The Paracale Intrusion: geologic setting and petrogenesis of a trondhjemite intrusion in the Philippine Island Arc

Abstract On the northern shore of Camarines Norte (Southern Luzon, Philippines) a tonalite/trondhjemite intrusion hosted by an ultramafic complex is exposed. The ultramafic complex is composed of metamorphic, depleted harzburgite and is considered as part of an ophiolite-sequence. The trondhjemites, which comprise the Paracale Intrusion, may have formed by partial melting of tholeiitic materials under high water pressure. The magma may have been intruded as semi-solid plagioclase cumulate which resulted in a pronounced flow lamination of the rocks.