Regional trends in matrix porosity and dry density of the Chalk of England

Bloomfield, John P.; Brewerton, L. J.; Allen, Debbie

doi:10.1144/gsl.qjegh.1995.028.s2.04

Cited by 49 publications

(40 citation statements)

References 18 publications

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“…This is consistent with previously reported depth trends in Chalk matrix porosity (Bloomfield et al 1995) and reflects the diagenetic grade and maximum burial depth of the Chalk. Variations from this overall trend reflect primary lithological variations such as the presence of marls and hardgrounds.…”

Section: Introductionsupporting

confidence: 93%

Interaction between groundwater, the hyporheic zone and a Chalk stream: a case study from the River Lambourn, UK

et al. 2010

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Understanding the processes controlling groundwater-surface water interaction is essential for effective resource management and for protecting sensitive ecosystems. Through intensive monitoring of Chalk groundwater, surface water, and shallow gravel groundwater along a river bank and below the river, using a combination of hydrochemical and hydrophysical techniques a complex pattern of interactions has been elucidated. The river is broadly in hydraulic contact with the river bed and adjacent gravels and sands (although with local variability), but these sediments are mainly hydraulically separate from the underlying Chalk at the site. The relationship between the river and underlying alluvium is variable, involving components of groundwater flow both parallel and transverse to the river and with both effluent and influent behaviour seen. The degree of groundwater-surface water interaction within the hyporheic zone at this site seems to be controlled by a number of factors including lithology, topography, and the local groundwater flow regime. While the gravel aquifer is significant in controlling groundwater-surface water interaction, its importance as a route for flow down the catchment is likely to be modest compared with river discharge.

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Section: Introductionsupporting

confidence: 93%

Interaction between groundwater, the hyporheic zone and a Chalk stream: a case study from the River Lambourn, UK

et al. 2010

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“…Various factors were considered including the depositional, structural and glacial history (Bloomfield et al (1995) used the same divisions in describing trends in the matrix properties of the Chalk). The transmissivity distribution shows broad similarities over the four regions.…”

Section: Regional Distribution Of Aquifer Propertiesmentioning

confidence: 99%

“…Summary data for the areas are shown in Table 2 Lincolnshire, is the different chalk lithology. Lower porosity and harder Chalk (Foster & Crease 1974;Barker 1994;Bloomfield 1995) will significantly reduce the elastic storage. Since confined storage depends wholly on elastic storage, the measured storage coefficient would be very low.…”

Section: Regional Distribution Of Aquifer Propertiesmentioning

confidence: 99%

Aquifer properties of the Chalk of England

MacDonald

Allen²

2001

QJEGH

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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- The data indicate several trends and relationships in Chalk aquifer properties. Transmissivity is highest in the harder Chalk of Yorkshire and Lincolnshire (median 1800 m²/d). Throughout much of the Chalk aquifer a direct relation is observed between transmissivity and storage coefficient, reflecting the importance of fractures in governing both storage and transmissivity. Pumping tests undertaken in unconfined conditions give consistently higher measurements of transmissivity than in confined areas, probably as a result of increased dissolution enhancement of fractures in unconfined areas. At a catchment scale the data illustrate a relation between transmissivity and winter flowing streams. Word Count 7500QJEGH 34:371-384Alan MacDonaldPage 2 of 26 submitted QJEGHThe Chalk is the most important aquifer within the UK. It accounts for 60% of the groundwater used inEngland and Wales and 20% of the total water used in England and Wales (UK Groundwater Forum 1998). To protect and manage this unique resource it is essential to know and understand the variations of aquifer properties throughout the Chalk.Against this background a three-year collaborative project between the British Geological Survey (BGS) and the Environment Agency (EA) was devised. The aim of the study was to collect, collate and present information concerning the physical properties of the major aquifers in England and Wales (Allen et al. 1997). This included creating a database of available pumping tests for the major aquifers. This paper presents an analysis and interpretation of all available Chalk data in the Aquifer Properties Database. OVERVIEW OF THE DEVELOPMENT OF CHALK AQUIFER PROPERTIESThe presence and development of fractures gives the Chalk the properties of an aquifer. Without fractures, the permeability and specific yield of the Chalk would be negligible. Furthermore, without solution enhancement of the fractures, the high transmissivity of the Chalk would be impossible, and without further concentration of groundwater flow and dissolution of chalk, conduits and karstic features would not be observed. The Chalk is often referred to as possessing dual porosity (Price 1987;Barker 1991;Price et al. 1993). In a classic dual porosity aquifer, the matrix pores provide the storage, and the fractures provide the permeable pathways to permit groundwater flow. Groundwater movement within the Chalk is more complex: the high porosity (produced by the coccoliths) is not readily drained, due to the very small pore throats (Price et al. 1976), therefore effective groundwater storage is primarily within the fracture network and the larger pores....

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“…Details on these properties and their measurement can be found in Paton (2005). The thermal properties are for the solid part of the materials where k s is the thermal conductivity, c s is the heat capacity and ρ s is the density (Bloomfield et al, 1995 1 Fig. 15.…”

Section: Resultsmentioning

confidence: 99%

Investigating thermal properties of gas-filled planetary regoliths using a thermal probe

Paton

Harri

Mäkinen

et al. 2012

Geosci. Instrum. Method. Data Syst.

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Abstract. We introduce a general purpose penetrator, fitted with a heater, for measuring temperature and thermal diffusivity. Due to its simplicity of deployment and operation the penetrator is well suited for remote deployment by spacecraft into a planetary regolith. Thermal measurements in planetary regoliths are required to determine the surface energy balance and to measure their thermal properties. If the regolith is on a planet with an atmosphere a good understanding of the role of convection is required to properly interpret the measurements. This could also help to identify the significant heat and mass exchange mechanisms between the regolith and the atmosphere. To understand the role of convection in our regolith analogues we use a network of temperature sensors placed in the target. In practical applications a penetrator will push material out of the way as it enters a target possible changing its thermal properties. To investigate this effect a custom built test rig, that precisely controls and monitors the motion of the penetrator, is used. The thermal diffusivity of limestone powder and sand is derived by fitting a numerical thermal model to the temperature measurements.Convection seems to play an important role in the transfer of heat in this case. Firstly a diffusion-convection model fits the laboratory data better than a diffusivity-only model. Also the diffusivity derived from a diffusivity-convection model was found to be in good agreement with diffusivity derived using other methods published in the literature. Thermal diffusivity measurements, inspection of the horizontal temperature profiles and visual observations suggests that limestone powder is compacted more readily than sand during entry of the penetrator into the target. For both regolith analogues the disturbance of material around the penetrator was determined to have an insignificant effect on the diffusivity measurements in this case.

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Regional trends in matrix porosity and dry density of the Chalk of England

Cited by 49 publications

References 18 publications

Interaction between groundwater, the hyporheic zone and a Chalk stream: a case study from the River Lambourn, UK

Interaction between groundwater, the hyporheic zone and a Chalk stream: a case study from the River Lambourn, UK

Aquifer properties of the Chalk of England

Investigating thermal properties of gas-filled planetary regoliths using a thermal probe

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