated carbonate ooze, throughout this depth interval compaction is the principal porosity reducing agent, but recrystallization has an...

  8. Province of Ontario nuclear emergency plan part V - Chalk River

    International Nuclear Information System (INIS)

    The aim of Part 5 of the Provincial Nuclear Emergency Plan is to describe the measures that shall be undertaken to deal with a nuclear emergency caused by the Chalk River Laboratories. This plan deals mainly with actions at the Provincial level and shall by supplemented by the appropriate Municipal Plan. The Townships of Rolph, Buchanan, Wylie, and McKay, the Town of Deep River and the Village of Chalk River are the designated municipalities with respect to CRL. 2 tabs., 5 figs

  9. Mound Laboratory contaminated waste inventory system

    International Nuclear Information System (INIS)

    With the advent of tighter security on all nuclear material--both on site and during site-to-site transporting--a unit control system was devised for Mound Laboratory's nuclear waste material. This system provides a unit identification technique for all SS material waste containers. The data capture system will provide intermediate, periodic data reports, control to minimize nuclear material diversion, a standard shipment manifest to national storage sites, and 20-year retrievable life of all data for an audit trail of all inventoried containers

  10. Ecological effects of harvester ant Messor capensis nest-mounds on Karoo plants

    OpenAIRE

    Dean, W. R. J.

    1995-01-01

    The influence of harvester ant Messor capensis nest-mounds on plants in arid shrubland was investigated at Tierberg, Prince Albert, Cape Province, during 1991. Nest-mound soils contained significantly more phosphorus, potassium, nitrogen and organic matter than surrounding soils. Nest-mound soils also contained more viable seeds than the soil of inter-mound spaces, and more seedlings germinated on nest-mounds than in inter-mound spaces.

  11. Biodiversity and ecological composition of macrobenthos on cold-water coral mounds and adjacent off-mound habitat in the bathyal Porcupine Seabight, NE Atlantic

    OpenAIRE

    Henry, L.A. (Lea Anne); Roberts, M. J.

    2007-01-01

    The cold-water scleractinian corals Lophelia pertusa and Madrepora oculata form mound structures on the continental shelf and slope in the NE Atlantic. This study is the first to compare the taxonomic biodiversity and ecological composition of the macrobenthos between on- and off-mound habitats. Seven box cores from the summits of three mounds and four cores from an adjacent off-mound area in the Belgica, Mound Province in the Porcupine Seabight yielded 349 species, including 10 undescribed s...

  12. Initial field measurements on the Chalk River superconducting cyclotron

    International Nuclear Information System (INIS)

    The midplane magnetic field of the Chalk River superconducting cyclotron has been mapped in detail over the full operating range of 2.5 to 5 tesla. The field measuring apparatus is described and results given include measurements of the field stability, reproducibility and harmonic content. (author)

  13. Chalk porosity and sonic velocity versus burial depth

    DEFF Research Database (Denmark)

    Fabricius, Ida Lykke; Gommesen, Lars; Krogsbøll, Anette Susanne;

    2008-01-01

    Seventy chalk samples from four formations in the overpressured Danish central North Sea have been analyzed to investigate how correlations of porosity and sonic velocity with burial depth are affected by varying mineralogy, fluid pressure, and early introduction of petroleum. The results show th...

  14. Nano sized clay detected on chalk particle surfaces

    DEFF Research Database (Denmark)

    Skovbjerg, Lone; Hassenkam, Tue; Makovicky, Emil;

    2012-01-01

    that in calcite saturated water, both the polar and the nonpolar functional groups adhere to the nano sized clay particles but not to calcite. This is fundamentally important information for the development of conceptual and chemical models to explain wettability alterations in chalk reservoirs...

  15. Specific surface as a measure of burial diagenesis of chalk

    DEFF Research Database (Denmark)

    Borre, Mai Kirstine; Lind, Ida; Mortensen, Jeanette

    ODP Leg 130, Site 807, in the western equatorial Pacific, penetrates a sequence of pelagic carbonate ooze, chalk and limestone. Compaction, recrystallisation and cementation of the carbonate matrix are diagenetic processes expected to be taking place more or less simultaneously. In order to assess...

  16. Quantitative 1D saturation profiles on chalk by NMR

    DEFF Research Database (Denmark)

    Olsen, Dan; Topp, Simon; Stensgaard, Anders;

    1996-01-01

    Quantitative one-dimensional saturation profiles showing the distribution of water and oil in chalk core samples are calculated from NMR measurements utilizing a 1D CSI spectroscopy pulse sequence. Saturation profiles may be acquired under conditions of fluid flow through the sample. Results reveal...

  17. Groundwater conversion areas in chalk in the southern Frankish Alps

    International Nuclear Information System (INIS)

    In order to collect hydro-geological data, chalk water marking was done and/or interpreted, water balances were produced, the contents tritium, oxygen 18, calcium, magnesium and the groundwater temperatures and electrolytic conductivity of the groundwater were examined and the dry weather drainage of individual sources was analysed. (orig./PW)

  18. Ekofisk chalk: core measurements, stochastic reconstruction, network modeling and simulation

    Energy Technology Data Exchange (ETDEWEB)

    Talukdar, Saifullah

    2002-07-01

    This dissertation deals with (1) experimental measurements on petrophysical, reservoir engineering and morphological properties of Ekofisk chalk, (2) numerical simulation of core flood experiments to analyze and improve relative permeability data, (3) stochastic reconstruction of chalk samples from limited morphological information, (4) extraction of pore space parameters from the reconstructed samples, development of network model using pore space information, and computation of petrophysical and reservoir engineering properties from network model, and (5) development of 2D and 3D idealized fractured reservoir models and verification of the applicability of several widely used conventional up scaling techniques in fractured reservoir simulation. Experiments have been conducted on eight Ekofisk chalk samples and porosity, absolute permeability, formation factor, and oil-water relative permeability, capillary pressure and resistivity index are measured at laboratory conditions. Mercury porosimetry data and backscatter scanning electron microscope images have also been acquired for the samples. A numerical simulation technique involving history matching of the production profiles is employed to improve the relative permeability curves and to analyze hysteresis of the Ekofisk chalk samples. The technique was found to be a powerful tool to supplement the uncertainties in experimental measurements. Porosity and correlation statistics obtained from backscatter scanning electron microscope images are used to reconstruct microstructures of chalk and particulate media. The reconstruction technique involves a simulated annealing algorithm, which can be constrained by an arbitrary number of morphological parameters. This flexibility of the algorithm is exploited to successfully reconstruct particulate media and chalk samples using more than one correlation functions. A technique based on conditional simulated annealing has been introduced for exact reproduction of vuggy

  19. Morphology and environment of cold-water coral carbonate mounds on the NW European margin

    Science.gov (United States)

    Wheeler, A. J.; Beyer, A.; Freiwald, A.; de Haas, H.; Huvenne, V. A. I.; Kozachenko, M.; Olu-Le Roy, K.; Opderbecke, J.

    2007-02-01

    Cold-water coral carbonate mounds, owing their presence mainly to the framework building coral Lophelia pertusa and the activity of associated organisms, are common along the European margin with their spatial distribution allowing them to be divided into a number of mound provinces. Variation in mound attributes are explored via a series of case studies on mound provinces that have been the most intensely investigated: Belgica, Hovland, Pelagia, Logachev and Norwegian Mounds. Morphological variation between mound provinces is discussed under the premise that mound morphology is an expression of the environmental conditions under which mounds are initiated and grow. Cold-water coral carbonate mounds can be divided into those exhibiting “inherited” morphologies (where mound morphology reflects the morphology of the colonised features) and “developed” morphology (where the mounds assume their own gross morphology mainly reflecting dominant hydrodynamic controls). Finer-scale, surface morphological features mainly reflecting biological growth forms are also discussed.

  20. Decomposition and reduction of N2O over Limestone under FBC Conditions

    DEFF Research Database (Denmark)

    Johnsson, Jan Erik; Jensen, Anker; Vaaben, Rikke;

    1997-01-01

    The addition of limestone for sulfur retention in FBC has in many cases been observed to influence the emission of N2O. The catalytic activity of N2O over calcined Stevns Chalk for decomposition of N2O in a laboratory fixed bed quartz reactor was measured. It was found that calcined Stevns Chalk ...

  1. Asphalt mounds and associated biota on the Angolan margin

    Science.gov (United States)

    Jones, Daniel O. B.; Walls, Anne; Clare, Michael; Fiske, Mike S.; Weiland, Richard J.; O'Brien, Robert; Touzel, Daniel F.

    2014-12-01

    Release of hydrocarbons from sediments is important in increasing habitat heterogeneity on deep ocean margins. Heterogeneity arises from variation in abiotic and biotic conditions, including changes in substratum, geochemistry, fluid flow, biological communities and ecological interactions. The seepage of heavy hydrocarbons to the seafloor is less well studied than most other cold seep systems and may lead to the formation of asphalt mounds. These have been described from several regions, particularly the Gulf of Mexico. Here, we describe the structure, potential formation and biology of a large asphalt mound province in Block 31SE Angola. A total of 2254 distinct mound features was identified by side-scan sonar, covering a total area of 3.7 km2 of seafloor. The asphalt mounds took a number of forms from small (<0.5 m diameter; 13% observations) mounds to large extensive (<50 m diameter) structures. Some of the observed mounds were associated with authigenic carbonate and active seepage (living chemosynthetic fauna present in addition to the asphalt). The asphalt mounds are seabed accumulations of heavy hydrocarbons formed from subsurface migration and fractionation of reservoir hydrocarbons primarily through a network of faults. In Angola these processes are controlled by subsurface movement of salt structures. The asphalt mounds were typically densely covered with epifauna (74.5% of mounds imaged had visible epifauna) although individual mounds varied considerably in epifaunal coverage. Of the 49 non-chemosynthetic megafaunal taxa observed, 19 taxa were only found on hard substrata (including asphalt mounds), 2 fish species inhabited the asphalt mounds preferentially and 27 taxa were apparently normal soft-sediment fauna. Antipatharians (3.6±2.3% s.e.) and poriferans (2.6±1.9% s.e.) accounted for the highest mean percentage of the observed cover, with actinarians (0.9±0.4% s.e.) and alcyonaceans (0.4±0.2% s.e.) covering smaller proportions of the area

  2. Environmental assessment for Mound Plant decontamination and decommissioning projects, Mound Plant, Miamisburg, Ohio

    International Nuclear Information System (INIS)

    The U.S. Department of Energy (DOE) has prepared an Environmental Assessment (EA) for seven decontamination and decommissioning (D ampersand D) projects at the Mound Plant in Miamisburg, Ohio, that have not been previously addressed in the Final Environmental Impact Statement for the Mound Facility (June 1979). Based on the information presented in the EA, the DOE has determined that the proposed action is not a major Federal action significantly affecting the quality of the human environment within the meaning of the National Environmental Policy Act (NEPA) of 1969. Therefore, the preparation of an Environmental Impact Statement (EIS) is not required and the Department is issuing this Finding of No Significant Impact (FONSI)

  3. Environmental assessment for Mound Plant decontamination and decommissioning projects, Mound Plant, Miamisburg, Ohio

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-05-01

    The U.S. Department of Energy (DOE) has prepared an Environmental Assessment (EA) for seven decontamination and decommissioning (D&D) projects at the Mound Plant in Miamisburg, Ohio, that have not been previously addressed in the Final Environmental Impact Statement for the Mound Facility (June 1979). Based on the information presented in the EA, the DOE has determined that the proposed action is not a major Federal action significantly affecting the quality of the human environment within the meaning of the National Environmental Policy Act (NEPA) of 1969. Therefore, the preparation of an Environmental Impact Statement (EIS) is not required and the Department is issuing this Finding of No Significant Impact (FONSI).

  4. Mound's decommissioning experience, tooling, and techniques

    International Nuclear Information System (INIS)

    Monsanto Research Corporation (MRC), which operates Mound for the Department of Energy (DOE), has been decommissioning radioactively contaminated facilities since 1949. We are currently decommissioning three plutonium-238 contaminated facilities (approximately 50,000 ft2) that contained 1100 linear ft of gloveboxes; 900 linear ft of conveyor housing; 2650 linear ft of dual underground liquid waste lines; and associated contaminated piping, services, equipment, structures, and soil. As of June 1982, over 29,000 Ci of plutonium-238 have been removed in waste and scrap residues. As a result of the current and previous decommissioning projects, valuable experience has been gained in tooling and techniques. Special techniques have been developed in planning, exposure control, contamination control, equipment removal, structural decontamination, and waste packaging

  5. Partial Safety Factors for Rubble Mound Breakwaters

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Burcharth, H. F.; Christiani, E.

    1995-01-01

    section 3. First Order Reliability Methods are described in section 4, and in section 5 it is shown how partial safety factors can be introduced and calibrated. The format of a code for design and analysis of rubble mound breakwaters is discussed in section 6. The mathematical formulation of the limit...... lifetimes from 20 to 100 years and different qualities of wave data. A code of practice where safety is taken into account using partial safety factors is called a level I code. The partial safety factors are calibrated using First Order Reliability Methods (FORM, see Madsen et al. [1]) where the......On the basis of the failure modes formulated in the various subtasks calibration of partial safety factors are described in this paper. The partial safety factors can be used to design breakwaters under quite different design conditions, namely probabilities of failure from 0.01 to 0.4, design...

  6. Pore Pressure Measurements Inside Rubble Mound Breakwaters

    DEFF Research Database (Denmark)

    Helgason, Einar; Burcharth, H. F.; Grüne, Joachim

    2004-01-01

    The present paper presents pore pressure measurements from large scale model tests performed at the Large Wave Channel, Hannover, Germany and small scale model test performed at the Hydraulic & Coastal Engineering Laboratory, Aalborg University, Denmark. Information on pore pressure attenuation and...... wave damping in the core and important for the scaling of core materials in small scale hydraulic models. The main objectives are to study and examine the wave damping in the core of rubble mound breakwater models. the acquired test results are compared with results available from the literature, and...... compared to a damping model presented by Burcharth et al. (1999). Reasonable agreement is found when considering the difference in the grading and uniformity of the model core materials. Comparison between results obtained from small and large scale model tests showed no clear evidence of scale effects....

  7. Tritium effluent control project at Mound Laboratory

    International Nuclear Information System (INIS)

    Tritium control technology and philosophies that have been developed at the various weapons complex sites can be drawn upon for the design and operation of fusion research facilities and Controlled Thermonuclear Reactor fuel cycle and tritium confinement systems. Historically, tritium control has been based on high volume air flows and dilution of effluent systems. As a consequence of the ''as low as practical'' criterion, control philosophies were reevaluated and control efforts intensified. It is the results of these recent efforts that are most applicable to the CTR program. At Mound Laboratory the tritium control development efforts are centered around an advanced technology project. The philosophy and goals of this project and a nearly completed pilot scale effluent control laboratory are described. (auth)

  8. In Operando GISAXS Studies of Mound Coarsening in Electrochemical Homoepitaxy

    Science.gov (United States)

    Ruge, Martin; Golks, Frederik; Zegenhagen, Jörg; Magnussen, Olaf M.; Stettner, Jochim

    2014-02-01

    Kinetic roughening during electrodeposition was studied by grazing incidence small angle x-ray scattering for the case of Au(001) homoepitaxial growth in Cl- containing electrolytes. The formation and coarsening of an isotropic mound distribution on unreconstructed Au(001) and of [110]-oriented anisotropic mounds on the "hex" reconstructed surface was observed. The lateral mound coarsening is described by a well-defined scaling law. On unreconstructed Au a transition in the coarsening exponent from ≈1/4 to ≈1/3 with increasing potential is found, which can be explained by the pronounced potential dependence of surface transport processes in an electrochemical environment.

  9. In operando GISAXS studies of mound coarsening in electrochemical homoepitaxy.

    Science.gov (United States)

    Ruge, Martin; Golks, Frederik; Zegenhagen, Jörg; Magnussen, Olaf M; Stettner, Jochim

    2014-02-01

    Kinetic roughening during electrodeposition was studied by grazing incidence small angle x-ray scattering for the case of Au(001) homoepitaxial growth in Cl- containing electrolytes. The formation and coarsening of an isotropic mound distribution on unreconstructed Au(001) and of [110]-oriented anisotropic mounds on the "hex" reconstructed surface was observed. The lateral mound coarsening is described by a well-defined scaling law. On unreconstructed Au a transition in the coarsening exponent from ≈1/4 to ≈1/3 with increasing potential is found, which can be explained by the pronounced potential dependence of surface transport processes in an electrochemical environment. PMID:24580610

  10. MHD instabilities in accretion mounds on neutron star binaries

    CERN Document Server

    Mukherjee, Dipanjan; Mignone, Andrea

    2013-01-01

    We have numerically solved the Grad-Shafranov equation for axisymmetric static MHD equilibria of matter confined at the polar cap of neutron stars. From the equilibrium solutions we explore the stability of the accretion mounds using the PLUTO MHD code. We find that pressure driven modes disrupt the equilibria beyond a threshold mound mass. This results in formation of dynamic structures inside the mound, as matter spreads over the neutron star surface. Our results show that local variation of magnetic field will significantly affect the shape and nature of the cyclotron features observed in the spectra of High Mass X-ray Binaries.

  11. Fractal-mound growth of pentacene thin films

    Science.gov (United States)

    Zorba, Serkan; Shapir, Yonathan; Gao, Yongli

    2006-12-01

    The growth mechanism of pentacene film formation on SiO2 substrate was investigated with a combination of atomic force microscopy measurements and numerical modeling. In addition to the diffusion-limited aggregation (DLA) that has already been shown to govern the growth of the ordered pentacene thin films, it is shown here that the Schwoebel barrier effect steps in and disrupts the desired epitaxial growth for the subsequent layers, leading to mound growth. The terraces of the growing mounds have a fractal dimension of 1.6, indicating a lateral DLA shape. This growth morphology thus combines horizontal DLA-like growth with vertical mound growth.

  12. Horizontal wells up odds for profit in Giddings Austin chalk

    International Nuclear Information System (INIS)

    This paper reports on horizontal drilling in the Giddings field Austin chalk which has significantly improved average well recoveries and more than offset increased drilling costs. Although not the panacea originally promoted, horizontal drilling, in Giddings field, offers economic profits to the average investor. Economic analysis indicates that the typical investor is making money by earning returns in excess of market values. Field-wide development will, therefore, remain active unless oil prices or average well recoveries fall below $12/bbl or 112,000 bbl of oil equivalent (BOE), respectively. The application of technological innovation in the Giddings field may culminate in the drilling of over 2,000 horizontal Austin chalk wells, and has conceivably increased recoverable reserves by 400 million BOE

  13. Biodiversity and ecological composition of macrobenthos on cold-water coral mounds and adjacent off-mound habitat in the bathyal Porcupine Seabight, NE Atlantic

    Science.gov (United States)

    Henry, Lea-Anne; Roberts, J. Murray

    2007-04-01

    The cold-water scleractinian corals Lophelia pertusa and Madrepora oculata form mound structures on the continental shelf and slope in the NE Atlantic. This study is the first to compare the taxonomic biodiversity and ecological composition of the macrobenthos between on- and off-mound habitats. Seven box cores from the summits of three mounds and four cores from an adjacent off-mound area in the Belgica Mound Province in the Porcupine Seabight yielded 349 species, including 10 undescribed species. On-mound habitat was three times more speciose, and was richer with higher evenness and significantly greater Shannon's diversity than off-mound. Species composition differed significantly between habitats and the four best discriminating species were Pliobothrus symmetricus (more frequent off-mound), Crisia nov. sp, Aphrocallistes bocagei and Lophelia pertusa (all more frequent on-mound). Filter/suspension feeders were significantly more abundant on-mound, while deposit feeders were significantly more abundant off-mound. Species composition did not significantly differ between mounds, but similarity within replicates decreased from Galway MoundMound. We propose that, despite having greater vertical habitat heterogeneity that supports higher biodiversity, coral mounds have a characteristic "reef fauna" linked to species' biology that contrasts with the higher horizontal habitat heterogeneity conferred by the action of deposit feeders and a varied seabed sedimentary facies off-mound. Standardisation of equipment and restriction of analyses to higher taxonomic levels would facilitate prospective comparative analyses of cold-water coral biodiversity across larger spatio-temporal scales.

  14. Widespread methanotrophic primary production in lowland chalk rivers

    OpenAIRE

    Shelley, Felicity; Grey, Jonathan; Trimmer, Mark

    2014-01-01

    Methane is oversaturated relative to the atmosphere in many rivers, yet its cycling and fate is poorly understood. While photosynthesis is the dominant source of autotrophic carbon to rivers, chemosynthesis and particularly methane oxidation could provide alternative sources of primary production where the riverbed is heavily shaded or at depth beneath the sediment surface. Here, we highlight geographically widespread methanotrophic carbon fixation within the gravel riverbeds of over 30 chalk...

  15. Widespread methanotrophic primary production in lowland chalk rivers.

    Science.gov (United States)

    Shelley, Felicity; Grey, Jonathan; Trimmer, Mark

    2014-05-22

    Methane is oversaturated relative to the atmosphere in many rivers, yet its cycling and fate is poorly understood. While photosynthesis is the dominant source of autotrophic carbon to rivers, chemosynthesis and particularly methane oxidation could provide alternative sources of primary production where the riverbed is heavily shaded or at depth beneath the sediment surface. Here, we highlight geographically widespread methanotrophic carbon fixation within the gravel riverbeds of over 30 chalk rivers. In 15 of these, the potential for methane oxidation (methanotrophy) was also compared with photosynthesis. In addition, we performed detailed concurrent measurements of photosynthesis and methanotrophy in one large chalk river over a complete annual cycle, where we found methanotrophy to be active to at least 15 cm into the riverbed and to be strongly substrate limited. The seasonal trend in methanotrophic activity reflected that of the riverine methane concentrations, and thus the highest rates were measured in mid-summer. At the sediment surface, photosynthesis was limited by light for most of the year with heavy shading induced by dense beds of aquatic macrophytes. Across 15 rivers, in late summer, we conservatively calculated that net methanotrophy was equivalent to between 1% and 46% of benthic net photosynthetic production within the gravel riverbed, with a median value of 4%. Hence, riverbed chemosynthesis, coupled to the oxidation of methane, is widespread and significant in English chalk rivers. PMID:24695425

  16. Environmental assessment for commercialization of the Mound Plant

    International Nuclear Information System (INIS)

    In November 1993 US DOE decided to phase out operations at the Mound Plant in Miamisburg, Ohio, with the goal of releasing the site for commercial use. The broad concept is to transform the plant into an advanced manufacturing center with the main focus on commercializing products and other technology. DOE proposes to lease portions of the Mound Plant to commercial enterprises. This Environmental Impact statement has a finding of no significant impact in reference to such action

  17. Hauterivian shallow marine calcareous biogenic mounds: S.E. Spain

    OpenAIRE

    Arias, Consuelo; Masse, Jean Pierre; Vilas Minondo, Lorenzo

    1995-01-01

    Hauterivian biogenic deposits from the Prebetic northern margin near Caudete (Albacete Province, southeastern Spain) are represented by low domed bodies, less than 10 m thick, surrounded by bioclastic sediments and capped by siliciclastics. They consist of a coral, stromatoporoid and microbial framework with cavities filled by mud, rapidly lithified. Intermound bioclastics, derived from the mound organic community, reflect high energy conditions and shallow water settings. Mound g...

  18. Environmental assessment for commercialization of the Mound Plant

    Energy Technology Data Exchange (ETDEWEB)

    1994-10-26

    In November 1993 US DOE decided to phase out operations at the Mound Plant in Miamisburg, Ohio, with the goal of releasing the site for commercial use. The broad concept is to transform the plant into an advanced manufacturing center with the main focus on commercializing products and other technology. DOE proposes to lease portions of the Mound Plant to commercial enterprises. This Environmental Impact statement has a finding of no significant impact in reference to such action.

  19. Formation and Control of Self-Sealing High Permeability Groundwater Mounds in Impermeable Sediment: Implications for SUDS and Sustainable Pressure Mound Management

    OpenAIRE

    David D. J. Antia

    2009-01-01

    A groundwater mound (or pressure mound) is defined as a volume of fluid dominated by viscous flow contained within a sediment volume where the dominant fluid flow is by Knudsen Diffusion. High permeability self-sealing groundwater mounds can be created as part of a sustainable urban drainage scheme (SUDS) using infiltration devices. This study considers how they form, and models their expansion and growth as a function of infiltration device recharge. The mounds grow through lateral macropore...

  20. Food preferences and mound-building behaviour of the mound-building mice Mus spicilegus

    Science.gov (United States)

    Hölzl, Michaela; Krištofík, Ján; Darolová, Alžbeta; Hoi, Herbert

    2011-10-01

    Optimal foraging strategies and food choice are influenced by various factors, e.g. availability, size and caloric content of the food type and predation risk. However, food choice criteria may change when food is not eaten immediately but has to be carried to a storage site for later use. For example, handling time in terms of harvesting and transport time should be optimized, particularly when the risk of predation is high. Thus, it is not clear whether food selected by hoarding animals reflects their food preference due to intrinsic features of the food type, e.g. size, caloric or lipid content, or whether the food type selected is a compromise that also considers the handling time required for harvesting and transport. We investigate this question in relation to food hoarding behaviour in mound-building mice. In autumn, mound-building mice Mus spicilegus collect seeds and other plant material and cover it with soil. Such above-ground storage is quite unusual for rodents. Here, we investigated whether there is a relationship between the seed species preferred as building materials and those preferred for food. We conducted a seed preference test using three most collected weed species for mound building. Controlling factors like food availability or predation risk, mice prefer Setaria spp. as food, although Amaranthus spp. and Chenopodium spp. were preferentially harvested and stored. By including the availability of the three species, our experimental results were confirmed, namely, a clear preference for Setaria spp. Also, handling time and seed size revealed to influence plant choice.

  1. Controls on mound formation and effects of fluid ascent on the gas hydrate system of mound structures offshore Costa Rica

    Science.gov (United States)

    Planert, L.; Klaeschen, D.; Berndt, C.; Hensen, C.; Brueckmann, W.

    2010-12-01

    Our analysis of 2D MCS seismic data from the Middle America margin provides an insight into the buildup and formation mechanisms of mound structures and the effects of fluid ascent on the gas hydrate system observed on the continental slope offshore Costa Rica. Our targets, Mounds 11&12, are the sites of IODP drilling proposal 633-Full2, which aims to enhance the general understanding of complex forearc dewatering processes of the erosive subduction system off Costa Rica. Major sites of dewatering planned for drilling are mounds, related to mud diapirism/volcanism and precipitation of authigenic carbonates, and large-scale slides related to the subduction of seamounts. Geochemical analysis of methane hydrate and chloride anomalies as well as heat flow modeling of the mounds indicate deeply sourced fluids discharged by clay dehydration at the decollement. Hence, the hydrogeological system at this margin appears to be dominated by the fracture porosity of faults which extend through the overriding plate and provide the paths for fluids liberated by early dehydration reactions from the plate boundary. In order to test the hypothesis of deeply sourced and fault-controlled dewatering sites and to better understand the interactions between gas hydrate formation and dissociation with the fluid ascent from the deep sources, new pre-site survey seismic profiles were acquired using the 36-gun, four-string linear gun array of R/V Marcus Langseth, and a 240 channel streamer with 3000 m of active length. The seismic lines were prestack depth migrated, in which the velocity model is iteratively improved using depth focusing analysis and residual moveout correction on common image point gathers. Improvement of the deep imaging involved multiple attenuation and detailed velocity analysis of the lower sedimentary portions and beneath the basement down to the plate boundary. Our results reveal an upward bending of the bottom simulating reflection (BSR) directly beneath the mounds

  2. Diagenetic Variations between Upper Cretaceous Outcrop and Deeply Buried Reservoir Chalks of the North Sea Area

    DEFF Research Database (Denmark)

    Hjuler, Morten Leth; Fabricius, Ida Lykke

    2007-01-01

    -particle connections and less altered particle shapes. The non-carbonate mineralogy of outcrop chalks is dominated by quartz, occasionally opal-CT and clinoptilolite, and the clay mineral smectite. In offshore chalks quartz still dominates, opal-CT has recrystallized into submicron-size quartz crystals and smectite...

  3. Current oil and gas production from North American Upper Cretaceous Chalks

    Energy Technology Data Exchange (ETDEWEB)

    Scholle, P.A.

    1977-01-01

    Production of oil and natural gas from North American chalks has increased significantly during the past five years. Chalk reservoirs have been discovered in the Gulf Coast in the Austin Group, Saratoga and Annona Chalks, Ozan Formation, Selma Group, Monroe gas rock, (an informal unit of Navarro age), and other Upper Cretaceous units. In the Western Interior, production has been obtained from the Cretaceous Niobrara and Greenhorn Formations. Significant discoveries of natural gas and gas condensate also have been made in the Upper Cretaceous Wyandot Formation on the Scotian Shelf of eastern Canada. All North American chalk units share a similar depositional and diagenetic history. The diagenetic history of a chalk is critical in determining its reservoir potential. All chalk has a stable composition (low-Mg calcite) and very high primary porosity. With subsequent burial, mechanical and chemical (solution-transfer) compaction can reduce or completely eliminate pore space. The degree of loss of primary porosity in chalk sections is normally a direct function of the maximum depth to which it has been buried. Pore-water chemistry, pore-fluid pressures, and tectonic stresses also influence rates of cementation. Oil or gas reservoirs of North American chalk fall into three main groups: 1. Areas with thin overburden and significant primary porosity retention. 2. Areas with thicker overburden but considerable fracturing. 3. Areas with thick overburden in which marine pore fluids have been retained.

  4. Dynamic up-scaling of relative permeability in chalk

    Energy Technology Data Exchange (ETDEWEB)

    Frykman, P.; Lindgaard, H.F.

    1997-12-31

    This paper describes how fine-scale geo-statistic reservoir models can be utilised for the up-scaling of two-phase flow properties, including both relative permeability and capillary pressure function. The procedure is applied to a North Sea chalk carbonate reservoir example, which is a high-porosity/low-permeability reservoir type. The study focuses on waterflooding as the main recovery scheme and for the given flow regime in the reservoir. The main purpose of the paper is to demonstrate the use of dynamic multi-step up-scaling methods in the preparation of detailed geological information for full field reservoir simulation studies. (au) EFP-96. 39 refs.

  5. Mortality among long-term Chalk River employees

    International Nuclear Information System (INIS)

    Mortality among Chalk River Nuclear Laboratory (CRNL) employees who died during employment or after retirement has been updated to 1985 December 31. Data in tabular form are presented for overall mortality for male and female employees, for the participants in the clean-up for the NRX and NRU reactor accidents and for a group of CRNL staff with lifetime accumulative doses in excess of 0.2 Sv. Data are also presented on the different types of cancer causing death among male employees. No statistically significant increases in cancer deaths were found in any of the groups analyzed. 25 refs

  6. Recent developments in waste characterization at Chalk River Nuclear Laboratories

    International Nuclear Information System (INIS)

    The waste characterization program (WCP) at Chalk River Nuclear Laboratories (CRNL) was initiated in 1982 to determine the physical, chemical and radiological properties of wastes intended for disposal in IRUS (Intrusion Resistant Underground Structure), a belowground vault to be constructed at CRNL. During the last year, work on the WCP has centered on determining the radionuclide inventories in candidate wastes for IRUS by gamma-ray monitoring and destructive radiochemical analysis. This paper presents the technical problems associated with monitoring various waste forms (geometry considerations, shielding problems, operating environment, etc.) and also presents details of the destructive radiochemical analysis program

  7. Advanced waterflooding in chalk reservoirs: Understanding of underlying mechanisms

    DEFF Research Database (Denmark)

    Zahid, Adeel; Sandersen, Sara Bülow; Stenby, Erling Halfdan;

    2011-01-01

    pressure. We have also observed formation of a microemulsion phase between brine and oil with the increase in sulfate ion concentration at high temperature and pressure. In addition, sulfate ions can reduce interfacial tension (IFT) between oil and water. We propose that the decrease in viscosity and...... formation of a microemulsion phase could be the possible reasons for the observed increase in oil recovery with sulfate ions at high temperature in chalk reservoirs besides the mechanism of the rock wettability alteration, which has been reported in most previous studies....

  8. Origin of channel systems in the Upper Cretaceous chalk group of the Paris Basin

    DEFF Research Database (Denmark)

    Esmerode, E. V.; Surlyk, Finn

    2009-01-01

    presence of at least two distinct intra-chalk discordant reflections: a Top Santonian and a Mid-Campanian reflection. These reflections are in places associated with up to 120-m-deep channel-like structures trending preferentially N-S and NW-SE. The Mid-Campanian reflection is also sporadically associated......The Upper Cretaceous Chalk Group of the Anglo-Paris Basin is known to show wedging beds and channel-like features which disrupt the quietly deposited pelagic chalk that covered most of NW Europe in the Late Cretaceous. Two-D reflection seismic data from the Brie region, SE of Paris, show the...... collapse of the Cenozoic succession over the channel-like features as a result of intra-chalk dissolution. Both reflections correlate with indurated chalk layers and hardgrounds, and represent real unconformities. The Mid-Campanian reflection is furthermore associated with a stratigraphic hiatus. A...

  9. Improved Oil Recovery in Chalk. Spontaneous Imbibition affected by Wettability, Rock Framework and Interfacial Tension

    Energy Technology Data Exchange (ETDEWEB)

    Milter, J.

    1996-12-31

    The author of this doctoral thesis aims to improve the oil recovery from fractured chalk reservoirs, i.e., maximize the area of swept zones and their displacement efficiencies. In order to identify an improved oil recovery method in chalk, it is necessary to study wettability of calcium carbonate and spontaneous imbibition potential. The thesis contains an investigation of thin films and wettability of single calcite surfaces. The results of thin film experiments are used to evaluate spontaneous imbibition experiments in different chalk types. The chalk types were described detailed enough to permit considering the influence of texture, pore size and pore throat size distributions, pore geometry, and surface roughness on wettability and spontaneous imbibition. Finally, impacts of interfacial tension by adding anionic and cationic surfactants to the imbibing water phase are studied at different wettabilities of a well known chalk material. 232 refs., 97 figs., 13 tabs.

  10. Steady State Perched Groundwater Mounds on Thick Sublayers

    Science.gov (United States)

    Brock, Richard R.

    1982-04-01

    Perched mounds that develop beneath a strip recharge basin are considered using the potential theory for a saturated flow. The mounds are assumed to develop upon an aquitard or sublayer whose thickness is large enough so that the vertical velocity at the base of the mound does not vary with distance from the centerline of the basin. A finite difference technique was used to solve the potential theory, and 20 mound profiles were determined for K/KL = 10, 50, 100, 500 and R/K = 0.2, 0.35, 0.50, 0.65, 0.80. K/KL is the ratio of the permeabilities, and R is the recharge rate. These profiles are compared to those based on the approximate Dupuit-Forchheimer (DF) theory, and a criterion for the range of validity of the DF theory for predicting the maximum mount thickness H0 is derived. It is found that for a sufficiently large value of K/KL, which depends on R/K and the desired accuracy, the DF theory is adequate. For smaller values of K/KL the potential theory must be used. Equipotential lines and velocity distributions are presented for a typical case where the potential and DF mound profiles are quite different.

  11. Geochemical criteria for reservoir quality variations in chalk from the North Sea

    International Nuclear Information System (INIS)

    The influence of chalk geochemistry on petrophysical parameters determining porosity and permeability is investigated. The central well TWB-8 and eastern marginal well E-lx of the North Sea Tyra gas field were chosen. Drill core sections of Upper Maastrichtian and Danian chalk were selected. Chemical data on chalk samples were gathered by using X-ray fluorescence and instrumental neutron activation. Geochemical data are compared with the well-logging results. Geophysical logging suggests that there is reduced porosity in the Danian reservoir units LDP and UDT in both wells. The chalk drill core samples from the section with reduced porosity also show a lower Ca content. A high Si content is observed in these samples and a number of trace elements in chalk show a similar distribution with depth. Reservoir porosity may be estimated from the Si content of chalk. Chalk permeability may also be elements Al, Fe and Sc show the same trends as that for Si. Diagenetic changes in chalk also include clay minerals. The gas zone in TWB-8 is characterized by low contents of Na and Cl, i.e. lower water saturation is indicated. Low concentrations of rare earths in all chalk samples show a shale-normalized pattern that is characteristic of marine sediments laid down under oxic conditions. Some changes that occur with depth in the Ce anomaly may indicate a slight change in the depositional environment. The content of manganese continuously decreases with depth, from Danian (about 2000 ppm) to Maastrichtian strata (less than 200 ppm). In this respect, no other chemical element in chalk correlates with Mn. There is no indication as to which mineral or mineral phase one is likely to find in the element. (AB) 14 tabs., 49 ills., 147 refs

  12. Louth Crater: Evolution of a layered water ice mound

    CERN Document Server

    Brown, Adrian J; Tornabene, Livio L; Roush, Ted L

    2014-01-01

    We report on observations made of the ~36km diameter crater, Louth, in the north polar region of Mars (at 70{\\deg}N, 103.2{\\deg}E). High-resolution imagery from the instruments on the Mars Reconnaissance Orbiter (MRO) spacecraft has been used to map a 15km diameter water ice deposit in the center of the crater. The water ice mound has surface features that include roughened ice textures and layering similar to that found in the North Polar Layered Deposits. Features we interpret as sastrugi and sand dunes show consistent wind patterns within Louth over recent time. CRISM spectra of the ice mound were modeled to derive quantitative estimates of water ice and contaminant abundance, and associated ice grain size information. These morphologic and spectral results are used to propose a stratigraphy for this deposit and adjoining sand dunes. Our results suggest the edge of the water ice mound is currently in retreat.

  13. Solute transport in the unsaturated zone of the Chalk

    International Nuclear Information System (INIS)

    Groundwater is a major source of public supply in England and Wales, where it meets about 30% of the demand. In some areas, particularly south-east England, it is the major source. Much concern has been expressed in recent years about the pollution of groundwater resources by nitrates, and the Water Research Centre has undertaken an extensive programme of drilling and sampling to determine the reason for the rise in nitrate levels and to assess future trends. To assist with the interpretation of field data, mechanisms of water and solute movement through the unsaturated zone have been investigated, and the Chalk, our major aquifer, has received particular attention. The dating of groundwater by tritium measurements has led to considerable speculation regarding flow processes in the Chalk, and the additional information gained from the nitrates investigations has led to the formulation of a flow model in which water and its solutes move at very different velocities. It has been deduced that in the unsaturated zone water moves downwards through the fissure system at about 0.7 m/d, while any solutes carried from the land surface move downwards at about 1 m/a. Laboratory experiments have yielded evidence in support of this hypothesis, though further research is needed before a comprehensive model of the flow mechanism can be established. A similar flow mechanism is expected to be operative in many other aquifers, and has important implications for groundwater pollution trends. (author)

  14. Environmental survey preliminary report, Mound Plant, Miamisburg, Ohio

    Energy Technology Data Exchange (ETDEWEB)

    1987-03-01

    This report presents the preliminary findings from the first phase of the Environmental Survey of the United States Department of Energy (DOE) Mound Plant, conducted August 18 through 29, 1986. The objective of the Survey is to identify environmental problems and areas of environmental risk associated with the Mound Plant. The Survey covers all environmental media and all areas of environmental regulation. It is being performed in accordance with the DOE Environmental Survey Manual. The on-site phase of the Survey involves the review of existing site environmental data, observations of the operations carried on at the Mound Plant, and interviews with site personnel. The Survey found no environmental problems at the Mound Plant that represent an immediate threat to human life. The environmental problems identified at the Mound Plant by the Survey confirm that the site is confronted with a number of environmental problems which are by and large a legacy from past practices at a time when environmental problems were less well understood. Theses problems vary in terms of their magnitude and risk, as described in this report. Although the sampling and analysis performed by the Mound Plant Survey will assist in further identifying environmental problems at the site, a complete understanding of the significance of some of the environmental problems identified requires a level of study and characterization that is beyond the scope of the Survey. Actions currently under way or planned at the site, particularly the Phase II activities of the Comprehensive Environmental Analysis and Response Program (CEARP) as developed and implemented by the Albuquerque Operations Office, will contribute toward meeting this requirement. 85 refs., 24 figs., 20 tabs.

  15. Native American Calendric Orientation at Town Creek Indian Mound

    Science.gov (United States)

    Tiede, V. R.

    2005-12-01

    Evidence is presented for a newly discovered set of interior solar alignments - the equinox and summer solstice meridian transits - at a prehistoric Native American structure in the Southeast United States. Because North Carolina's Town Creek Indian Mound is the only Mississippian temple-mound accurately reconstructed from overhead photo-mosaics, the site is uniquely suited for applying the techniques of astro-archaeology (G. S. Hawkins 1983). Implications of the new findings for interpreting Muskogean ethnographic literature as well as future archaeoastronomical research at other Southeastern sites (e.g., Ocmulgee National Monument Earth Lodge, Georgia) are discussed.

  16. Innovative rubble mound breakwaters for overtopping wave energy conversion

    DEFF Research Database (Denmark)

    Vicinanza, Diego; Contestabile, Pasquale; Nørgaard, Jørgen Quvang Harck;

    2014-01-01

    This paper intends contributing to the development of an economically and environmentally sustainable coastal infrastructure, which combines rubble mound breakwaters with Wave Energy Converters (WEC). The energy is produced by collecting wave overtopping in a front reservoir, which is returned to...... experiments. The formulae are provided with the aim to be of direct use to engineers in the preliminary design of a first prototype of combined breakwater and wave energy converter.......This paper intends contributing to the development of an economically and environmentally sustainable coastal infrastructure, which combines rubble mound breakwaters with Wave Energy Converters (WEC). The energy is produced by collecting wave overtopping in a front reservoir, which is returned to...

  17. The Use of Gabbro Rock Armour in Rubble Mound Structures

    DEFF Research Database (Denmark)

    Beck, J. Blow; Burcharth, H. F.; Danielsen, S. W.;

    2000-01-01

    offer. In order to exploit the advantages of Gabbro, Franzefoss Bruk, Norway; Havnecon Consulting Aps and the Aalborg University, Denmark have entered a co-operation on the development of a Gabbro rubble mound breakwater. This paper describes the development of the project and explains the savings...

  18. Stable isotope sales: Mound customer and shipment summaries, FY 1982

    International Nuclear Information System (INIS)

    A listing is given of Mound's sales of stable isotopes of noble gases, carbon, oxygen, nitrogen, chlorine, and sulfur for Fiscal Year 1982. Purchasers are listed alphabetically and are divided into domestic and foreign groups. A cross-reference index by location is included for domestic customers. Cross-reference listings by isotope purchased are included for all customers

  19. Stable isotope sales: Mound customer and shipment summaries, FY 1984

    International Nuclear Information System (INIS)

    A listing is given of Mound's sales of stable isotopes of noble gases, deuterium, carbon, oxygen, nitrogen, chlorine, bromine, and sulfur for Fiscal Year 1984. Purchasers are listed alphabetically and are divided into domestic and foreign groups. A cross-reference index by location and a cross-reference listing by isotope purchased are included for all customers

  20. Stable isotopes sales: Mound customer and shipment summaries, FY 1985

    International Nuclear Information System (INIS)

    A listing is given of Mound's sales of stable isotopes of noble gases, deuterium, carbon, oxygen, nitrogen, chlorine, bromine, and sulfur for fiscal year 1985. Purchasers are listed alphabetically and are divided into domestic and foreign groups. A cross-reference index by location is included for domestic and foreign customers. Cross-reference listings by isotope purchased are included for all customers

  1. Avalanche Statistics of Driven Granular Slides in a Miniature Mound

    CERN Document Server

    Juanico, D E; Batac, R; Monterola, C

    2008-01-01

    We examine avalanche statistics of rain- and vibration-driven granular slides in miniature soil mounds using experimental and numerical approaches. A crossover from power-law to non power-law avalanche-size statistics is demonstrated as a generic driving rate $\

  2. Design And Construction Of Mounds For Breakwaters And Coastal Protection

    DEFF Research Database (Denmark)

    Burcharth, Hans F.; Barends, F.B.J.; Brebner, A.; Bretschneider, C.; Vasco Costa, F.; Funke, E.R.; van Garderen, A.; Günbak, A.; Houmb, O.G.; Johanneson, P.; Koutitas, C.; Kramer, A.; Larras, J.; Mansard, E.P.D.; Maquet, J.F.; Mesta, M.A.; Noble, S.; Rye, H.; Sackinger, W.; Sawaragi, T.; Smith, A.W.S.; Vellinga, P.; Viggoson, G.; Weggel, C.R.

    Design and construction of mound breakwaters has during the last 5 to 10 years entered a new era. The major reason for that is the realization of problems encountered as it became necessary to erect port structures on more exposed shores and in deeper waters. As a consequence of that the P...

  3. Displacement of Monolithic Rubble-Mound Breakwater Crown-Walls

    DEFF Research Database (Denmark)

    Nørgaard, Jørgen Harck; Andersen, Lars Vabbersgaard; Andersen, Thomas Lykke;

    2012-01-01

    studies on caisson breakwaters, but correction terms are suggested in the present paper to obtain almost equal measured and estimated displacements. This is of great practical importance since many existing rubble-mound crown-walls are subjected to increasing wave loads due to rising sea water level from...

  4. Numerical evaluation of stability methods for rubble mound breakwater toes

    NARCIS (Netherlands)

    Verpoorten, S.P.K.; Ockeloen, W.J.; Verhagen, H.J.

    2015-01-01

    Since 1977 dedicated studies are made to the stability of rubble mound break-water toes under wave attack. A large number of stability methods is available, but prediction accuracy is low and validity ranges are too small for use in prac-tice. In this research the decoupled model approach is used to

  5. Neutron activation analysis of chert artifacts from a Hopewell mound

    International Nuclear Information System (INIS)

    Six artifacts from a Hopewell mound located near Mt. Vernon, Indiana, and 21 geologic specimens from three different chert sources in the Ohio River Valley were analyzed by instrumental neutron activation analysis. Principal components analysis and posterior classification of the artifacts on the basis of Mahalanobis distance calculated probabilities were used to determine the most probable source for each of the artifacts. (author)

  6. Performance of the Chalk River 36Cl AMS system

    International Nuclear Information System (INIS)

    The MP Tandem Injector of the Chalk River TASCC (Tandem Accelerator Superconducting Cyclotron) Facility is being used for 36Cl determinations in studies relating to hydrology and low and high level nuclear waste management. In addition to the accelerator, the computer controlled system comprises a multiple-sample, medium-current ion source, a high resolution injector, a low resolution velocity filter, a gas filled magnet and a Bragg-type particle detection/identification system. Accuracies of 5--10% have been achieved with good suppression of 36S and background levels as low as 5x10-1536Cl/Cl. Following a brief overview of the system, detailed results are presented for the performance of the gas-filled magnet and particle detector as well as for sources of background including ion source memory effects

  7. Advanced fuel cycle development at Chalk River Laboratories

    International Nuclear Information System (INIS)

    Chalk River Laboratories (CRL) has a mandate from the Canadian government to develop nuclear technologies that support generation of clean, safe energy. This includes the development of advanced nuclear fuel technologies to ensure sustainable energy sources for Canadians. The Fuel Development Branch leads CRL's development of advanced nuclear-reactor fuels. CRL capabilities include fuel fabrication development, irradiation testing, post-irradiation examination (PIE), materials characterization and code development (modeling). This paper provides an overview of these capabilities and describes recent development activities that support fuel-cycle flexibility in heavy-water reactors. This includes a review of irradiation testing and PIE for mixed-oxide, thoria, high-burnup UO2 and low-void reactivity fuels and burnable neutron absorbers. Fabrication development, material characterizations and modeling associated with these tests are also described. (author)

  8. Experience at Chalk River with a cw electron accelerator

    International Nuclear Information System (INIS)

    For several years a group at Chalk River has been studying the behaviour of structures operated in the cw mode under heavy beam loading. Three side-coupled structures, modelled on the LAMPF design, have been built and tests up to 50% beam loading have been performed on two of them. Control systems have been developed to regulate the disturbances arising from high average power in a multi-tank accelerator and procedures worked out to handle beam currents up to 20 mA at 4 MeV. A pancake-coupled structure has been designed for high power operation and results of low power tests on an aluminum model are presented. Tests at high power with a 50 mA electron beam are planned. (author)

  9. A parameter identifiability study of two chalk tracer tests

    Directory of Open Access Journals (Sweden)

    S. A. Mathias

    2006-08-01

    Full Text Available As with most fractured rock formations, Chalk is highly heterogeneous. Therefore, meaningful estimates of model parameters must be obtained at a scale comparable with the process of concern. These are frequently obtained by calibrating an appropriate model to observed concentration-time data from radially convergent tracer tests (RCTT. Arguably, an appropriate model should consider radially convergent dispersion (RCD and Fickian matrix diffusion. Such a model requires the estimation of at least four parameters. A question arises as to whether or not this level of model complexity is supported by the information contained within the calibration data. Generally modellers have not answered this question due to the calibration techniques employed. A dual-porosity model with RCD was calibrated to two tracer test datasets from different UK Chalk aquifers. A multivariate sensitivity analysis, which assumed only a priori upper and lower bounds for each model parameter, was undertaken. Rather than looking at measures of uncertainty, the shape of the multivariate objective function surface was used to determine whether a parameter was identifiable. Non-identifiable parameters were then removed and the procedure was repeated until all remaining parameters were identifiable.

    It was found that the single fracture model (SFM (which ignores mechanical dispersion obtained the best mass recovery, excellent model performance and best parameter identifiability in both the tests studied. However, there was no objective evidence suggesting that mechanical dispersion was negligible. Moreover, the SFM (with just two parameters was found to be good at approximating the Single Fracture Dispersion Model SFDM (with three parameters when different, and potentially erroneous parameters, were used. Overall, this study emphasises the importance of adequate temporal sampling of breakthrough curve data prior to peak concentrations, to ensure adequate characterisation of

  10. Diversity of fungi from the mound nests of Formica ulkei and adjacent non-nest soils.

    Science.gov (United States)

    Duff, Lyndon B; Urichuk, Theresa M; Hodgins, Lisa N; Young, Jocelyn R; Untereiner, Wendy A

    2016-07-01

    Culture-based methods were employed to recover 3929 isolates of fungi from soils collected in May and July 2014 from mound nests of Formica ulkei and adjacent non-nest sites. The abundance, diversity, and richness of species from nest mounds exceeded those of non-mound soils, particularly in July. Communities of fungi from mounds were more similar to those from mounds than non-mounds; this was also the case for non-mound soils with the exception of one non-mound site in July. Species of Aspergillus, Paecilomyces, and Penicillium were dominant in nest soils and represented up to 81.8% of the taxa recovered. Members of the genus Aspergillus accounted for the majority of Trichocomaceae from nests and were represented almost exclusively by Aspergillus navahoensis and Aspergillus pseudodeflectus. Dominant fungi from non-mound sites included Cladosporium cladosporioides, Geomyces pannorum, and species of Acremonium, Fusarium, Penicillium, and Phoma. Although mound nests were warmer than adjacent soils, the dominance of xerotolerant Aspergillus in soils from mounds and the isolation of the majority of Trichocomaceae at 25 and 35 °C suggests that both temperature and water availability may be determinants of fungal community structure in nests of F. ulkei. PMID:27192606

  11. Are termite mounds biofilters for methane? - Challenges and new approaches to quantify methane oxidation in termite mounds

    Science.gov (United States)

    Nauer, Philipp A.; Hutley, Lindsay B.; Bristow, Mila; Arndt, Stefan K.

    2015-04-01

    Methane emissions from termites contribute around 3% to global methane in the atmosphere, although the total source estimate for termites is the most uncertain among all sources. In tropical regions, the relative source contribution of termites can be far higher due to the high biomass and relative importance of termites in plant decomposition. Past research focused on net emission measurements and their variability, but little is known about underlying processes governing these emissions. In particular, microbial oxidation of methane (MOX) within termite mounds has rarely been investigated. In well-studied ecosystems featuring an oxic matrix above an anoxic methane-producing habitat (e.g. landfills or sediments), the fraction of oxidized methane (fox) can reach up to 90% of gross production. However, conventional mass-balance approaches to apportion production and consumption processes can be challenging to apply in the complex-structured and almost inaccessible environment of a termite mound. In effect, all field-based data on termite-mound MOX is based on one study that measured isotopic shifts in produced and emitted methane. In this study a closed-system isotope fractionation model was applied and estimated fox ranged from 10% to almost 100%. However, it is shown here that by applying an open-system isotope-pool model, the measured isotopic shifts can also be explained by physical transport of methane alone. Different field-based methods to quantify MOX in termite mounds are proposed which do not rely on assumptions of physical gas transport. A simple approach is the use of specific inhibitors for MOX, e.g. difluoromethane (CH2F2), combined with chamber-based flux measurements before and after their application. Data is presented on the suitability of different inhibitors and first results of their application in the field. Alternatively, gas-tracer methods allow the quantification of methane oxidation and reaction kinetics without knowledge of physical gas

  12. Biot Critical Frequency Applied as Common Friction Factor for Chalk with Different Pore Fluids and Temperatures

    DEFF Research Database (Denmark)

    Andreassen, Katrine Alling; Fabricius, Ida Lykke

    Injection of water into chalk hydrocarbon reservoirs has lead to mechanical yield and failure. Laboratory experiments on chalk samples correspondingly show that the mechanical properties of porous chalk depend on pore fluid and temperature. Water has a significant softening effect on elastic...... we propose that the fluid effect on mechanical properties of highly porous chalk may be the result of liquid‐solid friction. Applying a different strain or stress rate is influencing the rock strength and needs to be included. The resulting function is shown to relate to the material dependent and...... rate independent b-factor used when describing the time dependent mechanical properties of soft rock or soils. As a consequence it is then possible to further characterize the material constant from the porosity and permeability of the rock as well as from pore fluid density and viscosity which is...

  13. Hydro-chemistry of paleontology of depression of Tajikistan in Late chalk period

    International Nuclear Information System (INIS)

    In this chapter authors made conclusion that on formation of clayey layers of upper chalk did influence following factors: shallow sea basin and its relatively small dimensions, climate aridity, relatively nearness nutrition areas, frequent change sea transgressions its recessions

  14. IODP Expedition 307 Drills Cold-Water Coral Mound Along the Irish Continental Margin

    Directory of Open Access Journals (Sweden)

    Trevor Williams

    2006-03-01

    Full Text Available Introduction Over the past decade, oceanographic and geophysical surveys along the slope of the Porcupine Seabight off the southwestern continental margin of Ireland have identified upwards of a thousand enigmatic mound-like structures (Figs. 1 and 2. The mounds of the Porcupine Seabight rise from the seafl oor in water depths of 600–900 m and formimpressive conical bodies several kilometers wide and up to 200 m high. Although a few mounds such as Thérèse Mound and Galway Mound are covered by a thriving thicket of coldwater corals, most mound tops and fl anks are covered by dead coral rubble or are entirely buried by sediment (De Mol et al., 2002; Fig. 2, Beyer et al., 2003. Lophelia pertusa (Fig.3 and Madrepora oculata are the most prominent cold-water corals growing without photosynthetic symbionts. The widespread discovery of large and numerous coral-bearing banks and the association of these corals with the mounds have generated signifi cant interest as to the composition, origin and development of these mound structures.Challenger Mound, in the Belgica mound province, has an elongated shape oriented along a north-northeast to south-southwest axis and ispartially buried under Pleistocene drift sediments. In high-resolution seismic profiles the mounds appear to root on an erosion surface (van Rooij et al., 2003. During IODP Expedition307 the Challenger Mound in the Porcupine Seabight was drilled with the goal of unveiling the origin and depositional processes withinthese intriguing sedimentary structures. Challenger Mound, unlike its near neighbors the Thérèse and Galway mounds, has little to no livecoral coverage and, therefore, was chosen as the main target for drilling activities, so that no living ecosystem would be disturbed.

  15. The role of alluvial valley deposits in groundwater–surface water exchange in a Chalk river

    OpenAIRE

    Abesser, Corinna; Shand, Paul; Gooddy, Daren; Peach, Denis

    2008-01-01

    To understand the processes of surface water–groundwater exchange in Chalk catchments, a detailed hydrogeochemical study was carried out in the Lambourn catchment in southeast England. Monthly monitoring of river flow and groundwater levels and water chemistry has highlighted a large degree of heterogeneity at the river-corridor scale. The data suggest an irregular connection between the river, the alluvial deposits, and the Chalk aquifer at the study site. The groundwaters in the alluvial gr...

  16. Change of Static and Dynamic Elastic Properties due to CO² Injection in North Sea Chalk

    OpenAIRE

    Alam, Mohammad Monzurul; Hjuler, M.L.; Christensen, H.F.; Fabricius, Ida Lykke

    2012-01-01

    Reservoir modeling and monitoring uses dynamic data for predicting and determining static changes. Dynamic data are achieved from the propagation velocity of elastic waves in rock while static data are obtained from the mechanical deformation. Reservoir simulation and monitoring are particularly importantin enhanced oil recovery by CO2 injection (CO2-EOR) in chalk as, chalk reservoirs are vulnerable to compaction under changed stress and pore fluid. From South Arne field, North Sea, we used E...

