Electrical properties of basalts of ODP Sites 124-768 and 124-770

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Hauptverfasser: Jarrard, Richard D, Schaar, Ralph
Format: Dataset Open Access
Sprache:en
Veröffentlicht: PANGAEA 1991
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author Jarrard, Richard D
Schaar, Ralph
author_facet Jarrard, Richard D
Schaar, Ralph
collection Datos científicos de ciencias marinas y ambientales
contents Conductivity of 54 basalt samples from ODP Sites 768 and 770 was measured as a function of temperature and fluid salinity. Porosity was also measured for all samples, and cation exchange capacity was measured for 46 of the samples. Porosity measurements indicated that porosity is underestimated for basalts like these, unless one uses extensive drying at high vacuum. At salinities greater than 29 ppt, and throughout the range of salinity and temperatures likely in situ, sample conductivity (Co) is controlled by porosity (phi) according to the Archie relation Co = 0.22*Cw phi*1-3 (orFF = 4.5/f1.3), where Cw is conductivity of the pore fluids and FF = Cw/CO is the formation factor. At lower salinity, clay-surface conduction or microcrack conduction may dominate. We are unable to distinguish reliably between the two mechanisms, but we do detect their effects subtly at high salinity and strongly at low salinity.
format Dataset Open Access
id pangaea_https___doi_org_10_1594_PANGAEA_762188
institution PANGAEA
language en
publishDate 1991
publisher PANGAEA
record_format pangaea
spellingShingle Electrical properties of basalts of ODP Sites 124-768 and 124-770
Jarrard, Richard D
Schaar, Ralph
124-768C; 124-770B; 124-770C; DRILL; Drilling/drill rig; Joides Resolution; Leg124; Mindanao Sea; Ocean Drilling Program; ODP; Sulu Sea
Conductivity of 54 basalt samples from ODP Sites 768 and 770 was measured as a function of temperature and fluid salinity. Porosity was also measured for all samples, and cation exchange capacity was measured for 46 of the samples. Porosity measurements indicated that porosity is underestimated for basalts like these, unless one uses extensive drying at high vacuum. At salinities greater than 29 ppt, and throughout the range of salinity and temperatures likely in situ, sample conductivity (Co) is controlled by porosity (phi) according to the Archie relation Co = 0.22*Cw phi*1-3 (orFF = 4.5/f1.3), where Cw is conductivity of the pore fluids and FF = Cw/CO is the formation factor. At lower salinity, clay-surface conduction or microcrack conduction may dominate. We are unable to distinguish reliably between the two mechanisms, but we do detect their effects subtly at high salinity and strongly at low salinity.
title Electrical properties of basalts of ODP Sites 124-768 and 124-770
topic 124-768C; 124-770B; 124-770C; DRILL; Drilling/drill rig; Joides Resolution; Leg124; Mindanao Sea; Ocean Drilling Program; ODP; Sulu Sea
url https://doi.org/10.1594/PANGAEA.762188