MAPPING PORPHYRY COPPER DEPOSITS IN THE PHILIPPINES WITH IP

Abstract

The induced polarization (IP) method has played a very important role in the recent discovery of several new Philippine porphyry copper deposits. It was found, however, that the electrical response measured over different deposits can be extremely variable, even in a limited geographical area. Four main classes of response have been recognized; these appear to arise primarily from different structural control and possibly from differing levels of erosion in the Lowell and Guilbert (1970) and Hollister et al. (1974) porphyry copper models. Since the distribution of economic mineralization is highly dependent upon erosional level and structural control. It is important in IP interpretation to (1) recognize the type of deposit (2) determine the position of controlling structural features, and (3) map the existing alteration zones, before attempting to define the location of economic mineralization.