  17. Investigated Miscible CO2 Flooding for Enhancing Oil Recovery in Wettability Altered Chalk and Sandstone Rocks

    OpenAIRE

    Tabrizy, Vahid Alipour

    2012-01-01

    The thesis addresses oil recovery by miscible CO2 flooding from modified sandstone and chalk rocks. Calcite mineral surface is modified with stearic acid (SA) and asphaltene, and the silicate mineral surfaces are modified with N,N-dimethyldodecylamine (NN-DMDA) and asphaltene. The stability of adsorbed polar components in presence of SO4 2- and Mg2 + ions is also investigated. Recovery from sandstone cores is consistently lower than that from chalk cores saturated with...

  18. Persistent and emerging micro-organic contaminants in Chalk groundwater of England and France

    International Nuclear Information System (INIS)

    The Chalk aquifer of Northern Europe is an internationally important source of drinking water and sustains baseflow for surface water ecosystems. The areal distribution of microorganic (MO) contaminants, particularly non-regulated emerging MOs, in this aquifer is poorly understood. This study presents results from a reconnaissance survey of MOs in Chalk groundwater, including pharmaceuticals, personal care products and pesticides and their transformation products, conducted across the major Chalk aquifers of England and France. Data from a total of 345 sites collected during 2011 were included in this study to provide a representative baseline assessment of MO occurrence in groundwater. A suite of 42 MOs were analysed for at each site including industrial compounds (n = 16), pesticides (n = 14) and pharmaceuticals, personal care and lifestyle products (n = 12). Occurrence data is evaluated in relation to land use, aquifer exposure, well depth and depth to groundwater to provide an understanding of vulnerable groundwater settings. - Highlights: • Broad range of microorganics detected in Chalk groundwater in England and France. • Plasticisers, pesticides, BPA and THM detected at the highest concentrations. • Pesticides higher in outcrop Chalk, caffeine and BPA at concealed sites. • Occurrences show some relationship to land use, borehole depth and water level. - Broad screening reveals for the first time the extent of emerging microorganic pollution in Chalk groundwater sources across England and France

  19. A novel representation of chalk hydrology in a land surface model

    Science.gov (United States)

    Rahman, Mostaquimur; Rosolem, Rafael

    2016-04-01

    Unconfined chalk aquifers contain a significant portion of water in the United Kingdom. In order to optimize the assessment and management practices of water resources in the region, modelling and monitoring of soil moisture in the unsaturated zone of the chalk aquifers are of utmost importance. However, efficient simulation of soil moisture in such aquifers is difficult mainly due to the fractured nature of chalk, which creates high-velocity preferential flow paths in the unsaturated zone. In this study, the Joint UK Land Environment Simulator (JULES) is applied on a study area encompassing the Kennet catchment in Southern England. The fluxes and states of the coupled water and energy cycles are simulated for 10 consecutive years (2001-2010). We hypothesize that explicit representation for the soil-chalk layers and the inclusion of preferential flow in the fractured chalk aquifers improves the reproduction of the hydrological processes in JULES. In order to test this hypothesis, we propose a new parametrization for preferential flow in JULES. This parametrization explicitly describes the flow of water in soil matrices and preferential flow paths using a simplified approach which can be beneficial for large-scale hydrometeorological applications. We also define the overlaying soil properties obtained from the Harmonized World Soil Database (HWSD) in the model. Our simulation results are compared across spatial scales with measured soil moisture and river discharge, indicating the importance of accounting for the physical properties of the medium while simulating hydrological processes in the chalk aquifers.

  20. Hydrodynamics and cold-water coral facies distribution related to recent sedimentary processes at Galway Mound west of Ireland

    OpenAIRE

    Dorschel, B.; D. Hebbeln; Foubert, A.; White, M.; Wheeler, A.J.

    2007-01-01

    Cold-water coral carbonate mound development is the result of complex and interactive hydrographical, biological and geological processes that can result in morphostructures several hundred meters high. The case study presented here investigates one of these large mounds – Galway Mound – in the eastern Porcupine Seabight to build an understanding of mound forming processes and the driving factors. For the first time, bottom current data have been recorded at six locations over a mound thus al...

  1. Growth and form of the mound in Gale Crater, Mars: Slope-wind enhanced erosion and transport

    OpenAIRE

    Kite, Edwin S.; Lewis, Kevin W.; Lamb, Michael P.

    2012-01-01

    Ancient sediments provide archives of climate and habitability on Mars. Gale Crater, the landing site for the Mars Science Laboratory (MSL), hosts a 5 km high sedimentary mound. Hypotheses for mound formation include evaporitic, lacustrine, fluviodeltaic, and aeolian processes, but the origin and original extent of Gale's mound is unknown. Here we show new measurements of sedimentary strata within the mound that indicate ~3 degree outward dips oriented radially away from the mound center, inc...

  2. Trace elemental analysis of school chalk using energy dispersive X-ray florescence spectroscopy (ED-XRF)

    Science.gov (United States)

    Maruthi, Y. A.; Das, N. Lakshmana; Ramprasad, S.; Ram, S. S.; Sudarshan, M.

    2015-08-01

    The present studies focus the quantitative analysis of elements in school chalk to ensure the safety of its use. The elements like Calcium (Ca), Aluminum (Al), Iron (Fe), Silicon (Si) and Chromium (Cr) were analyzed from settled chalk dust samples collected from five classrooms (CD-1) and also from another set of unused chalk samples collected from local market (CD-2) using Energy Dispersive X-Ray florescence(ED-XRF) spectroscopy. Presence of these elements in significant concentrations in school chalk confirmed that, it is an irritant and occupational hazard. It is suggested to use protective equipments like filtered mask for mouth, nose and chalk holders. This study also suggested using the advanced mode of techniques like Digital boards, marker boards and power point presentations to mitigate the occupational hazard for classroom chalk

  3. Trace elemental analysis of school chalk using energy dispersive X-ray florescence spectroscopy (ED-XRF)

    International Nuclear Information System (INIS)

    The present studies focus the quantitative analysis of elements in school chalk to ensure the safety of its use. The elements like Calcium (Ca), Aluminum (Al), Iron (Fe), Silicon (Si) and Chromium (Cr) were analyzed from settled chalk dust samples collected from five classrooms (CD-1) and also from another set of unused chalk samples collected from local market (CD-2) using Energy Dispersive X-Ray florescence(ED-XRF) spectroscopy. Presence of these elements in significant concentrations in school chalk confirmed that, it is an irritant and occupational hazard. It is suggested to use protective equipments like filtered mask for mouth, nose and chalk holders. This study also suggested using the advanced mode of techniques like Digital boards, marker boards and power point presentations to mitigate the occupational hazard for classroom chalk

  4. Trace elemental analysis of school chalk using energy dispersive X-ray florescence spectroscopy (ED-XRF)

    Energy Technology Data Exchange (ETDEWEB)

    Maruthi, Y. A., E-mail: ymjournal2014@gmail.com [Associate professor, Dept of Environmental Studies, GITAM Institute of Science, GITAM University, Visakhapatnam, A.P (India); Das, N. Lakshmana, E-mail: nldas9@gmail.com [Professor, Dept of Physics, GITAM Institute of Science, GITAM University, Visakhapatnam, A.P (India); Ramprasad, S., E-mail: ramprasadsurakala@gmail.com [Research Scholar, Dept of Environmental science, GITAM Institute of Science, GITAM University, Visakhapatnam, A.P (India); Ram, S. S., E-mail: tracebio@gmail.com [Research Scholar, Dept of Trace element research, UGC-DAE Consortium Centre, Kolkata centre India (India); Sudarshan, M., E-mail: sude@alpha.iuc.res.in [Scientist-F, Dept of Trace element research, UGC-DAE Consortium Centre, Kolkata centre India (India)

    2015-08-28

    The present studies focus the quantitative analysis of elements in school chalk to ensure the safety of its use. The elements like Calcium (Ca), Aluminum (Al), Iron (Fe), Silicon (Si) and Chromium (Cr) were analyzed from settled chalk dust samples collected from five classrooms (CD-1) and also from another set of unused chalk samples collected from local market (CD-2) using Energy Dispersive X-Ray florescence(ED-XRF) spectroscopy. Presence of these elements in significant concentrations in school chalk confirmed that, it is an irritant and occupational hazard. It is suggested to use protective equipments like filtered mask for mouth, nose and chalk holders. This study also suggested using the advanced mode of techniques like Digital boards, marker boards and power point presentations to mitigate the occupational hazard for classroom chalk.

  5. Non-dune eolian sand in Indian mounds

    Science.gov (United States)

    Tanner, William F.

    1980-02-01

    Indian mounds, near Careyville, Florida, about 2.0 m high, are located on hillsides and hilltops 10 to 20 m above the floodplain of the nearest river (Choctawhatchee). Each mound is composed largely of quartz sand, with a scattering of artefacts and stream pebbles (not in layers), but with no visible bedding. Probability plots showed 25 Gaussian distributions, 18 having the 'dune hump', three having the 'surf break' and nine being doubly-truncated or having other patterns of unknown or uncertain origin. The surf breaks probably were inherited from pre-Pleistocene marine terraces in the area. The pebbles and the sand were not introduced by the same agency. The sand probability plots, taken as a set, indicate an eolian origin. The rough symmetry of the mounds, and the lack of cross-bedding, argue against a migrating dune origin. On a variability plot (showing the variability of the means versus the variability of the standard deviations), one suite of samples fell clearly within the 'dune' number field, a second suite in the overlap area between 'dune' and 'beach', and a third suite, taken immediately adjacent to a creek bed, plotted in the overlap area between 'beach' and 'coastal plain stream'. The pebbles, of common Southern Appalachian types, are attributed to the activities of the inhabitants, perhaps children. The sand is thought to have been carried by the wind, perhaps from nearby river sand bars, or from areas burned either by lightning-set wildfires or as part of "slash-and-burn" agriculture. The mounds are thought to represent clearings (for huts), and hence good trapping devices for wind-borne sand.

  6. Benign familial disease with muscle mounding and rippling.

    OpenAIRE

    Burns, R. J.; Bretag, A H; Blumbergs, P C; Harbord, M G

    1994-01-01

    Four members of a family in three generations exhibited unusual clinical features of localised transient swelling of muscle induced by percussion (muscle mounding or myoedema) and were able, voluntarily, to induce rhythmic waves of contraction in certain muscles (muscle rippling or rolling). All had raised serum creatine kinase activity. Muscle biopsy in two members showed no specific abnormality. Experimental studies performed on excised intercostal muscle showed that abnormal "after-contrac...

  7. Fractal-Mound Growth of Pentacene Thin Films

    OpenAIRE

    Zorba, Serkan; Shapir, Yonathan; Gao, Yongli

    2006-01-01

    The growth mechanism of pentacene film formation on SiO2 substrate was investigated with a combination of atomic force microscopy measurements and numerical modeling. In addition to the diffusion-limited aggregation (DLA) that has already been shown to govern the growth of the ordered pentacene thin films, it is shown here for the first time that the Schwoebel barrier effect steps in and disrupts the desired epitaxial growth for the subsequent layers, leading to mound growth. The terraces of ...

  8. Are reefs and mud mounds really so different?

    Science.gov (United States)

    Wood, Rachel

    2001-12-01

    Although both 'ecologic reefs' and mud mounds are demonstrably rigid, framework reefs, they are still considered to be distinct in terms of their dominant processes of formation and preferred environmental settings. This distinction has rested largely upon the assumption that ecologic reefs are dominated by skeletal metazoans growing in shallow waters, in contrast to the complex autochthonous micrite-supported cavity systems that characterise deep-water mud mounds, now considered to represent either organomineralic deposits (where carbonate precipitation has taken place in association with nonliving organic substrates to form 'automicrite') or various types of microbialite (where carbonate forms as a direct result of the physiological activity or decay of benthic microorganisms). Yet, such autochthonous micrite is increasingly recognised as an important component of many ancient shallow ecologic reefs as well as some modern coral reefs, and indeed may contribute locally up to 80% of the reef rock. These observations raise doubts as to the validity of current fabric-based definitions used to distinguish between mud mounds and ecologic reefs. Whether the autochthonous micrite in mud mounds proves to be dominated by either automicrite or microbialite, both require particular environmental conditions for their formation. Automicrites form where surplus organic matter from metazoans has degraded to release quantities of acidic amino acids with a significant ability to bind Ca 2+ , and microbialite formation also often requires either unusual marine chemistries or ecological conditions. Such conditions might include changes in terrigenous influx, ground water seepage, local anoxia, and increases in the pH of interstitial reef waters or in nutrient concentration.

  9. Manipulation/Extraction of Adatom on a Mound: AG(111)

    International Nuclear Information System (INIS)

    We present results of an extensive study of the manipulation/extraction of an atom from a small Ag mound on Ag(111) using a Ag tip. Molecular dynamics (MD) and molecular static (MS) simulations were carried out using interaction potentials from the embedded atom method. In order to evaluate the manipulation capabilities of the tip, we first examine in detail the characteristics of the energy landscape in the absence of the tip. We find that the energy barrier for the extraction of the Ag atom, either through lateral (sliding downwards) or through vertical (climbing upwards) diffusion, to be about 0.3 eV. We show that the presence of the tip lowers the energy barrier for both lateral and vertical diffusion. We find that when the tip is above the edge of the mound (at a height of 2.43 A A from the Ag atom) the barrier for diffusion drops to 0.032 eV for lateral and 0.18 eV for vertical manipulation. We discuss the effect of the tip shape and geometry on the energetics, and present a detailed explanation of how the adatom is extracted from a mound in good agreement with experimental observations

  10. Impact of supercritical CO2 injection on petrophysical and rock mechanics properties of chalk: an experimental study on chalk from South Arne field, North Sea

    DEFF Research Database (Denmark)

    Alam, Mohammad Monzurul; Hjuler, Morten Leth; Christensen, Helle Foged;

    2011-01-01

    Changes in chalk due to EOR by injecting supercritical CO2 (CO2-EOR) can ideally be predicted by applying geophysical methods designed from laboratory-determined petrophysical and rock mechanics properties. A series of petrophysical and rock mechanics tests were performed on Ekofisk Formation and...

  11. Anthropogenic radionuclides in Ottawa River sediment near Chalk River Laboratories

    International Nuclear Information System (INIS)

    The Ottawa River has received nuclear reactor effluent from Chalk River Laboratories (CRL) for more than 60 years, including releases from a NRX accident in 1952. Recent interest in the potential impact of these historical releases and the possible need for remediation of a small region immediately downstream from the release point has led to comprehensive studies to assess risk to people and wildlife. In this paper, the results of an extensive survey of gamma-emitting anthropogenic radionuclides in Ottawa River sediment in the vicinity of CRL are presented. Anthropogenic radionuclides detected in Ottawa River sediment include 60Co, 94Nb, 137Cs, 152Eu, 154Eu, 155Eu and 241Am. Concentrations of all anthropogenic radionuclides decline rapidly with distance downstream of the process outfall, reaching stable concentrations about 2 km downstream. All of these radionuclides are found at some sites within 2 km upstream of the process outfall suggesting limited upstream transport and sedimentation. Comparison of anthropogenic radionuclides with several representative primordial radionuclides shows that with the exception of sites at the process outfall and within 2 km downstream of the process outfall, primordial radionuclide concentrations greatly exceed CRL derived anthropogenic radionuclide concentrations. Thus, over 60 years of radionuclide releases from operations at CRL have had little impact on radionuclide concentrations in Ottawa River sediment, except at a few sites immediately adjacent to the process outfall. (author)

  12. Effects of the restoration mortar on chalk stone buildings

    Science.gov (United States)

    Ion, R. M.; Teodorescu, S.; Ştirbescu, R. M.; Dulamă, I. D.; Şuică-Bunghez, I. R.; Bucurică, I. A.; Fierăscu, R. C.; Fierscu, I.; Ion, M. L.

    2016-06-01

    The monument buildings as components of cultural heritage are exposed to degradation of surfaces and chemical and mechanical degradation, often associated to soiling and irreversible deterioration of the building. In many conservative and restorative works, a cement-based mortar was used without knowing all the adverse effects of this material on the building. This paper deals with the study of the effects of natural cement used in restorative works in the particular case of the Basarabi-Murfatlar Churches Ensemble. Cement-based materials exposed to sulfate present in the chalk stone - gypsum (CaSO4.2H2O), can induce signs of deterioration, due to ettringite ([Ca3Al (OH)612H2O]2(SO4)32H2O) or thaumasite (Ca3[Si(OH)612H2O](CO3)SO4) formation. These phases contribute to strain within the material, inducing expansion, strength loss, spalling and severe degradation. Several combined techniques (XRD, EDXRF, ICP-AES, SEM, EDS, sulphates content, FT-IR and Raman analysis were carried out to put into evidence the effects of them on the building walls.

  13. Molten fuel moderator interaction program at Chalk River Laboratories

    Energy Technology Data Exchange (ETDEWEB)

    Nitheanandan, T.; Kyle, G.; O' Connor, R.; Sanderson, D.B. [Atomic Energy of Canada Limited, Chalk River, Ontario (Canada)

    2006-12-15

    The Canadian nuclear power generation industry, represented by the CANDU Owners Group (COG), has been funding an experimental program at Chalk River Laboratories (CRL) to study the interaction between molten material ejected from a fuel channel and the moderator. These experiments were designed to address one of the very low probability postulated accident events considered for CANDU Pressurized Heavy Water Reactors. The reactor consists of an array of horizontal fuel channels that contain the UO{sub 2}, nuclear fuel and high-temperature, high-pressure heavy water coolant. Under severely restricted flow blockage conditions, approaching 100% reduction of the flow area, postulated in a fuel channel, the temperature excursion could result in fuel melting, consequential failure of the fuel channel, and ejection of the molten fuel at high pressures into the heavy water moderator at near atmospheric pressure. In preparation for these tests, a chemical mixture called a thermite, that could produce a simulated molten fuel when ignited, was developed in partnership with Argonne National Laboratory (USA). Following this thermite development, two base-case reference tests were completed. The two base-case reference tests, with no molten material present, were performed in the Molten-Fuel Moderator-Interaction (MFMI) facility at CRL. Following the base-case reference tests, a high-pressure melt ejection test using prototypical corium was conducted. The objectives of this paper are to provide an overview of the MFMI program and present the results obtained from thermite development, base-case and melt ejection experiments. (author)

  14. Molten fuel moderator interaction program at Chalk River Laboratories

    International Nuclear Information System (INIS)

    The Canadian nuclear power generation industry, represented by the CANDU Owners Group (COG), has been funding an experimental program at Chalk River Laboratories (CRL) to study the interaction between molten material ejected from a fuel channel and the moderator. These experiments were designed to address one of the very low probability postulated accident events considered for CANDU Pressurized Heavy Water Reactors. The reactor consists of an array of horizontal fuel channels that contain the UO2, nuclear fuel and high-temperature, high-pressure heavy water coolant. Under severely restricted flow blockage conditions, approaching 100% reduction of the flow area, postulated in a fuel channel, the temperature excursion could result in fuel melting, consequential failure of the fuel channel, and ejection of the molten fuel at high pressures into the heavy water moderator at near atmospheric pressure. In preparation for these tests, a chemical mixture called a thermite, that could produce a simulated molten fuel when ignited, was developed in partnership with Argonne National Laboratory (USA). Following this thermite development, two base-case reference tests were completed. The two base-case reference tests, with no molten material present, were performed in the Molten-Fuel Moderator-Interaction (MFMI) facility at CRL. Following the base-case reference tests, a high-pressure melt ejection test using prototypical corium was conducted. The objectives of this paper are to provide an overview of the MFMI program and present the results obtained from thermite development, base-case and melt ejection experiments. (author)

  15. The Pen Duick Escarpment off Morocco: A promising biogeochemically active carbonate mound laboratory (MiCROSYSTEMS)

    OpenAIRE

    Templer, S. P.; Maignien, L.; McKenzie, J.A.; Henriet, J.P.; Vasconcelos, C.

    2007-01-01

    Carbonate mud mounds, found in marine environments from shallow- to deep-water settings, span from Proterozoic to recent times. During the past decades, numerous active venting fields were discovered in deep marine environments and became a subject of extensive study for marine scientists. Mound building seems to be a fundamental but still enigmatic strategy for life. Various arguments suggest that microorganisms are playing a major role in the reef development, mound formation and biodiversi...

  16. Variability of soil properties within large termite mounds in South Katanga, DRC - origins and applications.

    Science.gov (United States)

    Erens, Hans; Bazirake Mujinya, Basile; Boeckx, Pascal; Baert, Geert; Mees, Florias; Van Ranst, Eric

    2014-05-01

    The miombo woodlands of South Katanga (D.R. Congo) are characterized by a high spatial density of large conic termite mounds built by Macrotermes falciger (3 to 5 ha-1). With an average height of 5.05 m and diameter of 14.88 m, these are some of the largest biogenic structures in the world. The mound material is known to differ considerably from the surrounding Ferralsols. Specifically, mound material exhibits a finer texture, higher CEC and exchangeable basic cation content, lower organic matter content, and an accumulation of phosphorous, nitrate and secondary carbonates. However, as demonstrated by the present study, these soil properties are far from uniform within the volume of the mound. The termites' nesting and foraging activity, combined with pedogenic processes over extended periods of time, generates a wide range of physical, chemical, and biological conditions in different parts of the mound. Analysis of samples taken along a cross-section of a large active mound allowed generating contour plots, thus visualizing the variability of soil properties within the mound. The central columns of three other mounds were sampled to confirm apparent trends. The contour plots show that the mounds comprise four functional zones: (i) the active nest, found at the top; (ii) an accumulation zone , in more central parts of the mound; (iii) a dense inactive zone, surrounding the accumulation zone and consisting of accumulated erosion products from former active nests; and (iv) the outer mantle, characterized by intense varied biological activity and by a well-developed soil structure. Intermittent leaching plays a key role in explaining these patterns. Using radiocarbon dating, we found that some of these mounds are at least 2000 years old. Their current size and shape is likely the result of successive stages of erosion and rebuilding, in the course of alternating periods of mound abandonment and recolonization. Over time, termite foraging combined with limited leaching

  17. SPATIAL VARIABILITY AND VITALITY OF EPIGEOUS TERMITE MOUNDS IN PASTURES OF MATO GROSSO DO SUL, BRAZIL

    Directory of Open Access Journals (Sweden)

    Sandra Santana Lima

    2015-02-01

    Full Text Available Epigeous termite mounds are frequently observed in pasture areas, but the processes regulating their population dynamics are poorly known. This study evaluated epigeous termite mounds in cultivated grasslands used as pastures, assessing their spatial distribution by means of geostatistics and evaluating their vitality. The study was conducted in the Cerrado biome in the municipality of Rio Brilhante, Mato Grosso do Sul, Brazil. In two pasture areas (Pasture 1 and Pasture 2, epigeous mounds (nests were georeferenced and analyzed for height, circumference and vitality (inhabited or not. The area occupied by the mounds was calculated and termite specimens were collected for taxonomic identification. The spatial distribution pattern of the mounds was analyzed with geostatistical procedures. In both pasture areas, all epigeous mounds were built by the same species, Cornitermes cumulans. The mean number of mounds per hectare was 68 in Pasture 1 and 127 in Pasture 2, representing 0.4 and 1 % of the entire area, respectively. A large majority of the mounds were active (vitality, 91 % in Pasture 1 and 84 % in Pasture 2. A “pure nugget effect” was observed in the semivariograms of height and nest circumference in both pastures reflecting randomized spatial distribution and confirming that the distribution of termite mounds in pastures had a non-standard distribution.

  18. Fractures and Rock Mechanics, Phase 1

    DEFF Research Database (Denmark)

    Havmøller, Ole; Krogsbøll, Anette

    1997-01-01

    The main objectives of the project are to combine geological description of fractures, chalk types and rock mechanical properties, and to investigate whether the chosen outcrops can be used as analogues to reservoir chalks. Five chalk types, representing two outcrop localities: Stevns and...

  19. Climate change impacts on Chalk groundwater resources in eastern England

    Science.gov (United States)

    Hiscock, K.; Sandhu, C.; Conway, D.

    2004-05-01

    Climate change is expected to cause higher summer temperatures, less summer rainfall and more evapotranspiration in eastern England during this century, thereby increasing the stress on the underlying Chalk aquifer. This study, funded by the Tyndall Centre for Climate Change Research, investigates how future scenarios of climate change will influence groundwater availability in this major regional aquifer in terms of groundwater levels and river baseflow quantities. To examine these scenarios, a two-layer regional groundwater model was constructed with Visual MODFLOW for the Wensum and Nar river catchments in northern East Anglia. The UKCIP02 database for the `2020s High' and `2050s High and Low' gas emission scenarios was used to define selected future climate conditions. Historic recharge (1981-90) to the model is calculated separately, using the FAO approved method incorporating dominant land cover (crop type) and soil moisture content. Future recharge to the model is estimated by perturbing historic rainfall and evapotranspiration with scaling factors relating average monthly simulated future and baseline (1961-90) meteorological parameters. The model results predict an overall decrease in recharge for all three scenarios, with a maximum decrease in October of 62% and 91%, for both the 2020s High and 2050s High scenarios, respectively. The future drier summer periods are likely to cause a delay in the onset of recharge by a month, due to a corresponding overall increase in the evapotranspiration for all scenarios. Faced with these conditions, water companies are planning for less reliable groundwater resources within an overall risk-based approach to managing future water supply and demand.

  20. The Canadian HT dispersion experiment at Chalk River - June 1987

    International Nuclear Information System (INIS)

    A trace amount (3.54TBq) of tritiated hydrogen, HT, was released to the atmosphere at an experimental field at the Chalk River Laboratories on June 10, 1987 in order to study the environmental behaviour of HT. Experimental results showed that direct oxidation of HT in the atmosphere was small and confirmed that surface soils convert atmospheric HT to HTO. The HTO formed in the soil was slowly emitted to the atmosphere giving rise to the small concentrations of HTO observed in the air during the release and for a period of several weeks thereafter. HTO/HT ratios in air during the plume passage increased with downwind distance from a value of order 10-5 at 5 m to values between 4 x 10-4 and 8 x 10-4 at 400 m. Deposition velocities for HT to soil were in the range 10-4 to 10-3 m s-1. Rates of reemission of tritium from the soil to the atmosphere were typically a few percent per hour within one to two days of the release, declining to less than one percent per hour over two weeks. Tritium deposition velocities and reemission rates determined for soils in the field agreed well with laboratory measurements on field samples, and were similar in range to previous exposure chamber experiments carried out in various countries in the laboratory and field under non-winter conditions. Direct uptake of HT by vegetation was not detected. The time history of vegetation tritium was consistent with uptake of HTO from soil and atmosphere and with incorporation of tritium into the organically bound form through photosynthesis. The experiment provides an extensive data base suitable for the detailed evaluation of mathematical models describing the short range dispersion of tritium. The results indicate that the short range dose from a release of HT would be much less than the dose from an equivalent release of HTO

  1. Contaminated groundwater characterization at the Chalk River Laboratories, Ontario, Canada

    Energy Technology Data Exchange (ETDEWEB)

    Schilk, A.J.; Robertson, D.E.; Thomas, C.W.; Lepel, E.A. [Pacific Northwest National Lab., Richland, WA (United States); Champ, D.R.; Killey, R.W.D.; Young, J.L.; Cooper, E.L. [Chalk River Labs., Chalk River, Ontario (Canada)

    1993-03-01

    The licensing requirements for the disposal of low-level radioactive waste (10 CFR 61) specify the performance objectives and technical requisites for federal and commercial land disposal facilities, the ultimate goal of which is to contain the buried wastes so that the general population is adequately protected from harmful exposure to any released radioactive materials. A major concern in the operation of existing and projected waste disposal sites is subterranean radionuclide transport by saturated or unsaturated flow, which could lead to the contamination of groundwater systems as well as uptake by the surrounding biosphere, thereby directly exposing the general public to such materials. Radionuclide transport in groundwater has been observed at numerous commercial and federal waste disposal sites [including several locations within the waste management area of Chalk River Laboratories (CRL)], yet the physico-chemical processes that lead to such migration are still not completely understood. In an attempt to assist in the characterization of these processes, an intensive study was initiated at CRL to identify and quantify the mobile radionuclide species originating from three separate disposal sites: (a) the Chemical Pit, which has received aqueous wastes containing various radioisotopes, acids, alkalis, complexing agents and salts since 1956, (b) the Reactor Pit, which has received low-level aqueous wastes from a reactor rod storage bay since 1956, and (c) the Waste Management Area C, a thirty-year-old series of trenches that contains contaminated solid wastes from CRL and various regional medical facilities. Water samples were drawn downgradient from each of the above sites and passed through a series of filters and ion-exchange resins to retain any particulate and dissolved or colloidal radionuclide species, which were subsequently identified and quantified via radiochemical separations and gamma spectroscopy. These groundwaters were also analyzed for anions

  2. Waste management activities at Chalk River Nuclear Laboratories

    International Nuclear Information System (INIS)

    Low-level radioactive waste-management operations at the Chalk River Nuclear Laboratories (CRNL) of Atomic Energy of Canada Limited began in 1946 and currently include waste processing and interim storage in engineered facilities built in unsaturated sandy overburden. In addition, an R and D program has been underway for about ten years directed at preparations for a transition from the current storage mode to one of permanent disposal for the management of about 5000 m3/a (as-generated volume) of low- and intermediate-level solid wastes generated on the CRNL site or shipped there from the nuclear industry, radioisotope producers and users across Canada. The first phase of the disposal program was the development and demonstration of selected waste processing methods for the volume reduction and immobilization of solid and liquid low-level wastes. This phase is now nearing completion with the construction, commissioning and operation of the CRNL Waste Treatment Centre. The Centre consists of a controlled-air incinerator for combustible solid and liquid wastes, ultrafiltration, reverse-osmosis, and evaporator systems for aqueous wastes, and wipe-film and ribbon-blender bituminizers for immobilizing the ash and waste concentrates. The second phase of the program is directed at further advances in waste characterization and processing, and at the development of two disposal concepts potentially suitable for the local geological situation - Intrusion-resistant shallow land burial and excavated rock cavities at shallow depth. Also included is the preparation of safety-assessment methodologies for the two concepts. The intent is to carry one or both disposal concepts through the constriction and operation of prototype facilities at CRNL as a qualified component of an evolving integrated disposal strategy for the current inventory and future arisings of wastes to be managed

  3. Full-waveform Inversion of Crosshole GPR Data Collected in Strongly Heterogeneous Chalk

    DEFF Research Database (Denmark)

    Keskinen, Johanna; Zibar, Majken Caroline Looms; Nielsen, Lars;

    2015-01-01

    in an old chalk quarry in Eastern Denmark. Based on core data (including plug samples and televiewer logging data) collected in our four ~15-m-deep boreholes and results from previous related studies, it is apparent that the studied chalk is strongly heterogeneous. The upper ~7 m consist of variable coarse...... all the information contained in the data and is able to provide significantly improved images. Here, we apply full-waveform inversion to crosshole GPR data to image strong heterogeneity of the chalk related to changes in lithology and porosity. We have collected a crosshole tomography dataset...... address the importance of (i) adequate starting models, both in terms of the dielectric permittivity and the electrical conductivity, (ii) the estimation of the source wavelet, (iii) and the effects of data sampling density when imaging this rock type. Moreover, we discuss the resolution of the bedding...

  4. Characteristics and origin of Earth-mounds on the Eastern Snake River Plain, Idaho

    International Nuclear Information System (INIS)

    Earth-mounds are common features on the Eastern Snake River Plain, Idaho. The mounds are typically round or oval in plan view, <0.5 m in height, and from 8 to 14 m in diameter. They are found on flat and sloped surfaces, and appear less frequently in lowland areas. The mounds have formed on deposits of multiple sedimentary environments. Those studied included alluvial gravel terraces along the Big Lost River (late Pleistocene/early Holocene age), alluvial fan segments on the flanks of the Lost River Range (Bull Lake and Pinedale age equivalents), and loess/slopewash sediments overlying basalt flows. Backhoe trenches were dug to allow characterization of stratigraphy and soil development. Each mound has features unique to the depositional and pedogenic history of the site; however, there are common elements to all mounds that are linked to the history of mound formation. Each mound has a open-quotes floorclose quotes of a sediment or basement rock of significantly different hydraulic conductivity than the overlying sediment. These paleosurfaces are overlain by finer-grained sediments, typically loess or flood-overbank deposits. Mounds formed in environments where a sufficient thickness of fine-grained sediment held pore water in a system open to the migration to a freezing front. Heaving of the sediment occurred by the growth of ice lenses. Mound formation occurred at the end of the Late Pleistocene or early in the Holocene, and was followed by pedogenesis. Soils in the mounds were subsequently altered by bioturbation, buried by eolian deposition, and eroded by slopewash runoff. These secondary processes played a significant role in maintaining or increasing the mound/intermound relief

  5. Morphology and spatial patterns of Macrotermes mounds in the SE Katanga, D.R. Congo

    Science.gov (United States)

    Bazirake Mujinya, Basile; Mees, Florias; Erens, Hans; Baert, Geert; Van Ranst, Eric

    2015-04-01

    The spatial distribution patterns and morphological characteristics of Macrotermes falciger mounds were investigated in the Lubumbashi area, D.R. Congo. Examination of the spatial patterns of M. falciger mounds on high resolution satellite images reveals a mean areal number density of 2.9 ± 0.4 mounds ha-1. The high relative number of inactive mounds in the region, along with their regular distribution pattern, suggests that current termite mound occurrences are largely palaeostructures. Mound positions in the habitat are consistent with intraspecific competition rather than soil and substrate characteristics as controlling factor. Detailed morphological description of five deep termite-mound profiles (~7 m height/depth) shows that carbonate pedofeatures are present in all studied profiles, in contrast to the control soils. They mainly occur in the form of soft powdery masses, nodules and coatings on ped faces, all clearly pedogenic. Carbonate coatings occur mainly between 1 m above the soil surface and 1 m below that level in all mound profiles. Carbonate nodules do show a different distribution pattern at each site. Furthermore, when the studied profiles are considered to represent a toposequence, the stone layer occurs at greater depth in topographically low areas compared to crest and slope positions, which is mainly conditioned by erosion. The clay content of epigeal mounds increases from the summit to the toe slope, which can be largely related to differences in parent material. The Mn-Fe oxide concentrations occurring in all studied termite mound profiles reflect a seasonally high perched water table beneath the mound, which is more pronounced at the lower slope positions.

  6. Plant Mounds as Concentration and Stabilization Agents for Actinide Soil Contaminants in Nevada

    Energy Technology Data Exchange (ETDEWEB)

    D.S. Shafer; J. Gommes

    2009-02-03

    Plant mounds or blow-sand mounds are accumulations of soil particles and plant debris around the base of shrubs and are common features in deserts in the southwestern United States. An important factor in their formation is that shrubs create surface roughness that causes wind-suspended particles to be deposited and resist further suspension. Shrub mounds occur in some plant communities on the Nevada Test Site, the Nevada Test and Training Range (NTTR), and Tonopah Test Range (TTR), including areas of surface soil contamination from past nuclear testing. In the 1970s as part of early studies to understand properties of actinides in the environment, the Nevada Applied Ecology Group (NAEG) examined the accumulation of isotopes of Pu, 241Am, and U in plant mounds at safety experiment and storage-transportation test sites of nuclear devices. Although aerial concentrations of these contaminants were highest in the intershrub or desert pavement areas, the concentration in mounds were higher than in equal volumes of intershrub or desert pavement soil. The NAEG studies found the ratio of contaminant concentration of actinides in soil to be greater (1.6 to 2.0) in shrub mounds than in the surrounding areas of desert pavement. At Project 57 on the NTTR, 17 percent of the area was covered in mounds while at Clean Slate III on the TTR, 32 percent of the area was covered in mounds. If equivalent volumes of contaminated soil were compared between mounds and desert pavement areas at these sites, then the former might contain as much as 34 and 62 percent of the contaminant inventory, respectively. Not accounting for radionuclides associated with shrub mounds would cause the inventory of contaminants and potential exposure to be underestimated. In addition, preservation of shrub mounds could be important part of long-term stewardship if these sites are closed by fencing and posting with administrative controls.

  7. The treatment of low-level waste at Mound Laboratory

    International Nuclear Information System (INIS)

    The program at Mound Laboratory to handle low-level radioactive waste has two major objectives: 1) to design a volume reduction system for low-level combustible waste, both solid and liquid, and 2) to develop separation methods for removing radionuclides from liquid waste, both, low-level and intermediate-level. The result of the former effort is the Cyclone Incinerator which provides a volume reduction of >35:1. In meeting the latter objective, ultrafiltration has been demonstrated to be a feasible way of reducing the generation of secondary waste. Development of such techniques will significantly reduce waste management costs in the nuclear industry

  8. Biot Critical Frequency Applied to Description of Failure and Yield of Highly Porous Chalk with Different Pore Fluids

    DEFF Research Database (Denmark)

    Andreassen, Katrine Alling; Fabricius, Ida Lykke

    2010-01-01

    nature of dissolved salts have an effect.Water has a significant softening effect on elastic properties of chalk as calculated from wave data, and the softening increases with increasing critical frequency as defined by Biot. The critical frequency is the highest frequency where elastic wave propagation......Injection of water into chalk hydrocarbon reservoirs has led to mechanical yield and failure. Laboratory experiments on chalk samples correspondingly show that the mechanical properties of porous chalk depend on pore fluid and temperature. In case of water-saturated samples, the concentration and...... data include chalk samples that were tested at temperatures from 20 °C to 130 °C with the following pore fluids: fresh water, synthetic seawater, glycol, and oil of varying viscosity. The critical frequency is calculated for each experiment. For each specimen, we calculate the thickness to the slipping...

  9. Grain size distributions of chalk from image analysis of electron micrographs

    DEFF Research Database (Denmark)

    Røgen, Birte; Gommesen, Lars; Fabricius, Ida Lykke

    2001-01-01

    from image analysis due to rim effects inherent in backscatter images at high magnification. Thus, in order to obtain a consistent interpretation, we use total (He) porosity and insoluble residue as measured in the laboratory. We find that the volume density of larger grains (cross section larger than...... image analysis. The chalk is composed of a fine-grained matrix of nannofossils and predominantlycalcitic fossil debris with larger microfossil grains, but the chalk may also contain significant amounts of silica and siliciclastic clay. For image analysis, we used backscatter electron images of epoxy...

  10. Measuring and Modeling the Displacement of Connate Water in Chalk Core Plugs during Water Injection

    DEFF Research Database (Denmark)

    Korsbech, Uffe C C; Aage, Helle Karina; Andersen, Bertel Lohmann; Hedegaard, Kathrine; Springer, Niels

    2006-01-01

    The movement of connate water spiked with gamma emitting 22Na was studied during laboratory water flooding of oil saturated chalk from a North Sea oil reservoir. Using a one dimensional gamma monitoring technique is was observed that connate water is piled-up at the front of the injection water and...... forms a mixed water bank with almost 100% connate water in the front behind which a gradual transition to pure injection water occurs. This result underpins log interpretations from waterflooded chalk reservoirs. An ad hoc model was set up by use of the results, and the process was examined...

  11. Change of Static and Dynamic Elastic Properties due to CO² Injection in North Sea Chalk

    DEFF Research Database (Denmark)

    Alam, Mohammad Monzurul; Hjuler, M.L.; Christensen, H.F.;

    2012-01-01

    % non-carbonate. We studied difference in static and dynamic behavior. Furthermore, brine saturated data were compared with CO2 injected data to reveal the effect of supercritical CO2 injection in both static and dynamic elastic properties. We used strain gauges and LVDTs to measure static deformation....... We observed lower dynamic elastic modulus for chalk with higher non-carbonate content at porosities lower than 30%. In 30% porosity chalk, dynamic compressional and bulk modulus were found significantly higher than the static modulus. Static measurements with LVDT were found lowest. The effect of CO2...

  12. Plants in Your Ants: Using Ant Mounds to Test Basic Ecological Principles

    Science.gov (United States)

    Zettler, Jennifer A.; Collier, Alexander; Leidersdorf, Bil; Sanou, Missa Patrick

    2010-01-01

    Urban students often have limited access to field sites for ecological studies. Ubiquitous ants and their mounds can be used to study and test ecology-based questions. We describe how soil collected from ant mounds can be used to investigate how biotic factors (ants) can affect abiotic factors in the soil that can, in turn, influence plant growth.

  13. Dupuit-Forchheimer theories for the shape of groundwater recharge mounds

    Science.gov (United States)

    Brock, Richard R.

    1991-05-01

    The nonlinear Dupuit-Forchheimer theory and two linearized versions are considered as to their applicability for giving accurate results on recharge mound shapes beneath strip and square basins. Results on mound rises from the approximate theories are compared with those from the nonlinear theory to determine criteria for the use of the approximate theories.

  14. Formation and Control of Self-Sealing High Permeability Groundwater Mounds in Impermeable Sediment: Implications for SUDS and Sustainable Pressure Mound Management

    Directory of Open Access Journals (Sweden)

    David D. J. Antia

    2009-10-01

    Full Text Available A groundwater mound (or pressure mound is defined as a volume of fluid dominated by viscous flow contained within a sediment volume where the dominant fluid flow is by Knudsen Diffusion. High permeability self-sealing groundwater mounds can be created as part of a sustainable urban drainage scheme (SUDS using infiltration devices. This study considers how they form, and models their expansion and growth as a function of infiltration device recharge. The mounds grow through lateral macropore propagation within a Dupuit envelope. Excess pressure relief is through propagating vertical surge shafts. These surge shafts can, when they intersect the ground surface result, in high volume overland flow. The study considers that the creation of self-sealing groundwater mounds in matrix supported (clayey sediments (intrinsic permeability = 10–8 to 10–30 m3 m–2 s–1 Pa–1 is a low cost, sustainable method which can be used to dispose of large volumes of storm runoff (<20→2,000 m3/24 hr storm/infiltration device and raise groundwater levels. However, the inappropriate location of pressure mounds can result in repeated seepage and ephemeral spring formation associated with substantial volumes of uncontrolled overland flow. The flow rate and flood volume associated with each overland flow event may be substantially larger than the associated recharge to the pressure mound. In some instances, the volume discharged as overland flow in a few hours may exceed the total storm water recharge to the groundwater mound over the previous three weeks. Macropore modeling is used within the context of a pressure mound poro-elastic fluid expulsion model in order to analyze this phenomena and determine (i how this phenomena can be used to extract large volumes of stored filtered storm water (at high flow rates from within a self-sealing high permeability pressure mound and (ii how self-sealing pressure mounds (created using storm water infiltration can be used to

  15. Physiological and Biogeochemical Traits of Bleaching and Recovery in the Mounding Species of Coral Porites lobata: Implications for Resilience in Mounding Corals

    OpenAIRE

    Stephen J Levas; Andréa G Grottoli; Adam Hughes; Christopher L Osburn; Yohei Matsui

    2013-01-01

    Mounding corals survive bleaching events in greater numbers than branching corals. However, no study to date has determined the underlying physiological and biogeochemical trait(s) that are responsible for mounding coral holobiont resilience to bleaching. Furthermore, the potential of dissolved organic carbon (DOC) as a source of fixed carbon to bleached corals has never been determined. Here, Porites lobata corals were experimentally bleached for 23 days and then allowed to recover for 0, 1,...

  16. Behaviour and Ecological Impacts of Termites: Fecundity Investigations in Mounds

    Directory of Open Access Journals (Sweden)

    Wako Sutuma Edessa

    2015-03-01

    Full Text Available A radical study was conducted on the behaviour and ecological impacts of termites in Haru District of Western Oromia, Ethiopia. It was aimed at investigating the natural behaviour, fecundity in mounds, ecological impacts and recommending possible solutions to termite problems. Four mounds in different sites were vertically dug down to display the profile of the queen, soldiers, workers, number of laid eggs, nymphs and colonies of termites. On an average, termite queens of the study site may lay about 25 eggs per minute, 36, 000 eggs per day and 13, 140, 000 eggs annually. The fourth queen was unearthed to study the structure, size, number of ovaries and fecundity. It was examined that the death of a queen does not affect the colony, because four small queens are formed and one of them becomes the queen of queens and replaced the dead queen promptly. Accordingly, termites are found to be one of the most destructive agents of our ecosystems and their management requests careful and biological control methods. As a result, the negative effect of termites outweighs the positive effect of termites so that minimising the population size is important for human beings.

  17. Summary review of Mound Facility's experience in decontamination of concrete

    International Nuclear Information System (INIS)

    Most of the current concrete decontamination work at Mound Facility involves surfaces that are contaminated with plutonium-238. Approximately 60,000 sq. ft. of concrete floors will have to be decontaminated in Mound's current Decontamination and Decommissioning (D and D) Project. Although most of these surfaces are partially protected by a barrier (tile or paint), contaminated water and acid have penetrated these barriers. The technique for decontaminating these floors is desribed. The initial cleaning of the floor involes standard water and detergent. Acids are not used in cleaning as they tend to drive the contamination deeper into the concrete surface. Next, the floor tile is manually removed inside a temporary enclosure under negative and filtered ventilation. Finally, layers of contaminated concrete are mechanically removed inside the ventilated enclosure. The suspected depth and surface area of contamination determines the type of mechanical tool used. In summary, several generic methods of concrete decontamination can be utilized: chemical, such as water, detergent, acids, paint remover, strippable paints, etc.; rotary using sanders, grinders, scarifiers, etc.; impact such as pressure washers (hydrolasers), particle blasters, scabblers, needlers, spallers, paving and rock breakers, ram hoes, etc. The particular method used depends on several factors: surface and area involved; depth of contamination; cost and availability of equipment; usage safety and radiological control; and waste generated

  18. Rock physical aspects of CO{sub 2} injection in chalk

    Energy Technology Data Exchange (ETDEWEB)

    Alam, M.M.

    2011-04-15

    Impact of supercritical CO{sub 2} on the petrophysical and rock-mechanics properties of Ekofisk Formation and Tor Formation chalk from South Arne field, Danish North Sea, chalk was investigated. A series of laboratory experiments was performed on core material collected from the reservoir zone of the South Arne field in order to reveal the changes with respect to porosity, specific surface, pore stiffness, wettability, mineralogy and mechanical failure. In addition, a theoretical rock physical background was also established in order to be able to make sensible interpretation of laboratory data. Sound wave velocity was used as the central tool to study any change in petrophysical and rock mechanical properties. The main focus was to achieve a better understanding of effective stress coefficient (also known as Biot's coefficient); by means of which effective stress can be predicted more accurately. Independent theoretical studies were made on diagenesis, surface properties and stiffness of chalk and their relation with sonic velocity (or Biot's coefficient calculated from sonic velocity). The knowledge and experience from these studies was combined to achieve the main research objective of monitoring changes in hydrocarbon reservoirs in chalk due to CO{sub 2} injection. In order to understand the development of chalk from calcareous ooze and achieving pore stiffness, the diagenesis process of a sedimentary sequence from Kerguelen Plateau in the Indian Ocean was studied. The principal objective of the study was to explore how different porosity reduction mechanisms change the strength of these deep sea carbonate-rich sediments and how these mechanisms can be traced from the change in Biot's coefficient, alpha. In calcareous ooze, alpha was found close to one. Mechanical compaction reduces porosity, but only leads to a minor decrease in alpha. Recrystallization process renders particles smoother, but do not lead to reduction in alpha unless it gives

  19. On the influence of cold-water coral mound size on flow hydrodynamics, and vice versa

    Science.gov (United States)

    Cyr, Frédéric; Haren, Hans; Mienis, Furu; Duineveld, Gerard; Bourgault, Daniel

    2016-01-01

    Using a combination of in situ observations and idealistic 2-D nonhydrostatic numerical simulations, the relation between cold-water coral (CWC) mound size and hydrodynamics is explored for the Rockall Bank area in the North Atlantic Ocean. It is shown that currents generated by topographically trapped tidal waves in this area cause large isopycnal depressions resulting from an internal hydraulic control above CWC mounds. The oxygen concentration distribution is used as a tracer to visualize the flow behavior and the turbulent mixing above the mounds. By comparing two CWC mounds of different sizes and located close to each other, it is shown that the resulting mixing is highly dependent on the size of the mound. The effects of the hydraulic control for mixing, nutrient availability, and ecosystem functioning are also discussed.

  20. Annual environmental monitoring report: calender year 1977. [/sup 238/Pu, /sup 3/H, Mound Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Farmer, B.M.; Carfagno, D.G.

    1978-04-25

    The local environment surrounding Mound Facility was monitored for tritium and plutonium-238. The results are reported for calendar year 1977. The environmental parameters analyzed included air, water, foodstuffs, soil and silt. The average concentrations of plutonium-238 and tritium were within the applicable stringent standards for radioactive species adopted by the U.S. DOE. Mound Facility drinking water has been brought into compliance with the new EPA standard for tritium in community drinking water systems, and Mound has undertaken a program to achieve compliance for nine private wells adjacent to the Facility site. The program has partially achieved its objective by bringing Mound wells and some of the nine affected private wells in the vicinity of Mound Facility into compliance with the U.S. EPA standard and significantly reducing tritium concentration in the remaining wells. Data concerning nonradioactive species in air and water are also presented and compared to federal, state, and local standards, where applicable.

  1. The nature and origin of Mafic Mound in the South Pole-Aitken Basin

    Science.gov (United States)

    Moriarty, Daniel P.; Pieters, Carle M.

    2015-10-01

    "Mafic Mound" is a distinctive and enigmatic feature 75 km across and 1 km high near the center of the vast South Pole-Aitken Basin (SPA). Using several modern data sets, we characterize the composition, morphology, and gravity signature of the structure in order to assess its origin. Mafic Mound is found to exhibit a perched circular depression and a homogeneous high-Ca pyroxene-bearing composition. Several formation hypotheses based on known lunar processes are evaluated, including the possibilities that Mafic Mound represents (1) uplifted mantle, (2) SPA-derived impact melt, (3) a basalt-filled impact crater, or (4) a volcanic construct. Individually, these common processes cannot fully reproduce the properties of Mafic Mound. Instead, we propose a hybrid origin in which Mafic Mound is an edifice formed by magmatic processes induced by the formation and evolution of SPA. This form of nonmare volcanism has not previously been documented on the Moon.

  2. Hydrographic Conditions At The Carbonate Mound Locations In The NE Atlantic

    Science.gov (United States)

    van Weering, T.; de Hass, H.; White, M.; de Stigter, H.

    As part of the component 5th framework projects that form part of the OMARC clus- ter, hydrographic measurements have been made in the region of the deep water car- bonate mounds provinces of the NE Atlantic. These mounds are located at depths 600-1000m depth along the continental slopes of the Porcupine Sea Bight and Bank and the SE Rockall Bank. These regions correspond to the vertical and horizontal boundaries of the intermediate water masses that occupy the region, providing differ- ent hydrographic regimes between mound locations,. In addition there is a large vari- ability in temperature/salinity conditions and both characteristics have implications for the distribution of mound fauna. The deep water coral associated with carbonate mound structures coincide with strong benthic current activity and this is confirmed from benthic current measurements from landers and current meters at the SE Rockall and NW Porcupine Bank mound loca- tions. Near seabed currents are strong, with a typical mean speed of 20cm/s and a max- imum in excess of 50cm/s. At the SE Rockall Bank site, a mean SW along isobath flow is measured, whilst at the NW Porcupine mound location, a poleward slope current is measured. Bottom Ekman dynamics is apparent with a changes in near seabed verti- cal stratification related to changes to overlying slope current strength. Strong diurnal variability is found at the Rockall Bank site, providing strong cross-slope currents. The diurnal current forcing over both the Rockall and Porcupine Banks may result in enclosed circulation patterns over the banks and retention of organic material supplied to the mounds. In contrast, currents at the Hovland and Magellan mound sites in the northern Porcupine Sea Bight, where there are numerous buried mounds, are relatively low.

  3. COCARDE - a research platform for a new look to ancient mounds

    Science.gov (United States)

    Rüggeberg, Andres; Henriet, Jean-Pierre; Foubert, Anneleen; van Rooij, David; Samankassou, Elias; Dullo, Wolf-Christian; Spezzaferri, Silvia; Science Community, Cocarde

    2010-05-01

    Carbonate mounds are important contributors of life in different settings, from warm-water to cold-water environments, and throughout geological history. Research on modern carbonate mounds over the last years made a major contribution to our overall understanding of these particular sedimentary systems. By looking to the modern carbonate mound community, some fundamental questions could be addressed, until now not yet explored in fossil mound settings. The international network COCARDE (Cold-Water Carbonate Reservoir Systems in Deep Environment) is a platform for exploring new insights in cold- and warm-water carbonate mound research of recent and ancient mound systems (http://www.cocarde.eu). One aim of the COCARDE network is to bring scientific communities together, to study recent carbonate mounds in midslope environments in the present ocean, and to investigate fossil mounds spanning the whole Phanerozoic time. Scientific challenges on modern and ancient carbonate mound systems got already well defined during two dedicated workshops of the COCARDE network: 1) the ESF Magellan COCARDE Workshop in Fribourg, Switzerland, January 21-24, 2009, and 2) the ESF MiCROSYSTEMS - FWO COCARDE Flanders - ESF CHECREEF Workshop and Field Seminar, Oviedo, Spain, September 16-20, 2009. The wide spectrum of disciplines in geosciences and biology are summarized in the following five topics for the carbonate mound research: i) Palaeoenvironment; ii) The Microbial Filter; iii) Petrophysical Characterization; iv) Connectivity and Compartmentalization - the Fluid System; v) Advancing our Insight in Phanerozoic Reef Systems - the Slope Niche. One of the most important outcomes of these meetings was the identification of the need for combined research efforts on fossil and modern carbonate settings to provide the baseline reference standard for a better understanding of these exceptional systems and their potential as hydrocarbon reservoirs.

  4. ACE - an algebraic compiler and encoder for the Chalk River datatron computer

    International Nuclear Information System (INIS)

    ACE is a program written for the Chalk River Datatron (Burroughs 205) Computer to enable the machine to compile a program for solving a problem from instructions supplied by the user in a notation related much more closely to algebra than to the machine's own code. (author)

  5. Strength and Biot's coefficient for high-porosity oil- or water-saturated chalk

    DEFF Research Database (Denmark)

    Andreassen, Katrine Alling

    during hydrostatic loading. The hypothesis is that the Biot coefficient and the theory of poroelasticity may cover the fluid effect by including the increased fluid bulk modulus from oil to water. A high number of test results for both oil- and water-saturated high-porosity outcrop chalk show correlation...

  6. Ultrasonic velocities of North Sea chalk samples: influence of porosity, fluid content and texture

    DEFF Research Database (Denmark)

    Rogen, B.; Fabricius, Ida Lykke; Japsen, P.; Høier, Camilla Kruse; Mavko, G.; Pedersen, J.M.

    2005-01-01

    the South Arne Field than from the Dan Field for identical porosities. This difference may be due to textural differences between the chalk at the two locations because we observe that large grains (i.e. filled microfossils and fossil fragments) that occur more frequently in samples from the Dan Field...

  7. WIMS-CRNL: A user's manual for the Chalk River version of WIMS

    International Nuclear Information System (INIS)

    This report describes the preparation of the input for WIMS-CRNL, the Chalk River version of the WIMS lattice code. Also included are notes on the operation of the code, contents of the associated libraries, and the relation of WIMS-CRNL to other versions of the code

  8. Nuclear magnetic resonance and sound velocity measurements of chalk saturated with magnesium rich brine

    DEFF Research Database (Denmark)

    Katika, Konstantina; Alam, Mohammad Monzurul; Fabricius, Ida Lykke

    The use of low field Nuclear Magnetic Resonance (NMR) to determine petrophysical properties of reservoirs has proved to be a good technique. Together with sonic and electrical resistivity measurements, NMR can contribute to illustrate the changes on chalk elasticity due to different pore water...

  9. The surface reactivity of chalk (biogenic calcite) with hydrophilic and hydrophobic functional groups

    Science.gov (United States)

    Okhrimenko, D. V.; Dalby, K. N.; Skovbjerg, L. L.; Bovet, N.; Christensen, J. H.; Stipp, S. L. S.

