Apparent resistivity and spectral induced polarization in the submarine environment

Citation
H. De Souza et Ees. Sampaio, Apparent resistivity and spectral induced polarization in the submarine environment, AN AC BRASI, 73(3), 2001, pp. 429-444
Citations number
23
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Multidisciplinary
Journal title
ANAIS DA ACADEMIA BRASILEIRA DE CIENCIAS
ISSN journal
0001-3765 → ACNP
Volume
73
Issue
3
Year of publication
2001
Pages
429 - 444
Database
ISI
SICI code
0001-3765(200109)73:3<429:ARASIP>2.0.ZU;2-0
Abstract
Relatively few investigations have employed electrical methods in the subma rine environment, which may be promising for mineral deposits or threatened by environmental problems. We have measured the electric field using both disk and bar electrodes in the sea water at three different levels: sea sur face, seven meters deep, and sea bottom at a depth of ten meters, employing a 2 m spacing dipole-dipole array with 7 array spacings of investigation, and 13 values of frequencies at steps of (2(N) hertz, N = -2, -1, 0. 1, 2.. .... 10). The measurement allowed the analysis of the electric field as a f unction of frequency and spacing, and of the spectral induced polarization. Modelling and interpretation of the apparent resistivity yielded a good fi t with previous drilling data. Analysis of the spectrum of the complex appa rent resistivity and the comparison with equivalent circuits, provided info rmation about the grain size, the mineral composition and the major induced polarization phenomenon occurring below the sea. Therefore the result of t he present research show the feasibility of measuring the variation of seaw ater resistivity in situ, as well as the resistivity of sea bottom sediment s.