A Gravity Investigation of the Southern Leyte Geothermal Prospect

Abstract

A gravity investigation was undertaken in and adjacent lo the Southern Leyte Geothermal Prospect. This work was done in conjunction with n detailed geologic and geochemical resiuvey inorder to rcevnlirate the geeolheritral resouire potential of' ths area. The residunl gra\.i{i.- ittap dispiqs (I lasge central positive anonia!v with at least two superittiposed smaller positive anonralies. d shallow intrusive beneath the edijice o l ' Ms. Cabalian anti Can[odoc, and a dense dike-like bo<\: west-northwest of the volcano, irlenti,fecl on the surface as a probable microdiorite iirq\: be the cniise of the positive gravi@ anoniolies srrperit~rposed on the main nnoma~v. L:7traina$c rocks which had risen to shallow deprhs as a result of faulting and upl$ is responsible jor the positive anoina!v in the extrente Ivest-sotrth~i,estern port of SLGP. T~~~o-tlirtiension(I/ rriodels to explain the local gravih. anoimlies indicate a near horizontal seqirence of old wIcanics and sediments over(ving an ultrartiajc basetilent. The iliain heat source for ik ,oz.oiheniial phenomena in SLGP is cppo,--m@ the broad and west recent intrusion which feeds the eruption vent of 31:. G.:baIim Z?-. host rocks consisting of Icjs dense volmnics and Tertian, seditnenr, xost like!v coitipri::z the reservoir rocks of the postulated hwirotherinal ?stein at SLGP.