    2014-03-01

    The surface properties of calcium carbonate minerals play an important role in a number of industrial and biological processes. Properties such as wettability and adsorption control liquid-solid interface behaviour and thus have a strong influence on processes such as biomineralisation, remediation of aquifers and oil recovery. We investigated how two model molecules of different polarity, namely water and ethanol, interact with reservoir and outcrop chalk samples and we compared their behaviour with that of pure, inorganically precipitated calcite. Thermodynamic quantities, such as the work of wetting, surface energy and isosteric adsorption enthalpy, were determined from vapour adsorption isotherms. The chalks were studied fresh and after extraction of organic residues that were originally present in these samples. The work of wetting correlates with the amount of organic matter present in the chalk samples but we observed a fundamental difference between the adsorption properties of chalk and pure, inorganically precipitated calcite toward the less polar, ethanol molecule. Further analysis of the chemical composition of the organic matter extracted from the chalk samples was made by gas chromatography (GC-MS). Monitoring surface composition by X-ray photoelectron spectroscopy (XPS) before and after extraction of the organic material, and with atomic force microscopy (AFM), showed that nanometer sized clay crystals observed on the chalk particle surfaces could be an important part of the reason for the differences. Removal of the extractable portion of the hydrocarbons liberates adsorption sites that have different wetting properties than the rest of the chalk and these have an energy distribution that is similar to clays. Thus, the results exemplify the complexity of biogenic calcite adsorption behaviour and demonstrate that chalk wetting in drinking water aquifers as well as oil reservoirs is controlled partly by the nanoparticles of clay that have grown on the

  10. Seismic stratigraphy and sedimentary architecture of the Chalk Group in south-west Denmark

    DEFF Research Database (Denmark)

    Larsen, Connie; Ineson, Jon; Boldreel, Lars Ole

    2014-01-01

    The article focuses on a study undertaken by the Chalk Group on the western onshore region of the Danish Basin in Eastern Denmark related on the seismic stratigraphy and sedimentary architecture of the region. The study is undertaken through subdividing the northern North German Basin and the south...

  11. SNG-log in borehole P7 in Faxe Chalk Quarry

    DEFF Research Database (Denmark)

    Korsbech, Uffe C C

    1996-01-01

    A spectral natural gamma-ray log in a 190 m borehole in Faxe chalk quarry confirms that Danish bryozoan and corallic limestones contain very low levels of natural radioactivity. Due to the low content of natural radioactivity it has been possible to observe the influence from cosmic radiation. The...

  12. Nuclear Magnetic Resonance and Elastic Wave Velocity of Chalk Saturated with Brines Containing Divalent Ions

    DEFF Research Database (Denmark)

    Katika, Konstantina; Alam, Mohammad Monzurul; Fabricius, Ida Lykke

    Nuclear magnetic resonance (NMR) has proven a good technique for measuring pore size distribution in reservoir rocks. The use of low field NMR together with sonic and electrical resistivity measurements, can contribute to illustrate the effect of adsorbing ions on chalk elasticity. NMR is useful...

  13. Nuclear magnetic resonance and sound velocity measurements of chalk saturated with magnesium rich brine

    DEFF Research Database (Denmark)

    Katika, Konstantina; Alam, Mohammad Monzurul; Fabricius, Ida Lykke

    2013-01-01

    The use of low field Nuclear Magnetic Resonance (NMR) to determine petrophysical properties of reservoirs has proved to be a good technique. Together with sonic and electrical resistivity measurements, NMR can contribute to illustrate the changes on chalk elasticity due to different pore water...

  14. Using Raman spectroscopic imaging for non-destructive analysis of filler distribution in chalk filled polypropylene

    DEFF Research Database (Denmark)

    Boros, Evelin; Porse, Peter Bak; Nielsen, Inga;

    2016-01-01

    A feasibility study on using Raman spectral imaging for visualization and analysis of filler distribution in chalk filled poly-propylene samples has been carried out. The spectral images were acquired using a Raman spectrometer with 785 nm light source.Eight injection-molded samples with...

  15. Measuring and Modeling the Displacement of Connate Water in Chalk Core Plugs during Water Injection

    DEFF Research Database (Denmark)

    Korsbech, Uffe C C; Aage, Helle Karina; Andersen, Bertel Lohmann;

    2006-01-01

    The movement of connate water spiked with gamma emitting 22Na was studied during laboratory water flooding of oil saturated chalk from a North Sea oil reservoir. Using a one dimensional gamma monitoring technique is was observed that connate water is piled-up at the front of the injection water a...

  16. How burial diagenesis of chalk sediments controls sonic velocity and porosity

    DEFF Research Database (Denmark)

    Fabricius, Ida Lykke

    2003-01-01

    , whereby IF increases and chalk forms. Rock mechanical tests show that when compaction requires more than in-situ stress, porosity reduction is arrested. During subsequent burial, crystals and pores grow in size as a consequence of the continuing recrystallization. ne lack of porosity loss during...

  17. Effective-stress-law behavior of Austin chalk rocks for deformation and fracture conductivity

    Energy Technology Data Exchange (ETDEWEB)

    Warpinski, N.R.; Teufel, L.W.

    1994-08-01

    Austin chalk core has been tested to determine the effective law for deformation of the matrix material and the stress-sensitive conductivity of the natural fractures. For deformation behavior, two samples provided data on the variations of the poroelastic parameter, {alpha}, for Austin chalk, giving values around 0.4. The effective-stress-law behavior of a Saratoga limestone sample was also measured for the purpose of obtaining a comparison with a somewhat more porous carbonate rock. {alpha} for this rock was found to be near 0.9. The low {alpha} for the Austin chalk suggests that stresses in the reservoir, or around the wellbore, will not change much with changes in pore pressure, as the contribution of the fluid pressure is small. Three natural fractures from the Austin chalk were tested, but two of the fractures were very tight and probably do not contribute much to production. The third sample was highly conductive and showed some stress sensitivity with a factor of three reduction in conductivity over a net stress increase of 3000 psi. Natural fractures also showed a propensity for permanent damage when net stressed exceeded about 3000 psi. This damage was irreversible and significantly affected conductivity. {alpha} was difficult to determine and most tests were inconclusive, although the results from one sample suggested that {alpha} was near unity.

  18. Investigation of spore forming bacterial flooding for enhanced oil recovery in a North Sea chalk Reservoir

    DEFF Research Database (Denmark)

    Halim, Amalia Yunita; Nielsen, Sidsel Marie; Eliasson Lantz, Anna;

    2015-01-01

    Little has been done to study microbial enhanced oil recovery (MEOR) in chalk reservoirs. The present study focuses on core flooding experiments designed to see microbial plugging and its effect on oil recovery. A pressure tapped core holder was used for this purpose. A spore forming bacteria Bac...

  19. Probing the intrinsically oil-wet surfaces of pores in North Sea chalk at subpore resolution

    DEFF Research Database (Denmark)

    Hassenkam, Tue; Skovbjerg, Lone Lindbæk; Stipp, Susan Louise Svane

    2009-01-01

    of the controlling factors for the effectiveness of water flooding, one of the most common methods to improve oil recovery in Chalk reservoirs. Understanding surface wetting and its variability at scales smaller than the pore dimension will potentially provide clues for more effective oil production...

  20. Laboratory measurements of the electrokinetic and electrochemical potential in chalk, with application to monitoring of saline intrusion in the UK chalk aquifer

    Science.gov (United States)

    MacAllister, D.; Jackson, M.; Butler, A. P.; Vinogradov, J.

    2012-12-01

    Saline intrusion is a global phenomenon affecting the availability of freshwater in coastal aquifers. The aim of this work is to investigate whether measurements of spontaneous potential (SP) can be used to monitor the intrusion of seawater into coastal aquifers, with specific application to the chalk aquifer near Brighton on the south coast of the UK. SP arises to maintain electrical neutrality when a separation of charge occurs due to gradients in pressure (electrokinetic or streaming potential), concentration (electrochemical potential) and temperature (thermoelectric potential). Concentration gradients are a characteristic feature of saline intrusion and may give rise to a measureable electrochemical potential (EC). In addition the electrokinetic potential (EK) will arise during abstraction and up-coning of the saline front. The intruding saline front could therefore be detected and monitored continuously, with SP measurements in boreholes and at the surface providing dense monitoring in space and time. To determine the likely magnitude of EK and EC signals during saline intrusion into the chalk aquifer, we measured EK and EC potentials in samples of Seaford chalk saturated with (i) natural, potable groundwater from the aquifer and (ii) seawater sampled from the English Channel. The EK coupling coefficient, which relates the gradient in voltage to the gradient in water pressure when the total current is zero, was found to be -60 mV/MPa in samples saturated with groundwater. In seawater saturated samples it was found to be only -1 mV/MPa. This result agrees with earlier work suggesting the EK potential is suppressed in high salinity environments due to a compressed electrical double layer. The EK coupling coefficient was negative in both cases, suggesting that the surface charge of Seaford chalk is negative when in contact with groundwater and seawater. The electrochemical experiments involved establishing a concentration gradient across the chalk samples

  1. Benthic macrofauna variations and community structure in Cenomanian cyclic chalk-marl from Southerham Grey Pit, SE England

    DEFF Research Database (Denmark)

    Lauridsen, Bodil Wesenberg; Gale, A. S.; Surlyk, Finn

    2009-01-01

    . The material comprises washing residues of 24 bulk samples collected from chalk and marl half-cycles. A total of 5055 invertebrate specimens were retrieved and referred to 68 species, forming the basis for the recognition of six guilds. In general, the fauna is more diverse in marl than in chalk, but...... clearly well adapted to both facies and thus to the fine grain size of the substrate rather than to lithology. The systematic difference in diversity between chalk and marl samples was possibly caused by long-term climatic and oceanographic changes and thus could represent a biological response to...

  2. Influence of clay and silica on permeability and capillary entry pressure of chalk reservoirs in the North Sea

    DEFF Research Database (Denmark)

    Røgen, Birte; Fabricius, Ida Lykke

    2002-01-01

    The permeability and capillary entry pressure of chalk reservoirs are controlled by their porosity and specific surface area. Measured permeabilities are in the range 0.025-5.3 mD and are successfully predicted by use of the Kozeny equation. In this paper we focus on the factors that control...... specific surface area. Fifty-nine Tor and Ekofisk Formation chalk samples from five North Sea chalk reservoirs were investigated. All contain quartz and clay minerals, most commonly kaolinite and smectite, with trace amounts of illite. The contents of calcite and quartz are inversely correlated and both...

  3. Porosity and sonic velocity depth trends of Eocene chalk in Atlantic Ocean: Influence of effective stress and temperature

    DEFF Research Database (Denmark)

    Awedalkarim, Ahmed; Fabricius, Ida Lykke

    2014-01-01

    We aimed to relate changes in porosity and sonic velocity data, measured on water-saturated Eocene chalks from 36 Ocean Drilling Program drill sites in the Atlantic Ocean, to vertical effective stress and thermal maturity. We considered only chalk of Eocene age to avoid possible influence of...... geological age on chalk compaction trends. For each depth, vertical effective stresses as defined by Terzaghi and by Biot were calculated. We used bottom-hole temperature data to calculate the time–temperature index of thermal maturity (TTI) as defined by Lopatin. Porosity and compressional wave velocity...

  4. The occurrence and development of peat mounds on King George Island (Maritime Antarctic

    Directory of Open Access Journals (Sweden)

    Jerzy Fabiszewski

    2014-02-01

    Full Text Available On King George Island, South Shetlands Islands, a type of peat formation has been discovered which has not previously been reported from the Antarctic. These formations are in shape of mounds up to 7x 15 m in area, with a peat layer of about I m thick. About twenty five cm below the surface there is a layer of permanently frozen peat. The mounds are covered by living mosses (Polytrichum alpinum and Drepanocladus uncinatus, Antarctic hair grass (Deschampsia antarctica and lichens. Erosion fissures occurring on the surface are evidence of contemporary drying and cessation of the mound's growth. The initial phase of the development of the mounds began with a community dominated by Calliergidium austro-stramineum and Deschampsia antarctica, and their further development has been due to peat accumulation formed almost entirely by Calliergidium. The location of the mounds is near a penguin rookery, which clearly conditioned the minerotrophic character of these formations, as compared with the "moss peat banks" formed by Chorisodontium aciphyllum and Polytrichum al-pestre. Moreover, the peat mounds differ from the latter in several ways, e.g. rate of growth and floristic composition. Radiocarbon dating of peat from the base of one mound gave an age of 4090±60 years B.P. This suggests that the age of the tundra on King George Island is about 5000-4000 years.

  5. Wave Run-Up on a Rubble Mound Breakwater

    DEFF Research Database (Denmark)

    Rouck, J. De; Troch, P.; Walle, B. Van de;

    2001-01-01

    found by laboratory testing and reported in literature. The design of the crest height of a breakwater is mainly based on wave run-up values obtained by small scale model tests. Prototype measurements are seen as the big challenge to be addressed to verify small scale model test results. Therefore, a......-o dimensional models (1:30) and on one thr-e dimensional scale model (1:40). For a better determination of wave run-up on the scale models, a novel step gauge is developed. Still, differences between results of prototype measurement and small scale model test results and between the various laboratory results...... rubble mound breakwater protecting the outer harbour of Zeebrugge (Belgium) and armoured with 25 ton grooved cubes is fully instrumented to measure sea state, wave run-up and wave overtopping. Wave run-up is measured by two different measuring devices. Extensive laboratory testing is carried out on two t...

  6. An Alternative Stability Equation For Rock Armoured Rubble Mound Breakwaters

    DEFF Research Database (Denmark)

    Hald, Tue; Burcharth, H. F.

    straight forward to assume, that a relation between the exerted wave loads and the stability of the armour layer would be of major interest, but the normal approach to the problem has simply been to relate easy accessible wave parameters, e.g. wave height and period, directly to the single unit weight....... Taking a closer look on the stability formulae large differences in the influence of the different parameters are observed although several points of resemblance are observed. Despite the major efforts in obtaining a reliable stability equation a large scatter between damage predicted by the stability......Rubble mound breakwaters are by far the most common type of breakwater, the importance of which is clearly reflected in the vast amount of published research. Especially, the hydraulic stability of the main armour layer has been studied in order to obtain reliable design equations. It should be...

  7. Wave Induced Loading and Stability of Rubble Mound Breakwaters

    DEFF Research Database (Denmark)

    Hald, Tue

    conducting model tests very large variability in e.g. the degree of stability is observed. This background motivated the investigations conducted in the present study. The objective was to investigate and clarify which wave parameters are important for the hydraulic stability of the armour layer on typical...... rubble mound breakwaters. Furthermore, it was intended to quantify the influence on the stability of each parameter. Focus was put on the wave induced loading on single armour stones and the relation to the stability. Based on existing literature the state of physical understanding of the processes...... related to the hydraulic stability was discussed. Further, governing parameters influencing the stability were identified and their influence quantified to retrieve the state- of-the-art. Model tests were conducted at SINTEF with scale models of prototype breakwaters and both the wave induced loading and...

  8. Evaporation from Banksia woodland on a groundwater mound

    Science.gov (United States)

    Farrington, P.; Greenwood, E. A. N.; Bartle, G. A.; Beresford, J. D.; Watson, G. D.

    1989-01-01

    Annual evaporation from a site within a Banksia woodland on a groundwater mound near Perth, Western Australia, was estimated from measurements of daily evaporation by ventilated chambers on fourteen occasions during a 12-month period. The total evaporation for this period was estimated to be 666 mm (77% of annual rainfall). About two-thirds of the total evaporation came from the ground flora, one-fifth from Banksia trees, and the remainder from the tall shrub Adenanthos cygnorum. Depth to water table, which ranged from 4 to 12 m over the site, had little effect on total evaporation. This work suggests that regular reduction in ground flora foliage, for example, by controlled burning could increase recharge.

  9. Innovative rubble mound breakwaters for wave energy conversion

    International Nuclear Information System (INIS)

    This paper presents a new Wave Energy Converter named Overtopping BReakwater for Energy Conversion (OBREC) which consists of a rubble mound breakwater with a front reservoir designed with the aim of capturing the wave overtopping in order to produce electricity. The energy is extracted via low head turbines, using the difference in water levels between the reservoir and the mean sea water level. The new design should be capable of adding a revenue generation function to a breakwater while adding cost sharing benefits due to integration. The design can be applied to harbour expansions, existing breakwater maintenance or upgrades due to climate change for a relatively low cost, considering the breakwater would be built regardless of the inclusion of a WEC

  10. Indigenous utilization of termite mounds and their sustainability in a rice growing village of the central plain of Laos

    Directory of Open Access Journals (Sweden)

    Sivilay Sengdeaune

    2011-08-01

    Full Text Available Abstract Background The objective of this study was to investigate the indigenous utilization of termite mounds and termites in a rain-fed rice growing village in the central plain of Laos, where rice production is low and varies year-to-year, and to assess the possibility of sustainable termite mound utilization in the future. This research was carried out from 2007 to 2009. Methods The termites were collected from their mounds and surrounding areas and identified. Twenty villagers were interviewed on their use of termites and their mounds in the village. Sixty-three mounds were measured to determine their dimensions in early March, early July and middle to late November, 2009. Results Eleven species of Termitidae were recorded during the survey period. It was found that the villagers use termite mounds as fertilizer for growing rice, vegetable beds and charcoal kilns. The villagers collected termites for food and as feed for breeding fish. Over the survey period, 81% of the mounds surveyed increased in volume; however, the volume was estimated to decrease by 0.114 m3 mound-1 year-1 on average due to several mounds being completely cut out. Conclusion It was concluded that current mound utilization by villagers is not sustainable. To ensure sustainable termite utilization in the future, studies should be conducted to enhance factors that promote mound restoration by termites. Furthermore, it will be necessary to improve mound conservation methods used by the villagers after changes in the soil mass of mounds in paddy fields and forests has been measured accurately. The socio-economic factors that affect mound utilization should also be studied.

  11. Microbial assemblages on a cold-water coral mound at the SE Rockall Bank (NE Atlantic): interactions with hydrography and topography

    OpenAIRE

    J. D. L. van Bleijswijk; Whalen, C.; Duineveld, G.C.A.; Lavaleye, M.S.S.; Witte, H.J.; Mienis, F.

    2015-01-01

    This study characterizes the microbial community composition over Haas Mound, one of the most prominent cold-water coral mounds of the Logachev Mound province (Rockall Bank, NE Atlantic). We outline patterns of distribution vertically – from the seafloor to the water column – and laterally – across the mound – and couple these to mound topography and hydrography. Samples of water, sediment and Lophelia pertusa were collected in 2012 and 2013 from locations that were chose...

  12. Sedimentary Mounds on Mars: Tracing Present-day Formation Processes into the Past

    Science.gov (United States)

    Niles, P. B.; Michalski, J.; Edwards, C. S.

    2014-01-01

    High resolution photography and spectroscopy of the martian surface (MOC, HiRISE) from orbit has revolutionized our view of Mars with one and revealed spectacular views of finely layered sedimentary materials throughout the globe [1]. Some of these sedimentary deposits are 'mound' shaped and lie inside of craters (Fig 1). Crater mound deposits are found throughout the equatorial region, as well as ice-rich deposits found in craters in the north and south polar region [2-4]. Despite their wide geographical extent and varying volatile content, the 'mound' deposits have a large number of geomorphic and structural similarities that suggest they formed via equivalent processes. Thus, modern depositional processes of ice and dust can serve as an invaluable analog for interpreting the genesis of ancient sedimentary mound deposits.

  13. Spatial Vegetation Data for Effigy Mounds National Monument Vegetation Mapping Project

    Data.gov (United States)

    National Park Service, Department of the Interior — The vegetation spatial database coverage (vegetation map) is a product of the Effigy Mounds National Monument Vegetation Mapping Project, USGS-NPS Vegetation...

  14. Archaeological mounds as analogs of engineered covers for waste disposal sites: Literature review and progress report. [Appendix contains bibliography and data on archaeological mounds

    Energy Technology Data Exchange (ETDEWEB)

    Chatters, J C; Gard, H A

    1991-09-01

    Closure caps for low-level radioactive waste disposal facilities are typically designed as layered earthen structures, the composition of which is intended to prevent the infiltration of water and the intrusion of the public into waste forms. Federal regulations require that closure caps perform these functions well enough that minimum exposure guidelines will be met for at least 500 years. Short-term experimentation cannot mimic the conditions that will affect closure caps on the scale of centuries, and therefore cannot provide data on the performance of cap designs over long periods of time. Archaeological mounds hundreds to thousands of years old which are closely analogous to closure caps in form, construction details, and intent can be studied to obtain the necessary understanding of design performance. Pacific Northwest Laboratory conducted a review and analysis of archaeological literature on ancient human-made mounds to determine the quality and potential applicability of this information base to assessments of waste facility design performance. A bibliography of over 200 English-language references was assembled on mound structures from the Americas, Europe, and Asia. A sample of these texts was read for data on variables including environmental and geographic setting, condition, design features, construction. Detailed information was obtained on all variables except those relating to physical and hydrological characteristics of the mound matrix, which few texts presented. It is concluded that an extensive amount of literature and data are available on structures closely analogous to closure caps and that this information is a valuable source of data on the long-term performance of mounded structures. Additional study is recommended, including an expanded analysis of design features reported in the literature and field studies of the physical and hydraulic characteristics of different mound designs. 23 refs., 10 figs., 12 tabs.

  15. Isotope Biogeochemistry of Sulfur in a Cold-Water Carbonate Mound (IODP Site 1317)

    Science.gov (United States)

    Ferdelman, T. G.; Boettcher, M. E.

    2007-12-01

    To establish a depositional model for cold-water carbonate mounds, Challenger Mound and adjacent continental slope sites were drilled during IODP Expedition 307 in May 2005. Although a role for methane seepage and subsequent anaerobic oxidation was discounted both as a hard-round substrate for mound initiation and as a principal source of carbonate within the mound succession, interstitial water profiles of sulfate, alkalinity, Mg, and Sr indicated a tight coupling between carbonate diagenesis and mircrobial sulfate reduction. The reaction of sulfide with siliciclastic iron-bearing minerals to form pyrite was proposed to account for enhanced diagenetic carbonate precipitation (Ferdelman et al., 2006; Proc. IODP, vol. 307; doi:10.2204/iodp.proc.307.2006). To characterize these geomicrobial sulfur transformations in the carbonate mound sediments, the inorganic and stable isotope geochemical compositions of pore water sulfate and solid phase reduced sulfur compounds were performed. Acid-volatile sulfur (AVS) and pyrite del 34S compositions were usually similar and exhibited an increasing trend of from -40 per mil near surface to -20 per mil at the mound base at 132 mbsf. However, several excursions to more 34S sulfur enriched pyrite to values >0 per mil were observed in the deeper sections of the mound sequence. These excursions may be linked transitory changes in the depth of the methane-sulfate transition zone during mound build-up. The oxygen isotopic composition of residual dissolved sulfate indicates intracellular isotope exchange processes within the cells of SRBs, leading to increasing equilibration between extracellular pore water and sulfate.

  16. Origin Hypotheses for Kilometer-Scale Mounds on Dwarf Planet Ceres

    Science.gov (United States)

    Sizemore, Hanna G.; Platz, Thomas; Schmidt, Britney E.; Scully, Jennifer E. C.; Russell, Christopher T.; Mest, Scott C.; Crown, David A.; Sykes, Mark V.; Hughson, Kynan H. G.; Chilton, Heather T.; Williams, David A.; Pieters, Carle M.; Marchi, Simone; Travis, Bryan; Raymond, Carol A.

    2015-11-01

    The Dawn Framing Camera has revealed numerous domical to conical features on Ceres, which may have relevance to the presence and history of near-surface ice. These features fall into two broad classes, large domes 10s to >100 km in diameter exhibiting 1-5 km of positive relief, and small mounds : Kilometer and sub-kilometer scale albedo variations; sub-kilometer flow features on individual mounds; localized vents; conical or domical shape. Challenge: Features are smaller than convective plumes expected from thermal evolution modeling.Hypothesis 2: Kilometer-scale mounds are analogous to terrestrial and martian pingos, which grow by drawing liquid water through a silicate matrix as a freezing front propagates downward. Observational tests: Mounds occurring on smooth material that floods or embays large-scale features; little or no local albedo variation; no small flows associated with individual mounds; domical or ring-shape; concentric or radial fractures on dome, or central depression. Challenge: Small Cerean mounds observed thus far are an order of magnitude larger than terrestrial or martian pingos.Hypothesis 3: Kilometer-scale mounds are rootless cones analogous to features observed on the surface of volcanic flows in volatile-rich regions of Earth and Mars. Rootless cones are produced when layers of fluid material inundate a region; localized devolatilization of a layer mobilizes clasts to form cone-shaped deposits. Observational tests: Mounds on smooth material that floods or embays large-scale features; conical, not domical, profile; large central depressions; cones in organized spatial patterns; no small-scale flows. Challenge: Low gravity environment and/or cryolava composition may be incompatible with this process.In addition to morphological observations, VIR data will help distinguish between these hypotheses.

  17. Recent benthic foraminiferal assemblages from cold-water coral mounds in the porcupine seabight

    OpenAIRE

    Schönfeld, Joachim; Dullo, Wolf-Christian; Pfannkuche, Olaf; Freiwald, André; Rüggeberg, Andres; Schmidt, Steffi; Weston, Janice

    2011-01-01

    Cold-water coral ecosystems are characterised by a high diversity and population density. Living and dead foraminiferal assemblages from 20 surface sediment samples from Galway and Propeller Mounds were analysed to describe the distribution patterns of benthic foraminifera on coral mounds in relation to different sedimentary facies. Hard substrates were examined to assess the foraminiferal microhabitats and diversities in the coral framework. We recognised 131 different species, of which 27 p...

  18. Integrated research on the Pen Duick cold-water coral mounds: the MiCROSYSTEMS approach

    OpenAIRE

    Van Rooij, D.; De Mol, L.; D. Blamart; Mienis, F.; L. M. Wehrmann; Barbieri, R; Maignien, L.; Templer, S. P.; Haas, H; Henriet, J.-P.; The MiCROSYSTEMS Science Team

    2010-01-01

    The ESF EuroDIVERSITY MiCROSYSTEMS project aimed to turn the cold-water coral (CWC) mounds on the Pen Duick Escarpment (PDE) in the Gulf of Cadiz into a natural laboratory, exploring this highly complex biotope and to characterize its biodiversity. A common point of discussion with all other CWC mound provinces, surpassing its broad range of regional and morphological variability, concerns the driving forces regarding the initiation of these complex deep-water systems. Both oceanographic and ...

  19. Lutz's spontaneous sedimentation technique and the paleoparasitological analysis of sambaqui (shell mound) sediments

    OpenAIRE

    Morgana Camacho; Thaíla Pessanha; Daniela Leles; Juliana MF Dutra; Rosângela Silva; Sheila Mendonça de Souza; Adauto Araujo

    2013-01-01

    Parasite findings in sambaquis (shell mounds) are scarce. Although the 121 shell mound samples were previously analysed in our laboratory, we only recently obtained the first positive results. In the sambaqui of Guapi, Rio de Janeiro, Brazil, paleoparasitological analysis was performed on sediment samples collected from various archaeological layers, including the superficial layer as a control. Eggs of Acanthocephala, Ascaridoidea and Heterakoidea were found in the archaeological layers. We ...

  20. Sedimentology of a Mid-Late Ordovician carbonate mud-mound complex from the Kathmandu nappe in Central Nepal

    Science.gov (United States)

    Pas, Damien; Da Silva, Anne-Christine; Dhital, Megh Raj; Boulvain, Frédéric

    2011-08-01

    This sedimentological study of the Godavari quarry is the first relating to the Palaeozoic Tethyan sedimentary rocks of the Katmandu nappe (Central Nepal). Sedimentological analyses led to the identification of six microfacies belonging to a large carbonate mud-mound complex, which can be divided into mound, flank and off-mound main depositional settings. Identification of two dasycladaceans ( Dasyporell a cf. silurica ( Stolley, 1893) and Vermiporella sp.) in the mound facies gives a Mid-Late Ordovician age to this newly discovered Godavari carbonate mud-mound, which makes this mound one of the oldest ever described in the Asian continent. The mound microfacies are characterized by a high micritic content, the presence of stromatactis and the prevalence of red coloured sediments (the red pigmentation probably being related to organic precipitation of iron). The flank microfacies are characterized by a higher crinoid and argillaceous content and the presence of bio- and lithoclasts concentrated in argillaceous lenses. Finally, the off-mound microfacies show very few bioclasts and a high argillaceous content. Palaeoenvionmental interpretation of microfacies, in terms of bathymetry, leads us to infer that the Godavari mud-mound started to grow in a deep environment setting below the photic and wave action zones and that it evolved to occupy a location below the fair weather wave base. Cementation of cavities within the mound facies underlines a typical transition from a marine to a burial diagenetic environment characterized by: (1) a radiaxial non luminescent feroan calcite cement (marine) showing a bright orange luminescent band in its middle part; (2) a bright zoned orange fringe of automorphic feroan calcite (meteoric phreatic); (3) a dull orange xenomorphic feroan calcite cement in the centre of cavities (burial) and (4) a saddle dolomite within the centre of larger cavities. The faunal assemblage (diversity and relative proportion) of the Godavari mound facies

  1. The Surales, Self-Organized Earth-Mound Landscapes Made by Earthworms in a Seasonal Tropical Wetland

    Science.gov (United States)

    Iriarte, José; Suarez Jimenez, Luz Elena; Adame Montoya, Kisay Lorena; Juilleret, Jérôme; McKey, Doyle

    2016-01-01

    The formation, functioning and emergent properties of patterned landscapes have recently drawn increased attention, notably in semi-arid ecosystems. We describe and analyze a set of similarly spectacular landforms in seasonal tropical wetlands. Surales landscapes, comprised of densely packed, regularly spaced mounds, cover large areas of the Orinoco Llanos. Although descriptions of surales date back to the 1940’s, their ecology is virtually unknown. From data on soil physical and chemical properties, soil macrofauna, vegetation and aerial imagery, we provide evidence of the spatial extent of surales and how they form and develop. Mounds are largely comprised of earthworm casts. Recognizable, recently produced casts account for up to one-half of total soil mass. Locally, mounds are relatively constant in size, but vary greatly across sites in diameter (0.5–5 m) and height (from 0.3 m to over 2 m). This variation appears to reflect a chronosequence of surales formation and growth. Mound shape (round to labyrinth) varies across elevational gradients. Mounds are initiated when large earthworms feed in shallowly flooded soils, depositing casts that form ‘towers’ above water level. Using permanent galleries, each earthworm returns repeatedly to the same spot to deposit casts and to respire. Over time, the tower becomes a mound. Because each earthworm has a restricted foraging radius, there is net movement of soil to the mound from the surrounding area. As the mound grows, its basin thus becomes deeper, making initiation of a new mound nearby more difficult. When mounds already initiated are situated close together, the basin between them is filled and mounds coalesce to form larger composite mounds. Over time, this process produces mounds up to 5 m in diameter and 2 m tall. Our results suggest that one earthworm species drives self-organizing processes that produce keystone structures determining ecosystem functioning and development. PMID:27168157

  2. The Surales, Self-Organized Earth-Mound Landscapes Made by Earthworms in a Seasonal Tropical Wetland.

    Science.gov (United States)

    Zangerlé, Anne; Renard, Delphine; Iriarte, José; Suarez Jimenez, Luz Elena; Adame Montoya, Kisay Lorena; Juilleret, Jérôme; McKey, Doyle

    2016-01-01

    The formation, functioning and emergent properties of patterned landscapes have recently drawn increased attention, notably in semi-arid ecosystems. We describe and analyze a set of similarly spectacular landforms in seasonal tropical wetlands. Surales landscapes, comprised of densely packed, regularly spaced mounds, cover large areas of the Orinoco Llanos. Although descriptions of surales date back to the 1940's, their ecology is virtually unknown. From data on soil physical and chemical properties, soil macrofauna, vegetation and aerial imagery, we provide evidence of the spatial extent of surales and how they form and develop. Mounds are largely comprised of earthworm casts. Recognizable, recently produced casts account for up to one-half of total soil mass. Locally, mounds are relatively constant in size, but vary greatly across sites in diameter (0.5-5 m) and height (from 0.3 m to over 2 m). This variation appears to reflect a chronosequence of surales formation and growth. Mound shape (round to labyrinth) varies across elevational gradients. Mounds are initiated when large earthworms feed in shallowly flooded soils, depositing casts that form 'towers' above water level. Using permanent galleries, each earthworm returns repeatedly to the same spot to deposit casts and to respire. Over time, the tower becomes a mound. Because each earthworm has a restricted foraging radius, there is net movement of soil to the mound from the surrounding area. As the mound grows, its basin thus becomes deeper, making initiation of a new mound nearby more difficult. When mounds already initiated are situated close together, the basin between them is filled and mounds coalesce to form larger composite mounds. Over time, this process produces mounds up to 5 m in diameter and 2 m tall. Our results suggest that one earthworm species drives self-organizing processes that produce keystone structures determining ecosystem functioning and development. PMID:27168157

  3. NMR response of non-reservoir fluids in sandstone and chalk.

    Science.gov (United States)

    van der Zwaag, C H; Stallmach, F; Skjetne, T; Veliyulin, E

    2001-01-01

    Transverse (T2) NMR relaxation time at 2 MHz proton resonance frequency was measured on core plug samples from two different lithologies, sandstone and chalk, before and after exposure to selected drilling fluids. The results show that NMR signal response was significantly altered after displacing 50% of the original pore fluids, crude oil and water, by drilling fluid filtrate. Relaxation spectra of the rock samples invaded by water-based filtrate shift to significantly shorter T2-values. This shift yields an underestimation of the free-fluid volumes when selecting cut-off values of 33 ms and 100 ms for sandstone and chalk, respectively. In opposite, rock samples affected by oil-based filtrate respond with a signal indicating significantly larger free-fluid volumes than present before exposure. NMR-permeability calculated based on the Timur-Coates Free Fluid model altered in some cases by one order of magnitude. PMID:11445352

  4. Investigation of Lecturer's Chalk by X-Ray Florescence and Fast Neutron Activation Techniques

    International Nuclear Information System (INIS)

    Different samples of lecturer's chalk were studied, using X-ray florescence (XRF) and Fast Neutron Activation Analysis (FNAA) techniques to ensure the safety of its use. The K (X-rays) and the gamma-rays were measured, using Si(Li) and high-purity germanium (HPGe) spectrometers to detect and determine qualitatively and quantitatively the constituents of the studied samples. For the investigated bulk chalk samples, the XRF was used for determination the average neutron flux of 2×107 n/cm2 sec. The concentrations of the elements (Ca and small traces of Al, Fe, Mg and Si) were measured and their presence was confirmed by γ-ray, lifetime and/or XRF measurements.

  5. Molluskan fauna in two shell mounds in the State of Parana coast, Brazil

    Directory of Open Access Journals (Sweden)

    Marcos de Vasconcellos Gernet

    2011-09-01

    Full Text Available The shell mounds are artificial formations consisting mostly of mollusk shells used in the feeding of the prehistoric peoples which inhabited our coast. These sites are found throughout the Brazilian coast, and hundreds of them were cataloged in the State of Paraná since the 1940s. The fragility of these sites, their importance as evidences of our prehistoric period, and its abrupt disappearance, justify the need for new researches which contribute to contextualize and draw up plans to preserve this heritage. The works related to the molluskan fauna found in the shell mounds are restricted to refer to the most common species and, sometimes, just their popular names. A greater knowledge on these prehistoric inhabitants’ diet allows a better understanding of ancient natural ecosystems. The survey of mollusks was carried out in the shell mounds Guaraguaçu and Boguaçu, in the towns of Pontal do Parana and Guaratuba, respectively, and performed through visual inspection, reading of specialized bibliography and comparison to previous works on the fauna of the shell mounds in the State of Parana coast. Altogether, 29 species were observed in the shell mound Guaraguaçu and 17 species were observed in the shell mound Boguaçu, resulting in a total of 31 species.

  6. Benthic dynamics at the carbonate mound regions of the Porcupine Sea Bight continental margin

    Science.gov (United States)

    White, Martin

    2007-02-01

    A brief review is given of some dynamical processes that influence the benthic dynamics within the carbonate mound provinces located at the Porcupine Bank/Sea Bight margin, NE Atlantic. The depth range of the mounds in this region (600-1,000 m) marks the upper boundary of the Mediterranean outflow water above which Eastern North Atlantic Water dominates. Both water masses are carried northwards by the eastern boundary slope current. In the benthic boundary layer both the action of internal waves, and other tidal period baroclinic waves, may enhance the bottom currents and add to both the residual and maximum flow strength. Both residual and maximum bottom currents vary at different mound locations, with stronger currents found at Belgica (SE Porcupine Sea Bight) mound and Pelagia (NW Porcupine Bank) mound regions, whilst weakest currents are found at the Hovland and Magellan Mounds at the northern Sea Bight margin. The differences may be attributed to the presence of internal waves (Pelagia) or bottom intensified diurnal waves (Belgica). These different dynamical regimes are likely to have implications for the distribution patterns of live coral at the different locations.

  7. Zonation of Microbial Communities by a Hydrothermal Mound in the Atlantis II Deep (the Red Sea)

    KAUST Repository

    Wang, Yong

    2015-10-20

    In deep-sea geothermal rift zones, the dispersal of hydrothermal fluids of moderately-high temperatures typically forms subseafloor mounds. Major mineral components of the crust covering the mound are barite and metal sulfides. As a result of the continental rifting along the Red Sea, metalliferous sediments accumulate on the seafloor of the Atlantis II Deep. In the present study, a barite crust was identified in a sediment core from the Atlantis II Deep, indicating the formation of a hydrothermal mound at the sampling site. Here, we examined how such a dense barite crust could affect the local environment and the distribution of microbial inhabitants. Our results demonstrate distinctive features of mineral components and microbial communities in the sediment layers separated by the barite crust. Within the mound, archaea accounted for 65% of the community. In contrast, the sediments above the barite boundary were overwhelmed by bacteria. The composition of microbial communities under the mound was similar to that in the sediments of the nearby Discovery Deep and marine cold seeps. This work reveals the zonation of microbial communities after the formation of the hydrothermal mound in the subsurface sediments of the rift basin.

  8. Gas compositions and processes in the unsaturated zone of the chalk and triassic sandstone aquifers, England

    International Nuclear Information System (INIS)

    Comparatively little is known about the nature of gas sources, sinks and transport in the unsaturated zone, yet this topic is of importance to a wide range of activities extending from agriculture to the construction industry. The composition of the unsaturated zone atmosphere in two different English aquifer types (Chalk and Triassic sandstone) was investigated by the construction of gas sampling boreholes with depths of up to 25 m. Monitoring took place at approximately 1-2 month intervals over 12-24 months. No significant seasonal variations in gas composition were noted. The following mean concentrations of gases was observed (Chalk, sandstone): N2 (77.7%, 77.7%), O2 (19.5%, 19.8%), CO2 (1.5%, 1.5%), N2O (4.2 ppmv, 2.4 ppmv), CH4 (0.1 ppmv, 0.3 ppmv), and δ13C-CO2 (-25.3 per mille, -19.9 per mille). The factor of 50 increase in CO2 reflects production from soil organic matter, supplemented in the sandstone by some CO2 from acidification or carbonate material. The decrease in O2 of little more than 1% absolute from atmospheric concentration indicates the persistence of oxidizing conditions in both unsaturated zones, and the relatively high concentrations of N2O therefore appear likely to have been derived from nitrification rather than denitrification. The limited magnitude of denitrification processes is further illustrated by N2/Ar and δ15N data. To understand better the rate of movement of gases in the unsaturated zone of a fissured aquifer, a tracer test using SF6 was carried out at the Chalk site. The results indicate a diffusion rate up to 103 times higher than that expected for the Chalk matrix alone. (author)

  9. Probing the intrinsically oil-wet surfaces of pores in North Sea chalk at subpore resolution

    OpenAIRE

    Hassenkam, T.; Skovbjerg, L. L.; Stipp, S. L. S.

    2009-01-01

    Pore surface properties control oil recovery. This is especially true for chalk reservoirs, where pores are particularly small. Wettability, the tendency for a surface to cover itself with fluid, is traditionally defined by the angle a droplet makes with a surface, but this macroscopic definition is meaningless when the particles are smaller than even the smallest droplet. Understanding surface wetting, at the pore scale, will provide clues for more effective oil recovery. We used a special m...

  10. Overview of research in physics and health sciences at the Chalk River Nuclear Laboratories

    International Nuclear Information System (INIS)

    Toxicology research was a logical extension of existing program at Chalk River. Research in radiotoxicology has been going on there since the early forties. An overview of the existing physics and health sciences research programs operating at the Research Company of Atomic Energy of Canada Limited was presented. Programs in nuclear physics, heavy ion nuclear physics, astrophysical neutrino physics, condensed matter physics, fusion, biology, dosimetry, and environmental sciences were briefly described. In addition, a description of the research company organization was provided

  11. Rock physics interpolation Used for velocity modeling of chalks: Ontong Java plateau example

    OpenAIRE

    Saberi, Mohammad Reza; Johansen, Tor Arne; Sælen, Gunnar

    2010-01-01

    Chalks are pelagic carbonate sediments that are deposited in deep-water environments. Their elastic behaviour is controlled by a combination of depositional conditions and subsequent diagenesis. In this paper, we incorporate geological information into rock physics modeling by constraining the pore structure (aspect ratio) variability. The strategy is to define a pore-model that reflects lithology, porosity and velocity. Then, a background velocity cube is constructed based on inf...

  12. Investigated Miscible CO2 Flooding for Enhancing Oil Recovery in Wettability Altered Chalk and Sandstone Rocks

    Energy Technology Data Exchange (ETDEWEB)

    Tabrizy, Vahid Alipour

    2012-07-01

    The thesis addresses oil recovery by miscible CO2 flooding from modified sandstone and chalk rocks. Calcite mineral surface is modified with stearic acid (SA) and asphaltene, and the silicate mineral surfaces are modified with N,N-dimethyldodecylamine (NN-DMDA) and asphaltene. The stability of adsorbed polar components in presence of SO4 2- and Mg2 + ions is also investigated. Recovery from sandstone cores is consistently lower than that from chalk cores saturated with the same oil and flooded with CO2 at all miscible flooding conditions. This may be due to the larger permeability contrasts in sandstone cores, which promote the fingering phenomenon. Miscible CO2 flooding for chalk and sandstone cores with distilled water, as initial water saturation, shows also lower oil recovery than cores saturated with different ions. At higher miscible flooding conditions, higher oil recovery is obtained. However, presence of light components (such as C1 or C3) in oil reduced the recovery. Oil recovery in presence of methane (C1) is lower than that in presence of methane and propane (C1/C3). A ternary diagram was constructed in order to understand the CO2 flooding mechanism(s) at the different flooding conditions and in presence of light components. The side effect of the flooding with CO2 is the probability for asphaltene deposition. An approach based on solubility parameter in the liquid, is used to assess the risk for asphaltene deposition during CO2 miscible flooding. The light components (C1/C3) and higher flooding conditions enhanced the risk for asphaltene instability. It is also shown higher amount of asphaltene deposition in chalk cores than that in sandstone cores at similar miscibility conditions.(au)

  13. Palaeo-ages of groundwaters in a fissured chalk aquifer, United Kingdom

    International Nuclear Information System (INIS)

    The Chalk aquifer in southeast England has a classic dual-porosity structure, with bulk advection occurring primarily in fractures/fissures, and largely immobile storage in the highly porous matrix blocks. For pumped samples, estimates of groundwater residence times using traditional geochemical correction models with 14C-dating, and assuming that ages reflect mobile fissure water signatures, indicate late-glacial recharge (≥25ka BP, pre-dating the Last Glacial Maximum (LGM) in the UK c.18 ka BP) for groundwaters in the centre of the basin. Cooler recharge temperatures than for modem waters evidenced in environmental isotopic (δ2H, δ18O) and dissolved noble gas (Ne, Ar, Kr, Xe) contents confirm their palaeowater status. However, hydraulic age estimates for transit times from recharge are much younger (tens of years). Closer consideration of solute transport in the Chalk allows reconciliation of these apparently discordant ages. It is argued that, on the regional aquifer scale, environmental tracers in the fissured Chalk move as though in an Equivalent Porous Medium (EPM), with significant tracer retardation due to sorption and/or matrix diffusion effects. Downgradient trends in δ18O and noble gases as independent tracers of past climatic changes can then be used to further constrain the groundwater ages better than for 14C-dating alone. This approach points to a significant revision of groundwater ages in the aquifer; all ages are seen to reflect post-glacial recharge having occurred ≤13 ka BP. An important consequence of this revision is that it is suggested that traditional geochemical models potentially undercorrect for the full effect of hydrodynamic processes on tracer ages in fissured porous media like the Chalk. (author)

  14. Biogeochemistry and geomicrobiology of cold-water coral carbonate mounds - lessons learned from IODP Expedition 307

    Science.gov (United States)

    Ferdelman, Timothy; Wehrmann, Laura; Mangelsdorf, Kai; Kano, Akihiro; Williams, Trevor; Jean-Pierre, Henriet

    2010-05-01

    Large mound structures associated with cold-water coral ecosystems commonly occur on the slopes of continental margins, for instance, west of Ireland in the Porcupine Seabight, the Gulf of Cadiz or the Straits of Florida. In the Porcupine Seabight over 1500 mounds of up to 5 km in diameter and 250 m height lie at water depths of 600 to 900 m. The cold-water coral reef ecosystems associated with these structures are considered to be "hotspots" of organic carbon mineralization and microbial systems. To establish a depositional and biogeochemical/diagenetic model for cold-water carbonate mounds, Challenger Mound and adjacent continental slope sites were drilled in May 2005 during IODP Expedition 307. One major objective was to test whether deep sub-surface hydrocarbon flow and enhanced microbial activity within the mound structure was important in producing and stabilizing these sedimentary structures. Drilling results showed that the Challenger mound succession (IODP Site U1317) is 130 to 150 meters thick, and mainly consists of floatstone and rudstone facies formed of fine sediments and cold-water branching corals. Pronounced recurring cycles on the scales of several meters are recognized in carbonate content (up to 70% carbonate) and color reflectance, and are probably associated with Pleistocene glacial-interglacial cycles. A role for methane seepage and subsequent anaerobic oxidation was discounted both as a hard-round substrate for mound initiation and as a principal source of carbonate within the mound succession. A broad sulfate-methane transition (approximately 50 m thick)within the Miocene sediments suggested that the zone of anaerobic oxidation of methane principally occurs below the moundbase. In the mound sediments, interstitial water profiles of sulfate, alkalinity, Mg, and Sr suggested a tight coupling between carbonate diagenesis and low rates of microbial sulfate reduction. Overall organic carbon mineralization within cold-water coral mound appeared

  15. Earth-mounded concrete bunker PLAP technical approach

    Energy Technology Data Exchange (ETDEWEB)

    Eng, R.

    1989-11-01

    Under the US DOE Prototype License Application Project (PLAP), Ebasco Services Incorporated was commissioned to develop a preliminary design of the Earth-Mounded Concrete Bunker (EMCB) concept for low-level radioactive waste (LLW) disposal. The EMCB disposal concept is of great interest because it represents the only engineered LLW disposal technology currently in use in the commercial sector. By definition, the EMCB disposal structure is located partially below grade and partially above grade. The concrete bunker is an engineered structure designed to be structurally stable for the prerequisite time horizon. The basic design parameters of the disposal facility were stipulated by US DOE, a northeast site location, representative waste, 30 year operational life, and a 250,000 ft{sup 3}/year disposal capacity. The design was developed to satisfy only US NRC Part 61 disposal requirements, not individual state requirements that may go beyond Part 61 requirements. The technical safety analysis of the preliminary design was documented according to the format specifications of NUREG-1199, to the extent practicable with quite limited resources.

  16. Bryan Mound SPR cavern 113 remedial leach stage 1 analysis.

    Energy Technology Data Exchange (ETDEWEB)

    Rudeen, David Keith [GRAM, Inc., Albuquerque, NM; Weber, Paula D.; Lord, David L.

    2013-08-01

    The U.S. Strategic Petroleum Reserve implemented the first stage of a leach plan in 2011-2012 to expand storage volume in the existing Bryan Mound 113 cavern from a starting volume of 7.4 million barrels (MMB) to its design volume of 11.2 MMB. The first stage was terminated several months earlier than expected in August, 2012, as the upper section of the leach zone expanded outward more quickly than design. The oil-brine interface was then re-positioned with the intent to resume leaching in the second stage configuration. This report evaluates the as-built configuration of the cavern at the end of the first stage, and recommends changes to the second stage plan in order to accommodate for the variance between the first stage plan and the as-built cavern. SANSMIC leach code simulations are presented and compared with sonar surveys in order to aid in the analysis and offer projections of likely outcomes from the revised plan for the second stage leach.

  17. Mortality among workers at the Mound Facility: A preliminary report

    International Nuclear Information System (INIS)

    Mortality among 4,697 white males who were employed at the Mound Facility between 1943 and 1979 was compared with expected mortality based on US white male death rates. Standardized mortality ratios (SMRs) of 96 were observed for both all causes and all cancers. SMRs for digestive cancers and unintentional injuries were significantly less than 100. No SMR was significantly greater than 100 for these workers. A significantly elevated lung cancer SMR was observed for the subcohort of workers employed from 1943--1959, a period during which polonium-210 was processed at the plant. To determine the potential impact of wartime selection factors, this time period was further divided into two periods, 1943--1945 and 1946--1959. In the 1943--1945 period, the SMR for lung cancer was 204 (90% CI = 140, 290), while in the later period the lung cancer SMR was 105 (90% CI = 77, 140). Similar results were observed for all causes, all cancers, cancers of the rectum, nonmalignant respiratory diseases, and all injuries for which the SMRs were elevated during the wartime period but were not elevated after the war. Additional analyses considering workers hired in the period 1960--1979, during which plutonium-238 was processed at the facility, yielded little information. Generally, a strong healthy worker effect was observed and was attributed to the limited follow-up time and small numbers of deaths among this subcohort. 22 refs., 9 tabs

  18. Three-dimensional architecture and development of Danianbryozoan mounds at Limhamn, south-west Sweden, usingground-penetrating radar

    DEFF Research Database (Denmark)

    Nielsen, Lars; Schack von Brockdorff, A.; Bjerager, Morten Gustav Erik;

    2009-01-01

    in the Limhamn limestone quarry, south-west Sweden, obtained from combined reflected ground-penetrating radar signals and outcrop analysis provide new information about the architecture and growth development of such mounds. The mounds are composed of bryozoan limestone and dark-grey to black flint...... the internal layering of the mounds which, typically, have widths and lengths of 30 to 60 m and heights of 5 to 10 m. Mound architecture and growth show great variability in the ground-penetrating radar images. Small-scale mound structures with a palaeorelief of only a few metres may constitute the...... during growth, although some mound structures indicate a preferential growth direction towards the south. Growth patterns interpreted from the ground-penetrating radar images suggest that the palaeocurrents in the study area may have shown great variability, even on a small scale. This observation is in...

  19. Indigenous utilization of termite mounds and their sustainability in a rice growing village of the central plain of Laos

    OpenAIRE

    Sivilay Sengdeaune; Adachi Yoshinao; Matsushita Yuichi; Kokubo Mika; Koyama Yusaku; Miyagawa Shuichi; Kawakubo Nobumitsu; Oba Shinya

    2011-01-01

    Abstract Background The objective of this study was to investigate the indigenous utilization of termite mounds and termites in a rain-fed rice growing village in the central plain of Laos, where rice production is low and varies year-to-year, and to assess the possibility of sustainable termite mound utilization in the future. This research was carried out from 2007 to 2009. Methods The termites were collected from their mounds and surrounding areas and identified. Twenty villagers were inte...

  20. Permanent groundwater storage in basaltic dyke fractures and termite mound viability

    Science.gov (United States)

    Mège, Daniel; Rango, Tewodros

    2010-04-01

    Many basaltic dykes of the Ethiopian flood basalt province are observed in the northwestern Ethiopian lowlands. In this area, the termites preferentially build their epigeous mounds on the top of dolerite dykes. The relationship between termite mounds and dykes is investigated from the analysis of their distribution along one of these dykes, of thickness 2-5 m, that we could follow over 2000 m. Termite mounds are periodically spaced (mean distance 63 m, R2 = 0.995), and located exclusively where the topographic relief of the dyke is not more than 2 m above the surrounding area. From these observations and from the geological context, a hydrological circuit model is proposed in which (1) dykes are preferential conduits for groundwater drainage during the rainy season due to pervasive jointing, (2) during the dry season, the portion of the dyke forming a local topographic relief area dries up more quickly than the surroundings, the elevation difference between the dyke summit and the surroundings being a factor restricting termite mound development. For dyke topographic relief >2 m, drying is an obstacle for maintaining the appropriate humidity for the termite colony life. Periodic termite mound spacing is unlikely to be related to dyke or other geological properties. It is more likely related to termite population behaviour, perhaps to clay shortage, which restricts termite population growth by limiting the quantity of building material available for mound extension, and triggers exploration for a new colonization site that will be located along the dyke at a distance from the former colony that may be controlled by the extent of the zone covered by its trail pheromones. This work brings out the importance of dykes in channelling and storing groundwater in semiarid regions, and shows that dykes can store groundwater permanently in such settings even though the dry season is half the year long. It contributes also to shedding light on water supply conditions

  1. A photographic and acoustic transect across two deep-water seafloor mounds, Mississippi Canyon, northern Gulf of Mexico

    Science.gov (United States)

    Hart, P.E.; Hutchinson, D.R.; Gardner, J.; Carney, R.S.; Fornari, D.

    2008-01-01

    In the northern Gulf of Mexico, a series of seafloor mounds lie along the floor of the Mississippi Canyon in Atwater Valley lease blocks 13 and 14. The mounds, one of which was drilled by the Chevron Joint Industry Project on Methane Hydrates in 2005, are interpreted to be vent-related features that may contain significant accumulations of gas hydrate adjacent to gas and fluid migration pathways. The mounds are located ???150 km south of Louisiana at ???1300 m water depth. New side-scan sonar data, multibeam bathymetry, and near-bottom photography along a 4 km northwest-southeast transect crossing two of the mounds (labeled D and F) reveal the mounds' detailed morphology and surficial characteristics. Mound D, ???250 m in diameter and 7-10 m in height, has exposures of authigenic carbonates and appears to result from a seafloor vent of slow-to-moderate flux. Mound F, which is ???400 m in diameter and 10-15 m high, is covered on its southwest flank by extruded mud flows, a characteristic associated with moderate-to-rapid flux. Chemosynthetic communities visible on the bottom photographs are restricted to bacterial mats on both mounds and mussels at Mound D. No indications of surficial gas hydrates are evident on the bottom photographs.

  2. Seepage carbonate mounds in Cenozoic sedimentary sequences from the Las Minas Basin, SE Spain

    Science.gov (United States)

    Pozo, M.; Calvo, J. P.; Scopelliti, G.; González-Acebrón, L.

    2016-04-01

    A number of carbonate mounds composed of indurate, strongly folded and/or brecciated calcite and dolomite beds occur interstratified in Cenozoic sedimentary sequences from the Las Minas Basin. Part of the fabric of the rock forming the carbonate mounds is composed of laminated to banded dolostone similar to the host rock but showing contrasted lithification. Moreover, the carbonate deposits of the mounds display aggrading neomorphism of dolomite, partial replacement of dolomite by calcite, calcite cementation, and extensive silicification, locally resulting in box-work fabric. Eight main lithofacies were distinguished in the carbonate mound deposits. In some lithofacies, chert is present as both microcrystalline to fibro-radial quartz and opal, the latter occurring mainly as cement whereas the former replace the carbonate and infill voids. Yet one of the carbonate mounds shows distinctive petrography and geochemical features thus suggesting a distinctive growth pattern. The carbon isotope compositions of calcite from the mound samples range from - 11.56 to - 5.15 δ‰ whilst dolomite is depleted in 13C, with values of - 12.38 to 3.02 δ‰. Oxygen isotopic compositions vary from - 9.42 to - 4.64 δ‰ for calcite and between - 6.68 and 8.19 δ‰ for dolomite. Carbonate in the mounds shows significant enrichment in Co, Cr, Ni and Pb content, especially in the strongly deformed (F-2-2 lithofacies) and brecciated carbonate (F-4). The carbonate deposits show depletion in REE and Y in contrast to that determined in lutite. The formation of the carbonate mounds was related to local artesian seepage thermal water flows of moderate to relative high temperatures. Pressure differences between the low permeability host rock and the circulating fluids accounted for dilational fracturing and brecciation of the host sediment packages, which combined with precipitation of new carbonate and silica mineral phases. Locally, some carbonate mounds developed where groundwater

  3. Distribution and density of Cubitermes Wasmann (Isoptera: Termitidae mounds in the northern Kruger National Park

    Directory of Open Access Journals (Sweden)

    V.W. Meyer

    2000-07-01

    Full Text Available This paper provides fundamental information on distribution and density of the genus Cubitermes, Wasm. quantified for future monitoring. After distribution trends have been established, changes in Cubitermes density over time can be brought into contention with other factors in the Kruger National Park, such as the impact of fire frequency, water distribution, and elephant density on these insects. At least ten 2 ha belt-transects were undertaken in each of the 20 northern landscape zones of the KNP. Termite mounds were recorded and their activity within was determined. Cubitermes accounts for 29.8% of all active termite mounds in the northern KNP, with an average density of 0.33 mounds/ha. Cubitermes favours the Nwambiya Sandveld (zone 32. These termites occur in high density in the Klipkoppies 1 land type (Gorge, but in low densities in the Phalaborwa 10-12, Bulweni 1-3, Letaba 1-7 and Pafuri 3-6 land types. Cubitermes mounds tend to occur in high numbers on the Nzhelele formation (Mn (sandstones; quartzite; basalt. Mounds of this genus in the Far North are highly concentrated on the Gaudam and Moriah soil series of the Hutton form, suggesting that these termites prefer very sandy soils with medium to coarse particles.

