MAGNETIC SIGNATURES OF LITHOLOGIC VARIATION, FAULT STRUCTURES AND HYDROTHERMAL MINERALIZATION - AN EXAMPLE FROM THE BAGUIO MINERAL DISTRICT, LUZON, PHILIPPINES

A reconnaissance ground magnetic survey was conducted in the Baguio Mi neral District in northern Luzon to investigate the geophysical signat ures of the different lithologic units and areas of mineralization. Th e magnetic-intensity contours match the varying rock types. Magnetic l ows were found to correspond to the sedimentary rocks. Magnetic highs coincide with the presence of intrusive bodies and the skarn/porphyry- copper deposits. This is to be expected since igneous rocks are more m agnetic than sedimentary rocks. Furthermore, the skarn/porphyry copper deposits consist of an ore assemblage of which magnetite is a compone nt. An anomalous zone, coincident with the sedimentary and igneous roc k boundary, was defined from the magnetic survey results. This sedimen tary and igneous rock boundary, inferred to be a zone of high permeabi lity, is the probable host to mineable mineral deposits. The geophysic ally defined anomalous area, characterized by magnetic lows, is consis tent with a previously defined prospective zone of mineralization. Cop yright (C) 1996 Elsevier Science Ltd