Geophysics for the Exploration Geologist: Traditional Approaches and Recent Innovations |
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Page 53
... effects have dissipated ( discussed in Section 7.6.3 ) , but before the IP voltage has decayed to the background noise level . The ratio of the maximum IP voltage at the instant the current is shut - off ( Vg ) , to the primary voltage ...
... effects have dissipated ( discussed in Section 7.6.3 ) , but before the IP voltage has decayed to the background noise level . The ratio of the maximum IP voltage at the instant the current is shut - off ( Vg ) , to the primary voltage ...
Page 55
... effects as much as possible ( i.e. usually less than 10 Hz ) . As shown in Figure 6.12 , there is a direct relationship between frequency effect and time - domain chargeability . The advantages of frequency - domain IP measurement are ...
... effects as much as possible ( i.e. usually less than 10 Hz ) . As shown in Figure 6.12 , there is a direct relationship between frequency effect and time - domain chargeability . The advantages of frequency - domain IP measurement are ...
Page 121
... effects can amount to several mgals and the correction cannot be estimated to better than 0.2 mgals accuracy . Overburden effects are similar to the terrain effects except that the density contrast between overburden and bedrock is only ...
... effects can amount to several mgals and the correction cannot be estimated to better than 0.2 mgals accuracy . Overburden effects are similar to the terrain effects except that the density contrast between overburden and bedrock is only ...
Common terms and phrases
AEROMAGNETIC SURVEYS airborne surveys amplitude anomalies anomalous response apparent resistivity basic borehole channels component conductive conductors contour correction density depth detection detector dipole earth effects electric electromagnetic estimates invalid Feldspathoidal felsic field strength Figure filter frequency domain gamma radiation gamma ray geological noise geological structures geophone gm/cc gradient graphite gravity ground hence HLEM horizontal host rock in-phase induced polarization induction INPUT instrument interpretation IP/resistivity line spacing magnetic field magnetic susceptibility magnetite magnetometer magnetotelluric measured meters mineral exploration moving-source multi-frequency normally operation orebody overburden parameter phase physical noise physical property pole-dipole potential primary field procedure profiles quadrature radiometric receiver coil refraction secondary field secondary response seismic reflection seismic wave sensitivity shear signal signal noise signal stacking spatial sulphide surface survey area telluric telluric currents terrain thorium tilt angle transient transmitter loop Turam Tx-Rx Typical uranium vertical voltage