  4. Structure of a carbonate/hydrate mound in the northern Gulf of Mexico

    Energy Technology Data Exchange (ETDEWEB)

    McGee, T.; Woolsey, J.; Macelloni, L. [Mississippi Univ., Oxford, MI (United States). Center for Marine Resources and Environmental Technology; Lapham, L. [Florida State Univ., Tallahassee, FL (United States); Kleinberg, R. [Schlumberger-Doll Research, Cambridge, MA (United States); Battista, B.; Knapp, C. [South Carolina Univ., Columbia, SC (United States); Caruso, S. [Univ. of Rome La Sapienza, Rome, (Italy). Dept. of Geological Sciences; Goebel, V. [Lookout Geophysical Co., Palisade, CO (United States); Chapman, R. [Victoria Univ., BC (Canada). School of Earth and Ocean Sciences; Gerstoft, P. [California Univ., San Diego, CA (United States). Marine Physical Laboratory

    2008-07-01

    A one-kilometer-diameter carbonate/hydrate mound located in the south-central portion of Mississippi Canyon block 118 in the Gulf of Mexico was the site of a multi-sensor, multi-discipline sea-floor observatory. In preparation for installing the observatory, several surveys were conducted. The resulting data provided detailed information about the mound's structure. This paper discussed the structure of the carbonate/hydrate mound in the Gulf of Mexico. The paper described the surface morphology of the mound, which was imaged by multi-beam bathymetric sonar from an autonomous underwater vehicle (AUV) 40 metres above the sea floor as well as by cameras at or a few meters above the sea floor deployed from drifting surface vessels or tethered submersibles. Visual observations were also made from manned submersibles. The paper also discussed the collection of gravity and box cores for lithologic and bio-geochemical studies. Gas sampling, venting activity, and seismo-acoustic studies were also presented. The internal structure of the mound was described as well. It was concluded that pore-fluid analyses conducted on the cores revealed that microbial sulfate reduction, anaerobic methane oxidation, and methanogenesis were important processes in the upper sediment as they controlled the diffusive flux of methane into the overlying water column. The activity of microbes was also focused within patches near active vents. 10 refs., 10 figs.

  5. Environmental assessment and planning at Mound - environmental monitoring capabilities and personnel profiles

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-07-01

    Through its long experience with radioactive materials, Mound has developed a comprehensive, routine, offsite, environmental surveillance program to safeguard its employees, the physical plant, and the integrity of the surrounding environment from any potential adverse effects of its widely diverse operations. Effluent samples are analyzed for radiological and non-radiological parameters. The environment surrounding Mound Facility is continuously monitored - air, water, foodstuffs, vegetation, soil, and silt samples are analyzed to ensure that radioisotopic concentrations and other possible pollutants are well within the stringent standards adopted by the Department of Energy, the Environmental Protection Agencies (both federal and state), and various regional and local agencies. Moreover, this environmental surveillance program has been designed to ensure that the facility is designed, constructed, managed, operated, and maintained in a manner that continues to meet all federal, state, and local standards for environmental protection. Work in environmental science has been broadened to assess environmental factors associated with various aspects of the National Energy Plan. Both the management and staff at Mound have undertaken a firm commitment to make Mound`s environmental monitoring capabilities available to agencies that have the responsibility for the resolution of important environmental issues.

  6. The effect of divalent ions on the elasticity and pore collapse of chalk evaluated from compressional wave velocity and low-field Nuclear Magnetic Resonance (NMR)

    DEFF Research Database (Denmark)

    Katika, Konstantina; Addassi, Mouadh; Alam, Mohammad Monzurul;

    2015-01-01

    The effects of divalent ions on the elasticity and the pore collapse of chalk were studied through rock-mechanical testing and low-field Nuclear Magnetic Resonance (NMR) measurements. Chalk samples saturated with deionized water and brines containing sodium, magnesium, calcium and sulfate ions were...

  7. Distribution and physical traits of red wood ant mounds in a managed Rhodope mountains forest.

    Science.gov (United States)

    Tsikas, Angelos; Karanikola, Paraskevi; Papageorgiou, Aristotelis C

    2016-07-01

    Red wood ants (RWA) are of great ecological importance for the forest ecosystem. Forestry practices, like clear-cutting, and trampling load, due to tourism, logging, and grazing stock, can greatly affect their colonies, disturbing their microhabitat. RWA in Greek forests have not been investigated so far. We herein report on the distribution and morphological traits of Formica lugubris mounds studied in Elatia forest (Rhodope mountains, Northern Greece), an all-aged managed mixed forest where selective logging practices are performed. Nearby vegetation, slope, canopy cover, shrub density, and distance from the nearest neighboring trees were also recorded. Mound density was shown to be much higher in this Greek forest compared to RWA mounds in other European-managed forests. Furthermore, we recorded a continuous nest establishment, despite forest management disturbances and trampling load. Our study suggests that single-tree selective forestry practices are essential for creating ideal microhabitats for the RWA and, therefore, for maintaining RWA populations. PMID:27345521

  8. The long term sustainability of Mound Springs in South Australia : implications for olympic dam

    International Nuclear Information System (INIS)

    The Mound Springs of South Australia are unique groundwater discharge features of the Great Artesian Basin, a deep regigonal groundwater system that covers over one-fifth of the Australia continent. They are the principal sources of water in the arid and semi-arid inland heart of Australia, and have great ecological, scientific, anthropological and economic significance. Excessive development of the Great Artesian Basin over the past century by European activity has seen an overall decline in the flows from the mound springs, and recent development of the water supply borefields for the WMC Olympic Dam Operations copper-uranium mine in the midst of the most important spring groups has exacerbated this problem. A review of the history of the borefields, an analysis of the impacts on the mound springs, and future recommendations for protection of the springs is presented. (orig.)

  9. The Pliocene sediment mounds of southwestern Caspian Sea:significance for stratigraphic traps

    International Nuclear Information System (INIS)

    Full text: The Caspian Sea is the world largest lake that is also considered as a totally enclosed sea.Morphologically it is divided into the northern, central and southern part.The thickness of terrigenous sediments in the southern Caspian sea is up to 20 km.This study evaluates significance of the Pliocene sediment mounds and clinoforms were found adjacent to this time line in the deep part of the basin.These mounds show features similar to deep sea fans, characterized by subparallel and hummocky reflection patterns.The estimated average thickness and width of the four studied mounds are 456 m and 14.2 km, respectively, suitable to form stratigraphic traps.

  10. High resolution microgravity investigations for the detection and characterisation of subsidence associated with abandoned, coal, chalk and salt mines

    Energy Technology Data Exchange (ETDEWEB)

    Styles, P.; Toon, S.; Branston, M.; England, R. [Keele Univ., Applied And Environmental Geophysics Group, School of Physical and Geographical Sciences (United Kingdom); Thomas, E.; Mcgrath, R. [Geotechnology, Neath (United Kingdom)

    2005-07-01

    The closure and decay of industrial activity involving mining has scarred the landscape of urban areas and geo-hazards posed by subsurface cavities are ubiquitous throughout Europe. Features of concern consist of natural solution cavities (e.g. swallow holes and sinkholes in limestone gypsum and chalk) and man-made cavities (mine workings, shafts) in a great variety of post mining environments, including coal, salt, gypsum, anhydrite, tin and chalk. These problems restrict land utilisation, hinder regeneration, pose a threat to life, seriously damage property and services and blight property values. This paper outlines the application of microgravity techniques to characterise abandoned mining hazard in case studies from Coal, Chalk and Salt Mining environments in the UK. (authors)

  11. High resolution microgravity investigations for the detection and characterisation of subsidence associated with abandoned, coal, chalk and salt mines

    International Nuclear Information System (INIS)

    The closure and decay of industrial activity involving mining has scarred the landscape of urban areas and geo-hazards posed by subsurface cavities are ubiquitous throughout Europe. Features of concern consist of natural solution cavities (e.g. swallow holes and sinkholes in limestone gypsum and chalk) and man-made cavities (mine workings, shafts) in a great variety of post mining environments, including coal, salt, gypsum, anhydrite, tin and chalk. These problems restrict land utilisation, hinder regeneration, pose a threat to life, seriously damage property and services and blight property values. This paper outlines the application of microgravity techniques to characterise abandoned mining hazard in case studies from Coal, Chalk and Salt Mining environments in the UK. (authors)

  12. Response of invertebrates from the hyporheic zone of chalk rivers to eutrophication and land use.

    Science.gov (United States)

    Pacioglu, Octavian; Moldovan, Oana Teodora

    2016-03-01

    Whereas the response of lotic benthic macroinvertebrates to different environmental stressors is a widespread practice nowadays in assessing the water and habitat quality, the use of hyporheic zone invertebrates is still in its infancy. In this study, classification and regression trees analysis were employed in order to assess the ecological requirements and the potential as bioindicators for the hyporheic zone invertebrates inhabiting four lowland chalk rivers (south England) with contrasting eutrophication levels (based on surface nitrate concentrations) and magnitude of land use (based on percentage of fine sediments load and median interstitial space). Samples of fauna, water and sediment were sampled twice, during low (summer) and high (winter) groundwater level, at depths of 20 and 35 cm. Certain groups of invertebrates (Glossosomatidae and Psychomyiidae caddisflies, and riffle beetles) proved to be good indicators of rural catchments, moderately eutrophic and with high fine sediment load. A diverse community dominated by microcrustaceans (copepods and ostracods) were found as good indicators of highly eutrophic urban streams, with moderate-high fine sediment load. However, the use of other taxonomic groups (e.g. chironomids, oligochaetes, nematodes, water mites and the amphipod Gammarus pulex), very widespread in the hyporheic zone of all sampled rivers, is of limited use because of their high tolerance to the analysed stressors. We recommend the use of certain taxonomic groups (comprising both meiofauna and macroinvertebrates) dwelling in the chalk hyporheic zone as indicators of eutrophication and colmation and, along with routine benthic sampling protocols, for a more comprehensive water and habitat quality assessment of chalk rivers. PMID:26531711

  13. Optimization of Spore Forming Bacteria Flooding for Enhanced Oil Recovery in North Sea Chalk Reservoir

    OpenAIRE

    Halim, Amalia Yunita; Nielsen, Sidsel Marie; Eliasson Lantz, Anna; Shapiro, Alexander

    2015-01-01

    Little has been done to study microbial enhanced oil recovery (MEOR) in chalk reservoirs. The present study focused on core flooding experiments to see microbial plugging and its effect on oil recovery. A pressure tapped core holder with pressure ports at 1.2 cm, 3.8 cm, and 6.3 cm from the inlet was used for this purpose. A spore forming bacterium, Bacillus licheniformis 421, was used as it was shown to be a good candidate in the previous study. Bacterial spore can penetrate deeper into the ...

  14. Prospects of Microbial Enhanced Oil Recovery  in Danish chalk rocks

    DEFF Research Database (Denmark)

    Rudyk, Svetlana Nikolayevna; Jørgensen, Leif Wagner; Bah Awasi, Ismail

      Microbial Enhanced Oil Recovery (MEOR) uses bacteria, producing gas (CO2), polymers or surfactants to help recover residual oil after the water injection depletes its possibilities. Two strains of Clostridia tyrobutiricum were investigated as possible candidates for MEOR  implementation in Danish...... chalk reservoir rocks. Parameters such as high salinity, low permeability, high temperature and toxic elements, being typical characteristics of Danish fields can cause limiting effects on MEOR applications. The work fulfilled showed that microbes can be adapted to higher salinities through a serial...

  15. Field burial results and SIMS analysis of the Chalk River glass blocks

    International Nuclear Information System (INIS)

    In 1959, 25 2-kg hemispherical blocks of aluminosilicate glass, each containing ∼90 MBq/g of mixed fission products, were buried in a sandy soil aquifer in the waste management area at the Chalk River Nuclear Laboratories. A second set of blocks, containing ∼260 MBq/g mixed fission products, was buried in 1960. One block from each test was retrieved in 1978 to undergo chemical and surface analysis. This report reviews the migration of the 90Sr and 137Cs plume in the soil and presents the results of SIMS depth profiling of the surface of a glass block. (author)

  16. CO2-foaming agent retention in fractured chalk models: Experiments and simulations

    OpenAIRE

    Kvæstad, Ann Helen

    2011-01-01

    Injection of CO2-gas can improve the oil recovery. In naturally fractured reservoirs such as chalk, injection of CO2-gas can result in early gas breakthrough because the gas can use the fractures as pathways from the injector to the producer. The pressure, temperature and oil properties in the reservoir can also lead to an unfavorable mobility for the gas. This can lead to low total sweep efficiency for the process. One method to increase the total sweep efficiency in the fractured reservoir ...

  17. Optimization of Spore Forming Bacteria Flooding for Enhanced Oil Recovery in North Sea Chalk Reservoir

    DEFF Research Database (Denmark)

    Halim, Amalia Yunita; Nielsen, Sidsel Marie; Eliasson Lantz, Anna;

    2015-01-01

    was used for this purpose. A spore forming bacterium, Bacillus licheniformis 421, was used as it was shown to be a good candidate in the previous study. Bacterial spore can penetrate deeper into the chalk rock, squeezing through the pore throats. Our results show that B. licheniformis 421 when......-1.2 cm and 1.2-3.8 cm) during bacteria injection. Further seawater flooding after three days shut in period showed that permeability gradually increased in the first two sections of the core and started to decrease in the third section of the core (3.8-6.3 cm). Complete plugging was never observed in our...

  18. Burial diagenesis of deep sea chalk as reflected in Biot’s coefficient

    DEFF Research Database (Denmark)

    Fabricius, Ida Lykke; Alam, Mohammad Monzurul

    particles apparently is low and not correlated with porosity, probably because the pore-filling cementation in this interval causes Biot’s coefficient to decline as burial increases. Limestone from the water zone of the North sea Chalk Group follows the same stress trend as deep sea limestone. These results...... limestone as burial increases and porosity decreases. The porosity decrease is accompanied by an increasing velocity to elastic waves, and consequently a decreasing Biot’s coefficient, as estimated from velocity and density of core samples. When the effective burial stress is normalized to total horizontal...

  19. Burial diagenesis of deep sea chalk as reflected in Biot's coefficient

    DEFF Research Database (Denmark)

    Fabricius, Ida Lykke; Alam, Mohammad Monzurul

    particles apparently is low and not correlated with porosity, probably because the pore-filling cementation in this interval causes Biot's coefficient to decline as burial increases. Limestone from the water zone of the North sea Chalk Group follows the same stress trend as deep sea limestone. These results...... limestone as burial increases and porosity decreases. The porosity decrease is accompanied by an increasing velocity to elastic waves, and consequently a decreasing Biot's coefficient, as estimated from velocity and density of core samples. When the effective burial stress is normalized to total horizontal...

  20. Tracking selenium in the Chalk aquifer of northern France: Sr isotope constraints

    International Nuclear Information System (INIS)

    Highlights: • We report the chemistry of the Chalk groundwater affected by Se contamination. • Strontium isotopes were used to identify the groundwater bodies and their mixings. • The spatial and temporal Se variability is mainly linked to the presence of Se-rich clays. • Saturation or desaturation of Se-rich clays control Se mobility. - Abstract: Groundwater at the southern and eastern edges of France’s Paris Basin has a selenium content that at times exceeds the European Framework Directive’s drinking-water limit value of 10 μg/L. To better understand the dynamics of the Chalk groundwater being tapped to supply the city of Lille and the Se origins, we used a combination of geochemical and isotopic tools. Strontium isotopes, coupled with Ca/Sr, Mg/Sr and Se/Sr ratios, were used to identify the main groundwater bodies and their mixings, with the Mg/Sr and Se/Sr ratios constraining a ternary system. Groundwater in the agricultural aquifer-recharge zone represents a first end-member and displays the youngest water ages of the catchment along with the highest Sr isotopic signature (0.70842) and low Se contents. Anaerobic groundwater constitutes a second major end-member affected by water-rock interactions over a long residence time, with the lowest Sr isotopic signature (0.70789) and the lowest Se content, its low SF6 content confirming the contribution of old water. Se-rich groundwater containing up to 30 μg/L of Se represents a third major end-member, with an intermediate Sr isotopic ratio (0.70826), and is mainly constrained by the clayey Se-rich formation overlying the Chalk aquifer. The spatial and temporal Se variability in the groundwater is clearly linked to the presence of this formation identified as Tertiary and also to the hydrological conditions; saturation of the Se-rich clays by oxygenated groundwater enhances Se mobility and also Sr adsorption onto the clays. This multi-tool study including Sr isotopes successfully identified the Se

  1. Full-waveform Inversion of Crosshole GPR Data Collected in Strongly Heterogeneous Chalk: Challenges and Pitfalls

    DEFF Research Database (Denmark)

    Keskinen, Johanna; Zibar, Majken Caroline Looms; Nielsen, Lars; Klotzsche, Anja; van der Kruk, Jan; Moreau, Julien; Stemmerik, Lars; Holliger, Klaus

    Chalk is an important reservoir rock for hydrocarbons and for groundwater resources for many major cities. Therefore, this rock type has been extensively investigated using both geological and geophysical methods. Many applications of crosshole GPR tomography rely on the ray approximation and...... address the importance of (i) adequate starting models, both in terms of the dielectric permittivity and the electrical conductivity, (ii) the estimation of the source wavelet, (iii) and the effects of data sampling density when imaging this rock type. Moreover, we discuss the resolution of the bedding...

  2. Field burial results and SIMS analysis of the Chalk River glass blocks

    International Nuclear Information System (INIS)

    In 1959, 25 2-kg hemispherical blocks of aluminosilicate glass, each containing ∼90 MBq/g of mixed fission products, were buried in a sandy soil aquifer in the waste management area at the Chalk River Nuclear Laboratories. A second set of blocks, containing ∼260 MBq/g mixed fission products, was buried in 1960. One block from each test was retrieved in 1978 to undergo chemical and surface analysis. This report reviews the migration of the /sup 90/Sr and /sup 137/Cs plume in the soil and presents the results of SIMS depth profiling of the surface of a glass block

  3. Waveform analysis of crosshole GPR data collected in heterogeneous chalk deposits

    DEFF Research Database (Denmark)

    Keskinen, Johanna; Nielsen, Lars; Zibar, Majken Caroline Looms;

    2014-01-01

    be divided into two main units based on the traveltime analysis and interpretation of the cored material from the boreholes. The lower unit consists mainly of porous calcareous mudstone with occasional occurrences of flint nodules. The upper succession is c. 8 m thick and is fairly heterogeneous...... methods are highly dependent on the quality of the starting models (usually obtained from ray-based tomography), as well as on the assumptions made regarding the source signal. Adequate estimation of starting models and source waveform is, however, a challenging task for the strongly heterogeneous chalk...

  4. Mounding of a non-Newtonian jet impinging on a solid substrate.

    Energy Technology Data Exchange (ETDEWEB)

    Schunk, Peter Randall; Grillet, Anne Mary; Roberts, Scott A.; Baer, Thomas A. (Procter & Gamble, Cincinnati, OH); Rao, Rekha Ranjana

    2010-06-01

    When a fluid jet impinges on a solid substrate, a variety of behaviors may occur around the impact region. One example is mounding, where the fluid enters the impact region faster than it can flow away, forming a mound of fluid above the main surface. For some operating conditions, this mound can destabilize and buckle, entraining air in the mound. Other behaviors include submerging flow, where the jet impinges into an otherwise steady pool of liquid, entraining a thin air layer as it enters the pool. This impact region is one of very high shear rates and as such, complex fluids behave very differently than do Newtonian fluids. In this work, we attempt to characterize this range of behavior for Newtonian and non-Newtonian fluids using dimensionless parameters. We model the fluid as a modified Bingham-Carreau-Yasuda fluid, which exhibits the full range of pseudoplastic flow properties throughout the impact region. Additionally, we study viscoelastic effects through the use of the Giesekus model. Both 2-D and 3-D numerical simulations are performed using a variety of finite element method techniques for tracking the jet interface, including Arbitrary Lagrangian Eulerian (ALE), diffuse level sets, and a conformal decomposition finite element method (CDFEM). The presence of shear-thinning characteristics drastically reduces unstable mounding behavior, yet can lead to air entrainment through the submerging flow regime. We construct an operating map to understand for what flow parameters mounding and submerging flows will occur, and how the fluid rheology affects these behaviors. This study has many implications in high-speed industrial bottle filling applications.

  5. Can mima-like mounds be Vertisol relics (Far North Region of Cameroon, Chad Basin)?

    Science.gov (United States)

    Diaz, Nathalie; Dietrich, Fabienne; Cailleau, Guillaume; Sebag, David; Ngounou Ngatcha, Benjamin; Verrecchia, Eric P.

    2016-05-01

    Non-anthropogenic earth mounds, defined as mima-like mounds in this study, have recently been observed in non-carbonate watersheds along the Sudano-Sahelian belt in the Chad Basin. In the Diamare piedmont (northern Cameroon) they are particularly well developed within stream networks. In less eroded areas, they occur as whaleback, flattened morphologies, or even as buried features. All these shapes are composed of clay-rich sediment associated with high proportions of secondary carbonate nodules and Fesbnd Mn micro-nodules. Their soil structure is prismatic to massive and vertical cracks are observed locally. Grain-size distributions emphasize the clay-rich nature of the sediment, with average clay contents of 32% ± 12.8% (n = 186), which is significantly higher than the clay content in the adjacent sediments in the landscape (mean = 10% ± 4%, n = 21). Moreover, high proportions of smectite characterize the soil, with average contents of 34 ± 7% (n = 25). At the micro-scale, the groundmass has a cross-striated b-fabric, with embedded smooth subangular quartz and feldspar grains of the silt-size fraction. All the characteristics point to altered vertic properties in the clay-rich sediment composing the mima-like mounds. Mima-like mounds are thus interpreted as degraded Vertisols. Compared to present-day Vertisols occurring in the piedmont, mima-like mounds are located upstream. It is thus proposed that the Vertisol areas were more extensive during a former and wetter period than the present-day. Subsequent changing climatic conditions increased erosion, revealing the gilgai micro-relief by preferential erosion in micro-lows rather than in micro-highs. Mima-like mounds of the Chad Basin might thus result from pedogenesis combined with later erosion. These local processes can be inherited from regional climatic variations during the Late Pleistocene-Holocene and likely be related to the African Humid Period.

  6. Overview of the earth mounded concrete bunker prototype license application project: Objectives and approach

    Energy Technology Data Exchange (ETDEWEB)

    Conner, J.E. [EG and G Idaho, Inc., Idaho Falls, ID (United States). Idaho National Engineering Lab.

    1989-11-01

    This paper presents an overview of the objectives and approach taken in developing the Earth-mounded Concrete Bunker Prototype License Application Project. The Prototype License Application Project was initiated by the Department of Energy`s National Low-Level Waste Management Program in early 1987 and completed in November 1988. As part of this project a prototype safety analysis report was developed. The safety analysis report evaluates the licensibility of an earth-mounded concrete bunker for a low-level radioactive waste (LLW) disposal facility located on a hypothetical site in the northeastern United States. The project required approximately five person-years and twenty months to develop.

  7. Lutz's spontaneous sedimentation technique and the paleoparasitological analysis of sambaqui (shell mound sediments

    Directory of Open Access Journals (Sweden)

    Morgana Camacho

    2013-04-01

    Full Text Available Parasite findings in sambaquis (shell mounds are scarce. Although the 121 shell mound samples were previously analysed in our laboratory, we only recently obtained the first positive results. In the sambaqui of Guapi, Rio de Janeiro, Brazil, paleoparasitological analysis was performed on sediment samples collected from various archaeological layers, including the superficial layer as a control. Eggs of Acanthocephala, Ascaridoidea and Heterakoidea were found in the archaeological layers. We applied various techniques and concluded that Lutz's spontaneous sedimentation technique is effective for concentrating parasite eggs in sambaqui soil for microscopic analysis.

  8. Mechanical Strength Modeling and Optimization of Lateritic Solid Block with 4% Mound Soil Inclusion

    OpenAIRE

    Onuamah, P. N.; Ezeokpube G.C.

    2015-01-01

    The work is an investigation for the model development and optimization of the compressive strength of solid sandcrete block with mound soil inclusion. The study applies the Scheffe’s optimization approach to obtain a mathematical model of the form f(xi1,xi2,xi3,,xi4), where xi are proportions of the concrete components, viz: cement, mound soil, laterite, and water. Scheffe’s experimental design techniques are followed to mould various solid block samples measuring 450mm x 225mm x 150mm...

  9. The long-term development of cold-water coral mounds in the NE-Atlantic

    OpenAIRE

    Eisele, Markus Hermann

    2010-01-01

    Cold-water corals are distributed all over the world's oceans where they form a high variety of ecosystems depending on their specific environment. This study is dealing with so called cold-water coral mounds that are mainly composed of fragments of cold-water corals and hemipelagic mud that is baffled in between the coral branches. Changes of the environment have a direct effect on coral growth and thus on mound growth. This study aims to unravel the environmental factors that influence moun...

  10. Environmental isotope studies related to groundwater flow and saline encroachment in the chalk aquifer of Lincolnshire, England

    International Nuclear Information System (INIS)

    The isotopes of tritium and carbon are used to study part of the North Lincolnshire Chalk aquifer in England. The tritium data support the view that the aquifer is a thin fissure system and indicate that some changes in flow direction have occurred owing to recent abstraction. The data are also consistent with other chemical data in elucidating groundwater entering the Chalk from deeper aquifers. Carbon isotopes are used to distinguish between saline water bodies and suggest that saline water was entrapped within the aquifer in the Eemian and Flandrian stages of the Pleistocene. (author)

  11. Deep saltwater in Chalk of North-West Europe: origin, interface characteristics and development over geological time

    DEFF Research Database (Denmark)

    Bonnesen, Ellen Prip; Larsen, F.; Sonnenborg, T.O.;

    2009-01-01

    location, saline water in the Chalk resides at depths from 40 to 80m and salinity increases with depth. Concentrations of chloride up to ca. 30,000ppm have been observed at depths of 400m. Measured vertical hydraulic heads in open boreholes suggest that advective groundwater flow is now restricted in...... deeper parts of the Chalk formation and diffusive transport is thus the predominant transport mechanism. Laboratory-measured porosity and effective diffusion coefficients were used as input to a numerical 1D diffusion model of the interface between freshwater in an upper, fractured aquifer and modified...

  12. The relation among porosity, permeability, and specific surface of chalk from the Gorm field, Danish North Sea

    DEFF Research Database (Denmark)

    Jeanette, Mortensen; Engstrøm, Finn; Lind, Ida

    1998-01-01

    The origin to the difference in the relationship between permeability and porosity for Danian and Maastrichtian chalk from the Gorm field offshore Denmark has been investigated. The investigation was based on 300 sets of core data (He-expansion porosity and air permeability) from the well Gorm N-22...... surface. Furthermore it was found that the nature of porosity (intrafossil, intergranular, etc.) had no significant influence on the air permeability, so that the permeability of the chalk can be calculated from total porosity and specific surface. Kozeny's empirical constant, c, was here determined...... analytically from a simple porosity model and Poiseuilles law....

  13. Physiological and biogeochemical traits of bleaching and recovery in the mounding species of coral Porites lobata: implications for resilience in mounding corals.

    Directory of Open Access Journals (Sweden)

    Stephen J Levas

    Full Text Available Mounding corals survive bleaching events in greater numbers than branching corals. However, no study to date has determined the underlying physiological and biogeochemical trait(s that are responsible for mounding coral holobiont resilience to bleaching. Furthermore, the potential of dissolved organic carbon (DOC as a source of fixed carbon to bleached corals has never been determined. Here, Porites lobata corals were experimentally bleached for 23 days and then allowed to recover for 0, 1, 5, and 11 months. At each recovery interval a suite of analyses were performed to assess their recovery (photosynthesis, respiration, chlorophyll a, energy reserves, tissue biomass, calcification, δ(13C of the skeletal, δ(13C, and δ(15N of the animal host and endosymbiont fractions. Furthermore, at 0 months of recovery, the assimilation of photosynthetically acquired and zooplankton-feeding acquired carbon into the animal host, endosymbiont, skeleton, and coral-mediated DOC were measured via (13C-pulse-chase labeling. During the first month of recovery, energy reserves and tissue biomass in bleached corals were maintained despite reductions in chlorophyll a, photosynthesis, and the assimilation of photosynthetically fixed carbon. At the same time, P. lobata corals catabolized carbon acquired from zooplankton and seemed to take up DOC as a source of fixed carbon. All variables that were negatively affected by bleaching recovered within 5 to 11 months. Thus, bleaching resilience in the mounding coral P. lobata is driven by its ability to actively catabolize zooplankton-acquired carbon and seemingly utilize DOC as a significant fixed carbon source, facilitating the maintenance of energy reserves and tissue biomass. With the frequency and intensity of bleaching events expected to increase over the next century, coral diversity on future reefs may favor not only mounding morphologies but species like P. lobata, which have the ability to utilize heterotrophic

  14. Microbial assemblages on a cold-water coral mound at the SE Rockall Bank (NE Atlantic): interactions with hydrography and topography

    NARCIS (Netherlands)

    van Bleijswijk, J.D.L.; Whalen, C.; Duineveld, G.C.A.; Lavaleye, M.S.S.; Witte, H.J.; Mienis, F

    2015-01-01

    This study characterizes the microbial community composition over Haas Mound, one of the most prominent cold-water coral mounds of the Logachev Mound province (Rockall Bank, NE Atlantic). We outline patterns of distribution vertically – from the seafloor to the water column – and laterally – across

  15. Proceedings of a workshop on geophysical and related geoscientific research at Chalk River, Ontario

    International Nuclear Information System (INIS)

    A large part of the Canadian Nuclear Fuel Waste Management Program is geoscience research and development aimed at obtaining information to quantify the transport of radionuclides through the geosphere and at determining the geotechnical properties required for disposal vault design. The geosphere at potential disposal sites is characterized in part by the use of remote sensing (geophysical) methods. In 1977 public concern about the disposal of radioactive waste resulted in field work being restricted to the site of Chalk River Nuclear Laboratories, which was used to develop, evaluate and compare various techniques in order to optimize the methods for obtaining geoscience information. Methods tested at Chalk River are to be applied at other research sites. Most investigations have been carried out around Maskinonge Lake, using about thirty boreholes sink into bedrock. The boreholes provide subsurface geological information that can be used as a reference to compare the responses of various geophysical methods and equipment. Regional studies, including airborne geophysical surveys, have also been conducted. The 25 papers presented at this workshop provide comprehensive documentation of the most significant results of geophysical studies. The workshop also provided an evaluation of geophysical techniques and their utility to the Nuclear Fuel Waste Management Program

  16. What are the governing processes during low-flows in a chalk catchment?

    Science.gov (United States)

    Lubega Musuuza, Jude; Coxon, Gemma; Hutton, Chris; Howden, Nicholas; Woods, Ross; Freer, Jim; Wagener, Thorsten

    2016-04-01

    Low flows are important because they lead to the prioritisation of different consumptive water usages, imposition of restrictions and bans, raising of water tariffs and higher production costs to industry. The partitioning of precipitation into evaporation, storage and runoff depends on the local variability in meteorological variables and site-specific characteristics e.g., topography, soils and vegetation. The response of chalk catchments to meteorological forcing especially precipitation is of particular interest because of the preferential flow through the weathered formation. This makes the observed stream discharge groundwater-dominated and hence, out of phase with precipitation. One relevant question is how sensitive the low flow characteristics of such a chalk catchment is to changes in climate and land use. It is thus important to understand all the factors that control low stream discharge periods. In this study we present the results from numerical sensitivity analysis experiments performed with a detailed physically-based model on the Kennet, a sub-catchment of the River Thames, in the UK during the historical drought years of the 1970's.

  17. The early diagenetic and PETROphysical behaviour of recent cold-water CARbonate mounds in Deep Environments (PETROCARDE)

    Science.gov (United States)

    Foubert, Anneleen; Pirlet, Hans; Thierens, Mieke; de Mol, Ben; Henriet, Jean-Pierre; Swennen, Rudy

    2010-05-01

    Sub-recent cold-water carbonate mounds localized in deeper slope settings on the Atlantic continental margins cannot be any longer neglected in the study of carbonate systems. They clearly play a major role in the dynamics of mixed siliciclastic-carbonate and/or carbonate-dominated continental slopes. Carbonate accumulation rates of cold-water carbonate mounds are about 4 to 12 % of the carbonate accumulation rates of tropical shallow-water reefs but exceed the carbonate accumulation rates of their slope settings by a factor of 4 to 12 (Titschack et al., 2009). These findings emphasize the importance of these carbonate factories as carbonate niches on the continental margins. The primary environmental architecture of such carbonate bodies is well-characterized. However, despite proven evidences of early diagenesis overprinting the primary environmental record (e.g. aragonite dissolution) (Foubert & Henriet, 2009), the extent of early diagenetic and biogeochemical processes shaping the petrophysical nature of mounds is until now not yet fully understood. Understanding (1) the functioning of a carbonate mound as biogeochemical reactor triggering early diagenetic processes and (2) the impact of early diagenesis on the petrophysical behaviour of a carbonate mound in space and through time are necessary (vital) for the reliable prediction of potential late diagenetic processes. Approaching the fossil carbonate mound record, through a profound study of recent carbonate bodies is innovative and will help to better understand processes observed in the fossil mound world (such as cementation, brecciation, fracturing, etc…). In this study, the 155-m high Challenger mound (Porcupine Seabight, SW of Ireland), drilled during IODP Expedition 307 aboard the R/V Joides Resolution (Foubert & Henriet, 2009), and mounds from the Gulf of Cadiz (Moroccan margin) will be discussed in terms of early diagenetic processes and petrophysical behaviour. Early differential diagenesis

  18. Construction, Maintenance and Repair as Elements in Rubble Mound Breakwater Design

    DEFF Research Database (Denmark)

    Burcharth, Hans F.; Rietveld, C.F.W.

    Very often rubble mound breakwater designs seem to be a result only of stability considerations corresponding to design wave conditions. Designers tend to put too little emphasis on practical problems related to construction, maintenance and repair. As is discussed in the paper due consideration of...

  19. On the Choice of Structure and Layout of Rubble Mound Breakwater Heads

    DEFF Research Database (Denmark)

    Maciñeira, Enrique; Burcharth, Hans F.

    2006-01-01

     The paper discusses the various functional, environmental and structural conditions to consider related to the choice of breakwater head type. Results from hydraulic model tests of rubble mound and caisson head solutions for the new deep water port at Punto Langosteira, La Coruña, Spain, are pre...

  20. Stability of Monolithic Rubble Mound Breakwater Crown Walls Subjected to Impulsive Loading

    DEFF Research Database (Denmark)

    Nørgaard, Jørgen Harck; Andersen, Lars Vabbersgaard; Andersen, Thomas Lykke; Burcharth, Hans F.

    2012-01-01

    This paper evaluates the validity of a simple onedimensional dynamic analysis as well as a FEM model to determine the sliding of a rubble mound breakwater crown wall. The evaluation is based on a case example with real wave load time series and displacements measured from two-dimensional physical...

  1. Stable isotope sales: Mound Facility customer and shipment summaries, FY 1980

    International Nuclear Information System (INIS)

    A listing is given of Mound Facility's sales of stable isotopes of noble gases, carbon, oxygen, nitrogen, chlorine, and sulfur for Fiscal Year 1980. Purchasers are listed alphabetically and are divided into domestic and foreign groups. A cross-reference index by location is included for domestic customers. Cross-reference listings by isotope purchased are included for all customers

  2. Scour at the round head of a rubble-mound breakwater

    DEFF Research Database (Denmark)

    Fredsøe, Jørgen; Sumer, B. Mutlu

    This study complements the investigation on scour around the head of a breakwater, reported in the companion paper where the case of vertical-wall breakwater was considered, The present study deals with the case of rubble-mound breakwater. Two key mechanisms with regard to the scour processes aro...

  3. Single Wave Overtopping Volumes and their Travel Distance for Rubble Mound Breakwaters

    DEFF Research Database (Denmark)

    Andersen, Thomas Lykke; Burcharth, Hans F.; Gironella, F. X.

    2009-01-01

    In the present paper small and large scale overtopping data for rubble mound structures have been analysed with respect to single wave overtopping volumes and their travel distance. The analysis has led to formulae for estimation of maximum single wave overtopping volumes and their travel distance...... similar to the spatial distribution of the total overtopping volume in a sea state....

  4. Experimental study of 2D scour and its protection at a rubble-mound breakwater

    DEFF Research Database (Denmark)

    Sumer, B. Mutlu; Fredsøe, Jørgen

    2000-01-01

    This study deals with the 2D scour at the trunk section of a rubble-mound breakwater. Two breakwater models with slopes of 1:1.2 and 1:1.75 are employed for the experimental study of the scour in a wave flume. 2D scour at a vertical-wall breakwater was also included as a reference case. Tests wer...

  5. Scour at the round head of a rubble-mound breakwater

    DEFF Research Database (Denmark)

    Fredsøe, Jørgen; Sumer, B. Mutlu

    1997-01-01

    This study complements the investigation on scour around the head of a breakwater, reported in the companion paper where the case of vertical-wall breakwater was considered, The present study deals with the case of rubble-mound breakwater. Two key mechanisms with regard to the scour processes aro...

  6. Timing of mounding for bambara groundnut affects crop development and yield in a rainfed tropical environment

    DEFF Research Database (Denmark)

    Ouedrago, Mahama; M'bi, Bertin Zagre; Liu, Fulai;

    2013-01-01

    Mounding, also known as earthing up, is widely carried out at any time during the growth cycle of Vigna subterranea (L.) Verdcourt, viz. bambara groundnut – a species with underground pod setting – by subsistence farmers throughout Africa. This agricultural practice consists of bringing soil...

  7. A tale of negotiations: CERCLA interagency agreement at the Mound plant

    International Nuclear Information System (INIS)

    The purpose of this paper is to explain some of the more important provisions of the Mound agreement and to explore some lessons learned from the Mound experience about CERCLA Interagency Agreement negotiations. The authors have chosen six specific IAG provisions to discuss because they represent key elements in their attempt to merge what may sometimes seem like incongruous goals - the need to conduct a thorough CERCLA cleanup under the direction of another federal agency and the desire to protect the public's money. The provisions they will discuss are: integration of CERCLA and RCRA requirements; EPA's covenant not to sue or assess administrative penalties against DOE's contractors for any of their actions which may have given rise to the releases covered by the agreement; inclusion of a streamlined Statement of Work; the procedure whereby investigative work already completed at the Mound site which was not conducted utilizing EPA-approved methods may be accepted for future reports; the short list of primary documents; and use of a yearly schedule for work activities.. Tritium, as well as trace levels of chlorinated organics, have been found in the groundwater at Mound. On-site and off-site soils are contaminated with plutonium and several on-site locations are contaminated with thorium

  8. Stable isotope sales: Mound Facility customer and shipment summaries, FY 1981

    International Nuclear Information System (INIS)

    A listing is given of Mound Facility's sales of stable isotopes of noble gases, carbon, oxygen, nitrogen, chlorine, and sulfur for Fiscal Year 1981. Purchasers are listed alphabetically and are divided into domestic and foreign groups. A cross-reference index by location is included for domestic customers. Cross-reference listings by isotope purchased are included for all customers

  9. Influence of clay and silica on permeability and capillary entry pressure of chalk reservoirs in the North Sea

    DEFF Research Database (Denmark)

    Røgen, Birte; Fabricius, Ida Lykke

    2002-01-01

    The permeability and capillary entry pressure of chalk reservoirs are controlled by their porosity and specific surface area. Measured permeabilities are in the range 0.025-5.3 mD and are successfully predicted by use of the Kozeny equation. In this paper we focus on the factors that control spec...

  10. Sub-kilometre (intra-crater) mounds in Utopia Planitia, Mars: character, occurrence and possible formation hypotheses

    Science.gov (United States)

    Soare, Richard J.; Conway, Susan J.; Pearce, Geoffrey D.; Costard, François; Séjourné, Antoine

    2013-08-01

    At the middle latitudes of Utopia Planitia (˜35-45°N; ˜65-101°E) hundreds of small-sized mounds located in sub-kilometre impact craters dot the landscape. Their shape varies from circular to crescentic and their height ranges from ˜10 to 50 m. Often, metre to decametre pitting is observed, as is metres-thick banding or stratification. Mound albedo is relatively high, i.e. ˜0.16. The plain's terrain in the region, previously linked to the latitude-dependent mantle (LDM) of ice-dust, displays pitting and albedo similar to the small intra-crater mounds. Some workers have suggested that the mounds and the plain's terrain share a common ice-dust origin. If so, then scrutinising the mounds could provide analogical insight on the key geological characteristics and spatial distribution of the LDM itself. Other workers have hypothesised that the mounds are eroded sedimentary landforms or periglacial mounds underlain by a perennial ice-core (closed-system pingos). In this article we develop and then discuss each of the three mound-hypotheses in a much more substantial manner than has been done hitherto. Towards this end we use high-resolution images, present a detailed regional-map of mound distribution and establish a regional platform of topographical analysis using MOLA data superposed on a large-scale CTX mosaic. Although the ice-dust hypothesis is consistent with some observations and measurements, we find that a (loess-based) sedimentary hypothesis shows greater plausibility. Of the three hypotheses evaluated, the pingo or periglacial one is the weakest.

  11. Estimation of groundwater recharge to chalk and sandstone aquifers using simple soil models

    Science.gov (United States)

    Ragab, R.; Finch, J.; Harding, R.

    1997-03-01

    On the assumption that the water draining below the root zone is potentially available for groundwater recharge, two current UK methods for estimating annual groundwater recharge have been compared with a new soil model using data from four sites under permanent grass in the UK: two sites representative of the Chalk aquifer at Bridgest Farm (Hampshire) and Fleam Dyke (Cambridgeshire), and two sites on the Triassic sandstone at Bicton College (Devon) and Bacon Hall (Shropshire). A Four Root Layers Model (FRLM), the Penman-Grindley model and the UK Meteorological Office Rainfall and Evaporation Calculation System (MORECS) were used. The new soil model was run with potential evaporation as input both from the MORECS and from the Penman-Monteith equation. The models were run for the Chalk sites both with and without a bypass flow of 15% of rainfall. Bypass was not considered for the sandstone sites. The performance of the models was tested against neutron probes measurements of soil moisture deficits. In addition, the annual groundwater recharge estimated from the models was compared with the published values obtained from the 'zero flux plane' method. Generally, the Penman-Grindley model was more successful in predicting the time for soil to return to its field capacity than in predicting the magnitude of the soil moisture deficit. The annual groundwater recharge was predicted with reasonable accuracy. The MORECS relatively tended to overestimate the soil moisture deficits and to delay the time at which the soil returns to its field capacity. The consequences were underestimates of annual groundwater recharge, owing either to the higher values of potential evaporation calculated from the MORECS or tothe high available water capacity values associated with the soils under consideration. The new soil model (FRLM) predicts the soil moisture deficits successfully and hence is reliable in estimating the annual groundwater recharge. The model is capable of doing this with

  12. Magnetic field related mechanical tolerances for the proposed Chalk River superconducting heavy-ion cyclotron

    International Nuclear Information System (INIS)

    A four sector azimuthally varying field cyclotron with superconducting main coils has been proposed as a heavy-ion post-accelerator for the Chalk River MP Tandem van de Graaff. The radial profile of the average axial field will be variable using movable steel trim rods. The field errors due to coil, trim rod and flutter pole imperfections are calculated. Those considered are errors in the axial field, first and second azimuthal harmonic axial fields, transverse field and first azimuthal harmonic transverse field. Such fields induce phase slip, axial or radial coherent oscillations and can result in axial or radial beam instability. The allowed imperfections (tolerances) required to retain stability and maintain acceptably small coherent oscillation amplitudes are calculated. (author)

  13. Water temperatures within spawning beds in two chalk streams and implications for salmonid egg development

    Science.gov (United States)

    Acornley, R. M.

    1999-02-01

    Water temperatures within brown trout (Salmo trutta L.) spawning gravels were measured in two Hampshire chalk streams from October 1995 to April 1996 inclusive. During the winter, mean intra-gravel water temperatures were higher than those in the stream, and increased with depth in the gravel bed. The amplitude of diel fluctuations in water temperature decreased with depth in the gravel bed, although diel fluctuations were still evident at a depth of 30 cm. Differences in intra-gravel temperature gradients between the two study sites were attributed to differences in the amplitude of stream water temperature fluctuations and there was no evidence that either of the study sites were located in zones of upwelling groundwater. Published equations are used to predict, from temperature, the timing of important stages in the development of brown trout embryos (eyeing, hatching and emergence) for eggs spawned in the autumn and winter and buried at different depths in the gravel bed.

  14. Isotope and dissolved gas evidence for nitrogen attenuation in landfill leachate dispersing into a chalk aquifer

    International Nuclear Information System (INIS)

    The authors present data for the chemical, stable isotope (13C/12C, 15N/14N and 34S/32S), and dissolved gas (N2, Ar, O2 and CH4) composition of groundwaters sampled in and around a landfill site in Cambridgeshire, England. Decomposition of 3 x 106 m3 of largely domestic waste, placed in unlined quarries, has given rise to the formation of an NH4-rich leachate dispersing as a plume into the surrounding Middle Chalk aquifer. In addition to identifying zones of methanogenesis and SO4 reduction, the data indicate processes of NH4 transformation by either assimilation or oxidation, and losses by formation of N2. Depending on the mixing ratio between leachate and background water, it may be possible to account for all NH4 loss by combined nitrification + denitrification in a system where there are abrupt temporal and spatial changes in redox conditions

  15. Multi isotopic tools to understand selenium origins in groundwaters of the Chalk aquifer in Northern France

    Science.gov (United States)

    Cary, Lise; Gourcy, Laurence; Benabderraziq, Hind; Elkhattabi, Jamal; Laurent, Alexandra; Négrel, Philippe

    2013-04-01

    Four field wells exploiting the Chalk aquifer supply Lille city in water. The little catchment area is submitted to quantitative and qualitative pressure from industrial, urban and agriculture origins. Selenium (Se) concentrations are often higher than EU standards (0.12 µmol.L-1) for potable drinking water and can reach 0.4 μmol.L-1 leading to exploitation restrictions. An integrated study was settled to determine the water sources and dynamics of elements, with a focus on Se, with the goal of managing both water quality and quantity. After a large chemical characterisation of the system, a monthly sampling campaign was held in 2012 in four wells and in the close Deûle channel. In situ physical and chemical parameters, chemical analysis of major and trace elements with a special focus on redox-sensitive elements including SeIV, SeVI, FeII, stable water isotopes (δ18O, δ2H) and δ34S and δ18O of sulphates measures were undertaken. The chemical composition of solids sampled at various depths at vicinity of the four wells was analysed. Se concentrations in groundwaters and in the solid phase vary significantly. In the northern part of the Ansereuilles north of the Deûle channel, where the highest Se concentrations in solids was found in a 13 m alluvial clay deposit above the chalk, a first main type of waters can be defined with the variable and locally highest Se concentrations (0.19 to 0.4 µmol.L-1), relatively high and stable sulphate concentrations (2.5 µmol/L), no nitrates, dissolved Fe and Mn, negative δ34S (around -20 ‰) and δ18O typical of evaporated waters. A second main type of waters can be described at Houplin, south of the Deûle channel, where the geological profile show less than 1 mg/kg of Se, with intermediate Se concentrations (0.1 to 0.2 µmol/L), variable nitrate concentrations (0.4 to 1.2 mmol/L), not quantified dissolved Fe and Mn, sulphate concentrations close to 1.5 mmol/L, variable negative δ34S (-8 to -24 ‰) and δ18O in the

  16. Tracking selenium behaviour in chalk aquifer (northern France): Sr and 34S-sulphates isotopes constraints.

    Science.gov (United States)

    Cary, Lise; Benabderraziq, Hind; Elkhattabi, Jamal; Parmentier, Marc; Gourcy, Laurence; Négrel, Philippe

    2014-05-01

    Groundwaters in parts of the Paris Basin (France) are facing increasing selenium (Se) contents that can exceed the drinking water limit of 10 μg/L according to the European Framework Directive in the field of water policy (2000/60/EC). To better understand the groundwater origins and the selenium dynamics, the water chemistry of the Chalk aquifer supplying drinkable water to Lille city was studied. This area is submitted to quantitative and qualitative pressure from industrial, urban and agriculture origins. An integrated study was settled to determine the water sources and dynamics of elements, with a focus on Se. After a large chemical characterisation of the groundwater chemistry in the four field wells, a monthly monitoring was held in four wells and in the Deûle channel. Chemical analysis of major and trace elements, stable isotopes (δ18O, δ2H), strontium isotopes, and δ34S and δ18O of sulphates were realised. The chemical composition of solids sampled at various depths at vicinity of the four wells was also analysed. The specific geochemical signature of groundwater as revealed by Sr isotopes, in addition to element concentrations ratios like Mg/Sr and Se/Sr, highlighted mixture of three main groundwaters bodies: (1) the upstream groundwaters in the recharge area with the most radiogenic 87Sr/86Sr isotopic signature; (2) the confined groundwaters with high Sr concentrations due to water-rock interactions and the lowest 87Sr/86Sr isotopic signature close to the one of the chalk in Paris and London basins; (3) the Se-rich formations of Tertiary and Quaternary. The contents of Se, mainly present as SeV I (and locally as SeIV ), displayed spatial and temporal disparities that can be explained by geological and hydrogeological conditions. Se-rich clayed sediments originating from the dismantling of Se-rich tertiary formations (i.e. Ypresian) overlay the chalk formation and can be found in saturated conditions depending of the water table level. Oxidation of

  17. A description of the tritium facility at the Chalk River Laboratories

    International Nuclear Information System (INIS)

    AECL's Tritium Facility is located at its Chalk River Laboratories (CRL). The Tritium Facility was originally built to support the tritium technology needs for CANDU reactors and Canadian fusion program. The Tritium Facility commenced its operation in 1979. Since its inception, it has been involved in the development of heavy water detritiation and upgrading processes, development and testing of tritium-breeder materials and design and testing of fusion-fuel cleanup systems for fusion reactor applications, investigation of tritium-materials interactions, tritium storage getters etc. The Tritium Facility also contributed to the design, construction and commissioning activities of the Combined Electrolysis and Catalytic Exchange Upgrading and Detritiation (CECE-UD) Facility at CRL and the Wolsong Tritium Removal Facility (WTRF) in Korea. This paper describes the general set-up of the laboratory, its capabilities and the current tritium-related activities. (author)

  18. Sediment transport and siltation of brown trout (Salmo trutta L.) spawning gravels in chalk streams

    Science.gov (United States)

    Acornley, R. M.; Sear, D. A.

    1999-02-01

    Deposition rates of fine sediment into brown trout spawning gravels were measured at monthly intervals for a period of one year in a small channel of the River Test, Hampshire. Data were also collected on stream discharge, water depth, flow velocity and suspended sediment concentrations. Deposition rates followed a seasonal pattern and were maximal during periods of high discharge in the late winter/early spring when suspended sediment concentrations were high. The material deposited in the spawning gravels included silts and fine sands (<250 m) that were transported in suspension and coarser fragments of low density tufa-like material that were transported as bed load. The ecological implications of fine sediment deposition for salmonid egg survival in chalk streams are considered.

  19. Change in Biot's effective stress coefficient of chalk during pore collapse

    DEFF Research Database (Denmark)

    Alam, M. Monzurul; Fabricius, Ida Lykke

    2013-01-01

    grains could also change during elastic deformation of the grains in a rock mechanics test. Diagenetic change in grain contact cement of chalk can be compared with stress-induced change in the laboratory. The change in porosity is studied with reference to the change in effective stress on grain contacts...... porosity reduces at a slower rate. We noticed that presence of non carbonates and hydrocarbon could increase σ'm. During rock mechanics test in the lab, with increased applied stress, σ'm increases, Biot's effective stress coefficient shows a decreasing trend, while a minor porosity reduction was observed......Biot's effective stress coefficient (α) is a measure of how well grains in the rocks are connected with each other. The amount of contact cements between the grains determines the stiffness of rocks. Change in grain contact occurs during natural diagenesis of sedimentary rock. Contact between the...

  20. Water weakening of chalk explaied from a fluid-solid friction factor

    DEFF Research Database (Denmark)

    Andreassen, Katrine Alling; Fabricius, Ida Lykke

    2010-01-01

    to the macroscale failure and pore collapse properties. The Biot critical frequency incorporates the porosity, permeability, fluid density and fluid viscosity, where the latter is highly temperature dependent – it does not include the applied sound velocity frequency. The listed parameters are usually determined......The hypothesis behind this paper proposal is that the Biot critical frequency can be used to characterize the water weakening phenomenon physically. The Biot critical frequency determines the transition from where an applied sound velocity on a saturated porous chalk is dominated by viscous forces...... were tested at temperatures from 20°C to 130°C with the following pore fluids: fresh water, synthetic seawater of different chemical compositions, methanol, glycol, and oil of varying viscosity. The data was evaluated according to failure lines and yield envelopes for all fluids and temperatures while...

  1. Organically bound tritium (OBT) in soil at different depths around Chalk River Laboratories (CRL), Canada

    International Nuclear Information System (INIS)

    Atomic Energy of Canada Limited (AECL) Chalk River Laboratories (CRL) is a large nuclear research and test establishment with nuclear and non-nuclear facilities located in Chalk River, Ontario. The CRL Environmental Monitoring Program is designed to demonstrate that radiological exposure resulting from releases from the CRL site remain below the public dose limit specified in the regulations (1 mSv/year). This study was conducted to consolidate environmental effects following a continuous atmospheric tritium release observed at CRL. Soil samples were collected at depths of up to 20 cm using soil probes at the CRL site and surrounding areas. The samples were sectioned at 5 cm intervals, and HTO and OBT concentrations were measured in the samples. Prevailing winds at CRL are from NW and SE, which was suggested to be in close relationship with tritium distribution in environmental samples such as soils and plant leaves. The HTO concentration was the highest in surface soil water and plant leaves at a given sampling point. This result suggests that the concentration of tritium in surface soil water and in plants tissue free water essentially reflects the surrounding atmospheric tritium concentration. OBT concentrations in soil were measured at the historical HT release site, Plant Road, Mattawa Road and three background sites near CRL. The top layer of soil generally had the highest OBT concentration among collected soil samples. This result suggests that OBT concentrations are different from HTO concentrations at the same site and can be representative of previously released environmental tritium at the sampling point. The relationship between the OBT concentration in soil and the amount of tritium released into the environment will be useful for the evaluation of environmental tritium effects and the fate of tritium in the terrestrial ecosystem. The study points out that HTO shows shorter-term dynamic conditions, whereas OBT shows longer-term steady-state conditions

  2. Managing extremes in groundwater-dominated catchments: the Chalk of SE England (Invited)

    Science.gov (United States)

    Wheater, H. S.

    2009-12-01

    The Chalk aquifers of Southern and Eastern England are a dominant local and regional water resource, and rivers located on the Chalk outcrop have a characteristic behaviour and support valuable and protected aquatic ecosystems. In these catchments, typically less than 2% of rainfall is translated into stormflow response. Infiltration occurs into an unsaturated zone that varies in depth from zero at the stream to 100m at the interfluve. Seasonal groundwater recharge is translated into a seasonal river hydrograph, and the length of flowing river expands and contracts seasonally - so-called ‘bourne’ behaviour. Groundwater catchment areas also vary temporally, and stream-aquifer interactions can be complex. Extensive and long duration flooding in 2000/2001 highlighted the vulnerability of these systems to extremes of long duration rainfall (weeks and months). Source areas for runoff expand into dry valleys, springs break out in ‘new’ locations and given the normally low %runoff, highly non-linear flow response occurs. Conversely, droughts are also of major concern, particularly given scenarios of climate change for SE England. Water quality issues are also important, particularly nutrient pollution. These management concerns have focussed attention on the need for improved understanding, and for appropriate modelling tools for flood risk assessment and drought and water quality management. The paper addresses recent research into the historic behaviour of these systems under extremes, the relative roles of fracture and porous matrix flow in the unsaturated zone under extremes, and the nature of stream-aquifer interactions, including detailed experimental studies. Challenges for modelling are identified; for groundwater flooding conventional flood design approaches are inadequate, but groundwater models lack appropriate topographic constraints and the required spatial and temporal resolution; for drought, recharge estimation and diffuse pollution, better

  3. Environmental assessment of Chalk Point cooling tower drift and vapor emissions

    Energy Technology Data Exchange (ETDEWEB)

    Davis, E.A.

