WARREN Manse パプアニューギニア大学, 理学部, 助教授
TAGUCHI Sachihiro Ass. Professor, Fac. Sciences, Fukuoka Univ., 理学部, 助教授 (00108771)
HIGASHI Shoji Ass. Professor, Fac. Sciences, Kochi Univ., 理学部, 助教授 (90036583)
SHIGA Yoshihide Ass. Professor, Coll. Liberal Arts, Kagoshima Univ., 教養部, 助教授 (50154191)
YAMAMOTO Masahiko Ass. Professor, Fac. Sciences, Kagoshima Univ., 理学部, 助教授 (00041236)
MANSER Warren Ass. Professor, Fac. Sciences, Univ. P.N.G.
Papua New Guinea is situated geologically on the contact region between Pacific Ocean Plate and Australia Plate, and is divided mainly into continental platform, orogenic zone and island arcs. Various types of mineralization related to magmatism are located in each zone, on which labolatory works have been done.
1. Igneous complexs exist in many mining district. Each intrusive complex can be divided into two groups; the older intrusives which are relatively basic and rich in incompatible elements and the younger intrusives. The younger magma is closely related to mineralization, and had Kept high f_<HC>/f_<H20> value during differentiation. The fluids from the later magma also have rather high f_<HC1> to carry the base metal as chloride complex.
2. The intrusive complex in the continental platform (the Porgera district) is characterized by basic and alkaline in composition, compared to those in other region. The complex is related to Zn-Pb-Au mineralization, and the time interval between the older intrusive and mineralization is long up to 4 m.y. 3T-octahedral mica which is rare in nature was found as a gangue mineral.
3. The volcanic rocks in the island arc region are shoshonitic to calcalkaline in composition. The Wild Dog deposit is shallow type mineralization in the age from late Oligocene to early miocene, and is characterized by the enrichment in telluride and polymetallic assemblage (Mo, W, Sn, Ni, Au, Ag, Fe, Cu, Bi, Pb, As, Zn, S and Te).
The relationship between the properties of magma and the origin of oreforming metals should be desolved in detail in future.