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Pseudosections 

Plotting Raw Resistivity /IP Data [top]

Data recorded are usually transmitter current, resulting voltage, and geometry. Results are usually saved as apparent resistivity versus geometry. Potentials are usually measured at several positions for every current source location. Results at wider separations between the potential pair and the transmitter pair provide some information about deeper structures. The conventional method of plotting results for interpretation is the pseudosection, so called because it is not a true geological cross-section. Values of apparent resistivity or apparent chargeability are plotted on the graph as shown below. The vertical axis is in terms of the separation distance rather than depth. When all values are plotted, the result is contoured. Interpretation is tricky and requires some experience.

Plotting dipole-dipole data: current electrodes are spaced a metres apart (same for potential electrodes), and current - voltage separation is n*a metres (n is an integer).

Examples: The figures below are synthetic resistivity pseudosections. For examples of real data, see the case histories elsewhere on this web site, for example the Century Deposit case history. Chargeability pseudosections are constructed in exactly the same manner, except of course apparent chargeability is the data type. Here are examples corresponding to the first two resistivity pseudosection examples above.
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