    1979-03-01

    An assessment is provided of selected environmental effects of operating the cooling towers and stacks of Units No. 3 and No. 4 of the Potomac Electric Power Company's generating station at Chalk Point, Maryland. The emphasis is on the magnitude of salt deposition to the area surrounding the cooling tower due to saline water drift. A secondary but important consideration is the magnitude of salt loading due to saline drift from the stack which uses saline river water in scrubbing flue gases. This salt loading together with that of the ambient salt background is assessed for its effects on soils, crops, native vegetation and man-made structures. Other atmospheric effects examined are: enhancement of ground level fogging and icing, enhancement of precipitation, and the flight hazards to aircraft. A numerical model of drift deposition has been developed and validated against the data collected in the Dyed Drift Experiment at Chalk Point. Use of the available data model predictions indicate that with fulltime, full load operation of both 600 MW(e) units significant levels of salt deposition occur only on the plant site within 0.4 km of the source. The predicted maximum salt deposition rates are given. The effects on soils, crops and native vegetation are predicted to be negligible at off-site locations. Significant effects to foliage of dogwood is predicted to occur at the most impacted on-site locations. Corrosion of structures at these locations could be enhanced under conditions of heavy plant operation. Enhancement of ground-level fogging, icing, and precipitation is expected to be negligible for all conditions of plant use. Hazards to aircraft because of restricted visibility, turbulence, and icing of structures and engines are estimated to be very slight and of no consequence.

  4. Yield Stress and Physical Data Results for the Tank 19F Radioactive Mound Sample and Tank 19F Simulant Samples

    International Nuclear Information System (INIS)

    The purpose of this work was to characterize and compare the settling behavior of the radioactive Tank 19F mound sample and non-radioactive Pacific Northwest Nation Laboratory simulants at 6, 11, and 16 weight percent total solids

  5. Growth and form of the mound in Gale Crater, Mars: Slope-wind enhanced erosion and transport

    CERN Document Server

    Kite, Edwin S

    2012-01-01

    Gale crater, the landing site of the Curiosity Mars rover, hosts a 5 kilometer high layered mound of uncertain origin which may represent an important archive of the planet's past climate. Although widely considered to be an erosional remnant of a once crater-filling unit, we combine structural measurements and a new model of formation to show how this mound may have grown in place near the center of the crater under the influence of topographic slope-induced winds. This mechanism implicates airfall-dominated deposition with a limited role for lacustrine or fluvial activity in the formation of the Gale mound, and is not favorable for the preservation of organic carbon. Slope-wind enhanced erosion and transport is widely applicable to a range of similar sedimentary mounds found across the Martian surface.

  6. Upper Cretaceous chalk facies and depositional history recorded in the Mona-1 core, Mona Ridge, Danish North Sea

    Directory of Open Access Journals (Sweden)

    Finn Surlyk

    2011-12-01

    Full Text Available The 331 m long core from the Mona-1 well in the Danish North Sea spans almost the entire Upper Cretaceous Chalk Group but only about 10% of Late Cretaceous time is represented. The succession comprises 14 facies representing pelagic deposition, turbidity flow, and mass-transport processes, including mudflow, debris flow, and slumping. Pelagic deposits vary mainly in terms of the concentration of siliciclastic material, the trace-fossil assemblage, and the presence or ab¬sence of primary sedimentary structures. Pelagic sedimentation was probably punctuated by the deposition of thin turbidites, and the resultant deposits were thoroughly bioturbated if deposited during normal oxygenation at the sea floor. Periodic benthic dysoxia resulted in the preservation of primary structures, as represented by laminated chalk which consists of thin pelagic laminae alternating with thin turbidites. In addition to the thin turbidites in the laminated chalk, four dif¬ferent turbidite facies are interpreted as representing high- to low-energy flows. Clast-supported chalk conglomerates have previously not been differentiated from other turbidites, but are here interpreted to be directly related to the down-slope evolution of debris flows. Debris flows are rep¬resented by matrix-supported conglomerates, which form one of the most common facies in the succession. High-concentration, gravity-driven suspension flows passed into dilute visco-plastic flows during the final stages of deposition and resulted in the deposition of structureless chalks. Limited shear deformation produced distinct quasi-facies from which the precursor facies can be deduced, whereas intense or continued shear deformation produced a shear-banded quasi-facies from which the precursor facies cannot be deduced in all cases. A series of major slump packages (14–18 in total are interpreted, forming over 40% of the succession; debrites appear to be the most common precursor facies involved in

  7. Upper Cretaceous chalk facies and depositional history recorded in the Mona-1 core, Mona Ridge, Danish North Sea: Plate 1

    Directory of Open Access Journals (Sweden)

    Surlyk, Finn

    2011-12-01

    Full Text Available The 331 m long core from the Mona-1 well in the Danish North Sea spans almost the entire Upper Cretaceous Chalk Group but only about 10% of Late Cretaceous time is represented. The succession comprises 14 facies representing pelagic deposition, turbidity flow, and mass-transport processes, including mudflow, debris flow, and slumping. Pelagic deposits vary mainly in terms of the concentration of siliciclastic material, the trace-fossil assemblage, and the presence or ab¬sence of primary sedimentary structures. Pelagic sedimentation was probably punctuated by the deposition of thin turbidites, and the resultant deposits were thoroughly bioturbated if deposited during normal oxygenation at the sea floor. Periodic benthic dysoxia resulted in the preservation of primary structures, as represented by laminated chalk which consists of thin pelagic laminae alternating with thin turbidites. In addition to the thin turbidites in the laminated chalk, four dif¬ferent turbidite facies are interpreted as representing high- to low-energy flows. Clast-supported chalk conglomerates have previously not been differentiated from other turbidites, but are here interpreted to be directly related to the down-slope evolution of debris flows. Debris flows are rep¬resented by matrix-supported conglomerates, which form one of the most common facies in the succession. High-concentration, gravity-driven suspension flows passed into dilute visco-plastic flows during the final stages of deposition and resulted in the deposition of structureless chalks. Limited shear deformation produced distinct quasi-facies from which the precursor facies can be deduced, whereas intense or continued shear deformation produced a shear-banded quasi-facies from which the precursor facies cannot be deduced in all cases. A series of major slump packages (14–18 in total are interpreted, forming over 40% of the succession; debrites appear to be the most common precursor facies involved in

  8. The early diagenetic and PETROphysical behaviour of recent cold-water CARbonate mounds in Deep Environments (PETROCARDE)

    OpenAIRE

    Foubert, A.; H. Pirlet; Thierens, M.; Van Mol, B.; Henriet, J.-P.; Swennen, R.

    2010-01-01

    Sub-recent cold-water carbonate mounds localized in deeper slope settings on the Atlantic continental margins cannot be any longer neglected in the study of carbonate systems. They clearly play a major role in the dynamics of mixed siliciclastic-carbonate and/or carbonate-dominated continental slopes. Carbonate accumulation rates of cold-water carbonate mounds are about 4 to 12 % of the carbonate accumulation rates of tropical shallow-water reefs but exceed the carbonate accumulation rates of...

  9. Association among active seafloor deformation, mound formation, and gas hydrate growth and accumulation within the seafloor of the Santa Monica Basin, offshore California

    Science.gov (United States)

    Paull, C.K.; Normark, W.R.; Ussler, W., III; Caress, D.W.; Keaten, R.

    2008-01-01

    Seafloor blister-like mounds, methane migration and gas hydrate formation were investigated through detailed seafloor surveys in Santa Monica Basin, offshore of Los Angeles, California. Two distinct deep-water (??? 800??m water depth) topographic mounds were surveyed using an autonomous underwater vehicle (carrying a multibeam sonar and a chirp sub-bottom profiler) and one of these was explored with the remotely operated vehicle Tiburon. The mounds are > 10??m high and > 100??m wide dome-shaped bathymetric features. These mounds protrude from crests of broad anticlines (~ 20??m high and 1 to 3??km long) formed within latest Quaternary-aged seafloor sediment associated with compression between lateral offsets in regional faults. No allochthonous sediments were observed on the mounds, except slumped material off the steep slopes of the mounds. Continuous streams of methane gas bubbles emanate from the crest of the northeastern mound, and extensive methane-derived authigenic carbonate pavements and chemosynthetic communities mantle the mound surface. The large local vertical displacements needed to produce these mounds suggests a corresponding net mass accumulation has occurred within the immediate subsurface. Formation and accumulation of pure gas hydrate lenses in the subsurface is proposed as a mechanism to blister the seafloor and form these mounds. ?? 2008 Elsevier B.V. All rights reserved.

  10. Experimental Study on Friction Coefficient Between Concrete and the Top Surface of Rubble Mound Foundation

    Institute of Scientific and Technical Information of China (English)

    LI Yan-bao; JIANG Xue-lian; GUO Hong-yi

    2005-01-01

    Experimental studies on the friction coefficient between concrete and the top surface of a rubble mound foundation in China are reviewed. Through comparison of different test results, the development of this research is comprehensively analyzed. An experiment is carried out in the condition similar to prototype. The process curve of friction coefficient with the test block sliding is analyzed and a standard for determination of the friction coefficient is defined. The variation features of the friction coefficient are analyzed on the basis of the present experimental results and other studies in China. It is shown that the friction coefficient between concrete and the top surface of a rubble mound foundation decreases with the increase of the foundation pressure, and the friction coefficient for a very fine leveling bed is smaller than that for a fine leveling bed.

  11. Geometry-Lithology-Origin: Solving the mystery of the Late Miocene mounded features below Lake Balaton

    Science.gov (United States)

    Visnovitz, Ferenc; Horváth, Ferenc; Surányi, Gergely

    2014-05-01

    The Department of Geophysics and Space Sciences of Eötvös University has carried out single- and multichannel water seismic surveys at the Lake Balaton since 1993. The dense grid of 2D profiles offers a high resolution image of the Late Miocene sedimentary strata (Tihany, Somló and Szák Formations) up to a thickness of 200 meters below the lake. These strata can be divided into smaller sedimentary units by numerous parasequence boundaries (Sztanó&Magyar, 2007). In one of these parasequence interesting, high amplitude mounded features have been observed that follow a seismic horizon over large area. It means that these features indicate a Late Miocene regional event. In terms of their shape these mounds are few tens of meters wide, several tens to a hundreds of meters long and few meters high. Their geometry and inner structure were mapped from 2D segments that were used for 3D reconstructions. The shape and stratigraphic position of these features have inspired Sacchi and Horvath (1999) to interpret them as the subsurface equivalent of the fresh-water siliceous-limestone mounds exposed on the Tihany Peninsula. They held these mounds as an evidence of dryland conditions in the time period of the formation of a Late Miocene erosional surface (PAN-2) that they regarded as a 3rd order sequence boundary. In addition to this so called "travertine" concept another explanation was also formulated as the mounds are the product of sedimentary failures e.g. slumps or water escape. To solve the problem an offshore drilling with a total depth of 19 meters was accomplished in October 2013 to sample one of these mounds and determine their origin. The well has not crossed any travertine body, instead alternating layers of clay-silt and very fine sand - without any convincing sign of fluid escape structures - were found in the core (typical lithology of the Tihany Formation). 3D structural analysis of the mounds revealed spherical organization composing bodies that are

  12. Phase dependent view of Cyclotron lines from model accretion mounds on Neutron Stars

    CERN Document Server

    Dipanjan, Mukherjee

    2011-01-01

    In this paper we make a phase dependent study of the effect of the distortion of local magnetic field due to confinement of accreted matter in X-ray binaries on the cyclotron spectra emitted from the hotspot . We have numerically solved the Grad-Shafranov equation for axisymmetric static MHD equilibria of matter confined at the polar cap of neutron stars. From our solutions we model the cyclotron spectra that will be emitted from the region by integrating the emission from all parts of the mound to get the resultant spectra. We perform a phase dependent analysis of the spectra to study the effect of the viewing geometry on the resultant emission from the local mound with distorted magnetic field.

  13. Mechanical Strength Modeling and Optimization of Lateritic Solid Block with 4% Mound Soil Inclusion

    Directory of Open Access Journals (Sweden)

    Onuamah, P.N

    2015-05-01

    Full Text Available The work is an investigation for the model development and optimization of the compressive strength of solid sandcrete block with mound soil inclusion. The study applies the Scheffe’s optimization approach to obtain a mathematical model of the form f(xi1,xi2,xi3,,xi4, where xi are proportions of the concrete components, viz: cement, mound soil, laterite, and water. Scheffe’s experimental design techniques are followed to mould various solid block samples measuring 450mm x 225mm x 150mm and tested for 28 days strength. The task involved experimentation and design, applying the second order polynomial characterization process of the simplex lattice method. The model adequacy is checked using the control factors. Finally a software is prepared to handle the design computation process to take the desired property of the mix, and generate the optimal mix ratios.

  14. Organic matter quality and supply to deep-water coral/mound systems of the NW European Continental Margin

    Science.gov (United States)

    Kiriakoulakis, K.; Freiwald, A.; Fisher, E.; Wolff, G. A.

    2007-02-01

    Comparison of five deep-water coral (DWC)/mound ecosystems along the European Continental Margin shows that suspended particulate organic matter (sPOM), a potential food source, is lipid rich and of high quality. However, there are differences between the sites. The Darwin and Pelagia Mounds (N. Rockall Trough and N. Porcupine Bank, respectively) have higher proportions of labile particulate lipids (including high proportions of polyunsaturated fatty acids) in the benthic boundary layer than Logachev, Hovland and Belgica Mounds (Rockall Bank, S. Porcupine Bank and Porcupine Seabight, respectively). The high quality sPOM could be transported downslope from the euphotic zone. There is some evidence for inter-annual variability at some sites (e.g. Hovland and Logachev Mounds) as large differences in suspended lipid and particulate organic carbon concentrations were observed over the sampling period. Elevated total organic carbon contents of sediments at mound sites, relative to control sites in some cases (particularly Darwin Mounds), probably reflect local hydrodynamic control and the trapping of sPOM by the DWC. Fresh POM can be relatively rapidly transferred to significant depth (up to 8 cm) through bioturbation that is evident at all sites. There is no clear evidence of present day hydrocarbon seepage at any of the sites.

  15. Macrofauna community inside and outside of the Darwin Mounds SAC, NE Atlantic

    Directory of Open Access Journals (Sweden)

    N. Serpetti

    2012-11-01

    Full Text Available Over the past two decades, growing concerns have been raised regarding the effects of towed fishing gears, such as trawls and dredges, on deep-sea biodiversity and ecosystem functioning. Trawling disturbs the benthic communities both physically and biologically, and can eliminate the most vulnerable organisms and modify habitat structure; chronically disturbed communities are often dominated by opportunistic species. The European Union is under obligation to designate a network of offshore Special Areas of Conservation (SACs and Marine Protected Areas (MPAs by the end of 2012 based on the perceived expectation that these networks will help protect marine biodiversity and that within these areas, faunal abundance and diversity will be higher than the surrounding fished areas.

    The Darwin Mounds, only discovered in 1998, are located in the Rockall Trough, NE Atlantic at a depth of ~ 1000 m. Deep-water trawling regularly took place in the region of the Darwin Mounds; however in 2004 the mounds were designated as the first offshore SAC in UK and the area is now closed to bottom trawling. As part of the HERMIONE programme the influence of human impact on the Oceans was one of the key themes and in June 2011, an investigation of the macrofaunal community structure at comparable sites both inside and outside of the Darwin Mound SAC was undertaken. Macrofaunal communities were found to differ significantly, with the difference mostly driven by changes in the abundance of polychaetes, crustaceans and nematodes whilst no significant differences were seen for the other phyla. Whereas overall macrofaunal abundance was higher outside the SAC compared to within, this pattern varies considerably between phyla. Diversity indices showed no significant differences between protected and unprotected sites. This could indicate that a few years of preservation are not enough time to determine a recovery by the macrofaunal community of cold-water ecosystems

  16. The settlement mound of Birnin Lafiya: new evidence from the eastern arc of the Niger River

    OpenAIRE

    Haour, Anne; Nixon, Sam; N'Dah, Didier; Magnavita, Carlos; Livingstone Smith, Alexandre

    2016-01-01

    The development of complex social organisation and trade networks during the first and second millennia AD in the Sahel region of West Africa has long been hampered by a paucity of reliable data. Investigations at Birnin Lafiya, a large settlement mound of this period on the eastern arc of the Niger River, help to fill this gap. The site can now be placed within its broader landscape, and discoveries of early mud architecture, circular structures, human burial remains, personal ornamentation ...

  17. Origin, growth and demise of cold-water coral mound Challenger (IODP Site 1317)

    OpenAIRE

    Raddatz, Jacek

    2011-01-01

    The Integrated Ocean Drilling Program (IODP) Expedition 307 was proposed to obtain evidence for understanding the origin and evolution of a 155 m high deepwater carbonate mound in the Porcupine Seabight. The major aim of this study is the reconstruction of environmental parameters using well-developed paleoceanographic proxies derived from calcareous tests and skeletons of benthic organisms based on sediment cores from this expedition. In particular, this study uses different archives such as...

  18. Origin,Growth and demise of the cold-water coral mound Challenger (IODP Site 1317)

    OpenAIRE

    Raddatz, Jacek

    2011-01-01

    The Integrated Ocean Drilling Program (IODP) Expedition 307 was proposed to obtain evidence for understanding the origin and evolution of a 155 m high deepwater carbonate mound in the Porcupine Seabight. The major aim of this study is the reconstruction of environmental parameters using well-developed paleoceanographic proxies derived from calcareous tests and skeletons of benthic organisms based on sediment cores from this expedition. In particular, this study uses different archives such as...

  19. Seismic delineation of Algal Mound Reservoirs, Humble City South Field, Lea County, New Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Caughey, C.A.

    1988-01-01

    Pennsylvanian algal mounds near Lovington, New Mexico, typify the targets remaining for exploration in the Permian basin. The Strawn trend new Lovington comprises numerous small (200-800 ac) reservoirs of clean algal limestone encased in unfossiliferous carbonate mudrocks. Vuggy porosity occurs in algal micrites and sporadically in crinoidal or foraminiferal grainstones associated with the mound. Some of the Lovington area fields encountered downdip water, but difficulty in finding the mound facies remains the principal dry-hole hazard. Vague acoustical boundaries complicate seismic detection of relatively minor (50-150 ft) carbonate buildups at depths of 11,200-11,600 ft. Stratigraphic interpretation of high-resolution seismic data recently led to several new field discoveries and major extensions. Development drilling, however, can be an even greater challenge to reservoir prediction. Humble City South field illustrates the difficulty of developing a stratigraphic oil field in an area of poor seismic definition and sparse well control. A shooting program following the wildcat discovery only heightened confusion about the size and shape of the new reservoir. Two subsequent dry holes missed the mound entirely and provided only negative control. Seismic modeling, careful stratigraphic interpretation, and saturation coverage with a three-dimensional seismic project ultimately defined the existing reservoir and revealed the presence of a separate, nearby pool. Exact reservoir delineation remains difficult, but this program presented the first clear picture of overall mount geometry. The Humble City experience showed that three-dimensional seismic can be an important tool in the critical period following a wildcat discovery.

  20. Decadal-scale variations in geomagnetic field intensity from ancient Cypriot slag mounds

    OpenAIRE

    Shaar, R; Tauxe, L.; Ben-Yosef, E; V. Kassianidou; Lorentzen, B; Feinberg, JM; Levy, TE

    2015-01-01

    © 2015. American Geophysical Union. All Rights Reserved. Geomagnetic models based on direct observations since the 1830s show that the averaged relative change in field intensity on Earth's surface over the past 170 years is less than 4.8% per decade. It is unknown if these rates represent the typical behavior of secular variations due to insufficient temporal resolution of archaeomagnetic records from earlier periods. To address this question, we investigate two ancient slag mounds in Cyprus...

  1. Stable isotope sales: Mound Laboratory customer and shipment summaries, FY 1976 and FY 1976A

    Energy Technology Data Exchange (ETDEWEB)

    Ruwe, A.H. Jr. (comp.)

    1977-06-06

    A listing is given of Mound Laboratory's sales of stable isotopes of noble gases, carbon, oxygen, nitrogen, chlorine, and sulfur for fiscal years 1976 and 1976A (the period July 1, 1975 through September 30, 1976). Purchasers are listed alphabetically and are divided into domestic and foreign groups. A cross-reference index by location is included for domestic customers. Cross-reference listings by isotope purchased are included for all customers.

  2. Stable isotope sales: Mound Laboratory customer and shipment summaries, FY 1976 and FY 1976A

    International Nuclear Information System (INIS)

    A listing is given of Mound Laboratory's sales of stable isotopes of noble gases, carbon, oxygen, nitrogen, chlorine, and sulfur for fiscal years 1976 and 1976A (the period July 1, 1975 through September 30, 1976). Purchasers are listed alphabetically and are divided into domestic and foreign groups. A cross-reference index by location is included for domestic customers. Cross-reference listings by isotope purchased are included for all customers

  3. Mound activities in chemical and physical research: January-June 1983

    International Nuclear Information System (INIS)

    Progress and activities are reported on: low-temperature trennschaukel (thermistor calibration, thermal conductivity of He-Ne), liquid-phase thermal diffusion (properties of ethyl chloride), zinc isotope separation, mutal diffusion, molecular beam scattering, calcium isotope separation by ion exchange, thermal stability of crystalline and amorphous ZrPdH/sub x/, and measurement of environmental HT and HTO in the air near Mound

  4. Slope Stability Estimation of the Kościuszko Mound in Cracow

    Directory of Open Access Journals (Sweden)

    Wrana Bogumił

    2015-06-01

    Full Text Available In the paper, the slope stability problem of the Kościuszko Mound in Cracow, Poland is considered. The slope stability analysis was performed using Plaxis FEM program. The outer surface of the mound has complex geometry. The slope of the cone is not uniform in all directions, on the surface of the cone are pedestrian paths. Due to its complicated geometry it was impossible to do computing by Plaxis input pre-procesor. The initial element mesh was generated using Autodesk Autocad 3D and next it was updated by Plaxis program. The soil parameters were adopted in accordance with the detailed geological soil testing performed in 2012. Calculating model includes geogrids. The upper part was covered by MacMat geogrid, while the lower part of the Mound was reinforced using Terramesh Matt geogrid. The slope analysis was performed by successives reduction of φ /c parameters. The total multiplayer ΣMsf is used to define the value of the soil strength parameters. The article presents the results of slope stability before and after the rainfall during 33 days of precipitation in flood of 2010.

  5. Stability formula for armor units to tsunami on rubble mound breakwater

    International Nuclear Information System (INIS)

    The mechanism of the failure of armor units of the rubble mound breakwater due to tsunami was investigated based on the experiments. Tsunamis with leading wave, negative leading wave and soliton fissions were the target tsunamis in the present work. Two different sizes of the wave flumes were used in the experiments. A shorter wave flume is 76m long, 1.2m deep and 0.90m wide and the longer one 205m long, 6.0m deep and 3.4m wide. The mass of the armor unit used ranges from 14g, 30g, 50g, 112g, 240g to 400g. The stability formula was derived from the balance of the fluid force acting armor units and the resistance force of the armor unit in the armor layer. The two coefficients such as the drag coefficient of the armor unit and the friction coefficient are determined to give the stability condition. The relationship between the mass of armor units and the maximum velocity on the crest of the rubble mound breakwater was obtained to determine the conditions of no damage of the armor layer. The numerical simulation method to estimate the velocity on the crest of the rubble mound breakwater was described in the present work. The numerical simulation results were verified with the experimental results of the time histories of the water depth and the horizontal component of the velocity and a good agreements was confirmed. (author)

  6. The use of resistivity and gamma logging in lithostratigraphical studies of the chalk in Lincolnshire and South Humberside

    International Nuclear Information System (INIS)

    Electrical resistivity and natural gamma logs obtained from 70 boreholes in Lincolnshire and South Humberside can be interpreted in terms of lithology and show excellent agreement with the detailed lithostratigraphical divisions of the Chalk, obtained by Wood and Smith (1978) from the study of surface exposures. As, to the best of our knowledge, this sequence is complete, for the first time a direct correlation between continuous borehole logs and a detailed lithostratigraphical succession is possible. Important marl bands and some erosion surfaces and flint bands can be identified on the resistivity and gamma logs and traced over most of the study area. Stratigraphical positions of the logged boreholes can be determined and formation thicknesses measured. This information has enabled the construction of an accurate contour map of the elevation of the base of the Chalk and the eastward extension of the Caistor Monocline has been identified. (author)

  7. Changes in Specific Surface as observed by NMR, caused by saturation of Chalk with porewater bearing divalent Ions

    DEFF Research Database (Denmark)

    Katika, Konstantina; Addassi, Mouadh; Alam, Mohammad Monzurul;

    2014-01-01

    Nuclear Magnetic Resonance (NMR) spectrometry has proved to be a good technique for determining the petrophysical properties of reservoir rocks; such as porosity and pore size distribution. We investigated how pore water rich in divalent ions affect the NMR signal from chalk with two different...... depositional textures. We compared two cases. The first experiments on outcrop chalk with high salinity brines showed that saturation with divalent ions (Mg2+,Ca2+and SO42-) cause major shifts in the T2 distribution curve, probably due to precipitation in the pore space. In a second set of experiments, fluid......-to-volume ratio of the pore space. The results of this work could benefit the ongoing study on the optimization of the water composition for Enhanced Oil Recovery (EOR) methods and shed light on how it can affect the mechanical and physical properties of the rock....

  8. Using environmental tracers to assess the extent of river-groundwater interaction in a quarried area of the English Chalk

    Energy Technology Data Exchange (ETDEWEB)

    Darling, W.G., E-mail: wgd@bgs.ac.uk [British Geological Survey, Maclean Building, Wallingford OX10 8BB (United Kingdom); Gooddy, D.C. [British Geological Survey, Maclean Building, Wallingford OX10 8BB (United Kingdom); Riches, J. [Thames Water Utilities Limited, Rose Kiln Court, Rose Kiln Lane, Reading RG2 0BY (United Kingdom); Wallis, I. [British Geological Survey, Maclean Building, Wallingford OX10 8BB (United Kingdom)

    2010-07-15

    The Swanscombe area of Kent, SE England represents a typical example of a heavily quarried Chalk area currently undergoing re-development. Because the Chalk is also an important aquifer, a good understanding of groundwater movement is required if environmental impacts are to be minimised and the water resource maximised. In particular, the nature of the relationship between the River Darent and groundwater in the Swanscombe Chalk Block requires better characterisation. Here, 'environmental tracers' in the form of ambient concentrations of stable isotopes, chlorofluorocarbons (CFCs), sulphur hexafluoride (SF{sub 6}) and tritium ({sup 3}H) are used to investigate this and other aspects of groundwater movement in the vicinity of the quarries. Stable isotopic contrasts indicate little evidence for widespread river infiltration to the regional Chalk aquifer, although stable isotope and {sup 3}H data suggest that 20-35% of the abstraction by river-valley public water supply boreholes may be derived from the river. The CFCs, while present at above-modern concentrations in almost all groundwaters, can be used as tracers, indicating basically S-N flowpaths in the area south of the quarries, though sub-karstic conduits associated with areas of Palaeogene cover add a level of uncertainty at the local scale. Simple piston flow residence times based on SF{sub 6} range from 1 to 17 a, but the data are probably better interpreted in terms of mixing between varying amounts of modern recharge derived from the south and deeper stored groundwater. The information gained from environmental tracers can therefore contribute to effective resource management.

  9. PowerPoint or chalk and talk: Perceptions of medical students versus dental students in a medical college in India

    OpenAIRE

    Vikas Seth; Prerna Upadhyaya; Mushtaq Ahmad; et al, ...

    2010-01-01

    Vikas Seth, Prerna Upadhyaya, Mushtaq Ahmad, Vijay MogheDepartment of Pharmacology, Mahatma Gandhi Medical College, Jaipur, Rajasthan, IndiaPurpose: To assess students’ perceptions of the impact of PowerPoint (PPT) presentations in lectures in comparison to the traditional chalk and talk method and lectures using ­transparencies and overhead projector (TOHP). The study analyzes the preferences for teaching aids of medical students versus dental students.Methods: Second year ...

  10. Controls on the spatial and temporal variability of Rn-222 in riparian groundwater in a lowland Chalk catchment.

    OpenAIRE

    Mullinger, Neil J.; Pates, Jackie M.; Binley, Andrew M.; Crook, N. P.

    2009-01-01

    Radon is a powerful tracer of stream-aquifer interactions. However, it is important to consider the source and behaviour of radon in groundwater when interpreting observations of river radon in relation to groundwater discharge. Here we characterise the variability in groundwater radon concentrations in the riparian zone of a Chalk catchment. Groundwater 222Rn (radon) concentrations were determined in riparian zone boreholes at two sites in the Lambourn catchment, Berkshire, UK, over a two ye...

  11. Mass-transport deposits and reservoir quality of Upper Cretaceous Chalk within the German Central Graben, North Sea

    Science.gov (United States)

    Arfai, Jashar; Lutz, Rüdiger; Franke, Dieter; Gaedicke, Christoph; Kley, Jonas

    2016-04-01

    The architecture of intra-chalk deposits in the `Entenschnabel' area of the German North Sea is studied based on 3D seismic data. Adapted from seismic reflection characteristics, four types of mass-transport deposits (MTDs) are distinguished, i.e. slumps, slides, channels and frontal splay deposits. The development of these systems can be linked to inversion tectonics and halotectonic movements of Zechstein salt. Tectonic uplift is interpreted to have caused repeated tilting of the sea floor. This triggered large-scale slump deposition during Turonian-Santonian times. Slump deposits are characterised by chaotic reflection patterns interpreted to result from significant stratal distortion. The south-eastern study area is characterised by a large-scale frontal splay complex. This comprises a network of shallow channel systems arranged in a distributive pattern. Several slide complexes are observed near the Top Chalk in Maastrichtian and Danian sediments. These slides are commonly associated with large incisions into the sediments below. Best reservoir properties with high producible porosities are found in the reworked chalk strata, e.g. Danish North Sea, therefore MTDs detected in the study area are regarded as potential hydrocarbon reservoirs and considered as exploration targets.

  12. POTENTIAL IMPACT OF BLENDING RESIDUAL SOLIDS FROM TANKS 18/19 MOUNDS WITH TANK 7 OPERATIONS

    International Nuclear Information System (INIS)

    High level waste tanks 18F and 19F have residual mounds of waste which may require removal before the tanks can be closed. Conventional slurry pump technology, previously used for waste removal and tank cleaning, has been incapable of removing theses mounds from tanks 18F and 19F. A mechanical cleaning method has been identified that is potentially capable of removing and transferring the mound material to tank 7F for incorporation in a sludge batch for eventual disposal in high level waste glass by the Defense Waste Processing Facility. The Savannah River National Laboratory has been requested to evaluate whether the material transferred from tanks 18F/19F by the mechanical cleaning technology can later be suspended in Tank 7F by conventional slurry pumps after mixing with high level waste sludge. The proposed mechanical cleaning process for removing the waste mounds from tanks 18 and 19 may utilize a high pressure water jet-eductor that creates a vacuum to mobilize solids. The high pressure jet is also used to transport the suspended solids. The jet-eductor system will be mounted on a mechanical crawler for movement around the bottom of tanks 18 and 19. Based on physical chemical property testing of the jet-eductor system processed IE-95 zeolite and size-reduced IE-95 zeolite, the following conclusions were made: (1) The jet-eductor system processed zeolite has a mean and median particle size (volume basis) of 115.4 and 43.3 microns in water. Preferential settling of these large particles is likely. (2) The jet-eductor system processed zeolite rapidly generates settled solid yield stresses in excess of 11,000 Pascals in caustic supernates and will not be easily retrieved from Tank 7 with the existing slurry pump technology. (3) Settled size-reduced IE-95 zeolite (less than 38 microns) in caustic supernate does not generate yield stresses in excess of 600 Pascals in less than 30 days. (4) Preferential settling of size-reduced zeolite is a function of the amount of

  13. Grainstones and cementstone mounds: The Trogkofel summit section (Lower Permian, Carnic Alps, Austria).

    Science.gov (United States)

    Schaffhauser, M.; Sanders, D.; Krainer, K.

    2009-04-01

    In the Carnic Alps, Austria, an Artinskian succession 400 m thick of shallow-water bioclastic limestones and of mounds composed of ?Archaeolithophyllum, Archaeolithoporella and abundant fibrous cementstone (after former aragonite) records deposition along a "grainstone-dominated" platform margin. The section was taken along the route through the east-facing cliff of Trogkofel. The Trogkofel Limestone (Artinskian pro parte) is excellently exposed and preserved the most complete along this route, but no section has hitherto been logged. The total thickness of the Trogkofel Limestone probably is about 550 meters; the summit section comprises its upper 400 meters. The section consists mainly of shallow-water bioclastic limestones (grainstones, packstones, rudstones) intercalated with cementstone mounds. Both the bioclastic limestones and the mounds typically are thick-bedded to, more commonly, unbedded. Throughout the section, intervals a few tens of meters in thickness dominated by bioclastic limestones change vertically with intervals dominated by cementstone mounds. Up-section, no clear-cut trend with respect to prevalent facies, mean depositional water depth, and energy index is obvious. Furthermore, no lime-muddy, meter-scale peritidal cycles, and no teepee structures and no pisolite levels were identified; thin intervals of fenestral lime mudstones and/or of cryptmicrobially-laminated limestones are very rare. The bioclastic limestones commonly weather out unstratified, or show subhorizontal stratification or, more rarely, low-angle cross-stratification. In the upper 100 meters of section, grainstones to fine-grained rudstones rich in keystone vugs are prevalent. The cementstone mounds comprise intervals up to a few meters in thickness; the biogenic component is characterized by foliose crusts pertaining to ?Archaeolithophyllum hidensis and Archaeolithoporella, overgrown by Tubiphytes and fenestrate bryozoans. The ?Archaeolithophyllum-Archaeolithoporella crusts

  14. Simulation of Groundwater Mound Resulting from Proposed Artificial Recharge of Treated Sewage Effluent Case study – Gaza waste water treatment plant, Palestine

    OpenAIRE

    Aish, Adnan Mousa

    2010-01-01

    Mounding of the groundwater table beneath recharge sources is of concern as the raised water table approaches closely to near-surface facilities or features. The shape and height of the mound depend on several factors including the recharge rate, hydraulic conductivity and thickness of the aquifer. The objective of this paper is to evaluate the suitability of the study area for a rapid infiltration system of treated wastewater effluent without causing excessive mounding of the water table. A ...

  15. Edibility of sport fishes in the Ottawa River near Chalk River Laboratories

    International Nuclear Information System (INIS)

    To address the question of edibility of fish in the Ottawa River near Chalk River Laboratories (CRL), 123 game fish were collected for analysis from four locations: Mackey and Rolphton (45 km and 35 km upstream of Chalk River Laboratories (CRL), respectively), the Sandspit (Pointe au Bapteme) and Cotnam Island (1.6 km and 45 km downstream of CRL, respectively). Twenty-six to thirty-six game fish were collected at each location in 2007 and samples of flesh or bone were analyzed. Trap nets were used to collect only the fish required, allowing release of management-sensitive species. The focus was on walleye (Sander vitreus) because they are abundant and popular among anglers. A few northern pike (Esox lucius) and a smaller number of smallmouth bass (Micropterus dolomieui) were also collected at three of the four sites. Samples of the fish were analyzed for cesium-137 (137Cs), strontium-90 (90Sr), mercury (Hg), and selected organo-chlorine compounds. Concentrations of 137Cs in the flesh and 90Sr in the bones of sport fish were low and similar at all four locations and appear to reflect the global residuals from nuclear weapons testing (primarily in the 1960's) as opposed to releases from CRL. Possible explanations are: 1) Reductions in radionuclide releases from CRL in recent decades and 2) Relatively large foraging ranges of sport fish. Mercury concentrations were elevated in fishes in the Ottawa River and were significantly higher at the Sandspit and Rolphton than at Mackey and Cotnam Island (p<0.001). Mercury concentrations from the four sites are comparable to concentrations in other Ontario and Quebec lakes. It is advisable therefore, that consumers follow the fish consumption guidelines issued by provincial authorities when eating fish from the Ottawa River. Organo-chlorine compounds were not detected in walleye; however, they were detected in all eight of the pike collected at Cotnam Island. The highest organo-chlorine concentrations were measured in two of the

  16. Development of an Integrated Waste Plan for Chalk River Laboratories - 13376

    International Nuclear Information System (INIS)

    To further its Strategic Planning, the Atomic Energy of Canada Limited (AECL) required an effective approach to developing a fully integrated waste plan for its Chalk River Laboratories (CRL) site. Production of the first Integrated Waste Plan (IWP) for Chalk River was a substantial task involving representatives from each of the major internal stakeholders. Since then, a second revision has been produced and a third is underway. The IWP remains an Interim IWP until all gaps have been resolved and all pathways are at an acceptable level of detail. Full completion will involve a number of iterations, typically annually for up to six years. The end result of completing this process is a comprehensive document and supporting information that includes: - An Integrated Waste Plan document summarizing the entire waste management picture in one place; - Details of all the wastes required to be managed, including volume and timings by waste stream; - Detailed waste stream pathway maps for the whole life-cycle for each waste stream to be managed from pre-generation planning through to final disposition; and - Critical decision points, i.e. decisions that need to be made and timings by when they need to be made. A waste inventory has been constructed that serves as the master reference inventory of all waste that has been or is committed to be managed at CRL. In the past, only the waste that is in storage has been effectively captured, and future predictions of wastes requiring to be managed were not available in one place. The IWP has also provided a detailed baseline plan at the current level of refinement. Waste flow maps for all identified waste streams, for the full waste life cycle complete to disposition have been constructed. The maps identify areas requiring further development, and show the complexities and inter-relationships between waste streams. Knowledge of these inter-dependencies is necessary in order to perform effective options studies for enabling

  17. Edibility of sport fishes in the Ottawa River near Chalk River Laboratories

    Energy Technology Data Exchange (ETDEWEB)

    Lee, D.R.; Chaput, T.; Miller, A.; Wills, C.A., E-mail: leed@aecl.ca [Atomic Energy of Canada Limited, Chalk River, Ontario (Canada)

    2013-12-15

    To address the question of edibility of fish in the Ottawa River near Chalk River Laboratories (CRL), 123 game fish were collected for analysis from four locations: Mackey and Rolphton (45 km and 35 km upstream of Chalk River Laboratories (CRL), respectively), the Sandspit (Pointe au Bapteme) and Cotnam Island (1.6 km and 45 km downstream of CRL, respectively). Twenty-six to thirty-six game fish were collected at each location in 2007 and samples of flesh or bone were analyzed. Trap nets were used to collect only the fish required, allowing release of management-sensitive species. The focus was on walleye (Sander vitreus) because they are abundant and popular among anglers. A few northern pike (Esox lucius) and a smaller number of smallmouth bass (Micropterus dolomieui) were also collected at three of the four sites. Samples of the fish were analyzed for cesium-137 ({sup 137}Cs), strontium-90 ({sup 90}Sr), mercury (Hg), and selected organo-chlorine compounds. Concentrations of {sup 137}Cs in the flesh and {sup 90}Sr in the bones of sport fish were low and similar at all four locations and appear to reflect the global residuals from nuclear weapons testing (primarily in the 1960's) as opposed to releases from CRL. Possible explanations are: 1) Reductions in radionuclide releases from CRL in recent decades and 2) Relatively large foraging ranges of sport fish. Mercury concentrations were elevated in fishes in the Ottawa River and were significantly higher at the Sandspit and Rolphton than at Mackey and Cotnam Island (p<0.001). Mercury concentrations from the four sites are comparable to concentrations in other Ontario and Quebec lakes. It is advisable therefore, that consumers follow the fish consumption guidelines issued by provincial authorities when eating fish from the Ottawa River. Organo-chlorine compounds were not detected in walleye; however, they were detected in all eight of the pike collected at Cotnam Island. The highest organo

  18. Lithology, fracture intensity, and fracture filling of drill core from Chalk River research area, Ontario

    International Nuclear Information System (INIS)

    In 1977, 1978, and 1979, nine inclined cored boreholes, ranging in length from 113 to 704 m, were drilled in the Chalk River Research Area in order to define the geological subsurface characteristics of the rock mass at several selected test areas. A total of 2,458 metres of NQ-3 and HQ-3 core was obtained from the nine boreholes. Orthogneiss was the most predominant rock type intersected by the boreholes. Pyroxenite, amphibolite, metagabbro and dykes of diabase, pegmatite and aplite were also encountered. The crosscutting relationships and textures within the rocks indicate that the relative ages of the rock units, from youngest to oldest, are diabase; aplite and pegmatite dykes with no defined fabric; pyroxenite; meta-ferrogabbro; amphibolite; aplite and pegmatite dykes and pegmatite pods with a defined fabric; and orthogneiss. Textural characteristics and mineral assemblages indicate that the orthogneisses in the Chalk River Area are a product of regional, medium to high-grade metamorphism and belong to the upper amphibilite to granulite facies. A total of 35,597 fractures (an average of 14.5 fractures per metre) was observed in the core. Brecciated zones and open fractures were noted in the core from all of the boreholes, and major faults were identified in four of the nine boreholes. Nearly all of the fractures have a thickness between 0.4 and 1.2 mm and contain one or more types of filling. Chlorite and calcite are the most common types of filling. Epidote, hematite, clays, sulphides, talc, sericite, and rock fragments also occur in the fractures. The crosscutting relationships between fractures and the sequence of filling layers within the fractures indicate that several episodes of fracturing have occurred and that fractures containing more than one filling have probably been reactivated. A comparison of the geological logs from one of the boreholes with natural gamma, neutron-neutron and magnetic susceptibility logs indicates that certain rock types and

  19. Models of Formation and Activity of Spring Mounds in the Mechertate-Chrita-Sidi El Hani System, Eastern Tunisia: Implications for the Habitability of Mars

    Directory of Open Access Journals (Sweden)

    Elhoucine Essefi

    2014-08-01

    Full Text Available Spring mounds on Earth and on Mars could represent optimal niches of life development. If life ever occurred on Mars, ancient spring deposits would be excellent localities to search for morphological or chemical remnants of an ancient biosphere. In this work, we investigate models of formation and activity of well-exposed spring mounds in the Mechertate-Chrita-Sidi El Hani (MCSH system, eastern Tunisia. We then use these models to explore possible spring mound formation on Mars. In the MCSH system, the genesis of the spring mounds is a direct consequence of groundwater upwelling, triggered by tectonics and/or hydraulics. As they are oriented preferentially along faults, they can be considered as fault spring mounds, implying a tectonic influence in their formation process. However, the hydraulic pressure generated by the convergence of aquifers towards the surface of the system also allows consideration of an origin as artesian spring mounds. In the case of the MCSH system, our geologic data presented here show that both models are valid, and we propose a combined hydro-tectonic model as the likely formation mechanism of artesian-fault spring mounds. During their evolution from the embryonic (early to the islet (“island” stages, spring mounds are also shaped by eolian accumulations and induration processes. Similarly, spring mounds have been suggested to be relatively common in certain provinces on the Martian surface, but their mode of formation is still a matter of debate. We propose that the tectonic, hydraulic, and combined hydro-tectonic models describing the spring mounds at MCSH could be relevant as Martian analogs because: (i the Martian subsurface may be over pressured, potentially expelling mineral-enriched waters as spring mounds on the surface; (ii the Martian subsurface may be fractured, causing alignment of the spring mounds in preferential orientations; and (iii indurated eolian sedimentation and erosional remnants are common

  20. Determination of transmissivity and dispersion in a confined chalk aquifer by simulation of field experiments with three tracers

    International Nuclear Information System (INIS)

    Storage and repumping of thermal energy in chalk aquifers during periods of surplus and deficit production respectively might be an economically feasible method to meet man's need for heating. To be able to evaluate the temporal and spatial variations of thermal energy transfer between water, which mainly flows in the chalk fissures, and the chalk matrix itself it is necessary to know the transmissivity and dispersion parameters of the aquifer. Based on this background, field tests with pumping of water and tracers have been carried out as shown. The fissured chalk aquifer of magnitude H = 16 m is confined by almost impervious top and bottom layers. Two wells with distance L = 101 m were established. A steady flow with Q1 Q2 = 10.9 m3/h was established within a period of 24 h. The radioactive tracers 3H and 82Br and the fluorescent tracer R-WT (rhodamine-water tracer) were injected at known concentrations within a period of 5 min. At time = 24 h valve V0 was opened and V2 closed and within the following 320 h a single well repumping (Q1 = -10.9 m3/h, Q2 = 0) and temporal detection of tracer concentrations were carried out until practically all concentrations were zero. The three concentration curves show a time to peak of about 12 h and a temporal distribution of the relative concentrations (peak concentration = 100% for all tracers) which is almost identical. The total repumped amount of tracer (with correction for radioactive decay) was 63%, 93% and 53% for 3H, 82Br and R-WT, respectively. The corresponding peak concentrations relative to injected concentrations were 1088, 1745 and 737 ppm. These data indicate a strong adsorption to the chalk matrix for R-WT and 3H but weak for 82Br. The simulation of measured concentration curves will be done by means of at least two models, M1-M2, which both include linear adsorption. With respect to permeability and dispersion M1 and M2 differ as follows: M1. Constant coefficients k and D for permeability and dispersion

  1. Inventory of radioactivity in Ottawa River-bed sediments near the Chalk River Laboratories

    International Nuclear Information System (INIS)

    AECL's Chalk River Laboratories (CRL) are situated on the Ontario side of the Ottawa River about 200 km NW of the City of Ottawa. Since 1947, water for cooling CRL's research reactors has been piped from and returned to the Ottawa River. From 1952 to the present time, cooling water has been discharged through the Process Sewer at a rate of 1.5 to 2 m3/s. The Outfall, which is the discharge from the Process Sewer, is in 18 m of water, 65 m offshore. Flow is directed toward the river surface through three 'diffuser vents,' creating a turbulent swirl at the surface and maintaining a patch of open water in winter. In addition to cooling water, the Outfall has, over the years, included small additional effluents from a heavy water recovery plant, a decontamination centre and a waste treatment centre. Although the effluent has been monitored and has met applicable regulatory requirements, investigations of the riverbed near the Outfall revealed radioactivity. In 2001, a riverbed reconnaissance and a detailed coring program were initiated for the purpose of determining the inventory of residual radioactivity. (author)

  2. Post-irradiation examination of the 37M fuel bundle at Chalk River Laboratories (AECL)

    Energy Technology Data Exchange (ETDEWEB)

    Armstrong, J. [Atomic Energy of Canada Limited, Chalk River, Ontario (Canada); Daniels, T. [Ontario Power Generation, Pickering, Ontario (Canada); Montin, J. [Atomic Energy of Canada Limited, Chalk River, Ontario (Canada)

    2014-03-15

    The modified (-element (37M) fuel bundle was designed by Ontario Power Generation (OPG) to improve Critical Heat Flux (CHF) performance in ageing pressure tubes. A modification of the conventional 37-element fuel bundle design, the 37M fuel bundle allows more coolant flow through the interior sub-channels by way of a smaller central element. A demonstration irradiation (DI) of thirty-two fuel bundles was completed in 2011 at OPG's Darlington Nuclear Generating Station to confirm the suitability of the 37M fuel bundles for full core implementation. In support of the DI, fuel elements were examined in the Chalk River Laboratories Hot Cells. Inspection activities included: Bundle and element visual examination; Bundle and element dimensional measurements; Verification of bundle and element integrity; and Internal Gas Volume Measurements. The inspection results for 37M were comparable to that of conventional 37-element CANDU fuel. Fuel performance parameters of the 37M DI fuel bundle and fuel elements were within the range observed for similarly operated conventional 37-element CANDU fuel. Based on these Post Irradiation Examination (PIE) results, 37M fuel performed satisfactorily. (author)

  3. Stratigraphy and palaeoceanography of upper Masstrichtian chalks, southern Danish Central Graben

    Energy Technology Data Exchange (ETDEWEB)

    Ineson, J.R.; Buchardt, B.; Lassen, Susanne; Rasmussen, Jan A.; Schioeler, P.; Schovsbo, N.H.; Sheldon, E.; Surlyk, F. [Geological Survey of Denmark and Greenland, Copenhagen (Denmark)

    2006-07-01

    Upper Maastrichtian chalks form important hydrocarbon reservoirs in the Danish sector of the North Sea and have been intensively studied, yet their lithological uniformity can frustrate attempts to develop a high-resolution stratigraphic subdivision and a genetic understanding of the factors controlling production and sedimentation of the pelagic carbonate ooze. Recent research into these topics, by means of a multidisciplinary study involving quantitative/semiquantitative palynology, micropalaeontology (nannofossils, foraminifers) and isotope geochemistry, integrated with detailed sedimentology. Two key wells were selected, the M-1OX well from the Dan Field and the E-5X well from the Tyra SE Field, based on the extensive core coverage in these wells and on their position in the southern part of the Danish Central Graben where evidence of large-scale resedimentation (and consequent stratigraphic complexity) is uncommon within the Maastrichtian section. This study concentrated on a number of palaeoceanographic signals that can be derived from the sedimentary record. Planktonic organisms, both phytoplankton (e.g. coccolithophores, some dinoflagellates) and zooplankton (e.g. foraminifers) provide a record of conditions in the upper watermasses, largely within the photic zone, while bottom conditions are indicated by epifaunal/infaunal organisms (e.g. benthic foraminifers) and bioturbation, and by the sedimentological evidence of depositional processes at the sea floor. (LN)

  4. Water recharge and solute transport through the vadose zone of fractured chalk under desert conditions

    International Nuclear Information System (INIS)

    In the present study the inferred mechanism of groundwater recharge and contamination was studied using tracer concentrations in the fractured vadose zone of the Avdat chalk. The results of this study are important for an evaluation of groundwater contamination from existing and planned facilities in the northern Negev desert in Israel. This study focused on the vicinity of the Ramat Hovav industrial chemical complex in the northern Negev, which also includes the national site for hazardous waste. Water recharge and solute migration rates were examined in five core holes and one borehole which penetrate the entire vadose zone and enabled the collection of rock samples for chemical and isotopic analyses, and an observation of fracture distribution with depth. Tritium profiles were used to estimate water percolation rates through the vadose zone, chloride profiles were used to assess the migration rate of nonreactive solutes, and bromide profiles were also used to evaluate the migration rate of nonreactive contaminants. Deuterium and oxygen 18 profiles were used to assess the evaporation of the infiltrating water at and near land surface

  5. Canadian fusion breeder blanket program: Irradiation facilities at chalk river*1

    Science.gov (United States)

    Hastings, I. J.; Burton, D. G.; Celli, A.; Delaney, R. D.; Fehrenbach, P. J.; Howe, L. M.; Larson, L. L.; MacEwen, S. R.; Miller, J. M.; Naeem, T. A.; Sawicki, J. A.; Swanson, M. L.; Verrall, R. A.; Zee, R. H.

    1986-11-01

    The major irradiation facility at Chalk River Nuclear Laboratories (CRNL) is the NRU research reactor. Both unvented and vented capsule experiments on candidate blanket ceramics can be performed. In the unvented tests, tritium release data (HT-to-HTO ratio, tritium retention) are obtained by post-irradiation heating of the breeder ceramic in the presence of a sweep gas. Four tests have been completed on Li 2O and LiAlO 2. Effects of sweep gas composition, extraction vessel material and ceramic properties have been determined. Two unvented irradiations under the BEATRIX international breeder exchange program have been completed; analysis is underway. The vented tests involve long-term irradiation of candidate blanket materials. CRITIC-I, scheduled for mid-1986 under BEATRIX, will examine ANL-fabricated Li 2O in a six-month irradiation at 700-1200 K, varying sweep gas composition, with on-line HT/HTO measurement. Additionally, accelerator simulation techniques are available, using 70 kV and 2.0 MV mass separators, a 2.5 MV Van de Graaff accelerator and a tandem accelerator super-conducting cyclotron, the latter allowing irradiation with protons, deuterons or helium at 18-20 MeV.

  6. An overview of the waste characterization program at Chalk River Nuclear Laboratories

    International Nuclear Information System (INIS)

    In the last five years, Chalk River Nuclear Laboratories (CRNL) placed 17,000 m3 of wastes into storage (excluding contaminated soil and fill). Almost half of the waste was generated off-site. CRNL is now developing IRUS, an Intrusion Resistant Underground Structure, and the IST, an Improved Sand Trench, to replace storage with safe, permanent disposal. IRUS will be used to dispose of wastes with radiologically hazardous lifetimes between 150 and 500 years duration and the IST will be used for wastes with radiologically hazardous lifetimes of less than 150 years. A comprehensive Waste Characterization Program (WCP) is in place to support disposal projects. The WCP is responsible for (1) specifying the manifests for waste shipments; (2) developing and maintaining central databases for waste inventories and analytical data; and (3) developing the technologies and procedures to characterize the radiological and the physical/chemical properties of wastes. WCP work is being performed under the umbrella of a newly developed waste management quality assurance (QA) program. This paper gives an overview of the WCP with an emphasis on the requirements for determining radionuclide inventories in wastes, for implementing record-keeping systems and for maintaining a QA program for disposal operations

  7. Paleomagnetism of late Cretaceous and Eocene limestones and chalks from Haiti - tectonic interpretations

    Science.gov (United States)

    van Fossen, Mickey C.; Channell, James E. T.

    1988-06-01

    We have conducted a paleomagnetic study of limestones and chalks from Haiti which suggests that the island of Hispaniola is a composite of at least two tectonically independent blocks. Sampling sites are distributed among three widely separated localities, namely: Les Cayes (nine sites; 18.3°N. Latitude; 73.6°W. Longitude) and Beloc (five sites; 18.4°N. Latitude; 72.6°W. Longitude) which are located on the southern peninsula of Haiti, and a northern locality, Ennery (six sites; 19.5°N. Latitude; 72.5°W. Longitude). Stable magnetization components of dual polarity and moderately high blocking temperature were revealed through progressive thermal demagnetization of samples from all of the Beloc and Ennery sites, while seven of the nine Les Cayes sites possessed unstable magnetizations. Mean paleolatitudes calculated from Beloc and Ennery data show 8° of latitudinal separation that is of at least Eocene age. Pole positions (Beloc: 43.2°N. Latitude; 185.8°E. Longitude, α95=25.1° and Ennery: 66.1°N. Latitude; 31.3°E. Longitude, α95=19.7°) show both colatitudinal and angular discordance with the North American apparent polar wander path. Based on these disparities, we demonstrate that the implied tectonic displacements tend to support some aspects of previously published Caribbean plate tectonic models.

  8. The reduction of sample memory effects in the Chalk River AMS ion source

    International Nuclear Information System (INIS)

    The mechanism underlying Cl and I sample-to-sample interference in the new Chalk River AMS ion source has been studied and compared with the interference observed in an earlier ion source of different internal geometry. The distribution of sputtered material and its degree of migration was measured with the radioactive tracer, 82Br. The temperature dependence of the surface constituents was measured with the elastic recoil detection (ERD) technique and the effect of sample geometry and ion source cleaning was studied with elevated (5 x 10-10) 36Cl/Cl and 129I/I samples. These measurements indicate that a hot (> 350oC) aperture plate ahead of the sample can prevent the sputtering of contaminated regions near the sample. The plate itself remains relatively free of Cl or I itself since these elements or their Cs-gettered compounds are desorbed at this temperature. A small, fixed quantity of Cl or I on this surface is observed, which if sputtered by Cs+ ions, may contribute to ion source memory. Relative sample-to-sample interference for both Cl and I is about 10-3 after 20 min or l0-4 after 60 min. (author)

  9. Simulating Heterogeneous Infiltration and Contaminant leaching Processes at Chalk River, Ontario

    Science.gov (United States)

    Ali, M. A.; Ireson, A. M.; Keim, D.

    2015-12-01

    A study is conducted at a waste management area in Chalk River, Ontario to characterize flow and contaminant transport with the aim of contributing to improved hydrogeological risk assessment in the context of waste management. Field monitoring has been performed to gain insights into the unsaturated zone characteristics, moisture dynamics, and contaminant transport rates. The objective is to provide quantitative estimates of surface fluxes (quantification of infiltration and evaporation) and investigations of unsaturated zone processes controlling water infiltration and spatial variability in head distributions and flow rates. One particular issue is to examine the effectiveness of the clayey soil cap installed to prevent infiltration of water into the waste repository and the top sand soil cover above the clayey layer to divert the infiltrated water laterally. The spatial variability in the unsaturated zone properties and associated effects on water flow and contaminant transport observed at the site, have led to a concerted effort to develop improved model of flow and transport based on stochastic concepts. Results obtained through the unsaturated zone model investigations are combined with the hydrogeological and geochemical components and develop predictive tools to assess the long term fate of the contaminants at the waste management site.

