Perturbations to temperature gradients by water flow in crystalline rock formations

1984 ◽  
Vol 103 (1-4) ◽  
pp. 19-32 ◽  
Author(s):  
Malcolm J. Drury
Keyword(s):  
Water Flow ◽  
Crystalline Rock ◽  
Temperature Gradients ◽  
Rock Formations

III.—The Crystalline Rock Areas of the Piémontese Alps

1916 ◽  
Vol 3 (5) ◽  
pp. 198-205
Author(s):  
C. S. Du Riche Preller
Keyword(s):  
Preceding Paper ◽  
Crystalline Rock ◽  
New Classification ◽  
Rock Formations ◽  
Starting Point

In continuation of the preceding paper (Geol. Mag., April, p. 156) which, as a preliminary to the present one, outlined the new classification of the crystalline rock formations and the nomenclature of the pietre verdi of the Piémontese Alps, I now propose to briefly describe the principal pietre verdi areas with which I became familiar during a long stay on repeated occasions in Turin. This city, apart from its rich collections of the rocks and minerals of the Piémontese Alps, is a most central and convenient starting-point for examining the different valleys debouching into the plain of the Po from the magnificent crescent formed by the Maritime, Cottian, Grajan, and Penniue Alps, which, as seen from Turin, afford by far the most extensive and fascinating Alpine panorama in Italy.

Rock Properties Input to the Site Screening Process

1983 ◽  
Vol 26 ◽  
Author(s):  
Arthur A. Bauer ◽  
Joe E. Ratigan
Keyword(s):  
Thermal Loading ◽  
Crystalline Rock ◽  
Rock Properties ◽  
Nuclear Waste Repository ◽  
Screening Process ◽  
Design Elements ◽  
Rock Formations ◽  
Wide Range ◽  
Stochastic Parameters ◽  
The Impact

ABSTRACTThe site-screening process is designed to provide information on rock formations that will serve as the basis for recoximnding potentially suitable sites for locating a nuclear waste repository. While the application of criteria to extrinsic characteristics of the host rock, such as minimum depth and areal extent, are based on requiremnts associated with repository design and waste isolation, the significance of intrinsic characteristics (e.g., thermal conductivity, heat capacity, Young's modulus) is less firmly based. This is of particular importance with crystalline or grantitic-type rocks since they exhibit a wide range of canpositions and properties.The range of crystalline rock property variations has been defined and results describing the impact of these variations on repository thermal, mechanical, chemical, and hydrological performance constraints obtained. Results also are presented for various repository design options (emplacement mode, thermal loading, package power/pitch). For the analysis, rock properties and repository design elements are treated as stochastic parameters by statistical methods. The output range of a performance parameter is determined with respect to the range of stochastic parameters to establish their importance in site selection.

Channeling and its Potential Consequences for Radionuclides Transport

1987 ◽  
Vol 112 ◽  
Author(s):  
Luis Moreno ◽  
Ivars Neretnieks
Keyword(s):  
Water Flow ◽  
Granitic Rock ◽  
Flow Distribution ◽  
Crystalline Rock ◽  
Fractured Media ◽  
Radionuclide Transport ◽  
Rock Matrix ◽  
Sorption Coefficient ◽  
The Matrix ◽  
Large Flow

SummaryRadionuclide transport through fractured media is usually calculated assuming that water flows in most of the fractures. Several observations in the field and the laboratory show that flow is very unevenly distributed in fractured crystalline rock. These observations indicate that most of the water flow takes place in a limited number of channels. The channels are seldom wider than a few meters and are often much narrower. This means that the surface of the fracture in contact with the flowing water (wetted surface) is less than one might expect.This low value of the wet surface of the fracture may considerably influence the transport of radionuclides through fractured media. If the channels do not intersect over a certain distance, then the channels may be modelled as a bundle of independent channels. Channels with a large flow and small sorption surface will carry the tracer rapidly and in large amounts.Calculations are performed for cases where channeling is assumed to take place. The most important entities to assess are the water flow distribution in the different channels, the wetted surface of the channels, the diffusivity into the rock matrix, and the sorption coefficient in the matrix. Experimental data for the water flow distribution are used and the transport of nuclides is calculated for the different channels. From these values the concentration of the effluent is determined. The results show that the retardation for the nonsorbing nuclides is negligible. Retardation is only important for the nuclides which are strongly sorbed on the granitic rock. Calculations are also done assuming other channel frequencies and other overall water flowrates.

