- journal_title：Geophysics
- Contributor：Heikki Vanhala ; Markku Peltoniemi
- Publisher：Society of Exploration Geophysicists
- Date：1992-
- Format：text/html
- Language：en
- Identifier：10.1190/1.1443222
- journal_abbrev：Geophysics
- issn：0016-8033
- volume：57
- issue：12
- firstpage：1545
- section：Articles
Spectral-induced polarization (IP) field measurements, both in the frequency domain and in the time domain, were made at six early Proterozoic sulfide, oxide, and graphitic-gneiss deposits in Finland. Core samples were also measured. The textures of the mineralizations were studied from thin and polished sections.Deposits with large differences in texture, such as graphitic gneiss and coarse-grained disseminated sulfide, can be separated on the basis of their phase-spectra time constants. A good correlation was found between the observed grain size in thin sections and the grain size calculated from the apparent, field-survey phase spectra in the case of homogeneous, disseminated textures.The measured frequency-domain phase spectra, and phase spectra calculated from the time-domain Cole-Cole parameters are very similar in a comparable frequency band. For both techniques, the phase maximum lies beyond the lowest measured frequency. The possibilities to expand the frequency band to levels low enough to reach the phase maximum seem to be restricted. However, the results indicate that contrasts between spectra from different ore-texture types also appear at higher frequencies.