  10. MAGS low level waste storage at Atomic Energy of Canada Limited's Chalk River Laboratories

    International Nuclear Information System (INIS)

    The recent introduction of Modular Above Ground Storage (MAGS) constitutes a substantial improvement in the way solid Low-Level Radioactive Waste (LLRW) is handled and stored at AECL's Chalk River Laboratories (CRL). The LLRW generally contains items such as lightly contaminated clothing, paper towels, glassware, used equipment and building materials produced at CRL, or received from Canadian hospitals, universities and other waste generators. These materials, previously stored in unlined sand trenches, are now being stored in a dry, monitored and more easily retrievable state in steel containers in MAGS storage buildings. The MAGS project involved design and construction of three elements: a Waste Handling Building, the first of a series of pre-engineered steel storage buildings, and a new Waste Management Area to house the storage buildings and containers of bulk waste. This project was well received by the local municipalities during the public consultation conducted as a part of the licensing process. The MAGS system entered service in 2002 and has operated satisfactorily since then. A second storage building was completed in 2003. (author)

  11. A critical assessment of simple recharge models: application to the UK Chalk

    Directory of Open Access Journals (Sweden)

    A. M. Ireson

    2012-10-01

    Full Text Available A framework for the rigorous quantification of the timing and magnitude of groundwater recharge is proposed. This involves developing a physically based model for the flow processes in the unsaturated and saturated zones that is consistent with the conceptualisation of the system, and with field observations. Subsequently, the essential behaviour of this model is emulated using a simpler model that can be applied within operational groundwater models. We take a UK Chalk aquifer as a case study. Flow processes are simulated convincingly using a dual permeability, equivalent continuum, Richards' equation model, applied to a 2-D hillslope transect along which four monitoring wells recorded water levels in the unconfined aquifer. A simple conventional recharge model that has been widely used was calibrated to reproduce the water table response simulated by the physically based model. The performance in reproducing the water table was surprisingly good, given the known discrepancies between the actual processes and the model representation. However, comparisons of recharge fluxes simulated by each model highlighted problems with the recharge processes in the simple model. Specifically, artificial bypass flow events during the summer were compensating for recharge that should have come from slow, continual drainage of the unsaturated zone. Such a model may still be useful for assessment of groundwater resources on a monthly basis, under non-extreme climatic conditions. However, under extreme wet or dry conditions, or under a changed climate the predictive capacity of such models is likely to be inadequate.

  12. Accelerated Clean-up of the United States Department of Energy, Mound Nuclear Weapons Facility in Miamisburg, Ohio

    International Nuclear Information System (INIS)

    CH2M HILL is executing a performance-based contract with the United States Department of Energy to accelerate the safe closure of the nuclear facilities at the former Mound plant in Miamisburg, Ohio. The contract started in January 2003 with a target completion date of March 31, 2006. Our accelerated baseline targets completion of the project 2 years ahead of the previous baseline schedule, by spring 2006, and for $200 million less than previous estimates. This unique decommissioning and remediation project is located within the City of Miamisburg proper and is designed for transfer of the property to the Miamisburg Mound Community Improvement Corporation for industrial reuse. The project is being performed with the Miamisburg Mound Community Improvement Corporation and their tenants co-located on the site creating significant logistical, safety and stakeholder challenges. The project is also being performed in conjunction with the United States Department of Energy, United States Environmental Protection Agency, and the Ohio Environmental Protection Agency under the Mound 2000 regulatory cleanup process. The project is currently over 95% complete. To achieve cleanup and closure of the Mound site, CH2M HILL's scope includes: - Demolition of 64 nuclear, radiological and commercial facilities - Preparation for Transfer of 9 facilities (including a Category 2 nuclear facility) to the Miamisburg Mound Community Improvement Corporation for industrial reuse - Removal of all above ground utility structures and components, and preparation for transfer of 9 utility systems to Miamisburg Mound Community Improvement Corporation - Investigation, remediation, closure, and documentation of all known Potential Release Sites contaminated with radiological and chemical contamination (73 identified in original contract) - Storage, characterization, processing, packaging and shipment of all waste and excess nuclear materials - Preparation for Transfer of the 306 acre site to the

  13. Ft-Ir Spectroscopic Analysis of Potsherds Excavated from the First Settlement Layer of Kuriki Mound, Turkey

    Science.gov (United States)

    Bayazit, Murat; Isik, Iskender; Cereci, Sedat; Issi, Ali; Genc, Elif

    The region covering Southeastern Anatolia takes place in upper Mesopotamia, so it has numerous cultural heritages due to its witness to various social movements of different civilizations in ancient times. Kuruki Mound is located on the junction point of Tigris River and Batman Creek, near Oymatas village which is almost 15 km to Batman, Turkey. The mound is dated back to Late Chalcolithic. Archaeological excavations are carried out on two hills named as “Kuriki Mound-1” and “Kuriki Mound-2” in which 4-layer and 2-layer settlements have been revealed, respectively. This region will be left under the water by the reservoir lake of Ilısu Dam when its construction is completed. Thus, characterization of ancient materials such as potsherds, metals and skeleton ruins should be rapidly done. In this study, 12 potsherds excavated from Layer-1 (the first settlement layer after the surface) in Kuriki Mound-2 were investigated by FT-IR spectrometry. Energy dispersive X-ray fluorescence (EDXRF) and X-ray diffraction (XRD) analyses were used as complementary techniques in order to expose chemical and mineralogical/phase contents, respectively. Obtained results showed that the potteries have been produced with calcareous clays and they include moderate amounts of MgO, K2O, Na2O and Fe2O3 in this context. Additionally, high temperature phases have also been detected with XRD analyses in some samples.

  14. Discovery of hydrothermally active and extinct talc mounds on the Mid-Cayman Rise

    Science.gov (United States)

    Hodgkinson, M.; Murton, B. J.; Roberts, S.

    2013-12-01

    Since 1977, hydrothermal vents have been the subject of intense scientific interest due to their role in cooling the oceanic crust and global geochemical cycles. Until now, two types of hydrothermal system have been identified: one, driven by magmatic heat extruding ';black smoker' fluids; and another, involving serpentinisation of ultramafic rocks and the precipitation of carbonate/brucite chimneys. Here, we present details of a new, off-axis type of hydrothermal system consisting of mounds of predominately botryoidal talc (a magnesium-silicate) with accessory silica and copper sulphides, and chimneys exhaling fluids of moderate temperature and pH. Discovered on the Mid-Cayman Rise (MCR) in 2010, the Von Damm Vent Field (VDVF) features a NNW-ESE-trending line of four overlapping cones, the largest of which is 75 m high by 150 m in diameter. The VDVF is hosted in the gabbroic footwall of the Mount Dent Oceanic Core Complex (MDOCC), which includes serpentinised peridotite at depth. The largest cone vents clear fluids from two main orifices at its summit, with primary temperatures of 215°C. Elsewhere, both focussed and diffuse flow areas emit fluids with temperatures of up to 150°C. The surrounding ~1 m thick pelagic sediment contains abundant pockmarks that emit methane-rich fluids at temperatures of less than 10°C. During the return to the MCR in early 2013, several other talc mounds were discovered within a kilometre of the active VDVF. These inactive mounds also comprise an assemblage of botryoidal talc, silica, disseminated sulphides (including chalcopyrite) and sulphates. One of these mounds (Mystic Mount) is double the volume of the active VDVF. The unique dominance of talc as the major mineral forming the hydrothermal structures indicates unusual vent fluid compositions that are able to carry both copper (at high-temperatures) and precipitate magnesium silicate. Thermodynamic modelling indicates that talc precipitates on mixing a moderately acidic, silica

  15. Vertical movements of frost mounds in subarctic permafrost regions analyzed using geodetic survey and satellite interferometry

    Science.gov (United States)

    Beck, I.; Ludwig, R.; Bernier, M.; Strozzi, T.; Boike, J.

    2015-08-01

    Permafrost-affected soils cover about 40-45 % of Canada. The environment in such areas, especially those located within the discontinuous permafrost zone, has been impacted more than any other by recorded climatic changes. A number of changes, such as surface subsidence and the degradation of frost mounds due to permafrost thawing, have already been observed at many locations. We surveyed three frost mounds (lithalsas) in the subarctic, close to Umiujaq in northern Quebec, using high-precision differential global positioning system (d-GPS) technology during field visits in 2009, 2010 and 2011, thus obtaining detailed information on their responses to the freezing and thawing that occur during the course of the annual temperature cycle. Seasonal pulsations were detected in the frost mounds, and these responses were shown to vary with their state of degradation and the land cover. The most degraded lithalsa showed a maximum amplitude of vertical movement (either up or down) between winter (freezing) and summer (thawing) of 0.19 ± 0.09 m over the study period, while for the least degraded lithalsa this figure was far greater (1.24 ± 0.47 m). Records from areas with little or no vegetation showed far less average vertical movement over the study period (0.17 ± 0.03 m) than those with prostrate shrubs (0.56 ± 0.02 m), suggesting an influence from the land cover. A differential interferometric synthetic aperture radar (D-InSAR) analysis was also completed over the lithalsas using selected TerraSAR-X images acquired from April to October 2009 and from March to October 2010, with a repeat cycle of 11 days. Interferograms with baselines shorter than 200 m were computed revealing a generally very low interferometric coherence, restricting the quantification of vertical movements of the lithalsas. Vertical surface movements of the order of a few centimeters were recorded in the vicinity of Umiujaq.

  16. Mesopotamian ceramics from the burial mounds of Bahrain, c.2250–1750 BC

    DEFF Research Database (Denmark)

    Laursen, Steffen

    2011-01-01

    in Mesopotamia’s interaction with the populations of the ‘Lower Sea’. The first import horizon is comprised of a vessel type found exclusively in the scattered mounds of Early Type which pre-date the rise of the Dilmun ‘state’ proper. The distribution of these vessels outside their areas of production...... demonstrates how they circulated widely in a network elsewhere considered to reflect the orbit of Mesopotamia’s late third-millennium ‘Magan trade’. Here it is consequently concluded that this particular type represents an important fossile directeur of the ‘Magan trade’ and pre-Dilmun florescence. The vessels...

  17. Parameters Influencing Wave Run-Up on a Rubble Mound Breakwater

    DEFF Research Database (Denmark)

    Walle, Björn Van de; Rouck, Julien De; Damme, Luc Van;

    2002-01-01

    Full scale wave run-up measurements have been performed on the Zebrugge rubble mound breakwater. Wave run-up also has been investigated on various small scale models of the Zeebrugge breakwater. A significant difference between the results has been noticed. Additional small scale model testing has...... been carried out on a slightly modified scale model: a regular armour unit pattern has been applied in stead of an irregular pattern as in full scale. The aim of the additional laboratory tests was to investigate the influence of the spectral width parameter and the influence of the position of the...

  18. An examination of recharge mound decay and fossil gradients in arid regional sedimentary basins

    International Nuclear Information System (INIS)

    In many of the vast arid sedimentary basins of the world, groundwater gradients exist that appear to be anomalous in the context of the probable modern recharge potential. The possibility that such gradients are in fact remnant fossil conditions representing the decay of ancient recharge mounds is examined. An example of decay condition is represented using a resistor-network analogue model in which the time control is based on 14C ages. The decay hypothesis is found to be plausible with realistic aquifer characteristics but a non-homogeneous flow is indicated from the 14C data. (author)

  19. Forest regeneration on nutrient-poor peatlands: Effects of fertilization, mounding and sowing.

    OpenAIRE

    Silfverberg, Klaus

    1995-01-01

    The effects of wood ash and PK fertilization on natural regeneration and sowing of Scots pine (Pinus sylvestris L.) were studied in field experiments on nitrogen-poor (Ntot 0.87–1.26%) peat substrates. The study material was derived from three drained, nutrient-poor pine mires (64°52'N, 25°08'E) at Muhos, near Oulu. The experimental fields were laid out in 1985 as a split-split-plot design including the following treatments: mounding, natural regeneration and sowing and fertilization; PK ...

  20. Wave Forces and Overtopping on Crown Walls of Rubble Mound Breakwaters

    DEFF Research Database (Denmark)

    Pedersen, Jan

    series in the coastal laboratory at Aalborg University. Based on analyses of experimental data a design method for assessing the maximum wave forces on the vertical face of the crown wall structures has been developed as well as new and more versatile design equation for the related overtopping...... stability of rubble mound breakwater crown walls. This background motivated the initialization of the present study on wave imposed forces and wave overtopping on crown wall structures. The two subjects where investigated through an excessive parametric model study involving more than 370 long duration test...

  1. Geologic feasibility of selected chalk-bearing sequences within the conterminous United States with regard to siting of radioactive-waste repositories

    Energy Technology Data Exchange (ETDEWEB)

    Gonzales, S.

    1975-11-01

    Various geologic and hydrologic parameters are evaluated in relation to assessing the potential for repository storage of high-level radioactive wastes within several stratigraphic sequences dominated by chalks and chalky limestones. The former lithology is defined as a carbonate rock consisting mainly of very fine-grained particles of micritic calcite. Although chalks also contain coarser-grained particles such as shells of fossil foraminifera and non-calcitic minerals like quartz, most contain more than 90 percent micritic material. The latter represents broken fossil coccolith plates. The chalk-dominated formations discussed are exposed and underlie two different physiographic provinces which nevertheless display a general similarity in both being regions of extensive plains. The Niobrara Formation occurs mainly within the Great Plains province, while the Austin Chalk of Texas and the Selma Group of Alabama and Mississippi are located in the western and eastern Gulf Coastal Plain, respectively. The preliminary assessment is that chalk-bearing sequences show some promise and are deserving of added consideration and evaluation. Containment for hundreds of thousands of years would seem possible given certain assumptions. The most promising units from the three studied are the Niobrara Formation and Selma Group. Regional and local conditions make the Austin more suspect.

  2. Paleoseawater density reconstruction and its implication for cold-water coral carbonate mounds in the northeast Atlantic through time

    Science.gov (United States)

    Rüggeberg, Andres; Flögel, Sascha; Dullo, Wolf-Christian; Raddatz, Jacek; Liebetrau, Volker

    2016-03-01

    Carbonate buildups and mounds are impressive biogenic structures throughout Earth history. In the recent NE Atlantic, cold-water coral (CWC) reefs form giant carbonate mounds of up to 300 m of elevation. The expansion of these coral carbonate mounds is paced by climatic changes during the past 2.7 Myr. Environmental control on their development is directly linked to controls on its main constructors, the reef-building CWCs. Seawater density has been identified as one of the main controlling parameter of CWC growth in the NE Atlantic. One possibility is the formation of a pycnocline above the carbonate mounds, which is increasing the hydrodynamic regime, supporting elevated food supply, and possibly facilitating the distribution of coral larvae. The potential to reconstruct past seawater densities from stable oxygen isotopes of benthic foraminifera has been further developed: a regional equation gives reliable results for three different settings, peak interglacials (e.g., Holocene), peak glacials (e.g., Last Glacial Maximum), and intermediate setting (between the two extremes). Seawater densities are reconstructed for two different NE Atlantic CWC carbonate mounds in the Porcupine Seabight indicating that the development of carbonate mounds is predominantly found at a seawater density range between 27.3 and 27.7 kg m-3 (σΘ notation). Comparable to recent conditions, we interpret the reconstructed density range as a pycnocline serving as boundary layer, on which currents develop, carrying nutrition and possibly coral larvae. The close correlation of CWC reef growth with reconstructed seawater densities through the Pleistocene highlights the importance of pycnoclines and intermediate water mass dynamics.

  3. Experimental explanation of the formation mechanism of surface mound-structures by femtosecond laser on polycrystalline Ni{sub 60}Nb{sub 40}

    Energy Technology Data Exchange (ETDEWEB)

    Peng, Edwin; Wang, Meiyu; Lucis, Michael J.; Gogos, George; Shield, Jeffrey E. [Department of Mechanical and Materials Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska 68588 (United States); Tsubaki, Alfred; Zuhlke, Craig A.; Bell, Ryan; Anderson, Troy P.; Alexander, Dennis R. [Department of Electrical and Computer Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska 68588 (United States)

    2016-01-18

    Femtosecond laser surface processing (FLSP) is an emerging technique for creating functionalized surfaces with specialized properties, such as broadband optical absorption or superhydrophobicity/superhydrophilicity. It has been demonstrated in the past that FLSP can be used to form two distinct classes of mound-like, self-organized micro/nanostructures on the surfaces of various metals. Here, the formation mechanisms of below surface growth (BSG) and above surface growth (ASG) mounds on polycrystalline Ni{sub 60}Nb{sub 40} are studied. Cross-sectional imaging of these mounds by focused ion beam milling and subsequent scanning electron microscopy revealed evidence of the unique formation processes for each class of microstructure. BSG-mound formation during FLSP did not alter the microstructure of the base material, indicating preferential valley ablation as the primary formation mechanism. For ASG-mounds, the microstructure at the peaks of the mounds was clearly different from the base material. Transmission electron microscopy revealed that hydrodynamic melting of the surface occurred during FLSP under ASG-mound forming conditions. Thus, there is a clear difference in the formation mechanisms of ASG- and BSG-mounds during FLSP.

  4. Palynology of two 4500 year old skua-mounds of the Arctic Skua (Stercorarius parasiticus (L.)) in Svalbard

    OpenAIRE

    van der Knaap, W.O.

    1988-01-01

    Skuamounds are peaty hillocks up to 70 cm high used by Arctic Skuas (Stercorarius parasiticus (L.)) for surveying their breeding territory. Well-developed skua-mounds in Svalbard can be considered as small guanogenic bogs', because the peat formation depends on manuring by birds and the water-table in the mound is higher than the surrounding tundra. Peat sections measuring 34 cm and 40 cm from two skuamounds from Edgeøya and Spitsbergen were radiocarbon dated and studied for pollen and spores...

  5. Groundwater monitoring and plume discharge zone characterization for the NRX radiostrontium plume at Chalk River Laboratories

    Energy Technology Data Exchange (ETDEWEB)

    Olfert, J.M.; Audet, M.; Killey, D., E-mail: olfertjm@aecl.ca [Atomic Energy of Canada Limited, Chalk River, Ontario (Canada)

    2013-12-15

    Groundwater is the principal pathway for the migration of most radiological and non-radiological compounds from past and present operating areas at Atomic Energy of Canada Limited's Chalk River Laboratories (CRL). The CRL Groundwater Monitoring Program (GWMP) was established to measure the groundwater quality around the perimeters of areas affected, or potentially affected, by groundwater plumes. One of these is the NRX Rod Bays plume, a legacy plume that originated from the fuel storage bays of the National Research Experimental (NRX) reactor. This plume contains primarily {sup 90}Sr migrating along the groundwater flow system to the Ottawa River. A characterization study of the shoreline region was completed recently to map the plume discharge zone by collecting samples from mini-piezometers and groundwater seeps (springs) during a period of low river level. Analysis of discharging groundwaters determined that the {sup 90}Sr concentrations were very similar to those sampled from nearby (upgradient) GWMP monitoring wells. With this favorable correlation, the high density of seep and mini-piezometer sampling along the shoreline allowed refinements to be made in defining the northerly and southerly boundaries of the radiostrontium plume. The seep and mini-piezometer sampling also provided evidence that the monitoring wells sampled routinely within the CRL GWMP are positioned appropriately for providing representative sampling of the plume. Shoreline seep and mini-piezometer sampling can lead to refinements in the conceptual site model for plumes with limited effort and cost. The supplemental characterization work can also potentially identify other targets for routine groundwater monitoring. (author)

  6. Current status of the waste identification program at AECL's Chalk River Laboratories

    International Nuclear Information System (INIS)

    The management of routine operating waste by Waste Management and Decommissioning (WM and D) at Atomic Energy of Canada Limited's (AECL) Chalk River Laboratories (CRL) is supported by the Waste Identification (WI) Program. The principal purpose of the WI Program is to minimize the cost and the effort associated with waste characterization and waste tracking, which are needed to optimize waste handling, storage and disposal. The major steps in the WI Program are: (1) identify and characterize the processes that generate the routine radioactive wastes accepted by WM and D - radioisotope production, radioisotope use, reactor operation, fuel fabrication, et cetera (2) identify and characterize the routine blocks of waste generated by each process or activity - the initial characterization is based on inference (process knowledge) (3) prepare customized, template data sheets for each routine waste block - templates contain information such as package type, waste material, waste type, solidifying agent, the average non-radiological contaminant inventory, the average radiological contaminant inventory, and the waste class (4) ensure generators 'use the right piece of paper with the right waste' when they transfer waste to WM and D - that is they use the correct template data sheets to transfer routine wastes, by: identifying and marking waste collection points in the generator's facility; ensuring that generators implement effective waste collection/segregation procedures; implementing standard procedures to transfer waste to WM and D; and, auditing waste collection and segregation within a generator's facility (5) determine any additional waste block characterization requirements (is anything needed beyond the original characterization by process knowledge?) This paper describes the WI Program, it provides an example of its implementation, and it summarizes the current status of its implementation for both CRL and non-CRL waste generators. (author)

  7. Magnetic susceptibility of rocks from boreholes CR-1 to CR-9 at Chalk River

    International Nuclear Information System (INIS)

    Magnetic susceptibility measurements made on rock cores obtained from boreholes at the Chalk River Research Area indicate that the foliated, granitic to granodioritic gneisses are weakly magnetic. Susceptibility values are about 5 x 10-4 S.I., two orders of magnitude less than average values for the Atikokan or Lac du Bonnet granites. Interpretation of the variations recorded in the gneisses in all cores is difficult because the average magnetic susceptibility level is near the limit of resolution of the measuring instrument used. However, in CR-6 and CR-9, mafic units intersect the boreholes and high magnetic susceptibility zones are seen. In CR-9 susceptibility values of the order of 5 x 10-2 S.I. characterize a dyke at depths of 40 to 60 m. A second high-susceptibility zone, distinctly different from the shallower one, is recorded at depths of 580 to 670 m with susceptibility of the orders of 5 x 10-3 S.I. This difference in susceptibility suggests mineralogical differences between the two units. The distinctive susceptibility signatures of these two units are better differentiated than signatures obtained from the other geophysical logs. In CR-6 only one high-susceptibility zone (of the order of 5 x 10-2 S.I.) is recorded in CR-6, at depths of 200 to 290 m. Its signature is similar in shape and intensity to the shallower unit observed in CR-9. Preliminary interpretation suggest continuity between these two zones. In CR-2 and CR-5, significant correlations exist among magnetic susceptibility, temperature anomalies and fracture occurrences. Contrary to observations at other research areas, fracture signatures in these two holes correspond to slight increases in susceptibility values. Alteration products associated with the fractures have higher susceptibility than the gneisses. Even though most of the recorded variations of the magnetic susceptibility are near the detection limit of the measuring instrument, significant features were observed and are discussed in

  8. Characterising the vertical variations in hydraulic conductivity within the Chalk aquifer

    Science.gov (United States)

    Williams, A.; Bloomfield, J.; Griffiths, K.; Butler, A.

    2006-10-01

    SummaryVarious field methods have been used to examine and quantify the vertical variations in aquifer properties within the Chalk aquifer at a LOCAR site in Berkshire, UK. The site contains three 100 m open boreholes and three sets of two nested piezometers within an area of about 100 m 2. There is also an 86 m deep abstraction borehole about 40 m from the site. The techniques that have been used at the site include: geophysical logging, borehole imaging, packer testing, dilution testing and pumping tests. The packer test results show that the permeability of the aquifer varies by three orders of magnitude over the 70 m of tested material with a strongly non-linear decrease with depth below ground level. Comparison with the borehole images show that some of the highly permeable zones appear to be associated with obvious fractures. However, large fractures can be seen in zones which have much lower permeability while some highly permeable zones appear to be associated with poorly developed fractures. Single borehole dilution tests have shown that there are differences in flow velocity depth profiles over a few tens of meters across the site. These are inferred to be because the different boreholes, although of similar drilled depth and very close proximity, intersect slightly different parts of the fracture network and hence the groundwater flow system. In particular, a flowing feature at the base of one borehole is not intersected by the second, which is drilled from a slightly higher elevation. A dilution test carried out whilst the aquifer was being pumped shows that different fractures become active when the aquifer is stressed. This has implications for the interpretation of flow logs performed under pumping.

  9. A compartment model for 90Sr contamination in a wetland at the Chalk River Laboratories

    International Nuclear Information System (INIS)

    Radioactive wastes originating from Canada's nuclear research and development program have been managed at the Atomic Energy of Canada Limited (AECL) Chalk River Laboratories (CRL) since 1946. In 1953 an area called Waste Management Area 'B' (WMA B) was developed to contain low and intermediate level solid waste (LLW and ILW respectively). Initially, all of the wastes were buried in unlined sand trenches or in asphalt lined trenches. These early trenches have been releasing strontium-90 (90Sr) to groundwater since 1954, resulting in an underground contaminant plume. A treatment system was constructed in 1994 and as a result the plume is being intercepted and treated for removal of 90SR. Prior to the establishment of the treatment system the plume extended south and discharged into a watercourse called 'Spring B', then into a wetland area called 'West Swamp'. Routine monitoring of Spring B and the West Swamp outflows for 90Sr has been conducted since the 1960s. A compartment model of the West Swamp was developed and validated against monitoring data for Spring B. The purpose of developing the model was to determine if a standard compartment model could describe 90Sr dynamics in a wetland to support environmental decision making. The model employed mass balance calculations to describe the movement/distribution of 90Sr between the primary system compartments: water/peat, sediment, vegetation and litter. This paper describes how the compartment model was developed and validated. The model can be used as a tool to evaluate remediation alternatives and to provide input to CRL site decommissioning plans. (author)

  10. Full-waveform inversion of cross-hole GPR data collected in a strongly heterogeneous chalk reservoir analogue with sharp permittivity and conductivity contrasts

    DEFF Research Database (Denmark)

    Keskinen, Johanna; Zibar, Majken Caroline Looms; Moreau, Julien;

    2014-01-01

    Chalk sediments form an important reservoir for groundwater onshore and for hydrocarbons in the Danish sector of the North Sea. Cross-hole Ground-penetrating radar (GPR) tomography is an efficient method to investigate subtle porosity variations in the chalk. Traditional ray-based inversion...... techniques provide models that are overly smooth and have relatively low resolution. We present preliminary results from full-waveform inversion of data collected in strongly heterogeneous chalk. The resolution of the tomograms has improved significantly compared to models obtained from travel......-time tomography. The new models also reflect the variability seen in 1D drill core analysis. The results indicate that full-waveform inversion is a well-suited inversion technique for high-resolution time-lapse-based flow characterization. Read More: http://library.seg.org/doi/abs/10.1190/segam2014-1199.1...

  11. Focused risk assessment: Mound Plant, Miami-Erie Canal Operable Unit 4

    International Nuclear Information System (INIS)

    In 1969, an underground waste line at Mound Plant ruptured and released plutonium-238 in a dilute nitric acid solution to the surrounding soils. Most of the acid was neutralized by the native soils. The plutonium, which in a neutral solution is tightly sorbed onto clay particles, remained within the spill area. During remediation, a severe storm eroded some of the contaminated soil. Fine grained plutonium-contaminated clay particles were carried away through the natural drainage courses to the remnants of the Miami-Erie Canal adjacent to Mound Plant, and then into the Great Miami River. This focused risk assessment considers exposure pathways relevant to site conditions, including incidental ingestion of contaminated soils, ingestion of drinking water and fish, and inhalation of resuspended soils and sediments. For each potential exposure pathway, a simplified conceptual model and exposure scenarios have been used to develop conservative estimates of potential radiation dose equivalents and health risks. The conservatism of the dose and risk estimates provides a substantive margin of safety in assuring that the public health is protected

  12. Remediation workers' exposure assessment feasibility study at the Department of Energy's Mound Site: Phase 1

    International Nuclear Information System (INIS)

    The Department of Health and Human Services (DHHS), subsequent to the implementation of a Memorandum of Understanding (MOU) between the Departments of Energy (DOE) and Health and Human Services, conducts a program of independent occupational and environmental research studies with funding from DOE. This document on the DOE Mound site represents the second background site document prepared for the development of the NIOSH project entitled: Exposure Assessment of Hazardous Waste (HW), Decontamination (De), Dismantlement (Di), and Clean Up Workers (CW). The purpose of this document is to assemble information relevant to Remediation Workers performing HW, De, Di, and CW task activities at the DOE Mound site addressing four primary objectives. The objectives are: identification of Remediation Workers performing HW, De, Di, and CW task activities anticipated or in progress from the recent past through the next five to 10 years; demographic definition of the workforce performing these activities; identification of the technologies in use or proposed to be used (including considerations regarding health and safety impact upon the workforce); and assembly of summary information for potential chemical, mixed, and radiological contaminant exposure that may be encountered during these processes

  13. Mound-ACT*DE*CONSM feasibility study. Phase 2: Final report

    International Nuclear Information System (INIS)

    A portion of the abandoned Miami-Erie Canal paralleling the Greater Miami River receives the runoff and storm-water discharge from Mound Laboratory. In 1969, a low-level plutonium leak contaminated sediment as far away as 1.5 mi from the Mound site along the old canal system. An estimated one million cubic feet of sediment requires remediation. The technology being evaluated for the remediation of the low-level plutonium-238 contamination of the sediment involves two processes: washing the sediments with ACT*DE*CONSM solution to dissolve the contaminant, followed by extraction of the solution and processing with the MAG*SEPSM process to concentrate the contaminant and allow reuse of the ACT*DE*CONSM solution. The processes are being optimized for pilot-scale and field demonstration. Phase 2 of the project primarily involved identification at the laboratory scale of the optimal ACT*DE*CONSM formulation, identification of the ion-exchanger and MAG*SEPSM particles, verification of the plutonium mobility in the treated soil, and evaluation of other process parameters according to a series of tasks

  14. Hydrochemical trends, palaeorecharge and groundwater ages in the fissured Chalk aquifer of the London and Berkshire Basins, UK

    International Nuclear Information System (INIS)

    The hydrochemical, radiochemical, stable isotope, 14C and dissolved noble gas composition of groundwaters has been determined along two profiles across the confined, fissured Chalk aquifer of the London Basin of southern England, and for selected sites in the adjacent Berkshire Basin. During downgradient flow in the London Basin aquifer, the groundwater chemistry is modified by water-rock interactions: congruent and incongruent reaction of the carbonate lithology resulting in enhanced Mg/Ca and Sr/Ca ratios and 13C contents with increased residence times; redox and ion exchange reactions; and towards the centre of the Basin, mixing with a residual saline connate water stored in the Chalk matrix. There is evidence from anomalous water chemistries for a component of vertical leakage from overlying Tertiary beds into the confined aquifer as a result of historical dewatering of the aquifer. Dissolved noble gas contents indicate the climate was up to 4.5C cooler than at present during recharge of the waters now found in the centres of both Basins; stable isotope (2H and 18O) depletions correspond to this recharge temperature change. For evolved waters having δ13 -8per thousand PDB a negative linear correlation is demonstrated between derived recharge temperatures and δ13C values, which is interpreted as mixing between relatively warm, light isotopic, fracture-borne waters and cooler stored waters of the matrix having a 13C signature more or less equilibrated with the Chalk. From geochemical (14C, 4He) age estimates, the abstracted water is interpreted as being either of wholly Holocene/post-Devensian glacial origin, or an admixture of Holocene and Late Pleistocene pre-glacial (cold stage interstadial) recharge. Devensian pleniglacial stage waters of the Last Glacial Maximum are not represented. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

  15. A biodetrital coral mound complex: Key to early diagenetic processes in the mississippian bangor limestone

    Science.gov (United States)

    Haywick, D.W.; Kopaska-Merkel, D. C.; Bersch, M.G.

    2009-01-01

    The Bangor Limestone is a Mississippian (Chesterian) shallow marine carbonate formation exposed over a large portion of the Interior Low Plateaus province of northern Alabama. It is dominated by oolitic grainstone and skeletal wackestone and packstone, but in one outcrop near Moulton, Alabama, the Bangor contains a five m thick, 25 m wide, oolitebiodetrital moundtidal flat succession. This sequence is interpreted as a 4th order sea level cycle. Four petrofacies (oolite, mound, skeletal and mudstone/dolomicrite) and four diagenetic phases (iron oxide, fibrous calcite cement, calcite spar cement and dolomite) are distinguished at the study site. Iron oxide, a minor component, stained and/or coated some ooids, intraclasts and skeletal components in the oolite petrofacies. Many of the allochems were stained prior to secondary cortical growth suggesting a short period of subaerial exposure during oolite sedimentation. The oolite petrofacies also contains minor amounts of fibrous calcite cement, a first generation marine cement, and rare infiltrated micrite that might represent a second phase of marine cement, or a first phase of meteoric cement (i.e., "vadose silt") (Dunham 1969). Intergranular pore space in all four petrofacies is filled with up to three phases of meteoric calcite spar cement. The most complete record of meteoric cementation is preserved within coralline void spaces in the mound petrofacies and indicates precipitation in the following order: (1) non-ferroan scalenohedral spar, (2) ferroan drusy spar (0.1-0.4 wt% Fe2+) and (3) non-ferroan drusy spar. The first scalenohedral phase of meteoric cement is distributed throughout the oolite and mound petrofacies. The ferroan phase of meteoric calcite is a void-filling cement that is abundant in the mound petrofacies and less common in the skeletal and mudstone/dolomicrite petrofacies. Non-ferroan drusy calcite is pervasive throughout the Bangor Limestone at the Moulton study site. Growth of the fourth

  16. Mechanical and chemical processes affecting the chalk during burial, insights from combined reflection seismics, well data and field work

    DEFF Research Database (Denmark)

    Moreau, Julien; Boussaha, Myriam; Thibault, Nicolas Rudolph;

    2014-01-01

    works have been performed with astronomical calibration based on stable isotope stratigraphy, wireline logs as well as several palaeontological proxies and detailed sedimentological analysis. Since a couple of decades, a specific kind of fractures has been described in the Chalk of Denmark, the so...... along the fractures (the compaction bands). The link between these different features has been realised thanks to the simultaneous analyses of large-scale geophysical data and small-scale core and field geological observations, providing a better understanding of the complex processes of lithification...

  17. Management of legacy spent nuclear fuel wastes at the Chalk River Laboratories: the challenges and innovative solutions implemented

    International Nuclear Information System (INIS)

    AECL has operated research reactors at the Chalk River Laboratories (CRL) site since 1947, for the purpose of nuclear energy and scientific research and for the production of radioisotopes. During the 1950s and 60s, a variety of spent nuclear fuel wastes were produced by irradiating metallic uranium and other prototype fuels. These legacy waste fuels were initially stored in water-filled fuel storage bays for a period of several years before being placed in storage containers and transferred to the CRL Waste Management Areas (WMAs), where they have been stored in below-grade, vertical cylindrical steel and concrete structures called 'tile holes'. (author)

  18. Canada, Atomic Energy of Canada Limited (AECL), Chalk River Labs: Reuse and Licence Termination of a Number of Facilities at the Chalk River Labs to Allow for Refurbishment of the Site. Annex A. I-1

    International Nuclear Information System (INIS)

    Chalk River Labs is located along the Ottawa River in Ontario, Canada, approximately 200 km north-west of Ottawa. The site began construction in 1944 following the expropriation of approximately 1 500 ha of land. A number of research reactors were constructed at the site along with numerous nuclear labs, hot cells and administrative facilities in support of the research and development work planned for the site. The principal occupants of the Chalk River site are AECL employees with a strong presence from National Resources Canada (NRC) and other small research groups. The site is undergoing substantial changes with an emphasis on minimizing the impact of increasing the builtup area footprint in conjunction with site upgrades and new build projects. To accomplish this task, a number of refurbishment and decommissioning projects were planned. Decommissioning projects were initiated to make room for new development through a number of initiatives. The decommissioning mandate includes the removal of a select group of original deteriorating facilities to make room for new construction and to decommission other facilities to facilitate redevelopment and reuse of the available space. In Canada, the Canadian Nuclear Safety Commission (CNSC) issues nuclear licences. The licensees must demonstrate that it is safe to continue operations of the nuclear site and request a renewal of their licence. CNSC will issue a new operating licence for a specific period of time at which the licensee must demonstrate that it is safe to proceed with a licence renewal. A request to terminate a licensable activity must be submitted to the CNSC. Upon approval to proceed, it must be demonstrated that the licensable activities have ceased and the facility has been appropriately decommissioned. Licence termination requires a demonstration that the land or previous activities presents a low risk and that the process can be used to support redevelopment because it results in a scrutinized

  19. The Guaymas Basin Hiking Guide to Hydrothermal Mounds, Chimneys, and Microbial Mats: Complex Seafloor Expressions of Subsurface Hydrothermal Circulation

    OpenAIRE

    Teske, Andreas; de Beer, Dirk; McKay, Luke J.; Margaret K. Tivey; Biddle, Jennifer F.; Hoer, Daniel; Lloyd, Karen G.; Lever, Mark A.; Røy, Hans; Albert, Daniel B.; Mendlovitz, Howard P.; MacGregor, Barbara J.

    2016-01-01

    The hydrothermal mats, mounds, and chimneys of the southern Guaymas Basin are the surface expression of complex subsurface hydrothermal circulation patterns. In this overview, we document the most frequently visited features of this hydrothermal area with photographs, temperature measurements, and selected geochemical data; many of these distinct habitats await characterization of their microbial communities and activities. Microprofiler deployments on microbial mats and hydrothermal sediment...

  20. Effects of vertical wall and tetrapod weights on wave overtopping in rubble mound breakwaters under irregular wave conditions

    Directory of Open Access Journals (Sweden)

    Park Sang Kil

    2014-12-01

    Full Text Available Rubble mound breakwaters protect the coastal line against severe erosion caused by wave action. This study examined the performance of different sizes and properties (i.e. height of vertical wall and tetrapod size of rubble mound breakwaters on reducing the overtopping discharge. The physical model used in this study was derived based on an actual rubble mound in Busan Yacht Harbor. This research attempts to fill the gap in practical knowledge on the combined effect of the armor roughness and vertical wall on wave overtopping in rubble mound breakwaters. The main governing parameters used in this study were the vertical wall height, variation of the tetrapod weights, initial water level elevation, and the volume of overtopping under constant wave properties. The experimental results showed that the roughness factor differed according to the tetrapod size. Furthermore, the overtopping discharge with no vertical wall was similar to that with relatively short vertical walls ( 1 γv = 1. Therefore, the experimental results highlight the importance of the height of the vertical wall in reducing overtopping discharge. Moreover, a large tetrapod size may allow coastal engineers to choose a shorter vertical wall to save cost, while obtaining better performance.

  1. Geoarchaeology and aggradation around Kinet Höyük, an archaeological mound in the Eastern Mediterranean, Turkey

    Science.gov (United States)

    Beach, Timothy P.; Luzzadder-Beach, Sheryl

    2008-10-01

    We examined the alluvial history of the plain near Kinet Höyük, an archaeological mound (or Tell) with a sequence of six millennia of occupation on the southeast Mediterranean coast of Turkey, through 17 excavations over a 1000 m transect near the Mound. Excavations ranged from 2 to 6 m deep and up to 20 m across. This low gradient, alluvial plain shows significantly different rates and processes of near-Mound sedimentation, with one unit having nearly 4 m of Late Bronze Age habitation and flood deposits and another having 4 m of Hellenistic channel and floodplain deposition. This flat, alluvial surface turns out to be a rich geoarchaeological landscape that shrouds Early and Late Bronze Age settlements, Hellenistic walls, and two epochs of Roman Roads. One widespread phenomenon was a Hellenistic or earlier paleosol and occupation level covered by channel gravels and overbank deposits mostly from the Hellenistic to the Late Roman period. These channel and floodplain deposits filled in and flattened out the off-Mound settlements, blanketing the Pre-Hellenistic topography and silting in a long active port. This glut of alluvium correlates in time with drier conditions and the most intensive land uses in the watershed, where Roman and Hellenistic sites today are severely eroded.

  2. Geotechnical Failure of a Concrete Crown Wall on a Rubble Mound Breakwater Considering Sliding Failure and Rupture Failure of Foundation

    DEFF Research Database (Denmark)

    Christiani, E.; Burcharth, H. F.; Sørensen, John Dalsgaard

    1995-01-01

    Sliding and rupture failure in the rubble mound are considered in this paper. In order to describe these failure modes the wave breaking forces have to be accounted for. Wave breaking forces on a crown wall are determined from Burcharth's wave force formula Burcharth (1992). Overtopping rates are...

  3. Estimating Heat Transfer from Grotto Mound, NEPTUNE Canada Cabled Observatory, Juan de Fuca Ridge

    Science.gov (United States)

    Rona, P. A.; Bemis, K. G.; Xu, G.

    2012-12-01

    Heat flux is a fundamental property of a seafloor hydrothermal system that relates to magnitude of sub-seafloor heat source and biosphere conditions, to distribution and style of seafloor venting and benthic biota, to chemical flux, plume formation, and dispersal of biological matter in the water column. We are working to estimate heat flux from Grotto mound, the site of the NEPTUNE Canada Cabled Observatory in the Main Endeavour Field on the Juan de Fuca Ridge. The mound is formed of two sulfide edifices that lie between ~2190 and 2180 m isobaths: 1) an elliptical edifice with major NE-SW-trending axis ~30 m long and minor axis ~ 14 m wide (area ~ 330 m2); 2) a columnar edifice ~ 10 m in diameter and 10 m high (area ~80 m2) named the North Tower, situated across a narrow (~5 m wide) saddle (area ~40 m2) at the W end of the elliptical edifice. Several black smokers discharge relatively small plumes at the E end of the elliptical edifice. A cluster of vigorous black smokers discharge from the top of North Tower and merge to form a large plume. Patchy diffuse flow occurs in areas around all of the black smokers and in the saddle between the two edifices. We are in process of measuring heat flux from components of hydrothermal discharge on Grotto mound, as follows: 1) for smokers on the North Tower an integrated heat flux of 28-55 MW is calculated based on temperature measurements in the initial 20 m rise of the plume assuming that the highest temperatures measured are closest to those of the plume centerline ; 2) for smokers on the E end of the elliptical edifice based on measurements of flow rate from video and acoustic Doppler phase shift, video of vent diameters, and in situ temperature measurements; 3) for discharge from flanges on some chimneys based on video of flow and in situ temperature measurements; 4) for diffuse flow based on area measured by Acoustic Scintillation Thermography and direct measurements of temperature and flow rate. We are evaluating

  4. Formation of carbonate concretions in surface sediments of two mud mounds, offshore Costa Rica: a stable isotope study

    Science.gov (United States)

    Mavromatis, Vasileios; Botz, Reiner; Schmidt, Mark; Liebetrau, Volker; Hensen, Christian

    2014-10-01

    The surface sediments of two mud mounds ("Mound 11" and "Mound 12") offshore southwest Costa Rica contain abundant authigenic carbonate concretions dominated by high-Mg calcite (14-20 mol-% MgCO3). Pore fluid geochemical profiles (sulfate, sulfide, methane, alkalinity, Ca and Mg) indicate recent carbonate precipitation within the zone of anaerobic oxidation of methane (AOM) at variable depths. The current location of the authigenic carbonate concretions is, however, not related to the present location of the AOM zone, suggesting mineral precipitation under past geochemical conditions as well as changes in the flow rates of upward migrating fluids. Stable oxygen and carbon isotope analysis of authigenic carbonate concretions yielded δ18Ocarbonate values ranging between 34.0 and 37.7 ‰ Vienna standard mean ocean water (VSMOW) and δ13Ccarbonate values from -52.2 to -14.2 ‰ Vienna Pee Dee belemnite (VPDB). Assuming that no temperature changes occurred during mineral formation, the authigenic carbonate concretions have been formed at in situ temperature of 4-5 °C. The δ18Ocarbonate values suggest mineral formation from seawater-derived pore fluid (δ18Oporefluid = 0 ‰ VSMOW) for Mound 12 carbonate concretions but also the presence of an emanating diagenetic fluid (δ18Oporefluid ≈5 ‰) in Mound 11. A positive correlation between δ13Ccarbonate and δ18Ocarbonate is observed, indicating the admixing of two different sources of dissolved carbon and oxygen in the sediments of the two mounds. The carbon of these sources are (1) marine bicarbonate (δ13Cporefluid ≈0 ‰) and (2) bicarbonate which formed during the AOM (δ13Cporefluid ≈-70 ‰). Furthermore, the δ18Oporefluid composition, with values up to +4.7 ‰ Vienna standard mean ocean water (VSMOW), is interpreted to be affected by the presence of emanating, freshened and boron-enriched fluids. Earlier, it has been shown that the origin of 18O-enriched fluids are deep diagenetic processes as it was

  5. Deep sourced mounds offshore Costa Rica: A mechanism for non-magmatic forearc recycling of oceanic crust ?

    Science.gov (United States)

    Moerz, T.; Brueckmann, W.; Kopf, A.; Kreiter, S.; Wallmann, K.; Suess, E.

    2003-04-01

    More than 30 small-scale mounds, resembling diapirs and/or mud volcanoes, were discovered and mapped by high resolution swath bathymetry off Costa Rica during the RV SONNE expeditions 144 and 163 expedition. Commonly, these mounds are nearly circular in shape, several 10s of meters high with an average diameter of several 100 meters and occur in water depths between 900 and 2000 m. Subsequently four such mounds off the Nicoya Peninsula (~1600 m ), and off Quepos (~1000 m) were sampled in detail by gravity-, piston-, and multi coring and video-guided grab sampling during Legs RV METEOR 54/2 and 54/3A.Overcompacted and tectonically deformed clays, fluid and mud channels (locally calcified), open hydrofractures, mineralized veins, various allochtonous fragments including mafic crystalline pebbles and hydrate layers where recovered at central mound locations. In contrast flank samples of these mounds are characterized by brecciated reworked authigenic carbonates, chaotic mud and debris flows, turbidite sequences and accumulations of clasts. In our ongoing work we use these characteristics and determine the sediment fabric using x-ray CT (computer tomography) in order to understand the role of fluids and solid phases in mound formation in the context of the erosional convergent margin development off Costa Rica. Critical with respect to the margin development and mound formation are reliable criteria for the source depth of the extruded material. So far the stress memory of clays derived from undrained shear strength gives a minimum source depth of >100 mbsf when compared to reference material from flanks and other slope sites. However, the recovered mafic crystalline clasts point to a much greater depth of at least 1500 mbsf for the source of solid phases and possibly fluids originating within the thin dewatered sediment wedge below the Costa Rica crystalline basement at ~7500 mbsf. Alternate source depth estimates from organic matter maturity indicators will

  6. Monitoring debris flow induced channel morphodynamics with terrestrial laser scanning, Chalk Cliffs, CO (Invited)

    Science.gov (United States)

    Wasklewicz, T. A.; Staley, D. M.

    2010-12-01

    Debris flows are important geomorphic agents in alpine drainages. They have been linked with channel initiation in headwater streams, connectivity of organic material and sediment through drainage basins, and as hazards to human development in and adjacent to steep watersheds. Debris flows also significantly alter channel morphometry at a variety of spatial scales. Of particular interest are topographic changes associated with multiple surge fronts within a debris flow as well as between several debris flows. An unnamed tributary stream to Chalk Creek, CO has over the last decade experienced one to four debris flow events annually. Four field sampling campaigns were conducted in the summer and fall of 2009. A Leica ScanStation 2, in conjunction with a robust local control network, were used to capture channel morphodynamics along five stream reaches prior to the debris flow season and after three debris flows. Point cloud data from the scanner permit the generation of two centimeter planimetric resolution digital terrain models (DTM). DTM-of-difference analyses and measures of slope, roughness, sediment transport volumes and channel dimensions were employed to detect spatial and temporal morphometric changes. The first debris flow occurred on unsaturated bed material and resulted in aggradation along 3 of the 5 reaches. One reach, a bedrock step, remained relatively unchanged, while the final reach saw significant erosion along boulder steps in the channel and an associated mass failure adjacent to the stream bank through this section. The second debris flow resulted in net aggradation along all of the reaches. The third and largest debris flow took place on saturated bed materials. The flow produced net erosion along all reaches. Significant channel changes were associated with the headward erosion of debris flow snouts and bank failures associated with undercutting of angle-of-repose slopes during debris flow erosion. Analysis of the potential relationships

  7. Spatial analysis of Carbon-14 dynamics in a wetland ecosystem (Duke Swamp, Chalk River Laboratories, Canada)

    International Nuclear Information System (INIS)

    A detailed survey was conducted to quantify the spatial distribution of 14C in Sphagnum moss and underlying soil collected in Duke Swamp. This wetland environment receives 14C via groundwater pathways from a historic radioactive Waste Management Area (WMA) on Atomic Energy Canada Limited (AECL)'s Chalk River Laboratories (CRL) site. Trends in 14C specific activities were evaluated with distance from the sampling location with the maximum 14C specific activity (DSS-35), which was situated adjacent to the WMA and close to an area of groundwater discharge. Based on a spatial evaluation of the data, an east-to-west 14C gradient was found, due to the influence of the WMA on 14C specific activities in the swamp. In addition, it was possible to identify two groups of sites, each showing significant exponential declines with distance from the groundwater source area. One of the groups showed relatively more elevated 14C specific activities at a given distance from source, likely due to their proximity to the WMA, the location of the sub-surface plume originating from the WMA, the presence of marsh and swamp habitat types, which facilitated 14C transport to the atmosphere, and possibly, 14C air dispersion patterns along the eastern edge of the swamp. The other group, which had lower 14C specific activities at a given distance from the groundwater source area, included locations that were more distant from the WMA and the sub-surface plume, and contained fen habitat, which is known to act as barrier to groundwater flow. The findings suggest that proximity to source, groundwater flow patterns and habitat physical characteristics can play an important role in the dynamics of 14C being carried by discharging groundwater into terrestrial and wetland environments. - Highlights: • Groundwater represents an important source of volatile radionuclides to wetlands. • Habitat type influenced 14C transport from sub-surface to surface environments. • C-14 specific activity

  8. Radon levels in dwellings in chalk terrain. Development and analysis of distributional and causal models

    International Nuclear Information System (INIS)

    This thesis investigates the range, distribution and causes of high radon levels in dwellings in the Brighton area of Southeast England. Indoor radon levels were measured in more than 1000 homes. The results show that high radon levels can arise in an area previously considered to offer low radon potential from local geological sources. Climate and building-related factors were found to affect significantly the radon levels in dwellings. Multiple regression was used to determine the influence of the various factors on indoor radon levels and an empirical model develop to predict indoor radon levels. The radon hazard, independent of building-related effects, was determined for each surveyed location by adjusting the radon measurement to that expected on the ground floor of a 'model' dwelling. This standardised set of radon levels was entered into a geographical information system (GIS) and related to surface geology. The geometric mean radon level for each lithological unit was plotted to produce a radon hazard map for the area. The highest radon levels were found to be associated with the youngest Chalk Formations, particularly where they meet overlying Tertiary deposits, and with Clay-with-Flints Quaternary deposits in the area. The results were also converted to the radon activity equivalent to that expected from the NRPB's standard dual-detector dwelling survey method and analysed by lognormal modelling to estimate the proportion of dwellings likely to exceed the UK Action Level of 200 Bq/m3 for each lithological unit. The likely percentages of dwellings affected by radon thus obtained were mapped to lithological boundaries to produce a radon potential map. The radon hazard map and the empirical radon model facilitate the prediction of radon levels in dwellings of comparable construction and above similar geology and should further the understanding of the behaviour of radon gas in buildings to allow indoor radon concentrations to be controlled. The radon

  9. Laboratory and field measurements of the self-potential (SP) in chalk, with application to monitoring of saline intrusion

    Science.gov (United States)

    MacAllister, D.; Jackson, M.; Butler, A. P.; Vinogradov, J.

    2013-12-01

    Saline intrusion is a global phenomenon, affecting the availability of freshwater in coastal aquifers. The aim of this work is to investigate whether measurements of self-potential (SP) can be used to monitor the intrusion of seawater into coastal aquifers, with specific application to the UK chalk aquifer in the vicinity of Brighton on the south coast of the UK. The SP arises to maintain electrical neutrality when a separation of charge occurs due to gradients in pressure (electrokinetic (EK) or streaming potential) and concentration (electrochemical (EC) potential). Concentration gradients are a characteristic feature of saline intrusion and may give rise to a measureable EC potential. In addition, an EK potential will arise during abstraction. Laboratory and field SP measurements are used to investigate the magnitude of the EK and EC potentials in the UK chalk aquifer during saline intrusion. Laboratory measurements yield an EK coupling coefficient, relating the gradient in voltage to the gradient in pressure when the total current is zero, of -60 mV/MPa in samples saturated with groundwater, and -1 mV/MPa in samples saturated with seawater. This result agrees with earlier work suggesting the EK potential is suppressed at high salinity due to a compressed electrical double layer. The EC coupling is dominated by diffusion potentials arising from the concentration gradient across the saline front. Field experiments suggest that the EK component of the SP in the chalk is very small under ambient conditions, even in freshwater zones, because gradients in hydraulic head are small owing to the high conductivity of the pervasive fracture networks. However, a pumping test conducted in the chalk aquifer at a field site in Berkshire induced a measureable EK response with a coupling coefficient of magnitude consistent with the freshwater EK coupling coefficient obtained in the laboratory. SP monitoring at an observation borehole near Brighton reveals semi-diurnal SP

  10. An overview of plutonium-238 decontamination and decommissioning (D and D) projects at Mound

    International Nuclear Information System (INIS)

    Mound is currently decontaminating for restricted reuse and/or decommissioning for conditional release four major plutonium-238 contaminated facilities that contained 1700 linear feet of gloveboxes and associated equipment and services. Several thousand linear feet of external underground piping, associated tanks, and contaminated soil are being removed. Two of the facilities contain ongoing operations and will be reused for both radioactive and nonradioactive programs. Two others will be completely demolished and the land area will become available for future DOE building sites. An overview of the successful techniques and equipment used in the decontamination and decommissioning of individual pieces of equipment, gloveboxes, services, laboratories, sections of buildings, entire buildings, and external underground piping, tanks, and soil in a highly populated residential area is described and pictorially presented

  11. The hill forts and castle mounds in Lithuania: interaction between geodiversity and human-shaped landscape

    Science.gov (United States)

    Skridlaite, Grazina; Guobyte, Rimante; Satkunas, Jonas

    2015-04-01

    Lithuania is famous for its abundant, picturesque hill forts and castle mounds of natural origin. In Lithuania as well as in whole Europe the fortified hills were used as the society dwelling place since the beginning of the Late Bronze Age. Their importance increased when Livonian and Teutonic Orders directed a series of military campaigns against Lithuania with the aim of expansion of Christianity in the region at the end of 1st millennium AD, and they were intensively used till the beginning of the 15th c. when most of them were burned down during fights with the Orders or just abandoned due to the changing political and economical situation. What types of the geodiversity were used for fortified dwellings? The choice in a particular area depended on a variety of geomorphology left behind the retreating ice sheets. High spots dominating their surroundings were of prime interest. In E and SE Lithuania, the Baltic Upland hills marking the eastern margin of the last Weichselian glacier hosted numerous fortified settlements from the end of 2nd millennium BC to the Medieval Ages (Narkunai, Velikuskes etc). In W Lithuania, plateau-like hills of the insular Samogitian Upland had been repeatedly fortified from the beginning of 1st millennium AD to the 14th century (Satrija, Medvegalis etc). Chains of hill forts and castle mounds feature the slopes of glaciofluvial valleys of Nemunas, Neris and other rivers where the slopes were dissected by affluent rivulets and ravines and transformed into isolated, well protected hills (Kernave, Punia, Veliuona etc). Peninsulas and headlands formed by the erosion of fluvial and lacustrine deposits were used in the lowlands, e.g. in central and N Lithuania (Paberze, Mezotne etc). How much the landscape was modified for defense purposes? Long-term erosion and overgrowing vegetation damaged the former fortified sites, however some remains and the archeological excavations allowed their reconstruction. The fortified Bronze Age settlements

  12. Characterization of magnetic material in the mound-building termite Macrotermes gilvus in Southeast Asia

    Science.gov (United States)

    Esa, Mohammad Faris Mohammad; Rahim, Faszly; Hassan, Ibrahim Haji; Hanifah, Sharina Abu

    2015-09-01

    Magnetic material such as magnetite are known as particles that respond to external magnetic field with their ferromagnetic properties as they are believed contribute to in responding to the geomagnetic field. These particles are used by terrestrial animals such as termites for navigation and orientation. Since our earth react as giant magnetic bar, the magnitude of this magnetic field present by intensity and direction (inclination and direction). The magnetic properties and presence of magnetite in termites Macrotermes gilvus, common mound-building termite were tested. M. gilvus termites was tested with a Vibrating Sample Magnetometer VSM to determine the magnetic properties of specimen. The crushed body sample was characterized with X-Ray Diffraction XRD to show the existent of magnetic material (magnetite) in the specimens. Results from VSM indicate that M. gilvus has diamagnetism properties. The characterization by XRD shows the existent of magnetic material in our specimen in low concentration.

  13. Mound Laboratory activities on the removal of plutonium and uranium from wastewater using bone char

    Energy Technology Data Exchange (ETDEWEB)

    Blane, D.W.; Murphy, E.L.

