Delineating hydrothermal stockwork copper deposits using controlled-source and radio-magnetotelluric methods : A case study from northeast Iran

• Radio- and controlled-source-tensor magnetotelluric (RMT and CSTMT)   methods are used to target hydrothermal veins of copper mineralization.   The data were acquired along six eastwest- and three   north-south-trending profiles, covering an area of about 500 x 400   m(2). The tensor RMT data were collected in the 10-250-kHz frequency   band. A double horizontal magnetic dipole transmitter in the 4-12.5-kHz   frequency range allowed us to constrain the deeper parts of the   resistivity models better. To obtain optimum field parameters, ground   magnetic profiling was conducted prior to the RMT and CSTMT surveys.   Although the study area (in Iran) is remote, a number of radio   transmitters with acceptable signal-to-noise ratio were utilized. The   2D inversion of RMT data led to unstable resistivity models with large   data misfits. Thus, the RMT data were used to complement and analyze   the near-surface resistivity anomalies observed in the 2D CSTMT models.   Analyses of strike and dimensionality from the CSTMT data suggests that   the low-resistivity structures are mainly three dimensional; therefore,   2D inversion of determinant data is chosen. Independent 2D inversion   models of the determinant CSTMT data along crossing profiles are in   good agreement. Known copper mineralization is imaged well in the CSTMT   models. The thinning of the conductive overburden correlates very well   with magnetic highs, indicating the bedrock is resistive and magnetic.   In this sense, the magnetic and electromagnetic fields complement each   other. Analysis of the 2D resistivity models indicates the volcanic   rock deepens at the center of the study area. This zone is associated   with a magnetic low and therefore is recommended for detailed   exploration work.

Ämnesord

NATURVETENSKAP  -- Geovetenskap och miljövetenskap (hsv//swe)

NATURAL SCIENCES  -- Earth and Related Environmental Sciences (hsv//eng)

Nyckelord

electromagnetics

2D

magnetics

inversion

magnetotelluric

Earth sciences

Geovetenskap

Geophysics with specialization in Solid Earth Physics

Geofysik med inriktning mot fasta jordens fysik

Mineralogi, petrologi och tektonik

Mineral Chemistry, Petrology and Tectonics

Publikations- och innehållstyp

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