scholarly journals HYDROGEOPHYSICS IN FRACTURED CRYSTALLINE AQUIFERS IN ENGLISH GUYANA

2019 ◽  
Vol 37 (3) ◽  
pp. 299
Author(s):  
Gerlane Cavalcante Messias ◽  
Jose Agnelo Soares ◽  
Felipe Kipper ◽  
Igor Fernandes Gomes ◽  
Vandir Pereira Soares Júnior ◽  
...  
Keyword(s):  
Electrical Resistivity ◽  
Crystalline Rock ◽  
Electrical Resistivity Imaging ◽  
Second Phase ◽  
Resistivity Imaging ◽  
Rock Formations ◽  
Controlled Porosity ◽  
Two Phases ◽  
Resistivity Meter

ABSTRACT: This work is a case study in Guyana with the goal of finding groundwater in rock layers with fracture-controlled porosity using electrical resistivity imaging. This work was carried out in two phases by the Brazilian Army, in eight communities in the region of Alto Tacutu – Alto Essequibo in southeast Guyana. All work was done in accordance with a technical agreement between Brazil and Guyana. In the first phase, the surveys were completed by the team which collected resistivity data using a SuperSting R8 electrical resistivity meter with dipole-dipole and dipole-gradient arrays. Then the software EarthImager was used to analyze the data and create two-dimensional (2D) pseudo-sections with depths up to 70m. In the second phase, eight wells were drilled in areas of low resistivity. The geology of this region consists of Precambrian granite rock layers with varying levels of fracturing. In this way, the effectiveness of the multielectrode resistivity imaging technique was demonstrated as a way to explore the availability of groundwater in crystalline rock formations with fracture-controlled porosity.Keywords: electrical resistivity imaging, well siting, groundwater.RESUMO: Este trabalho se constitui em um estudo de caso na Guiana Inglesa, com o objetivo de encontrar água subterrânea por meio de levantamentos de resistividade elétrica, nas áreas de porosidade controladas pelas zonas de fraturas. O trabalho foi realizado em duas fases pelo Exército Brasileiro em oito comunidades da região do Alto Tacutu – Alto Essequibo no sudeste da Guiana Inglesa, através de um acordo de cooperação técnica entre o Brasil e a Guiana. Na primeira fase, os levantamentos foram feitos por uma equipe que coletou dados de resistividade usando um eletrorresistivímetro SuperSting R8 com arranjos dos tipos dipolo-dipolo e dipolo gradiente. Em seguida foi utilizado o software EarthImager para analisar os dados e criar pseudoseções de duas dimensões (2D) até 70m de profundidade. Na segunda fase, oito poços foram perfurados em pontos de baixa resistividade. A geologia da região é constituída de rochas graníticas Pré-cambrianas com níveis variados de fraturamento. Desse modo, demonstrou-se a efetividade do método de resistividade elétrica multieletrodo para explorar a disponibilidade de água subterrânea em aquíferos fraturados em terrenos cristalinos.Palavras-chave: imageamento de resistividade elétrica, locação de poços, água subterrânea.

Modeling of Glass Dissolution and Transport With the Code SUGAR

1997 ◽  
Vol 506 ◽  
Author(s):  
J.S. Small ◽  
D.P. Trivedi ◽  
P.K. Abraitisti
Keyword(s):  
Reactive Transport ◽  
Preliminary Investigation ◽  
Radioactive Decay ◽  
Chemical Species ◽  
Steel Corrosion ◽  
Crystalline Rock ◽  
Geochemical Evolution ◽  
One Dimensional ◽  
Glass Dissolution ◽  
Rock Formations

ABSTRACTSUGAR (Simplified Understading of Glass And environment Reactions) is a one dimensional (lD) reactive transport code which sequentially couples dissolved chemical species transport and sorption with, chemical speciation, mineral precipitation and kinetic controlled glass dissolution. SUGAR also has the capability to model radioactive decay and steel corrosion. This paper describes the computer model and presents results of model testing against experimental data. The capabilities of the model are demonstrated by a preliminary investigation of the geochemical evolution of glass in crystalline rock formations.

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