    1976-09-30

    Pilot plant studies sponsored by the Division of Military Application (DMA) to treat Mound Laboratory's low risk waste streams with bone char columns have been completed. This project was to accomplish the following: (1) acquire engineering data such as flow rates, adsorption capacity, and optimum particle size for designing a tertiary treatment system, and (2) optimize the primary waste treatment process using coagulants and flocculants. Bone char, a natural product made from granulated cattle bone, is a form of calcium hydroxyapatite (Ca/sub 10/(PO/sub 4/)/sub 6/(OH)/sub 2/) and contains a small amount of carbon. It is characterized by a high porosity and good resistance to abrasion and crushing. Because plutonium and other actinides can be precipitated as phosphates from weakly acidic, neutral or alkaline solutions, it appeared possible to use an insoluble phosphate adsorbent such as bone char to remove them from waste streams.

  14. The Guaymas Basin Hiking Guide to Hydrothermal Mounds, Chimneys, and Microbial Mats

    DEFF Research Database (Denmark)

    Teske, Andreas; de Beer, Dirk; McKay, Luke J; Tivey, Margaret K; Biddle, Jennifer F; Hoer, Daniel; Lloyd, Karen G; Lever, Mark A; Røy, Hans; Albert, Daniel B; Mendlovitz, Howard P; MacGregor, Barbara J

    2016-01-01

    The hydrothermal mats, mounds, and chimneys of the southern Guaymas Basin are the surface expression of complex subsurface hydrothermal circulation patterns. In this overview, we document the most frequently visited features of this hydrothermal area with photographs, temperature measurements, and...... selected geochemical data; many of these distinct habitats await characterization of their microbial communities and activities. Microprofiler deployments on microbial mats and hydrothermal sediments show their steep geochemical and thermal gradients at millimeter-scale vertical resolution. Mapping these...... hydrothermal features and sampling locations within the southern Guaymas Basin suggest linkages to underlying shallow sills and heat flow gradients. Recognizing the inherent spatial limitations of much current Guaymas Basin sampling calls for comprehensive surveys of the wider spreading region....

  15. Characterization of magnetic material in the mound-building termite Macrotermes gilvus in Southeast Asia

    International Nuclear Information System (INIS)

    Magnetic material such as magnetite are known as particles that respond to external magnetic field with their ferromagnetic properties as they are believed contribute to in responding to the geomagnetic field. These particles are used by terrestrial animals such as termites for navigation and orientation. Since our earth react as giant magnetic bar, the magnitude of this magnetic field present by intensity and direction (inclination and direction). The magnetic properties and presence of magnetite in termites Macrotermes gilvus, common mound-building termite were tested. M. gilvus termites was tested with a Vibrating Sample Magnetometer VSM to determine the magnetic properties of specimen. The crushed body sample was characterized with X-Ray Diffraction XRD to show the existent of magnetic material (magnetite) in the specimens. Results from VSM indicate that M. gilvus has diamagnetism properties. The characterization by XRD shows the existent of magnetic material in our specimen in low concentration

  16. Dig-face monitoring during excavation of a radioactive plume at Mound Laboratory, Ohio

    International Nuclear Information System (INIS)

    A dig-face monitoring system consists of onsite hardware for collecting information on changing chemical, radiological, and physical conditions in the subsurface soil during the hazardous site excavation. A prototype dig-face system was take to Mount Laboratory for a first trial. Mound Area 7 was the site of historical disposals of 232Th, 227Ac, and assorted debris. The system was used to monitor a deep excavation aimed at removing 227Ac-contaminated soils. Radiological, geophysical, and topographic sensors were used to scan across the excavation dig-face at four successive depths as soil was removed. A 3-D image of the contamination plumes was developed; the radiation sensor data indicated that only a small portion of the excavated soil volume was contaminated. The spatial information produced by the dig-face system was used to direct the excavation activities into the area containing the 227Ac and to evaluate options for handling the separate 232Th plume

  17. Characterization of magnetic material in the mound-building termite Macrotermes gilvus in Southeast Asia

    Energy Technology Data Exchange (ETDEWEB)

    Esa, Mohammad Faris Mohammad; Hassan, Ibrahim Haji [School of Chemical Sciences and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi, Selangor (Malaysia); Rahim, Faszly; Hanifah, Sharina Abu [School of Environmental Scieces and Natural Resources Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi, Selangor (Malaysia)

    2015-09-25

    Magnetic material such as magnetite are known as particles that respond to external magnetic field with their ferromagnetic properties as they are believed contribute to in responding to the geomagnetic field. These particles are used by terrestrial animals such as termites for navigation and orientation. Since our earth react as giant magnetic bar, the magnitude of this magnetic field present by intensity and direction (inclination and direction). The magnetic properties and presence of magnetite in termites Macrotermes gilvus, common mound-building termite were tested. M. gilvus termites was tested with a Vibrating Sample Magnetometer VSM to determine the magnetic properties of specimen. The crushed body sample was characterized with X-Ray Diffraction XRD to show the existent of magnetic material (magnetite) in the specimens. Results from VSM indicate that M. gilvus has diamagnetism properties. The characterization by XRD shows the existent of magnetic material in our specimen in low concentration.

  18. Topological defect launches 3D mound in the active nematic sheet of neural progenitors

    CERN Document Server

    Kawaguchi, Kyogo; Sano, Masaki

    2016-01-01

    Cultured stem cells have become a standard platform not only for regenerative medicine and developmental biology but also for biophysical studies. Yet, the characterization of cultured stem cells at the level of morphology and macroscopic patterns resulting from cell-to-cell interactions remain largely qualitative, even though they are the simplest features observed in everyday experiments. Here we report that neural progenitor cells (NPCs), which are multipotent stem cells that give rise to cells in the central nervous system, rapidly glide and stochastically reverse its velocity while locally aligning with neighboring cells, thus showing features of an active nematic system. Within the two-dimensional nematic pattern, we find interspaced topological defects with +1/2 and -1/2 charges. Remarkably, we identified rapid cell accumulation leading to three-dimensional mounds at the +1/2 topological defects. Single-cell level imaging around the defects allowed quantification of the evolving cell density, clarifyin...

  19. Mound Laboratory Plutonium-238 Study Off-Site Analytical Data May-December 1974

    Energy Technology Data Exchange (ETDEWEB)

    Robinson, Bob; Rogers, D. R.; Westendorf, W. H.; Black, H. A.

    1975-03-01

    Preliminary samples collected from off-site sediment in the Miami-Erie Canal Area near Mound Laboratory indicated that plutonium-238 concentrations are substantially above baseline levels. As a result an extensive sampling and analysis program was performed to determine the plutonium-238 concentrations as a function of depth and location in a drainage ditch, the canal, two ponds, a run-off hollow, a canal overflow creek and the Great Miami River. The plutonium-238 concentration data was used to estimate the total inventory of 238Pu deposited in these waterways, to determine the extent of the contamination, and to evaluate the potential health hazards to the general population of the area. The scope of this report is to present the data collected during this study. Detailed interpretation of the data will be presented in subsequent reports.

  20. Termination of the Special Metallurgical (SM) Building at Mound Laboratory: a final report

    Energy Technology Data Exchange (ETDEWEB)

    Harris, W.R.; Kokenge, B.R.; Marsh, G.C.

    1976-12-22

    The report describes and highlights the more important factors associated with the termination of the Special Metallurgical (SM) Building at Mound Laboratory. As a result, a written record of the more important techniques and procedures is now available for reference by others involved in similar termination efforts. Included in this report is a description of the organizational units that were used in this effort along with a description of their responsibilities. A general description of the SM Building and a discussion of the more relevant procedures and equipment that were used are also presented. In addition, pertinent Health Physics information, such as personnel exposure, final wipe levels in the terminated facility, and assays of the structure, are provided. Based on the experience gained from this project, recommendations were made regarding the design of future radioactive material handling facilities so that when they are ultimately terminated the effort can be accomplished more efficiently.

  1. Why do we not have a Consistent Design Method for Rubble Mound Breakwaters

    DEFF Research Database (Denmark)

    Burcharth, Hans F.

    The title of my lecture might be a surprise to many professional engineers. Is it really possible that we do not have a consistent design method – after several hundred years of breakwater design and construction and also intensive research for the last 20 years? The answer is yes. The state of the...... art and the design tools are not satisfactory compared to those available in other branches of civil engineering such as for example structural engineering. I shall try to explain the difficulties e are facing in breakwater engineering, especially for rubble mound breakwaters, by summarizing some of...... the uncertainties we have to deal with in the design process. A good overview of the uncertainties and the related consequences is of paramount importance to the designer. Without such knowledge it is impossible to evaluate the safety of a structure – a situation hat is unacceptable for a professional...

  2. Strategic Petroleum Reserve (SPR) additional geologic site characterization studies, Bryan Mound Salt Dome, Texas

    Energy Technology Data Exchange (ETDEWEB)

    Neal, J.T. [Sandia National Labs., Albuquerque, NM (United States); Magorian, T.R.; Ahmad, S. [Acres International Corp., Amherst, NY (United States)

    1994-11-01

    This report revises the original report that was published in 1980. Some of the topics covered in the earlier report were provisional and it is now practicable to reexamine them using new or revised geotechnical data and that obtained from SPR cavern operations, which involves 16 new caverns. Revised structure maps and sections show interpretative differences as compared with the 1980 report and more definition in the dome shape and caprock structural contours, especially a major southeast-northwest trending anomalous zone. The original interpretation was of westward tilt of the dome, this revision shows a tilt to the southeast, consistent with other gravity and seismic data. This interpretation refines the evaluation of additional cavern space, by adding more salt buffer and allowing several more caverns. Additional storage space is constrained on this nearly full dome because of low-lying peripheral wetlands, but 60 MMBBL or more of additional volume could be gained in six or more new caverns. Subsidence values at Bryan Mound are among the lowest in the SPR system, averaging about 11 mm/yr (0.4 in/yr), but measurement and interpretation issues persist, as observed values are about the same as survey measurement accuracy. Periodic flooding is a continuing threat because of the coastal proximity and because peripheral portions of the site are at elevations less than 15 ft. This threat may increase slightly as future subsidence lowers the surface, but the amount is apt to be small. Caprock integrity may be affected by structural features, especially the faulting associated with anomalous zones. Injection wells have not been used extensively at Bryan Mound, but could be a practicable solution to future brine disposal needs. Environmental issues center on the areas of low elevation that are below 15 feet above mean sea level: the coastal proximity and lowland environment combined with the potential for flooding create conditions that require continuing surveillance.

  3. Origin of carbonate concretions from mud mounds in the Gulf of Cadiz (SW Iberian Peninsula)

    International Nuclear Information System (INIS)

    The Gulf of Cadiz displays a number of structures that are associated with fluid circulation (mud volcanoes, mud mounds and pockmarks).This area has been used as natural laboratory for the sedimentological, bio- logical and biogeochemical studies of these environments. Analysis of the associated authigenic carbonates has been widely used as a proxy to yield insights into the circulation and chemical composition of these flu- ids. A study of carbonate concretions from the Iberico, Cornide and Arcos mud mounds in the Diasom Field was undertaken to better understand the origin and type of fluids from which these concretions precipitated. The concretions display varying morphologies, some of which correspond to bioturbation traces. X-ray dif- fractions revealed that these carbonate concretions are mainly composed of dolomite, Fe-rich dolomite, high magnesium calcite (HMC) and ankerite. The δ13 C values of carbonate minerals ranged between -48.3 and-10.9 V-PDB, which suggests that the main processes involved in their genesis are organic matter oxidation, bac- terial sulphate-reduction (BSR) and anaerobic methane oxidation (AOM). The origin of the methane is main- ly thermogenic, and only few concretions yielded δ13C values lower than -40 V-PDB, suggesting oxidation of microbial methane. Fluids involved in the carbonate precipitation are interpreted as being related to gas hydrate destabilisation (δ18O fluid-V-SMOW values higher than +2%) and, to a lesser extent, modified seawater enriched in 18O due to rock-water interaction. Nevertheless, the highest δ18O fluid-V-SMOW values suggest that the influence of other deep-seated fluids due to clay-mineral dehydration cannot be ruled out. (Author)

  4. Monte Carlo simulation model for economic evaluation of rubble mound breakwater protection in Harbors

    Institute of Scientific and Technical Information of China (English)

    Richard M. Males; Jeffrey A. Melby

    2011-01-01

    The US Army Corps of Engineers has a mission to conduct a wide array of programs in the arenas of water resources,including coastal protection.Coastal projects must be evaluated according to sound economic principles,and considerations of risk assessment and sea level change must be included in the analysis.Breakwaters are typically nearshore structures designed to reduce wave action in the lee of the structure,resulting in calmer waters within the protected area,with attendant benefits in terms of usability by navigation interests,shoreline protection,reduction of wave runup and onshore flooding,and protection of navigation channels from sedimentation and wave action.A common method of breakwater construction is the rubble mound breakwater,constructed in a trapezoidal cross section with gradually increasing stone sizes from the core out.Rubble mound breakwaters are subject to degradation from storms,particularly for antiquated designs with under-sized stones insufficient to protect against intense wave energy.Storm waves dislodge the stones,resulting in lowering of crest height and associated protective capability for wave reduction.This behavior happens over a long period of time,so a lifecycle model (that can analyze the damage progression over a period of years) is appropriate.Because storms are highly variable,a model that can support risk analysis is also needed.Economic impacts are determined by the nature of the wave climate in the protected area,and by the nature of the protected assets.Monte Carlo simulation (MCS)modeling that incorporates engineering and economic impacts is a worthwhile method for handling the many complexities involved in real world problems.The Corps has developed and utilized a number of MCS models to compare project alternatives in terms of their costs and benefits.This paper describes one such model,Coastal Structure simulation (CSsim) that has been developed specifically for planning level analysis of breakwaters.

  5. Validity of chalk and bentonite application in soil and water on reducing the absorption of ratio-strontium and radio-cerium by crop

    International Nuclear Information System (INIS)

    Effects of the chalk and bentonite application in soil and surface water respectively on reducing the absorption of 89Sr and 141Ce by crop (especially in the edible part of crop) were studied by using isotope tracer techniques. The results showed that the specific activity of 89Sr in the ryegrass and Chinese cabbage could be decreased significantly by chalk application in the soil. The reduced ratio of 89Sr absorption of Chinese cabbage and ryegrass reached 77.7% and 35.2% respectively with the chalk application of 20 g/kg soil. The specific activity of 89Sr in ryegrass and Chinese cabbage followed obvious negative linear correlation with the quantity of application chalk in the soil. The specific activity of 141Ce in surface water, chaff and brown rice decreased by application bentonite in the surface water, which led to the lower accumulation of 141Ce in paddy. However, the absorption and accumulation of 141Ce in root and straw could not be changed. The specific activity of 141Ce in soil followed a negative exponential relation with depth of soil profile

  6. The role of diagenisis in the hydrogeological stratification of carbonate aquifers: an example from the chalk at Fair Cross, Berkshire, UK

    Directory of Open Access Journals (Sweden)

    J. Bloomfield

    1997-01-01

    Full Text Available Carbonate rocks form important aquifers in many parts of the world and in north-west Europe the Chalk is a primary source of potable water. When flushed with relatively fresh groundwaters, the Chalk may undergo significant diagenetic alteration at relatively shallow depths resulting in a physically and hydrogeochemically stratified aquifer. Diagenetic affects may have important implications for the effective exploitable thickness of the Chalk aquifer and for water quality. In order to assess the affects of diagenesis on the properties of carbonate aquifers, matrix porosity, permeability, pore water and rock chemistry profiles have been analysed for a 300 m deep borehole through the Chalk at the western end of the London Basin. An abrupt change in the matrix porosity profile at 155 mbgl indicates a change in dominant mode of historic diagenesis from mechanical compaction above 155 mbgl to predominantly pressure solution compaction below 155 mbgl. Pore water and rock chemistry profiles also change abruptly across this depth interval, suggesting that the present day hydrogeology is controlled by historic diagenetic trends. Below 155 mbgl, pore waters are relatively saline and there is no evidence for groundwater flow; above 155 mbgl pore waters are relatively fresh and geochemical evidence for incon-gruent carbonate dissolution indicates contemporary groundwater circulation. Possible physical and chemical evolution paths for the Chalk at Fair Cross are discussed. The results provide a hydrogeological context for other studies of the long-term response of carbonate aquifers to base-line changes in sea-level and pore water chemistry and also enable studies with relatively short time-frames or of localized phenomena to be placed in the broader context of the evolution of carbonate aquifers.

  7. Simulations of Two-Well Tracer Tests in Stratified Aquifers at the Chalk River and the Mobile Sites

    Science.gov (United States)

    Huyakorn, Peter S.; Andersen, Peter F.; Molz, Fred J.; Güven, Oktay; Melville, Joel G.

    1986-07-01

    A simulation study of two-well injection-withdrawal tracer tests in stratified granular aquifers at two widely separated sites is presented. The first site is located near the Chalk River Nuclear Laboratories in Canada, and the second site is located in Mobile, Alabama. Field data and test conditions at these sites are substantially different in terms of vertical distributions of hydraulic conductivity, well spacings, flow rates, test durations, and tracer travel distances. Furthermore, the test at the Chalk River site was conducted in a recirculating mode, whereas the test at the Mobile site was conducted in a nonrecirculating mode. Simulations of these tests were performed in three dimensions using the curvilinear finite element model developed in the previous paper of this series. The simulations incorporated measured vertical variations in relative hydraulic conductivity and local dispersivity values that are small fractions (between 1/1000 and 1/100) of the spacing between the injection and the withdrawal wells. The local dispersivities are used to account for local hydrodynamic dispersion and are chosen independently so that they are not affected by the scales of the tests. Simulation results obtained from the model are presented. Interpretation of these results is made in conjunction with measured breakthrough curves at the withdrawal well and multilevel observation wells. For the Chalk River site, predicted and measured breakthrough curves at the withdrawal well are in good agreement over the earlier part of the test duration. Deviation of the field data from the model prediction occurs over the second part, where the predicted breakthrough curves show a declining trend but the field data plot does not. For the Mobile site, predicted and measured breakthrough curves at the withdrawal well show similar trends throughout the entire test duration and are in good agreement overall. Model predictions of the effect of hydraulic conductivity stratification on

  8. The giant cold-water coral mound as a nested microbial/metazoan system: physical, chemical, biological and geological picture (ESF EuroDiversity MiCROSYSTEMS)

    Science.gov (United States)

    Henriet, J. P.; Microsystems Team

    2009-04-01

    The MiCROSYSTEMS project under the ESF EUROCORES EuroDiversity scheme is a holistic and multi-scale approach in studying microbial diversity and functionality in a nested microbial/metazoan system, which thrives in deep waters: the giant cold-water coral mound. Studies on prolific cold-water coral sites have been carried out from the canyons of the Bay of Biscay to the fjords of the Norwegian margin, while the Pen Duick carbonate mound province off Morocco developed into a joint natural lab for studying in particular the impact of biogeochemical and microbial processes on modern sedimentary diagenesis within the reef sediments, in complement to the studies on I0DP Exp. 307 cores (Challenger Mound, off Ireland). Major outcomes of this research can be summarized as follows. • IODP Exp. 307 on Challenger Mound had revealed a significant prokaryotic community both within and beneath the carbonate mound. MiCROSYSTEMS unveils a remarkable degree of compartmentalization in such community from the seawater, the coral skeleton surface and mucus to the reef sediments. The occurrence of such multiple and distinct microbial compartments associated with cold-water coral ecosystems promotes opportunities for microbial diversity in the deep ocean. • New cases of co-habitation of cold-water corals and giant deep-water oysters were discovered in the Bay of Biscay, which add a new facet of macrofaunal diversity to cold-water coral reef systems. • The discovery of giant, ancient coral graveyards on the Moroccan mounds not only fuels the debate about natural versus anthropogenic mass extinction, but these open frameworks simultaneously invite for the study of bio-erosion and early diagenesis, in particular organo-mineralization, and of the possible role and significance of these thick, solid rubble patches in 3D mound-building and consolidation. • The assessment of the carbonate budget of a modern cold-water coral mound (Challenger Mound) reveals that only 33 to 40 wt % of

  9. Analysis and applications of microorganisms from a chalk oil reservoir in the North Sea

    Energy Technology Data Exchange (ETDEWEB)

    Kaster, Krista Michelle

    2009-03-15

    Ekofisk a chalk oil reservoir in the Norwegian sector of the North Sea was found to harbour an active and diverse microbial community. Microbial actives may be deleterious in nature as in reservoir souring or maybe advantageous as in microbial enhanced oil recovery. The aim of this study was to characterise the microbial communities in the Ekofisk oil reservoir and to gain insight into the microbial mechanisms important for the a) control of reservoir souring, and b) which can be utilized in enhanced oil recovery. Produced water samples from the Ekofisk oil reservoir were analysed using both culture-dependent and -independent techniques. The Ekofisk microbial community was found to be dominated by thermophilic microorganisms many of which were capable of either sulphidogenic or methanogenic physiologies. They were similar to organisms that have been previously identified from oil reservoir fluids. The dominant organisms identified directly from the produced water samples had sequences similar to members of the genera Thermotoga, Caminicella, Thermoanaerobacter, Archaeoglobus, Thermococcus, and Methanobulbus. Enrichment cultures obtained from the produced water samples were dominated by sheathed rods. Sequence analyses of the cultures indicated predominance of the genera Petrotoga, Arcobacter, Archaeoglobus and Thermococcus. Reservoir souring caused by sulphide production due the activity of sulphate reducing prokaryotes (SRP) may be reduced by the injection of nitrate or nitrite. Nitrate or nitrite mitigates sulphide production either by the stimulation of nitrate reducing bacteria (NRB) through nitrate addition or via metabolic inhibition of the reduction of sulphite to sulphide by nitrite. Here we found that nitrate addition was ineffective at controlling souring whereas nitrite proved very effective at inhibiting sulphate reduction even at very low concentrations (0.25 mM - 1 mM) in both batch culture and bioreactor studies. To investigate microbial utilization

  10. High frequency seismic monitoring of debris flows at Chalk Cliffs (CO), USA

    Science.gov (United States)

    Coviello, Velio; Kean, Jason; Smith, Joel; Coe, Jeffrey; Arattano, Massimo; McCoy, Scott

    2015-04-01

    A growing number of studies adopt passive seismic monitoring techniques to investigate slope instabilities and landslide processes. These techniques are attractive and convenient because large areas can be monitored from a safe distance. This is particularly true when the phenomena under investigation are rapid and infrequent mass movements like debris flows. Different types of devices are used to monitor debris flow processes, but among them ground vibration detectors (GVDs) present several, specific advantages that encourage their use. These advantages include: (i) the possibility to be installed outside the channel bed, (ii) the high adaptability to different and harsh field conditions, and (iii) the capability to detect the debris flow front arrival tens of seconds earlier than contact and stage sensors. Ground vibration data can provide relevant information on the dynamics of debris flows such as timing and velocity of the main surges. However, the processing of the raw seismic signal is usually needed, both to obtain a more effective representation of waveforms and to decrease the amount of data that need to be recorded and analyzed. With this objective, the methods of Amplitude and Impulses are commonly adopted to transform the raw signal to a 1-Hz signal that allows for a more useful representation of the phenomenon. In that way, peaks and other features become more visible and comparable with data obtained from other monitoring devices. In this work, we present the first debris flows seismic recordings gathered in the Chalk Cliffs instrumented basin, central Colorado, USA. In May 2014, two 4.5-Hz, three-axial geophones were installed in the upper part of the catchment. Seismic data are sampled at 333 Hz and then recorded by a standalone recording unit. One geophone is directly installed on bedrock, the other one mounted on a 1-m boulder partially buried in colluvium. This latter sensor integrates a heavily instrumented cross-section consisting of a 225 cm2

  11. Assessing inventories of past radioactive waste arisings at Chalk River Laboratories

    International Nuclear Information System (INIS)

    Internationally, a great deal of progress has been made in improving the management of currently accumulating and anticipated future radioactive wastes. Progress includes improved waste collection, segregation, characterization and documentation in support of disposal facility licensing and operation. These improvements are not often very helpful for assessing the hazards of wastes collected prior to their implementation, since, internationally, historic radioactive wastes were not managed and documented according to today's methods. This paper provides an overview of Atomic Energy of Canada Limited's (AECL) unique approach to managing its currently accumulating, low-level radioactive wastes at Chalk River Laboratories (CRL) and it describes the novel method AECL-CRL has developed to assess its historic radioactive wastes. Instead of estimating the characteristics of current radioactive wastes on a package-by-package basis, process knowledge is used to infer the average characteristics of most wastes. This approach defers, and potentially avoids, the use of expensive analytical technologies to characterize wastes until a reasonable certainty is gained about their ultimate disposition (Canada does not yet have a licensed radioactive waste disposal facility). Once the ultimate disposition is decided, performance assessments determine if inference characterization is adequate or if additional characterization is required. This process should result in significant cost savings to AECL since expensive, resource-intensive, up-front characterization may not be required for low-impact wastes. In addition, as technological improvements take place, the unit cost of characterization usually declines, making it less expensive to perform any additional characterization for current radioactive wastes. The WIP-III data management system is used at CRL to 'warehouse' the average characteristics of current radioactive wastes. This paper describes how this 'warehouse of information

  12. Investigation of CO2 Enhanced Oil Recovery Using Dimensionless Groups in Wettability Modified Chalk and Sandstone Rocks

    Directory of Open Access Journals (Sweden)

    Vahid Alipour Tabrizy

    2014-01-01

    Full Text Available The paper addresses enhanced oil recovery in chalk and sandstone rocks by CO2 injection, with different wettability, porosity, and permeability as well as injection rate and flooding conditions. Results indicate that an increase in Bond number has a positive effect on oil recovery whereas for capillary number, there is a limit in which recovery is improving. This limit is estimated when the pressure drop by viscous force is approximately equal to the threshold balance between capillary and gravity forces. A dimensionless group is proposed that combines the effect of capillarity, injection rate, permeability, and CO2 diffusion on the oil recovery. Recovery from all experiments in this study and reported data in the literature shows a satisfactory relationship with the proposed group.

  13. Influence of coal mine tips on the chalk aquifer. Sampling methods for three dimensional sulphate infiltration study

    Energy Technology Data Exchange (ETDEWEB)

    Barrez, F.; Mania, J. [Polytech' Lille, Dept. Genie Civil, UMR CNRS 8107 (LML), 59 - Villeneuve d' Ascq (France); Mansy, J.L. [Lille-1 Univ., Lab. de Sedimentologie et de Geodynamique, UMR CNRS 8110 (PBDS), 59 - Villeneuve d' Ascq (France); Piwakowski, B. [Ecole Centrale de Lille, Groupe Electronique Acoustique IEMN-DOAE, UMR CNRS 8520, 59 - Villeneuve d' Ascq (France)

    2005-07-01

    The coal basin of the Nord-Pas-de-Calais region (France) shows a very strong deterioration of the Chalk aquifer quality. In order to better model the hydro-dynamism and to improve knowledge on the chemical interactions, sampling according to depth of the groundwater is undertaken. The low-flow sampling and the profiles of the in-situ physicochemical parameters allow the observation of various vertical heterogeneities of the aquifer. The areas where the coal mine tips are localised appear very interesting to study. The sulphates released by the pyrite oxidation allow a 'artificial tracing' and give a visualization of the flow as well as information on the implied chemical processes between the oxidizing and reducing zones. (authors)

  14. Drivers of abundance and community composition of benthic macroinvertebrates in Ottawa River sediment near Chalk River Laboratories

    International Nuclear Information System (INIS)

    The Ottawa River has received effluent from Chalk River Laboratories (CRL) for more than 60 years. Some radionuclides and contaminants released in effluents are bound rapidly to particles and deposited in bottom sediments where they may be biologically available to benthic invertebrates and other aquatic biota. As part of a larger ecological assessment, we assess the potential impact of contaminated sediments in the vicinity of CRL on local benthic community structure. Using bivariate and multivariate approaches, we demonstrate that CRL operations have had little impact on the local benthic community. Despite elevated anthropogenic radionuclide activity concentrations in sediment near CRL's process outfall, the benthic community is no less abundant or diverse than what is observed upstream at background levels. The Ottawa River benthic invertebrate community is structured predominantly by natural physical and biological conditions in the sediment, specifically sediment water content and organic content. These natural habitat conditions have a stronger influence on macroinvertebrate communities than sediment contamination. (author)

  15. Radon hazard and risk in Sussex, England and the factors affecting radon levels in dwellings in chalk terrain

    International Nuclear Information System (INIS)

    A survey was undertaken of radon levels in 1013 dwellings in Sussex, UK. A number of dwellings were identified with high radon levels in an area previously considered to offer low radon risk from geological sources. Multiple regression was used to determine the relative influence of the various geographical and building-related factors on indoor radon levels. The radon hazard, independent of building-related effects, was determined for each surveyed location by standardising radon measurements to a 'model' dwelling. These were entered into a geographic information system and related to surface geology. The highest radon levels were found to be associated with the youngest Chalk formations, Tertiary deposits and Clay-with-flints Quaternary deposits in the area. Radon potentials were also determined for the area which can be used to estimate radon risk and assist in environmental planning and development control. (authors)

  16. Influence of coal mine tips on the chalk aquifer. Sampling methods for three dimensional sulphate infiltration study

    International Nuclear Information System (INIS)

    The coal basin of the Nord-Pas-de-Calais region (France) shows a very strong deterioration of the Chalk aquifer quality. In order to better model the hydro-dynamism and to improve knowledge on the chemical interactions, sampling according to depth of the groundwater is undertaken. The low-flow sampling and the profiles of the in-situ physicochemical parameters allow the observation of various vertical heterogeneities of the aquifer. The areas where the coal mine tips are localised appear very interesting to study. The sulphates released by the pyrite oxidation allow a 'artificial tracing' and give a visualization of the flow as well as information on the implied chemical processes between the oxidizing and reducing zones. (authors)

  17. Drivers of abundance and community composition of benthic macroinvertebrates in Ottawa River sediment near Chalk River Laboratories

    Energy Technology Data Exchange (ETDEWEB)

    Bond, M.J.; Rowan, D.; Silke, R.; Carr, J., E-mail: bondm@aecl.ca [Atomic Energy of Canada Limited, Chalk River, Ontario (Canada)

    2013-12-15

    The Ottawa River has received effluent from Chalk River Laboratories (CRL) for more than 60 years. Some radionuclides and contaminants released in effluents are bound rapidly to particles and deposited in bottom sediments where they may be biologically available to benthic invertebrates and other aquatic biota. As part of a larger ecological assessment, we assess the potential impact of contaminated sediments in the vicinity of CRL on local benthic community structure. Using bivariate and multivariate approaches, we demonstrate that CRL operations have had little impact on the local benthic community. Despite elevated anthropogenic radionuclide activity concentrations in sediment near CRL's process outfall, the benthic community is no less abundant or diverse than what is observed upstream at background levels. The Ottawa River benthic invertebrate community is structured predominantly by natural physical and biological conditions in the sediment, specifically sediment water content and organic content. These natural habitat conditions have a stronger influence on macroinvertebrate communities than sediment contamination. (author)

  18. Tilting oil-water contact in the chalk of Tyra Field as interpreted from capillary pressure data

    DEFF Research Database (Denmark)

    Fabricius, Ida Lykke; Rana, M.A.

    2010-01-01

    logging data in the remaining wells. A westerly dipping oil–water contact was found from logging data. Comparison of the depth-wise trends in normalized water saturation among the different wells indicates a regional pattern: in the western side of the field, the trends correspond to a situation of...... imbibition, where the free water level overlies an interval of residual oil, whereas in the eastern part of the field, the depth-wise trends in normalized water saturation correspond to a situation of drainage. The free water level apparently dips to the east due either to hydrodynamic action or to pressure......The Tyra Field in the central North Sea is located in Palaeogene and Upper Cretaceous chalk. It contains a natural gas zone underlain by an oil leg. Based on analysis of logs and core data from ten wells drilled prior to the field being put into production, normalized water saturation depth...

  19. 15N isotope biogeochemistry and natural denitrification process in groundwater: Application to the chalk aquifer of norther France

    International Nuclear Information System (INIS)

    The use of 15N natural isotope tracing in an aquifer contained within chalk rocks in northern France indicates that, under certain hydrogeological conditions, major denitrification occurs. At the boundary where the aquifer becomes confined, the nitrate concentrations decrease in the direction of groundwater flow accompanied by an exponential increase in 15N (expressed in δ15N) of the residual nitrate. This is characteristic of kinetic isotope effects, which accompany the reduction of the nitrate ion during denitrification. Hydrogeochemical and bacteriological observations confirm this process. Natural isotope tracing also permits this process to be distinguished from local dilution with nitrate-free water, which would entail a major drop in nitrate values without 15N isotopic enrichment. A model is proposed to explain the relatively small observed magnitude of the isotopic fractionation effect

  20. Comparison ecological characteristics of mound-building mouse (mus spicilegus in two natural hotbeds of tularemia at North-West coast of the Black sea

    Directory of Open Access Journals (Sweden)

    І. T. Rusev

    2011-03-01

    Full Text Available The analysis of ecology-epizootic monitoring of North-West coast of the Black sea carried out in wintering seasons of 2004, 2005 and 2011 testifies the basic role of the Mound-building mouse (Mus spicilegus Petenyi, 1882 as a carrier of Francisella tularensis. Spatial distribution of the Mound-building mouse strongly dependson a biotope, geographical region and weather conditions of a specific season. Mice nests in the storage mounds are located normally at a depth of 20–40 cm under the food storage chamber. Average number of the mice in storage mounds is 3.08 ± 1.54 in the south of investigated region and 3.88 ± 2.63 – in the NE of the region.

  1. The sediment composition and predictive mapping of facies on the Propeller Mound—A cold-water coral mound (Porcupine Seabight, NE Atlantic)

    Science.gov (United States)

    Heindel, Katrin; Titschack, Jürgen; Dorschel, Boris; Huvenne, Veerle A. I.; Freiwald, André

    2010-10-01

    Here we provide a detailed qualitative and quantitative insight on recent sediment composition and facies distribution of a cold-water coral (CWC) mound using the example of the Propeller Mound on the Irish continental margin (Hovland Mound Province, Porcupine Seabight). Five facies types on Propeller Mound are defined: (1) living coral framework, (2) coral rubble, (3) dropstone, (4) hardground, representing the on-mound facies, and (5) hemipelagic sediment facies, which describes the off-mound area. This facies definition is based on already published video-data recorded by Remotely Operated Vehicle (ROV), photo-data of gravity cores, box cores, and dredges from sediment surfaces as well as on the composition of the sediment fraction coarser than 125 μm, which has been analyzed on five selected box cores. Sediment compositions of the living coral framework and coral rubble facies are rather similar. Both sediment types are mainly produced by corals (34 and 35 wt%, respectively), planktonic foraminifers (22 and 29 wt%, respectively), benthic foraminifers (both 7 wt%), and molluscs (21 and 10 wt%, respectively), whereas the living coral framework characteristically features additional brachiopods (6 wt%). Hardgrounds are well-lithified coral rudstones rich in coral fragments (>30 surf%), foraminifers, echinoderms, and bivalves. The dropstone facies and the hemipelagic sediment typically carry high amounts of lithoclasts (36 and 53 wt%, respectively) and planktonic foraminifers (35 and 32 wt%, respectively); however, their faunal diversity is low compared with the coral-dominated facies (12 and <2 wt% coral fragments, 7 and 6 wt% benthic foraminifers, and 4 and 0 wt% balanids). Using the maximum likelihood algorithm within ArcGIS 9.2, spatial prediction maps of the previously described mound facies are calculated over Propeller Mound and are based on mound morphology parameters, ground-truthed with the sedimentary and faunal information from box cores, photographs

  2. Litter-forager termite mounds enhance the ectomycorrhizal symbiosis between Acacia holosericea A. Cunn. Ex G. Don and Scleroderma dictyosporum isolates

    OpenAIRE

    Duponnois, Robin; Assigbetse, Komi; Ramanankierana, H.; Kisa, Marija; Thioulouse, J.; Lepage, Michel

    2006-01-01

    The hypothesis of the present study was that the termite mounds of Macrotermes subhyalinus (MS) (a litter-forager termite) were inhabited by a specific microflora that could enhance with the ectomycorrhizal fungal development. We tested the effect of this feeding group mound material on (i) the ectomycorrhization symbiosis between Acacia holosericea (an Australian Acacia introduced in the sahelian areas) and two ectomycorrhizal fungal isolates of Scleroderma dictyosporum (IR408 and IR412) in ...

  3. Middle Miocene mound-shaped sediment packages on the slope of the Xisha carbonate platforms, South China Sea: Combined result of gravity flow and bottom current

    Science.gov (United States)

    Tian, Jie; Wu, Shiguo; Lv, Fuliang; Wang, Dawei; Wang, Bin; Zhang, Xinyuan; Ma, Benjun

    2015-12-01

    Deep-water mound-shaped sediment packages on the northern slope of the Xisha carbonate platforms in the northern South China Sea were analyzed by integrating high-resolution multi-channel seismic and drilling data. The mounds are distributed in the Beijiao depression of the Qiongdongnan Basin within the T41-T40 seismic horizons, which correspond to the middle Miocene. Mound-shaped reflections were identified both in the NE-SW and NW-SE oriented seismic profiles. The mound shapes are most prominent in the center of the NW-SE oriented seismic profiles, and the undulating tops flatten out towards the NW and SE. Similar reflections are mostly asymmetric, with steeper eastern flanks in the NE-SW oriented seismic profiles, and they are mostly round in shape. The wave impedance from the inversion calculation is 6-8×106 kg/(m2·s). It is much lower than that of the reef reservoir in the LH11-1 Reef Oilfield. Paleogeographic analysis shows that the Xisha uplift was dominated by tropical shallow carbonate platforms, while the Beijiao depression became a bathyal environment in the middle Miocene. Drilling data confirmed that the mound-shaped sediment packages are mainly composed of calcareous mudstone. Therefore, we infer that the mound-shaped sediment packages could be reef complexes or they were presumably built by combined gravity flow and bottom current.

  4. Seafloor classification of the mound and channel provinces of the Porcupine Seabight: An application of the multibeam angular backscatter data

    Digital Repository Service at National Institute of Oceanography (India)

    Beyer, A.; Chakraborty, B.; Schenke, H.W.

    for the angular backscatter data of GLORIA side scan sonar was implemented by [ ]. Such classification technique for the seafloor sections involves the shape, variance, and magnitude of the angular response of the measured multi-beam angular backscatter strength... in the section three along with a presentation of the shape invariant backscatter results from the mounds and the channel seafloor. An semi-empirical method is applied to the multi-beam dataset to employ seafloor classification in section four. 2 Multi...

  5. An improved calculation model for the wave-induced pore pressure distribution in a rubble-mound breakwater core

    OpenAIRE

    Vanneste, D.; Troch, P.

    2012-01-01

    The spatial distribution of the wave-induced pore pressure height in the core of a conventional rubble-mound breakwater is studied in this work. Use is made of existing theoretical and experimental knowledge to establish a calculation model for the pressure distribution on the front core slope and the attenuation of pore pressures within the breakwater core. The new model formulae are derived empirically and calibrated by means of a non-linear regression analysis of pore pressure measurements...

  6. Microfossils, a Key to Unravel Cold-Water Carbonate Mound Evolution through Time: Evidence from the Eastern Alboran Sea.

    Directory of Open Access Journals (Sweden)

    Claudio Stalder

    Full Text Available Cold-water coral (CWC ecosystems occur worldwide and play a major role in the ocean's carbonate budget and atmospheric CO2 balance since the Danian (~65 m.y. ago. However their temporal and spatial evolution against climatic and oceanographic variability is still unclear. For the first time, we combine the main macrofaunal components of a sediment core from a CWC mound of the Melilla Mounds Field in the Eastern Alboran Sea with the associated microfauna and we highlight the importance of foraminifera and ostracods as indicators of CWC mound evolution in the paleorecord. Abundances of macrofauna along the core reveal alternating periods dominated by distinct CWC taxa (mostly Lophelia pertusa, Madrepora oculata that correspond to major shifts in foraminiferal and ostracod assemblages. The period dominated by M. oculata coincides with a period characterized by increased export of refractory organic matter to the seafloor and rather unstable oceanographic conditions at the benthic boundary layer with periodically decreased water energy and oxygenation, variable bottom water temperature/density and increased sediment flow. The microfaunal and geochemical data strongly suggest that M. oculata and in particular Dendrophylliidae show a higher tolerance to environmental changes than L. pertusa. Finally, we show evidence for sustained CWC growth during the Alleröd-Younger-Dryas in the Eastern Alboran Sea and that this period corresponds to stable benthic conditions with cold/dense and well oxygenated bottom waters, high fluxes of labile organic matter and relatively strong bottom currents.

  7. Termite mounds as hot spots of nitrous oxide emissions in South-Sudanian savanna of Burkina Faso (West Africa)

    Science.gov (United States)

    Brümmer, Christian; Papen, Hans; Wassmann, Reiner; Brüggemann, Nicolas

    2009-05-01

    Despite a considerable knowledge of the significant role of termites in the global methane budget, very little is known about their contribution to the global nitrous oxide (N2O) budget. Release of N2O from termite (Cubitermes fungifaber) mounds was measured at a natural savanna site in the southwest of Burkina Faso from May to September 2006. Termite N2O emissions were around 20 μg N2O-N m-2 h-1 at the end of the dry season, and up to two orders of magnitude higher than N2O emissions from the surrounding termite-free soil after the onset of the rainy season. The average N2O emission rate from termite mounds during the observation period was 204 μg N2O-N m-2 h-1, and termite mounds contributed 3.0% to total N2O emissions from this savanna ecosystem. However, in other tropical terrestrial ecosystems with other termite species and/or higher termite density this share might be significantly higher.

  8. Combining ER and GPR surveys for evidence of prehistoric landscape construction: case study at Mound City, Ohio, USA

    Science.gov (United States)

    Schneider, B. B.; Mandel, R. D.; Tsoflias, G. P.; De Vore, S. L.; Lynott, M.

    2016-06-01

    Mound City, located at the Hopewell Culture National Historical Park in south-central Ohio, USA, is a prehistoric earthwork (200 BC-500 AD) that consists of 24 mounds enclosed in a square embankment wall and is surrounded by eight pits. Recent excavation of two of these pits resulted in the discovery of a clay loam liner that appears to have been placed on the floor of the pits by a prehistoric society known as the Hopewell. The aim of this study was to determine the spatial pattern of this liner in one of the pits using non-invasive geophysical techniques, specifically electrical resistivity and ground-penetrating radar. Minimally invasive soil augers and a test trench yielded information that was used to corroborate interpretations of the geophysical data. The geophysical methods proved to be useful in locating and defining the remnants of the prehistoric clay loam liner, and the results of our investigation indicate that almost 50% of the liner still remains in the pit today. This discovery supports a new interpretation that the Hopewell excavated and preserved the pits at the Mound City site because they served as cultural landscape features.

  9. Preparation of substituting seaweed field mounds accompanying site preparation for No.3 plant in Ikata Nuclear Power Station

    International Nuclear Information System (INIS)

    Shikoku Electric Power Co., Inc. is constructing No.3 plant adjacently to No.1 and No.2 plants in operation in Ikata Nuclear Power Station. In the coastal area of Iyo-nada, many seaweed fields are distributed, which are important biologically and for fishery. In the works of site preparation for No.3 plant, a part of the site is created by reclamation of sea area, therefore the natural seaweed fields in the area disappear. From the viewpoint of various circumstances and environment preservation, it was decided to create about 60,000 m2 of seaweed field mounds on the seabed around the site as the substitute for disappearing natural seaweed fields. The Seaweed Field Study Group composed of the men of learning and experience was organized to obtain the guidance on the possibility of creating artificial seaweed fields, the techniques for creation and the effect on environment accompanying the creation of mounds. The creation works were started in October, 1985, and are in progress smoothly utilizing effectively the stones and rocks cut in the site preparation works. The topographic and geological features, sea conditions, the present state of seaweed fields, the experiment on creating artificial seaweed fields, the design and construction of mounds and others are reported. (Kako, I.)

  10. «Mud-mounds» en sedimentos lacustres someros del Mioceno medio de la cuenca de Madrid

    Directory of Open Access Journals (Sweden)

    Calvo, J. P.

    1985-12-01

    Full Text Available Several non-tuffaceous carbonate buildups have been recognized in middle Miocene sediments of the Madrid Basin. Facies associations lead to conclude that carbonate buildups developed in shallow lacustrine areas, Detailed morphology and internal structure of the buildups are shown. A dense, sometimes discontinuous, rhizolith network is displayed in the mud-mound cores whereas surficial dessicated crusts are commonly observed in the outer parto Small wedge-c1astic breccias from eroded flanks of the buildups have been locally distinguished as well. Mud-mound growth took place through successive stages controlled by lake level oscillations.

    Diversos edificios carbonáticos de carácter no tobáceo han sido reconocidos en sucesiones continentales correspondientes al Mioceno medio de la cuenca de Madrid. La asociación de facies en todos los casos observados conduce a caracterizar dichos edificios como propios de ambientes palustres o lacustres muy someros. Se describe en detalle la morfología y estructura interna de estos cuerpos cuyo núcleo aparece constituido por un espeso entramado de raíces con ciertas peculiaridades en sus rellenos. Distintas subfacies: núcleo, discontinuidades internas, corteza externa, brechas locales en los flancos , han sido distinguidas, sirviendo de base para la propuesta de un modelo de desarrollo en estadios sucesivos de los edificios, integrables bajo el término de "mud-mounds" en ambiente continental.

  11. Structure and composition of organic reefs and carbonate mud mounds: concepts and categories

    Science.gov (United States)

    Riding, Robert

    2002-07-01

    organisms are skeletal, synsedimentary cementation imparts extra strength and stability to what otherwise would be a Cluster or Frame Reef, and results in Skeleton-Cement Reefs. Cement Reefs exhibit complex relationships between cement, matrix and skeletons. Agglutinated Microbial, Cluster and Segment reefs tend to be structurally simple, have low primary relief, and may show bedding. Frame (including microbial Microframe) and Cement Reefs tend to be unbedded, structurally complex, and can have high relief. Carbonate Mud Mounds: carbonate mud-dominated deposits with topographic relief and few or no stromatolites, thrombolites or in place skeletons. Low Relief Carbonate Mud Mounds are typically thin. High Relief Carbonate Mud Mounds are thick, and internal bedding, slumping, stromatactis cavity systems, and steep marginal slopes may be common. Whereas Organic Reefs are biogenic, calcareous, and are created by essentially in place organisms, Carbonate Mud Mounds can be organic and/or inorganic in origin and it can be difficult to distinguish their origins.

  12. Amino acid racemization dating of marine shells: A mound of possibilities.

    Science.gov (United States)

    Demarchi, Beatrice; Williams, Matt G; Milner, Nicky; Russell, Nicola; Bailey, Geoff; Penkman, Kirsty

    2011-07-01

    Shell middens are one of the most important and widespread indicators for human exploitation of marine resources and occupation of coastal environments. Establishing an accurate and reliable chronology for these deposits has fundamental implications for understanding the patterns of human evolution and dispersal. This paper explores the potential application of a new methodology of amino acid racemization (AAR) dating of shell middens and describes a simple protocol to test the suitability of different molluscan species. This protocol provides a preliminary test for the presence of an intracrystalline fraction of proteins (by bleaching experiments and subsequent heating at high temperature), checking the closed system behaviour of this fraction during diagenesis. Only species which pass both tests can be considered suitable for further studies to obtain reliable age information. This amino acid geochronological technique is also applied to midden deposits at two latitudinal extremes: Northern Scotland and the Southern Red Sea. Results obtained in this study indicate that the application of this new method of AAR dating of shells has the potential to aid the geochronological investigation of shell mounds in different areas of the world. PMID:21776187

  13. Certification of the Mound 1 kW package for shipping of plutonium dioxide source material

    Energy Technology Data Exchange (ETDEWEB)

    Annese, C.E.; Mount, M.K.

    1994-01-01

    The Department of Energy (DOE) has established procedures for obtaining certification of packagings used by DOE and its contractors for the transport of radioactive materials. Specifically, DOE Orders 5480.3 and 1540.2 provide references for other DOE Orders which must be followed when an applicant submits a Safety Analysis Report for Packaging (SARP). From the orders, Department EH of DOE, has internal oversight responsibility for transportation and Packaging safety; package certification falls under EH responsibility; transportation and packaging safety division in EH certifies packages for DOE; and use of DOE certified packages is authorized by DOT. An independent review of the SARP must confirm that the packaging designs and operations meet safety criteria at least equivalent to these standards. This paper will discuss the independent review process of the shielding section of the Mound 1 kW SARP; describe the geometry of the packaging and the load configurations; discuss the analysis of the various neutron and photon source terms that were used for the load configuration under analysis; and provide illustrations of the use of the monte-carlo code, COG{sup 3}, which was utilized to perform the shielding analysis.

  14. 2011 Mound Site Groundwater Plume Rebound Exercise and Follow-Up - 13440

    International Nuclear Information System (INIS)

    The Mound Site facility near Miamisburg, Ohio, opened in 1948 to support early atomic weapons programs. It grew into a research, development, and production facility performing work in support of the U.S. Department of Energy (DOE) weapons and energy programs. The plant was in operation until 1995. During the course of operation, an onsite landfill was created. The landfill was located over a finger of a buried valley aquifer, which is a sole drinking water source for much of the Miami Valley. In the 1980's, volatile organic compounds (VOCs) were discovered in groundwater at the Mound site. The site was placed on the National Priorities List on November 21, 1989. DOE signed a Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) Federal Facility Agreement with the U.S. Environmental Protection Agency (EPA) and the Ohio Environmental Protection Agency. The agreement became effective in October 1990. The area that included the landfill was designated Operational Unit 1 (OU-1). In 1995, a Record of Decision was signed that called for the installation and operation of a pump and treatment (P and T) system in order to prevent the VOCs in OU-1 groundwater from being captured by the onsite water production wells. In addition to the P and T system, a soil vapor extraction (SVE) system was installed in 1997 to accelerate removal of VOCs from groundwater in the OU-1 area. The SVE system was successful in removing large amounts of VOCs and continued to operate until 2007, when the amount of VOCs removed became minimal. A rebound study was started in February 2003 to determine how the groundwater system and contaminants would respond to shutting down the P and T system. The rebound test was stopped in February 2004 because predetermined VOC threshold concentrations were exceeded down-gradient of the landfill. The P and T and SVE systems were restarted after the termination of the rebound test. In 2006, the remediation of the Mound site was completed

  15. Electron spin resonance dating of shells from the sambaqui (shell mound) Capelinha, Sao Paulo, Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Kinoshita, A. [Sao Paulo Univ., Ribeirao Preto, SP (Brazil). Faculdade de Filosofia, Ciencias e Letras. Dept. de Fisica e Matematica; Universidade do Sagrado Coracao, Bauru, SP (Brazil); Figuty, L. [Sao Paulo Univ., SP (Brazil). Museu de Arqueologia e Etnologia. Setor de Arqueologia; Baffa, O. [Sao Paulo Univ., Ribeirao Preto, SP (Brazil). Faculdade de Filosofia, Ciencias e Letras. Dept. de Fisica e Matematica

    2006-03-15

    Capelinha is a fluvial sambaqui (Brazilian Shell Mound) located in the Ribeira Valley in the State of Sao Paulo that is being studied. It is one of the oldest sambaquis located along a river dated so far in this region. The use of ESR to date other shells stimulated our group to apply this method to the Capelinha site. Shells from land snails (Megalobulimus sp.) obtained in two levels of excavations were analyzed; one of them was in contact with a skeleton that was dated by C-14. The archaeological doses obtained were (8.05{+-}0.07) Gy and (9.50{+-}0.03) Gy. Since the last site was previously dated by C-14 (Beta -Analytics, Beta 153988) giving: 8860 +/- 60 years BP (conventional age) and 10180 to 9710 years BP (calibrated age), the archaeological dose found for this shell was used to determine the local rate of (0.93 to 0.98) mGy/year, that aggress with other surveys done in the region. Using this dose rate the age of the second shell was found to be 8.14 to 8.73 ky BP that agrees with the stratigraphy of the site. (author)

  16. Electron spin resonance dating of shells from the sambaqui (shell mound) Capelinha, Sao Paulo, Brazil

    International Nuclear Information System (INIS)

    Capelinha is a fluvial sambaqui (Brazilian Shell Mound) located in the Ribeira Valley in the State of Sao Paulo that is being studied. It is one of the oldest sambaquis located along a river dated so far in this region. The use of ESR to date other shells stimulated our group to apply this method to the Capelinha site. Shells from land snails (Megalobulimus sp.) obtained in two levels of excavations were analyzed; one of them was in contact with a skeleton that was dated by C-14. The archaeological doses obtained were (8.05±0.07) Gy and (9.50±0.03) Gy. Since the last site was previously dated by C-14 (Beta -Analytics, Beta 153988) giving: 8860 +/- 60 years BP (conventional age) and 10180 to 9710 years BP (calibrated age), the archaeological dose found for this shell was used to determine the local rate of (0.93 to 0.98) mGy/year, that aggress with other surveys done in the region. Using this dose rate the age of the second shell was found to be 8.14 to 8.73 ky BP that agrees with the stratigraphy of the site. (author)

  17. PRELIMINARY BIOGEOCHEMICAL DATA ON MICROBIAL CARBONATOGENESIS IN ANCIENT EXTREME ENVIRONMENTS (KESS-KESS MOUNDS, MOROCCO

    Directory of Open Access Journals (Sweden)

    ADRIANO GUIDO

    2013-03-01

    Full Text Available The Devonian Kess-Kess mounds, cropping out in the Hamar Laghdad Ridge (SE Morocco, provide a useful case-study for understanding the relationships between the microbial metabolic activities and micrite precipitation in an extreme environment. Very fine dark and white wrinkled laminae record microbial activity and the geochemistry of the organic matter allows the  characterization of the source organisms. The biogeochemical characterization of extracted organic matter was performed through the functional group analyses by FT-IR Spectroscopy. FT-IR parameters indicate a marine origin and low thermal evolution for the organic material. The organic matter is characterized by the presence of stretching ?C=C vibrations attributable to alkene and/or unsaturated carboxylic acids. Preliminary analysis with GC-MS provides evidence for an autochthonous (

  18. The structure of iron-hydroxide mounds at hydrothermal environment in shallow marine, Satsuma Iwo-Jima, Kikai caldera, Japan

    Science.gov (United States)

    Kuratomi, T.; Kiyokawa, S.; Ikehara, M.; Goto, S.; Hoshino, T.; Ikegami, F.; Minowa, Y.

    2013-12-01

    Satsuma Iwo-Jima Island, located 38km south of Kyusyu, Japan, is a volcanic island in the northwestern rim of Kikai caldera. Iron-rich mounds develop with hydrothermal activity (pH=5.5, 50-60 °C) in Nagahama bay southwestern this island. The brownish seawater at the bay is due to mixing of the hot spring water (Shikaura and Tazaki, 2001) with the high deposition rate (1 m per year) of iron-rich sediments (Kiyokawa et al., 2012). In this study, we found the structure of mounds has unique information by the observation with X-ray CT scan, FE-SEM, and the thin-sectioned sample, and the chemical analysis with EDS, XRF, and XRD. Samples (20-30 cm long) were piece of mounds made from two layers: black high-density hard layer and brownish low-density soft layer. X-ray CT scan observation shows that the inside of samples is constructed from the aggregation of convex structure (3-4 cm). Low-density layers have many pipe-like structure (typical radius: 1 mm). Petrographic observations indicate that both high- and low-density layers have filament-like forms, however the form in low-density layer is perpendicular to those in high-density layer. In low-density layer, small particles on the filament-like form and the number increases toward high-density layer. FE-SEM observation shows that filament-like form in high-density layer consists of aggregation of bacillus-like form as the chain of particles (about 2 μm). At low-density layer, on the other hand, bacteria-like form with smaller particles (twisted). Furthermore, all particles are iron-hydroxides such as ferrihydrite with silica because they are consist of Fe, Si and O with broad peak in XRD. We conclude that the mounds at Nagahama bay were constructed form aggregation of convex structure with many pipes as the hydrothermal vent. Bacteria-like form probably is the stalk of neutrophilic, iron-oxidizing bacteria because of those unique forms. Such a bacteria prefers an environment of redox interface (Chan et al., 2011

  19. Organic matter remains in the Kess Kess mounds of the Hamar Laghadad (Anti Atlas, Morocco): record of microbial biomineralization

    Science.gov (United States)

    Demasi, Fabio; Barbieri, Roberto; Guido, Adriano; Mastandrea, Adelaide; Cavalazzi, Barbara; Russo, Franco

    2010-05-01

    Carbonate Mud Mounds are well documented in the geological record, and span from Proterozoic to recent times, in shallow- and deep-water settings. They are a significant expression of the history of Earth's microbial life. The origin of carbonate mud-mounds has long been debated and the discovery of seep- and vent-related ecosystems from different geotectonic settings, associated to authigenic carbonate mounds, allowed the re-interpretation of some mounds as the product of chemosynthetic microbial mediation. We analyzed the carbonate mounds, informally called 'Kess-Kess', cropping out in the Hamar Laghdad Ridge, eastern Anti-Atlas, SE Morocco. These mounds are the most spectacularly exposed carbonate buildups of the world and, due to differential erosion, they show their original shapes and the relationships with associated strata. The origin of these buildups is still under debate and the most consistent hypotheses are related to submarine hydrothermal vents or hydrocarbon seapage in which bacteria and/or archaea plaied a prominent role in the carbonate biomineralization. To investigate the possible remains of prokaryote metabolic activity we studied the micrite precipitation processes through microfacies and biogeochemical analyses. The more indicative micrite texture is stromatolitic with very fine wrinkled lamination organized in antigravitative pattern. High resolution SEM observations suggest the presence of widespread trace of organic phantoms. The geochemical characterization of extracted organic matter was performed through the functional group analyses by FT-IR spectroscopy. The infrared spectra showed bands between 600 and 3000 cm-1. They contain stretching aliphatic bands (νCHali) at 2950, 2925 and 2850 cm-1, and deformation bands of methyl (δCH3; 1365 cm-1) and both methyl and methylene [δ(CH2 + CH3); 1458 cm-1] groups. The spectra also display the band assigned to carbonyl and/or carboxyl groups (νC=O; 1740 cm-1). The νC-O vibration appears

  20. Contribution of piezometric measurement to knowledge and management of low water levels: examples on the chalk aquifer in the Champagne Ardennes region

    OpenAIRE

    Stollsteiner, P.; Bessiere, H.; Nicolas, J.; Allier, D.; Berthet, O.

    2015-01-01

    This article is based on a BRGM study on piezometric indicators, threshold values of discharge and groundwater levels for the assessment of potentially-exploitable water resources of chalky watersheds. A method for estimating low water levels based on groundwater levels is presented from three examples representing chalk aquifers with different cycles: annual, combined and interannual. The first is located in Picardy and the two others in the Champagne-Ardennes region. Piezometers with...

  1. Integrated seismic analysis of the Chalk Group in eastern Denmark—Implications for estimates of maximum palaeo-burial in southwest Scandinavia

    DEFF Research Database (Denmark)

    Nielsen, Lars; Boldreel, Lars Ole; Hansen, Thomas Mejer;

    2011-01-01

    The origin of the topography of southwest Scandinavia is subject to discussion. Analysis of borehole seismic velocity has formed the basis for interpretation of several hundred metres of Neogene uplift in parts of Denmark.Here, refraction seismic data constrain a 7.5km long P-wave velocity model of...... velocities are systematically higher than values of a chalk velocity curve determined in previous studies, and it is estimated that a significant part of the velocity anomaly may be explained by the presence of clay. The remaining velocity anomaly can be explained by 450–500m palaeo-burial of the Chalk Group....... The burial anomaly will be over-estimated by ~150–200m if the analysis is based on the average Chalk Group velocity and clay content is disregarded. Burial anomaly values of ~450–600m result if the strongest velocity contrast at ~600–650m depth is interpreted to be a result of diagenetic effects...

  2. Area balance and strain in an extensional fault system: Strategies for improved oil recovery in fractured chalk, Gilbertown Field, southwestern Alabama. Final report, March 1996--September 1998

    Energy Technology Data Exchange (ETDEWEB)

    Pashin, J.C.; Raymond, D.E.; Rindsberg, A.K.; Alabi, G.G.; Carroll, R.E.; Groshong, R.H.; Jin, G.

    1998-12-01

    This project was designed to analyze the structure of Mesozoic and Tertiary strata in Gilbertown Field and adjacent areas to suggest ways in which oil recovery can be improved. The Eutaw Formation comprises 7 major flow units and is dominated by low-resistivity, low-contrast play that is difficult to characterize quantitatively. Selma chalk produces strictly from fault-related fractures that were mineralized as warm fluid migrated from deep sources. Resistivity, dipmeter, and fracture identification logs corroborate that deformation is concentrated in the hanging-wall drag zones. New area balancing techniques were developed to characterize growth strata and confirm that strain is concentrated in hanging-wall drag zones. Curvature analysis indicates that the faults contain numerous fault bends that influence fracture distribution. Eutaw oil is produced strictly from footwall uplifts, whereas Selma oil is produced from fault-related fractures. Clay smear and mineralization may be significant trapping mechanisms in the Eutaw Formation. The critical seal for Selma reservoirs, by contrast, is where Tertiary clay in the hanging wall is juxtaposed with poorly fractured Selma chalk in the footwall. Gilbertown Field can be revitalized by infill drilling and recompletion of existing wells. Directional drilling may be a viable technique for recovering untapped oil from Selma chalk. Revitalization is now underway, and the first new production wells since 1985 are being drilled in the western part of the field.

  3. COMPARISON OF THE TRADITIONAL CHALK AND BOARD LECTURE SYSTEM VERSUS POWER POINT PRESENTATION AS A TEACHING TECHNIQUE FOR TEACHING GROSS ANATOMY TO THE FIRST PROFESSIONAL MEDICAL STUDENTS

    Directory of Open Access Journals (Sweden)

    Nusrat

    2015-02-01

    Full Text Available Traditionally and conventionally, gross anatomy is taught by lectures and cadaveric dissection and the lectures are taken with chalk and board (C&B or chalk and talk method in, India. But there is always a debate over the most effective method of lecture delivery. AIM : The aim of this study was to compare the role and effectiveness chalk and board method versus power point presentation ( S tudent’s perception as a lecture delivering method for teaching gross anatomy. METHODS: This was a questionnaire based study where 140 out of 150 first professional MBBS students of Medical College Jammu, were asked to fill anonymously a questionnaire about their perceptions of these two lecture delivery methods. The results were analyzed to see if there was any preference of students for any particular method. RESULTS: The majority of the medical students (90.7% preferred PPT presentations, while only 9.3% of students preferred the lectures using chalkboard method. CONCLUSION: Most of the students clearly preferred and accepted the use of PPT presentations, as compared to conventional board teaching for delivery method. So teaching gross anatomy should be carefully amalgamated with use of power point in lecture hall.

  4. Reconstructing the Palaeogeographies of a Neolithic - Bronze Age Settlement Mound at Ephesos, Turkey

    Science.gov (United States)

    Ehlers, Lisa; Friederike, Stock; Barbara, Horejs; Helmut, Brückner

    2014-05-01

    Although Ephesos and its surroundings has long been an area of archaeological interest and investigations, the focus has mainly been on sites related to Antiquity and Late Antiquity. Until recently systematic research concerning prehistoric phases of occupation within this region have been lacking. Due to the growing interest in these time periods along the West Anatolian coast, archaeological research projects involving the study of the newly discovered prehistoric settlement mounds located in the vicinity of the prominent ancient city were initiated. The aim of this study was to examine the palaeogeographical and geoarchaeological contexts of the mound (tell), Çukuriçi Höyük, in order to determine the thickness and age of the settlement layers as well as the spatial extent of the tell throughout the different periods of settlement. As additional research to the excavations, 20 sediment cores drilled on and around Çukuriçi Höyük were examined and their physical and geochemical properties as well as existing data were used to reconstruct the palaeoenvironment. The chronostratigraphy relies on AMS-14C ages and findings of diagnostic ceramics; a further attempt was made by luminescence dating. The results reveal that the inhabitants intentionally choose the location due to the beneficial topography, initially, i.e. during Pottery Neolithic times in the early 7th mill. BC, lying upon an elevation within a fertile alluvial plain about 1.5-2 km away from the coast. It seems that during the time of settling (Pottery Neolithic - Early Bronze Age) several rivers flowed in the direct vicinity of the tell. The elevated terrain provided the inhabitants security from the torrents. In addition, the corings reveal that the tell covers an area of about 11,000 m2 and a thickness of settlement layers of c. 8 m. Finally, as a possible result of water management conducted by the inhabitants, sediments related to low-energy depositional conditions are identified at the foot of

  5. Volume reduction of low-level, combustible, transuranic waste at Mound Facility

    International Nuclear Information System (INIS)

    Low-level combustible waste (<100 nCi per g of waste) generated during plutonium-238 processing is collected and stored in 55-gallon (200-liter) drums. The composition of this waste is approximately 32 wt % paper, 46% plastic, 16% rubber and cloth, and 6% metal. Treatment of this waste is initiated by burning in the Mound Cyclone Incinerator, which consists of a burning chamber, deluge tank, venturi scrubber and blower. During the two years of operating the Cyclone Incinerator, experiments have been performed on particle distribution throughout the system using various mixtures of feed material. Measurements were taken at the incinerator outlet, after the spray tank, and after the venturi scrubber. An average emission of 0.23 g of particles per kg of feed at the venturi outlet was determined. The distribution of chlorine from the combustion of polyvinyl chloride was studied. Analyses of the off-gas and scrubber solution show that approximately 75 wt % of the chlorine was captured by the scrubber solution and approximately 17 wt % remained in the off-gas after the venturi scrubber. Measurements of the amount of NO/sub chi/ present in the off-gas were also made during the chloride studies. An average of approximately 200 ppM NO/sub chi/ was produced during each incineration run. Immobilization of the incinerator ash is being studied with regard to long-term behavior of the product. The immobilization matrix which looks most promising is ash mixed with Portland 1A cement in a 65/35 wt % ash-to-cement ratio. This matrix exhibits good mechanical properties while maintaining a maximum volume reduction

  6. Paleoenvironmental reconstruction of a downslope accretion history: From coralgal-coralline sponge rubble to mud mound deposits (Eocene, Ainsa Basin, Spain)

    Science.gov (United States)

    Rodríguez-Martínez, Marta; Reitner, Joachim

    2015-12-01

    In the Lutetian intraslope Ainsa sub-basin, small, sub-spherical, carbonate mud mounds occur associated with hemipelagic marls and mixed gravity flow deposits. The studied mud mounds consist of a mixture of allochthonous, parautochthonous and autochthonous components that show evidences of reworking, bioerosion, and accretion by different fossil assemblages at different growth stages. The crusts of microbial-lithistid sponges played an important role stabilizing the rubble of coralgal-coralline sponges and formed low-relief small benthic patches in a dominant marly soft slope environment. These accidental hard substrates turned into suitable initiation/nucleation sites for automicrite production (dense and peloidal automicrites) on which the small mud mounds dominated by opportunistic epi- and infaunal heterozoan assemblages grew. A detailed microfacies mapping and paleoenvironmental analysis reveals a multi-episodic downslope accretion history starred by demosponges (coralline and lithistid sponges), agariciid corals, calcareous red algae, putative microbial benthic communities and diverse sclerobionts from the upper slope to the middle slope. The analyzed mud mound microfacies are compared with similar fossil assemblages and growth fabrics described in many fossil mud mounds, and with recent deep-water fore reefs and cave environments.

  7. Simulating the influence of two shallow, flow-through lakes on a groundwater system: implications for groundwater mounds and hinge lines

    Science.gov (United States)

    Gosselin, David C.; Khisty, Mohan J.

    2001-10-01

    Groundwater mounds and hinge lines are important features related to the interaction of groundwater and lakes. In contrast to the transient formation of groundwater mounds, numerical simulations indicate that permanent groundwater mounds form between closely spaced lakes as the natural consequence of adding two net sinks to a groundwater flow system. The location of the groundwater mound and the position of the hinge lines between the two lakes are intimately related. As the position of the mound changes there is a corresponding shift in the position of the hinge line. This results in a change in the ratio of groundwater inflow to outflow (Qi/Qo) for the lake. The response of the lake is an increase or decrease in the lake level. Our simulations indicate that the movement of the hinge line in a natural system is a consequence of the dynamic interrelationships between recharge, the slope of the water table upgradient and downgradient of the lake, and the loss of water from the lake by evaporation. The extent of the seasonal movement of the hinge line will vary from one year to the next depending on local changes in the magnitude of the hydrologic variables.

  8. Vertical movements of frost mounds in sub-Arctic permafrost regions analyzed using geodetic survey and satellite interferometry

    Science.gov (United States)

    Beck, I.; Ludwig, R.; Bernier, M.; Strozzi, T.; Boike, J.

    2015-04-01

    Permafrost-affected soils cover about 45% of Canada. The environment in such areas, especially those located within the discontinuous permafrost zone, has been impacted more than any other by recorded climatic changes. A number of changes, such as surface subsidence and the degradation of frost mounds due to permafrost thawing have already been observed at many locations. We surveyed three frost mounds (lithalsas) close to Umiujaq, northern Quebec, sub-Arctic, using a high-precision differential Global Positioning System (d-GPS) during field visits in 2009, 2010 and 2011, thus obtaining detailed information on their responses to the freezing and thawing that occurs during the course of the annual temperature cycle. Seasonal pulsations were detected in the frost mounds and these responses were shown to vary with the state of degradation and the land cover. The most degraded lithalsa showed a maximum amplitude of vertical movement (either up or down) between winter and summer (thawing) of 0.19 ± 0.09 m over the study period, while for the least degraded lithalsa this figure was far greater (1.24 ± 0.47 m). Records from patches with little or no vegetation showed far less average vertical movement over the study period (0.17 ± 0.03 m) than those with prostrate shrubs (0.56 ± 0.02 m), suggesting an influence from the land-cover. A differential Interferometric Synthetic Aperature Radar (D-InSAR) analysis was also completed over the lithalsas using selected TerraSAR-X images acquired from April to October 2009 and from March to October 2010, with a repeat cycle of 11 days. Interferograms with baselines shorter than 200 m were computed revealing a generally very low interferometric coherence, restricting the quantification of vertical movements of the lithalsas. Vertical surface movements in the centimeter range were recorded in the near vicinity of Umiujaq.

  9. Cold-water coral mounds and sponge-beds as habitats for demersal fish on the Norwegian shelf

    Science.gov (United States)

    Kutti, Tina; Bergstad, Odd Aksel; Fosså, Jan Helge; Helle, Kristin

    2014-01-01

    The importance of cold-water coral (CWC) mounds and sponge-beds as habitat for demersal fish was examined in the Træna Deep marine protected area and adjacent areas of the Norwegian continental shelf. Standardised longline fishing was conducted twice, in June and March, and predetermined fishing effort was allocated to multiple plots with varying densities of small CWC mounds and sponges, plus control plots with neither of these habitats. Catches within all examined habitats were dominated by the commercially exploited Brosme brosme (representing >70% of the total catch) followed by Galeus melastomus, Chimaera monstrosa, Etmopterus spinax and the commercially exploited Molva molva. Positive correlations were found between catch rates of B. brosme, G. melastomus and C. monstrosa and the density of small CWC mounds at one or both sampling occasions. No correlations were found between the catch rates of the same three species and sponge density; thus the sponge-beds did not seem to represent an ecologically equivalent habitat to the CWCs. On a local scale the CWC habitat appeared to attract higher abundances of B. brosme, G. melastomus and C. monstrosa; however, the differences in catch rates between coral and non-coral areas were quite low (2-4 times) and for most species the fish-habitat relationships varied temporarily and with the spatial scale used to delineate the habitat. Based on the methods and the results of this study and the fact that CWCs only occupy a very small proportion of the Norwegian shelf, the importance of CWCs as habitat for the populations of the demersal fish species examined is judged as marginal.

  10. Uranium series geochemistry in aquifers: quantification of transport mechanisms of uranium and daughter products: the chalk aquifer (Champagne, France)

    International Nuclear Information System (INIS)

    With the increase of contaminant flux of radionuclides in surface environment (soil, river, aquifer...), there is a need to understand and model the processes that control the distribution of uranium and its daughter products during transport within aquifers. We have used U-series disequilibria as an analogue for the transport of uranium and its daughter products in aquifer to understand such mechanisms. The measurements of uranium (234U et 238U), thorium (230Th et 232Th), 226Ra and 222Rn isotopes in the solid and liquid phases of the chalk aquifer in Champagne (East of France) allows us to understand the processes responsible for fractionation within the uranium decay chain. Fractionations are induced by physical and chemical properties of the elements (leaching, adsorption) but also by radioactive properties (recoil effect during α-decay). For the first time a comprehensive sampling of the solid phase has been performed, allowing quantifying mechanisms responsible for the long term evolution of the aquifer. A non steady state 1D model has been developed which takes into account leaching, adsorption processes as well as radioactive filiation and α-recoil effect. Retardation coefficients have been calculated for uranium, thorium and radium. The aquifer is characterised by a double porosity, and the contribution of fracture and matrix porosity on the water/rock interaction processes has been estimated. (author)

  11. Impacts of climate change on in-stream nitrogen in a lowland chalk stream. An appraisal of adaptation strategies

    Energy Technology Data Exchange (ETDEWEB)

    Whitehead, P.G.; Butterfield, D.; Wade, A.J. [Aquatic Environments Research Centre, Department of Geography, University of Reading, Reading, RG6 6AB (United Kingdom); Wilby, R.L. [Environment Agency, Trentside Office, Scarrington Road, West Bridgford, Nottingham, NG2 5FA (United Kingdom)

    2006-07-15

    The impacts of climate change on nitrogen (N) in a lowland chalk stream are investigated using a dynamic modelling approach. The INCA-N model is used to simulate transient daily hydrology and water quality in the River Kennet using temperature and precipitation scenarios downscaled from the General Circulation Model (GCM) output for the period 1961-2100. The three GCMs (CGCM2, CSIRO and HadCM3) yield very different river flow regimes with the latter projecting significant periods of drought in the second half of the 21st century. Stream-water N concentrations increase over time as higher temperatures enhance N release from the soil, and lower river flows reduce the dilution capacity of the river. Particular problems are shown to occur following severe droughts when N mineralization is high and the subsequent breaking of the drought releases high nitrate loads into the river system. Possible strategies for reducing climate-driven N loads are explored using INCA-N. The measures include land use change or fertiliser reduction, reduction in atmospheric nitrate and ammonium deposition, and the introduction of water meadows or connected wetlands adjacent to the river. The most effective strategy is to change land use or reduce fertiliser use, followed by water meadow creation, and atmospheric pollution controls. Finally, a combined approach involving all three strategies is investigated and shown to reduce in-stream nitrate concentrations to those pre-1950s even under climate change. (author)

  12. Identification of a New Hesperornithiform from the Cretaceous Niobrara Chalk and Implications for Ecologic Diversity among Early Diving Birds.

    Directory of Open Access Journals (Sweden)

    Alyssa Bell

    Full Text Available The Smoky Hill Member of the Niobrara Chalk in Kansas (USA has yielded the remains of numerous members of the Hesperornithiformes, toothed diving birds from the late Early to Late Cretaceous. This study presents a new taxon of hesperornithiform from the Smoky Hill Member, Fumicollis hoffmani, the holotype of which is among the more complete hesperornithiform skeletons. Fumicollis has a unique combination of primitive (e.g. proximal and distal ends of femur not expanded, elongate pre-acetabular ilium, small and pyramidal patella and derived (e.g. dorsal ridge on metatarsal IV, plantarly-projected curve in the distal shaft of phalanx III:1 hesperornithiform characters, suggesting it was more specialized than small hesperornithiforms like Baptornis advenus but not as highly derived as the larger Hesperornis regalis. The identification of Fumicollis highlights once again the significant diversity of hesperornithiforms that existed in the Late Cretaceous Western Interior Seaway. This diversity points to the existence of a complex ecosystem, perhaps with a high degree of niche partitioning, as indicated by the varying degrees of diving specializations among these birds.

  13. Pre-operational HTO/HT surveys in the vicinity of the Chalk River Laboratories tritium extraction plant

    International Nuclear Information System (INIS)

    Surveys of the concentrations of HT and HTO in the atmosphere downwind of the Chalk River Laboratories reactor facilities were carried out in 1986 November, and in 1989 March, April and September under different conditions of air temperature, wind direction, and snow or vegetative cover. HT usually amounted to 1-5% of total tritium, but values up to 20% were observed, probably resulting from preferential removal of HTO. In all of the surveys, the greater persistence in the atmosphere of HT than of HTO was evident. The existing levels of HT are such that they will not be augmented significantly by chronic releases from the Tritium Extraction Plant (TEP) when it comes into operation. Hence, operation of the TEP will not facilitate studies of the environmental behaviour of chronically released HT. However, longer term studies of the distribution of HT from the existing facilities would be worthwhile. Soil and vegetation HTO levels in the study area are reported. Further studies of the distribution of tritium between the air, soil and vegetation in areas subjected to chronic exposure would be valuable

  14. Management of Legacy Spent Nuclear Fuel Wastes at the Chalk River Laboratories: The Challenges and Innovative Solutions Implemented - 13301

    International Nuclear Information System (INIS)

    AECL's Fuel Packaging and Storage (FPS) Project was initiated in 2004 to retrieve, transfer, and stabilize an identified inventory of degraded research reactor fuel that had been emplaced within in-ground 'Tile Hole' structures in Chalk River Laboratories' Waste Management Area in the 1950's and 60's. Ongoing monitoring of the legacy fuel storage conditions had identified that moisture present in the storage structures had contributed to corrosion of both the fuel and the storage containers. This prompted the initiation of the FPS Project which has as its objective to design, construct, and commission equipment and systems that would allow for the ongoing safe storage of this fuel until a final long-term management, or disposition, pathway was available. The FPS Project provides systems and technologies to retrieve and transfer the fuel from the Waste Management Area to a new facility that will repackage, dry, safely store and monitor the fuel for a period of 50 years. All equipment and the new storage facility are designed and constructed to meet the requirements for Class 1 Nuclear Facilities in Canada. (authors)

  15. Borehole television surveys and acoustic televiewer logging at the National Hydrology Research Institute's hydrogeological research area in Chalk River, Ontario

    International Nuclear Information System (INIS)

    This paper presents the results of studies of the fracture distribution and fracture orientation encountered in 23 boreholes at the National Hydrology Research Institute's Hydrogeological Research Area in Chalk River. Borehole television camera and acoustic televiewer data were used to determine: the fracture distribution as a function of depth; the aperture distribution as a function of depth; and, the predominant fracture sets. Fracture frameworks of the rock mass were constructed based on these data. The rock mass was found to be moderately to well fractured. Many open fractures were detected in the CR-series boreholes, especially in the upper 70 m. Three interconnecting, highly fractured zones are intersected by the CR-series boreholes between elevations of 96.80 m and 56.56 m, 34.91 m and -22.42 m, and -56.56 m and -61.31 m, while two interconnecting fracture zones are encountered by the FS-series boreholes between elevations 103.89 m and 96.64 m, and 108.20 m and 95.08 m. The predominant fracture sets strike east-west, northwest and indeterminably subhorizontal. The predominant set of veins strikes to the south. The subsurface fracture patterns and vein patterns were found to be similar to those observed on surface outcrops

  16. US team measurements during the June 1987 experimental HT release at the Chalk River Nuclear Laboratories, Ontario, Canada

    International Nuclear Information System (INIS)

    In June 1987, an experiment was performed at the Chalk River Nuclear Laboratories in Ontario, Canada, to study the oxidation of HT in the environment. The experiment involved a 30-minute release of 100 Ci of HT to the atmosphere at an elevation of one meter. The HTOHT ratios were shown to slowly increase downwind (/approximately/4 /times/ 10/sup /minus/5/ at 50 meters to almost 10/sup /minus/3 at 400 meters) as conversion of HT takes place. For several days after the release, HTO concentrations in the atmosphere remained elevated. Freeze-dried water from vegetation samples was found to be very low in HTO immediately after the release suggesting a very low direct uptake of HTO in air by vegetation. The tritiated water concentration increased during the first day, peaking during the second day (about 400 to 600 pCiml of water at 50 meters from the source) and decreasing by the end of the second day. The organically bound tritium continued to accumulate during the period following exposure (about 10 pCigm dry weight at 50 meters after two days). 4 refs., 6 figs., 2 tabs

  17. Diagnosing hydrological limitations of a land surface model: application of JULES to a deep-groundwater chalk basin

    Science.gov (United States)

    Le Vine, N.; Butler, A.; McIntyre, N.; Jackson, C.

    2016-01-01

    Land surface models (LSMs) are prospective starting points to develop a global hyper-resolution model of the terrestrial water, energy, and biogeochemical cycles. However, there are some fundamental limitations of LSMs related to how meaningfully hydrological fluxes and stores are represented. A diagnostic approach to model evaluation and improvement is taken here that exploits hydrological expert knowledge to detect LSM inadequacies through consideration of the major behavioural functions of a hydrological system: overall water balance, vertical water redistribution in the unsaturated zone, temporal water redistribution, and spatial water redistribution over the catchment's groundwater and surface-water systems. Three types of information are utilized to improve the model's hydrology: (a) observations, (b) information about expected response from regionalized data, and (c) information from an independent physics-based model. The study considers the JULES (Joint UK Land Environmental Simulator) LSM applied to a deep-groundwater chalk catchment in the UK. The diagnosed hydrological limitations and the proposed ways to address them are indicative of the challenges faced while transitioning to a global high resolution model of the water cycle.

  18. Projecting impacts of climate change on hydrological conditions and biotic responses in a chalk valley riparian wetland

    Science.gov (United States)

    House, A. R.; Thompson, J. R.; Acreman, M. C.

    2016-03-01

    Projected changes in climate are likely to substantially impact wetland hydrological conditions that will in turn have implications for wetland ecology. Assessing ecohydrological impacts of climate change requires models that can accurately simulate water levels at the fine-scale resolution to which species and communities respond. Hydrological conditions within the Lambourn Observatory at Boxford, Berkshire, UK were simulated using the physically based, distributed model MIKE SHE, calibrated to contemporary surface and groundwater levels. The site is a 10 ha lowland riparian wetland where complex geological conditions and channel management exert strong influences on the hydrological regime. Projected changes in precipitation, potential evapotranspiration, channel discharge and groundwater level were derived from the UK Climate Projections 2009 ensemble of climate models for the 2080s under different scenarios. Hydrological impacts of climate change differ through the wetland over short distances depending on the degree of groundwater/surface-water interaction. Discrete areas of groundwater upwelling are associated with an exaggerated response of water levels to climate change compared to non-upwelling areas. These are coincident with regions where a weathered chalk layer, which otherwise separates two main aquifers, is absent. Simulated water levels were linked to requirements of the MG8 plant community and Desmoulin's whorl snail (Vertigo moulinsiana) for which the site is designated. Impacts on each are shown to differ spatially and in line with hydrological impacts. Differences in water level requirements for this vegetation community and single species highlight the need for separate management strategies in distinct areas of the wetland.

  19. Hydrogeochemical processes affecting the migration of radionuclides in a fluvial sand aquifer at the Chalk River Nuclear Laboratories

    International Nuclear Information System (INIS)

    In the mid-1950's two experimental disposals of liquid radioactive waste containing about 700 curries of strontium-90 and cesium-137 were made into pits in sandy ground at one of the disposal areas at Chalk River Nuclear Laboratories. Since then, the wastes have migrated into two nearby aquifers and have chromatographically separated into strontium-90 and cesium-137 plumes moving at velocities less than that of the transporting groundwater. Analysis of radioactively contaminated aquifer sediments showed that most of the strontium-90 is exchangeably adsorbed, primarily to feldspars and layer silicates (mainly biotite); the rest is either specifically adsorbed to iron (III) and perhaps manganese (IV) oxhydroxides or fixed to unknown sinks. Less than one half of adsorbed cesium-137 is exchangeable with 0.5 m calcium chloride; the high levels of cesium-137 adsorption and fixation are probably due to its reaction with micaceous minerals. Complexation of strontium-90 and cesium-137 does not appear to be an important factor affecting their transport or adsorption. In studies of groundwater quality or pollution, dissolved oxygen and sulfide should be measured in addition to the redox potential since it allows independent assessment of the redox levels. The latter were found to affect the mobility of multivalent transition metals and nonmetals. (DN)

  20. Cold-seep-driven carbonate deposits at the Central American forearc: contrasting evolution and timing in escarpment and mound settings

    Science.gov (United States)

    Liebetrau, V.; Augustin, N.; Kutterolf, S.; Schmidt, M.; Eisenhauer, A.; Garbe-Schönberg, D.; Weinrebe, W.

    2014-10-01

    Continuous surface cores of cold-seep carbonates were recovered offshore Pacific Nicaragua and Costa Rica from 800 to 1,500-m water depths (Meteor 66/3) in order to decipher their evolution and methane enriched fluid emanation in contrasting geological settings. Cores from the mounds Iguana, Perezoso, Baula V and from the Jaco Scarp escarpment were used for a multi-method approach. For both settings aragonite was revealed as dominant authigenic carbonate phase in vein fillings and matrix cementation, followed by Mg-calcite as second most abundant. This common precipitation process of CaCO3 polymorphs could be ascribed as indirectly driven by chemical changes of the advecting pore water due to anaerobic oxidation of methane. A more direct influence of seep-related microbial activity on the authigenic mineral assemblage in both settings is probably reflected by the observed minor amounts of dolomite and a dolomite-like CaMg carbonate (MgCO3 ~ 42 %). δ13C data of Jaco Scarp samples are significantly lower (-43 to -56 ‰ PDB) than for mound samples (-22 to -36 ‰ PDB), indicating differences in fluid composition and origin. Noteworthy, δ18O values of Scarp samples correlate most closely with the ocean signature at their time of formation. Documenting the archive potential, a high resolution case study of a mound core implies at least 40 changes in fluid supply within a time interval of approximately 14 ky. As most striking difference, the age data indicate a late-stage downward-progressing cementation front for all three mound cap structures (approx. 2-5 cm/ky), but a significantly faster upward carbonate buildup in the bulging sediments on top of the scarp environment (approx. 120 cm/ky). The latter data set leads to the hypothesis of chemoherm carbonate emplacement in accord with reported sedimentation rates until decompression of the advective fluid system, probably caused by the Jaco Scarp landslide and dating this to approximately 13,000 years ago.

  1. Beaufort Sea deep-water gas hydrate recovery from a seafloor mound in a region of widespread BSR occurrence

    Science.gov (United States)

    Hart, Patrick E.; Pohlman, John W.; Lorenson, T.D.; Edwards, Brian D.

    2011-01-01

    Gas hydrate was recovered from the Alaskan Beaufort Sea slope north of Camden Bay in August 2010 during a U.S. Coast Guard Cutter Healy expedition (USCG cruise ID HLY1002) under the direction of the U.S. Geological Survey (USGS). Interpretation of multichannel seismic (MCS) reflection data collected in 1977 by the USGS across the Beaufort Sea continental margin identified a regional bottom simulating reflection (BSR), indicating that a large segment of the Beaufort Sea slope is underlain by gas hydrate. During HLY1002, gas hydrate was sampled by serendipity with a piston core targeting a steep-sided bathymetric high originally thought to be an outcrop of older, exposed strata. The feature cored is an approximately 1100m diameter, 130 m high conical mound, referred to here as the Canning Seafloor Mound (CSM), which overlies the crest of a buried anticline in a region of sub-parallel compressional folds beneath the eastern Beaufort outer slope. An MCS profile shows a prominent BSR upslope and downslope from the mound. The absence of a BSR beneath the CSM and occurrence of gas hydrate near the summit indicates that free gas has migrated via deep-rooted thrust faults or by structural focusing up the flanks of the anticline to the seafloor. Gas hydrate recovered from near the CSM summit at a subbottom depth of about 5.7 meters in a water depth of 2538 m was of nodular and vein-filling morphology. Although the hydrate was not preserved, residual gas from the core liner contained >95% methane by volume when corrected for atmospheric contamination. The presence of trace C4+hydrocarbons (hydrate lenses is also a likely factor in CSM growth. Pore water analysis shows the sulfate-methane transition to be very shallow (0-1 mbsf), also supporting an active high-flux interpretation. Pore water with chloride concentrations as low as 160 mM suggest fluid migration pathways may extend to the mound from buried non-marine sediments containing low-salinity fluids.

  2. Plutonium working group report on environmental, safety and health vulnerabilities associated with the Department's plutonium storage. Volume II, part 7: Mound working group assessment team report

    International Nuclear Information System (INIS)

    This is the report of a visit to the Mound site by the Working Group Assessment Team (WGAT) to assess plutonium vulnerabilities. Purposes of the visit were: to review results of the site's self assessment of current practices for handling and storing plutonium; to conduct an independent assessment of these practices; to reconcile differences and assemble a final list of vulnerabilities; to calculate consequences and probability for each vulnerability; and to issue a report to the Working Group. This report, representing completion of the Mound visit, will be compiled along with those from all other sites with plutonium inventories as part of a final report to the Secretary of Energy

  3. The giant cold-water coral mound as a nested microbial/metazoan system: physical, chemical, biological and geological picture (ESF EuroDiversity MiCROSYSTEMS)

    OpenAIRE

    Henriet, J.-P.; The MICROSYSTEMS Team

    2009-01-01

    The MiCROSYSTEMS project under the ESF EUROCORES EuroDiversity scheme is a holistic and multi-scale approach in studying microbial diversity and functionality in a nested microbial/metazoan system, which thrives in deep waters: the giant cold-water coral mound. Studies on prolific cold-water coral sites have been carried out from the canyons of the Bay of Biscay to the fjords of the Norwegian margin, while the Pen Duick carbonate mound province off Morocco developed into a joint natural lab f...

  4. Feedbacks between flow, sediment motion and microbial growth on sand bars initiate and shape elongated stromatolite mounds

    Science.gov (United States)

    Mariotti, G.; Perron, J. T.; Bosak, T.

    2014-07-01

    Elongated stromatolites are often used as indicators of current direction and shoreline orientation, especially in paleoenvironmental reconstructions. However, mechanisms that create shore-parallel, m-scale elongated stromatolite mounds in carbonate sand are not well understood. We propose that this geometry is initiated by microbial growth on the parts of sand bars that experience low wave-induced bed shear stresses. We test this idea by growing microbial mats on carbonate sand bars in a laboratory wave tank. Cyanobacterial mats grow on the bar runnels, where sediment motion is negligible, but are absent from the bar ridges, where the waves generate migrating ripples. When microbially-promoted lithification reinforces and preserves this initial pattern, elongated stromatolites should initiate in the runnels of sand bars, with long wavelengths (5-100 m) and small width-to-wavelength ratios (∼0.3). These dimensions are consistent with modern shore-parallel stromatolites in Hamelin Pool, Western Australia, and with patterns of microbial colonization in other sandy sediments. This model of elongated stromatolite mounds can inform paleoenvironmental reconstructions by clarifying and quantifying feedbacks among waves, sediment transport and microbial growth.

  5. Evaluation of brine disposal from the Bryan Mound site of the strategic petroleum reserve program. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Case, Robert J.; Chittenden, Jr, Mark E.; Harper, Jr, Donald E.; Kelly, Jr, Francis J.; Loeblich, Laurel A.; McKinney, Larry D.; Minello, Thomas J.; Park, E. Taisoo; Randall, Robert E.; Slowey, J. Frank

    1981-01-01

    On March 10, 1980, the Department of Energy's Strategic Petroleum Reserve Program began leaching the Bryan Mound salt dome and discharging the resulting brine into the coastal waters off Freeport, Texas. During the months of March and April, a team of scientists and engineers from Texas A and M University conducted an intensive environmental study of the area surrounding the diffuser site. A pipeline has been laid from the Bryan Mound site to a location 12.5 statute miles (20 km) offshore. The last 3060 ft (933 m) of this pipeline is a 52-port diffuser through which brine can be discharged at a maximum rate of 680,000 barrels per day. Initially, 16 ports were open which permitted a maximum discharge rate of 350,000 barrels per day and a continuous brine discharge was achieved on March 13, 1980. The purpose of this report is to describe the findings of the project team during the intensive postdisposal study period of March and April, 1980. The major areas of investigation are physical oceanography, analysis of the discharge plume, water and sediment quality, nekton, benthos, phytoplankton, zooplankton, and data management.

  6. PowerPoint or chalk and talk: Perceptions of medical students versus dental students in a medical college in India

    Directory of Open Access Journals (Sweden)

    Vikas Seth

    2010-08-01

    Full Text Available Vikas Seth, Prerna Upadhyaya, Mushtaq Ahmad, Vijay MogheDepartment of Pharmacology, Mahatma Gandhi Medical College, Jaipur, Rajasthan, IndiaPurpose: To assess students’ perceptions of the impact of PowerPoint (PPT presentations in lectures in comparison to the traditional chalk and talk method and lectures using ­transparencies and overhead projector (TOHP. The study analyzes the preferences for teaching aids of medical students versus dental students.Methods: Second year medical and dental undergraduates were asked to fill in a nine-item questionnaire about their perceptions of the three lecture delivery methods. Following analysis of the questionnaire the students were interviewed further. The results were analyzed separately for medical and dental students to see if there was any difference in their perceptions.Results: The majority of the medical students (65.33% preferred PPT presentations, while 15.16% of students preferred the lectures using chalkboard, and 19.51% preferred TOHP for teaching (P < 0.001. Of the dental students: 41.84% preferred chalkboard, 31.21% preferred TOHP, and 25.85% students preferred PPT presentations in the lectures (P < 0.05. Some important comments of the students were also recorded on interview which could be valuable for the medical teachers.Conclusion: The medical students clearly preferred the use of PPT presentations while the dental students did not. The study does not bring out evidence based superiority of any lecture delivery method. It appears that in the hands of a trained teacher any teaching aid would be appropriate and effective. This highlights the need for formal training in teaching technologies to develop good presentation skills and thus motivate the students.Keywords: audiovisual aids, medical education, lecture delivery methods, PowerPoint presentations, OHP, chalkboard

  7. Evaluation of five surface EM techniques for fracture detection and mapping at the Chalk River research area, Ontario

    International Nuclear Information System (INIS)

    Experimental field surveys were carried out with five surface electromagnetic (EM) systems at the Chalk River research area in 1980 and 1981. The purpose of the surveys was to test the usefulness of some new and a few existing EM systems for mapping fracture and shear zones in the highly resistive monzonite gneiss in the survey area. Fractures in the gneiss are often filled with water rich in ions, making the fractures medium to poor-grade conductors. The detection of these fractures by surface electromagnetic surveys depends on their conductance values (product of conductivity (s) and thickness (t)), the conductivity of the host rock, depth of the conductors, and strength, orientation, and frequency of the exciting field. The five EM systems used in the test surveys were: the local loop VLF-EM system; Max-Min II horizontal loop EM system; geonics EM-34 ground-mapping system; geonics EM-37; and, Maxi-Probe systems. Analysis of the field results shows that: the local loop VLF transmitter is a suitable substitute for Navy VLF stations; VLF and Max-Min II systems can detect poor conductors coincident with geologically defined lineaments and fracture zones, however, it is difficult at the moment to distinguish between near-vertical conductors in the bedrock and conductive overburden filling depressions in the bedrock surface; geonics EM-34 is not suitable in highly resistive terrain or in the presence of near-vertical conductors; and, the geonics EM-37 and Maxi-Probe systems detected possible subhorizontal conductors at depths of over 200 m. The presence of these could not be verified because of the lack of borehole control in those areas. An evaluation of the five systems indicates that VLF-EM and Max-Min II systems are most useful for detection of vertical and near-vertical fracture zones in the top 100 m, while EM-37 and Maxi-Probe systems are useful for detecting fracture zones at greater depths

  8. Understanding groundwater, surface water, and hyporheic zone biogeochemical processes in a Chalk catchment using fluorescence properties of dissolved and colloidal organic matter

    Science.gov (United States)

    Lapworth, D. J.; Gooddy, D. C.; Allen, D.; Old, G. H.

    2009-09-01

    Understanding groundwater-surface water (GW-SW) interaction in Chalk catchments is complicated by the degree of geological heterogeneity. At this study site, in southern United Kingdom, alluvial deposits in the riparian zone can be considered as a patchwork of varying grades and types with an equally varied lateral connectivity. Some display good connection with the river system and others good connection with the groundwater system and, by definition, poorer connectivity with the surface water. By coupling tangential flow fractionation (TFF) with fluorescence analysis we were able to characterize the organic matter in the river and hyporheic zone. There is a significant proportion of particulate and colloidal fluorescent organic matter (FOM) within the river system and at depth within the gravels beneath the river channel. At depth in the hyporheic zone, the surface water inputs are dampened by mixing with deeper groundwater FOM. The shallow (0-0.5 m below river bed) hyporheic zone is highly dynamic as a result of changing surface water inputs from upstream processes. Labile C in the form of protein-like FOM appears to be attenuated preferentially compared to fulvic-like fluorescence in the hyporheic zone compared to the adjacent gravel and sand deposits. These preliminary findings have important implications for understanding nutrient and trace element mobility and attenuation within the groundwater, surface water, and hyporheic zone of permeable Chalk catchments. Fluorescence analysis of dissolved organic matter has been shown to be a useful environmental tracer that can be used in conjunction with other methods to understand GW-SW processes within a permeable Chalk catchment.

  9. The impact of broadleaved woodland on water resources in lowland UK: I. Soil water changes below beech woodland and grass on chalk sites in Hampshire

    Directory of Open Access Journals (Sweden)

    J. Roberts

    2005-01-01

    Full Text Available The possible effects of broadleaved woodland on recharge to the UK Chalk aquifer have led to a study of evaporation and transpiration from beech woodland (Black Wood and pasture (Bridgets Farm, growing in shallow soils above chalk in Hampshire. Eddy correlation measurements of energy balance components above both the forest and the grassland enabled calculation of latent heat flux (evaporation and transpiration as a residual. Comparative measurements of soil water content and soil water potential in 9 m profiles under both forest and grassland found changes in soil water content down to 6 m at both sites; however, the soil water potential measurements showed upward movement of water only above a depth of about 2 m. Below this depth, water continued to drain and the soil water potential measurements showed downward movement of water at both sites, notwithstanding significant negative soil water potentials in the chalk and soil above. Seasonal differences occur in the soil water content profiles under broadleaved woodland and grass. Before the woodland foliage emerges, greater drying beneath the grassland is offset in late spring and early summer by increased drying under the forest. Yet, when the change in soil water profiles is at a maximum, in late summer, the profiles below woodland and grass are very similar. A comparison of soil water balances for Black Wood and Bridgets Farm using changes in soil water contents, local rainfall and evaporation measured by the energy balance approach allowed drainage to be calculated at each site. Although seasonal differences occurred, the difference in cumulative drainage below broadleaved woodland and grass was small.

  10. Archaeomagnetic study of five mounds from Upper Mesopotamia between 2500 and 750 BCE: further evidence for an extremely strong geomagnetic field ca. 3000 years ago

    NARCIS (Netherlands)

    Ertepinar, P.; Langereis, C.G.; Biggin, A.J.; Frangipane, M.; Matney, T.; Ökse, T.; Engin, A.

    2012-01-01

    The distribution of archaeomagnetic data in eastern Europe and the Near and Middle East shows a remarkable gap in Turkey. This study presents the first archaeomagnetic results from five different mounds in southeast Turkey, the northern part of Mesopotamia. The rock magnetic experiments indicate tha

  11. Performance evaluation of termite-mound clay, concrete and steel silos for the storage of maize grains in the humid tropics

    Science.gov (United States)

    Inadequate storage facilities have contributed to severe maize postharvest losses in many developing countries. This study determined the potential of termite mound clay (TMC), a readily-available material in Nigeria, as a construction material for storage silos. The performance of the TMC silo was ...

  12. Mineralogy of Juventae Chasma: Sulfates in the light-toned mounds, mafic minerals in the bedrock, and hydrated silica and hydroxylated ferric sulfate on the plateau

    Science.gov (United States)

    Bishop, Janice L.; Parente, Mario; Weitz, Catherine M.; Noe Dobrea, Eldar Z.; Roach, Leah H.; Murchie, Scott L.; McGuire, Patrick C.; McKeown, Nancy K.; Rossi, Christopher M.; Brown, Adrian J.; Calvin, Wendy M.; Milliken, Ralph; Mustard, John F.

    2009-11-01

    Juventae Chasma contains four light-toned sulfate-bearing mounds (denoted here as A-D from west to east) inside the trough, mafic outcrops at the base of the mounds and in the wall rock, and light-toned layered deposits of opal and ferric sulfates on the plateau. Hyperspectral visible/near-infrared Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) spectra were used to identify monohydrated and polyhydrated sulfate (PHS) outcrops of layered material on the bright mounds. Most of the monohydrated sulfate signatures closely resemble those of szomolnokite (FeSO4·H2O), characterized by a water band near 2.08 μm, while some areas exhibit spectral features more similar to those of kieserite (MgSO4·H2O), with a band centered closer to 2.13 μm. The largest PHS outcrops occur on the top of mound B, and their spectral features are most consistent with ferricopiapite, melanterite, and starkeyite, but a specific mineral cannot be uniquely identified at this time. Coordinated analyses of CRISM maps, Mars Orbiter Laser Altimeter elevations, and High Resolution Imaging Science Experiment images suggest that mounds A and B may have formed together and then eroded into separate mounds, while mounds C and D likely formed separately. Mafic minerals (low-Ca pyroxene, high-Ca pyroxene, and olivine) are observed in large ˜2-10 km wide outcrops in the wall rock and in smaller outcrops ˜50-500 m across at the floor of the canyon. Most of the wall rock is covered by at least a thin layer of dust and does not exhibit strong features characteristic of these minerals. The plateau region northwest of Juventae Chasma is characterized by an abundance of light-toned layered deposits. One region contains two spectrally unique phases exhibiting a highly stratified, terraced pattern. CRISM spectra of one unit eroded into swirling patterns with arc-like ridges exhibit a narrow 2.23-μm band assigned to hydroxylated ferric sulfate. A thin layer of a fractured material bearing an

  13. Microbial assemblages on a cold-water coral mound at the SE Rockall Bank (NE Atlantic): interactions with hydrography and topography

    Science.gov (United States)

    van Bleijswijk, J. D. L.; Whalen, C.; Duineveld, G. C. A.; Lavaleye, M. S. S.; Witte, H. J.; Mienis, F.

    2015-07-01

    This study characterizes the microbial community composition over Haas Mound, one of the most prominent cold-water coral mounds of the Logachev Mound province (Rockall Bank, NE Atlantic). We outline patterns of distribution vertically - from the seafloor to the water column - and laterally - across the mound - and couple these to mound topography and hydrography. Samples of water, sediment and Lophelia pertusa were collected in 2012 and 2013 from locations that were chosen based on high definition video surveys. Temperature and current measurements were obtained at two sites at the summit and foot of Haas Mound to study near-bed hydrodynamic conditions. Overlaying water was collected from depths of 400 m as well as 5 and 10 m above the bottom using a CTD/Rosette system. Near-bottom water, sediment and L. pertusa mucus and skeleton samples were obtained with a box corer. Of all these biotopes, Roche GS-FLX amplicon sequencing targeting both Bacteria and Archaea was carried out, augmenting our understanding of deep sea microbial consortia. The pattern of similarities between samples, visualized by multi-dimensional scaling (MDS), indicates a strong link between the distribution of microbes and the specific biotopes. The microbial operational taxonomic unit (OTU) diversity was the highest in near-bottom water, which was sampled in the coral framework. For the first time, Thaumarchaeota marine group I (MGI) were found in L. pertusa mucus; Endozoicomonas was detected in skeleton, mucus and near-bottom water, whereas Mycoplasma was only detected in skeleton and near-bottom water, however not in mucus. Analysis of similarities (ANOSIM) indicates that overlaying water is well-mixed at 400 m depth but less so at 5 and 10 m above the bottom, where the composition of microbial communities differed significantly between summit, slope and off-mound. At all locations, the near-bottom water differed significantly from water at 5 m above the bottom, illustrating that the near

  14. Synsedimentary tectonics, mud-mounds and sea-level changes on a Palaeozoic carbonate platform margin: a Devonian Montagne Noire example (France)

    Science.gov (United States)

    Bourrouilh, Robert; Bourque, Pierre-André; Dansereau, Pauline; Bourrouilh-Le Jan, Françoise; Weyant, Pierre

    1998-06-01

    The Devonian sedimentary succession of the southern flank of the Montagne Noire (France) was deposited along a divergent margin. This paper is a contribution to describe and evaluate biogenic, sedimentary, geochemical and micropalaeontological features as indicators of sea-level changes and global history of the Devonian in this area. Following transgression and shallow-water environments during Early Devonian time (Lochkovian to early Emsian), biogenic mud-rich mounds with stromatactis developed during latest Emsian at the platform margin. The depth of the Devonian sea was increasing and the seafloor passed below the photic zone and the lower limit of storm wave base during the Emsian. Growth and seismic faults affected the mounds and created Neptunian cracks and crevices, quickly filled with sedimentary material (pisoids) and cements (Neptunian dykes and veins). Light and CL-microscopy, and stable isotope geochemistry show that stromatactis, cements of Neptunian dykes, veins and pisoid cortices are early marine, whereas the red finely crystalline material that forms the bulk of the mound has been cemented in the near-surface diagenetic environment, after the early marine cementation of stromatactis and Neptunian dykes and veins, by meteoric or hydrothermal fluids. The sedimentary rocks overlying the stromatactis mounds exhibit regularly condensed iron and manganese-rich layers, interrupted by the Kellwasser hypoxic horizon. These condensed deposits developed up to the Famennian in a context of carbonate gravity sedimentation and became more and more rhythmic and frequent up section. The occurrence and irregular distribution of large-scale submarine mass flows during Frasnian and Famennian times can be related to block faulting on which Lower Devonian stromatactis mounds could have been uplifted by this block faulting to form seamounts. The sea-level fluctuations detected in the southern flank of Montagne Noire are compared to the Devonian eustatic sea-level curve

  15. Estimation of Partial Safety Factors and Target Failure Probability Based on Cost Optimization of Rubble Mound Breakwaters

    DEFF Research Database (Denmark)

    Kim, Seung-Woo; Suh, Kyung-Duck; Burcharth, Hans F.

    2010-01-01

    The breakwaters are designed by considering the cost optimization because a human risk is seldom considered. Most breakwaters, however, were constructed without considering the cost optimization. In this study, the optimum return period, target failure probability and the partial safety factors...... of the national design standard and then the overall safety factor is calculated as 1.09. It is required that the nominal diameter and weight of armor are respectively 9% and 30% larger than those of the existing design method. Moreover, partial safety factors considering the cost optimization were compared...... were evaluated by applying the cost optimization to the rubble mound breakwaters in Korea. The applied method was developed by Hans F. Burcharth and John D. Sorensen in relation to the PIANC Working Group 47. The optimum return period was determined as 50 years in many cases and was found as 100 years...

  16. Area balance and strain in an extensional fault system: Strategies for improved oil recovery in fractured chalk, Gilbertown Field, southwestern Alabama. Annual report, March 1996--March 1997

    Energy Technology Data Exchange (ETDEWEB)

    Pashin, J.C.; Raymond, D.E.; Rindsberg, A.K.; Alabi, G.G.; Groshong, R.H.

    1997-08-01

    Gilbertown Field is the oldest oil field in Alabama and produces oil from chalk of the Upper Cretaceous Selma Group and from sandstone of the Eutaw Formation along the southern margin of the Gilbertown fault system. Most of the field has been in primary recovery since establishment, but production has declined to marginally economic levels. This investigation applies advanced geologic concepts designed to aid implementation of improved recovery programs. The Gilbertown fault system is detached at the base of Jurassic salt. The fault system began forming as a half graben and evolved in to a full graben by the Late Cretaceous. Conventional trapping mechanisms are effective in Eutaw sandstone, whereas oil in Selma chalk is trapped in faults and fault-related fractures. Burial modeling establishes that the subsidence history of the Gilbertown area is typical of extensional basins and includes a major component of sediment loading and compaction. Surface mapping and fracture analysis indicate that faults offset strata as young as Miocene and that joints may be related to regional uplift postdating fault movement. Preliminary balanced structural models of the Gilbertown fault system indicate that synsedimentary growth factors need to be incorporated into the basic equations of area balance to model strain and predict fractures in Selma and Eutaw reservoirs.

  17. Implementation of Enhanced Attenuation at the DOE Mound Site OU-1 Landfill: Accelerating Progress and Reducing Costs

    Energy Technology Data Exchange (ETDEWEB)

    Hooten, Gwendolyn [U.S. Department of Energy, Office of Legacy Management; Cato, Rebecca [Navarro Research and Engineering; Looney, Brian [Savannah River National Laboratory, Aiken, SC

    2016-03-06

    At the US Department of Energy (DOE), Office of Legacy Management, Mound, Ohio, Site, chlorinated organic contaminants (cVOCs) originating from the former solid-waste landfill have impacted groundwater in Operable Unit 1 (OU-1). The baseline groundwater remedy was groundwater pump and treat (P&T). Since the source materials have been removed from the landfill, the Mound core team, which consists of DOE, US Environmental Protection Agency (US EPA), Ohio EPA, and other stakeholders, is assessing the feasibility of switching from the active P&T remedy to a passive attenuation-based remedy. Toward this end, an enhanced attenuation (EA) strategy based on the creation of structured geochemical zones was developed. This EA strategy addresses the residual areas of elevated cVOCs in soil and groundwater while minimizing the rebound of groundwater concentrations above regulatory targets (e.g., maximum contaminant levels [MCLs]) and avoiding plume expansion while the P&T system is turned off. The EA strategy has improved confidence and reduced risk on the OU-1 groundwater transition path to monitored natural attenuation (MNA). To better evaluate the EA strategy, DOE is conducting a field demonstration to evaluate the use of edible oils to enhance the natural attenuation processes. The field demonstration is designed to determine whether structured geochemical zones can be established that expedite the attenuation of cVOCs in the OU-1 groundwater. The EA approach at OU-1 was designed based on “structured geochemical zones” and relies on groundwater flow through a succession of anaerobic and aerobic zones. The anaerobic zones stimulate relatively rapid degradation of the original solvent source compounds (e.g., cVOCs such as tetrachloroethene [PCE] and trichloroethene [TCE]). The surrounding aerobic areas encourage relatively rapid degradation of daughter products (such as dichloroethene [DCE] and vinyl chloride [VC]) as well as enhanced cometabolism of TCE resulting from

  18. Advection dispersion modeling of tritium and chloride migration in a shallow sandy aquifer at the Chalk River Laboratories

    International Nuclear Information System (INIS)

    Elevated tritium, helium-3 and chloride concentrations have been measured in groundwaters in a shallow sandy aquifer draining a small lake at the Chalk River Laboratories (CRL), Ontario, Canada. The chloride in the lakewater recharge is 25 times greater than precipitation recharge and forms a continuous, concentrated source of contamination to the aquifer. Tritium (3H) concentrations in both lake and precipitation recharge are elevated owing to the operation of a research reactor on the CRL site and form a continuous spatially distributed source of contamination. The transport of tritium and chloride over the 600 m groundwater flowpath from the lake to the discharge zone are simulated using a 3-D advection-dispersion model. The model requires information on the contaminant input concentrations, the velocity field, dispersion parameters, hydrostratigraphy and boundary conditions. The two independent sets of concentration data provide complementary information to minimize problems associated with the unknown input concentration. The velocity field was estimated from a 3-D simulation of the groundwater flow system; dispersion parameters were estimated from analysis of a controlled natural-gradient tracer test performed previously at the site. The hydrostratigraphy and boundary geometry was characterized by visual logging of borehole sediments, grain size analyses and ground penetrating radar surveys. The abundance of hydrogeologic and geophysical information allowed simulation of the spatial distribution of chloride concentrations with a remarkable degree of accuracy. Simulated and measured peak chloride concentrations differed by less than 15%. The excellent agreement between the simulated and observed chloride concentrations facilitated further modelling of the source and migrational behavior of 3H within this aquifer. We have solved the inverse problem for the 3H source function and successfully modelled the 3H source as a stepwise function. Estimates of

  19. Modelling of N2O Reduction in a Circulating Fluidized Bed Boiler

    DEFF Research Database (Denmark)

    Johnsson, Jan Erik; Åmand, Lars Erik; Dam-Johansen, Kim;

    1996-01-01

    The addition of limestone for sulphur retention in Fluidized Bed Combustion (FBC) has been observed to influence the emission of N2O, and in many cases a lower emission was observed. The catalytic activity of a Danish limestone (Stevns Chalk) for decomposition of N2O in a laboratory fixed bed...... quartz reactor was measured. It was found that calcined Stevns Chalk is a very active catalyst for N2O decomposition in an inert atmosphere compared to bed material, i.e. a mixture of ash and sand. However, in FBC the limestone is exposed to a mixture of gases, including CO, CO2 and SO2, and sulphation...... uncalcined or recarbonated limestone had negligible activity. Sulphation of the calcined limestone under oxidizing conditions lowered the activity, however sulphidation under reducing conditions showed that CaS is an active catalyst for the reduction of N2O by CO. Without CO present a gas solid reaction...

  20. Decomposition and Reduction of N2O over Limestone under FBC Conditions

    DEFF Research Database (Denmark)

    Johnsson, Jan Erik; Jensen, Anker; Vaaben, Rikke;

    1997-01-01

    The addition of limestone for sulfur retention in fluidized bed combustion (FBC) has in many cases been observed to influence the emission of N2O. The catalytic activity of N2O over calcined Stevns Chalk for decomposition of N2O in a laboratory fixed bed quartz reactor was measured. It was found...... that calcined Stevns Chalk is an active catalyst for N2O decomposition in an inert atmosphere at FBC temperatures, and the presence of 3 vol% CO increased the rate of N2O destruction by a factor of 5 due to the catalytic reduction of N2O by CO. The activity decreased with increasing CO2 concentration...... reaction between N2O and CaS takes place and SO2 is released....