GEOLOGI DAN KARAKTERISTIK MINERALOGI ENDAPAN SKARN BIG GOSSAN, ERTSBERG, TEMBAGAPURA, PAPUA

• Main Authors: , HERMINA HALUK, S.T, , Dr.rer.nat. Arifudin Idrus, ST., MT
• Format: Theses and Dissertations NonPeerReviewed
• Published: [Yogyakarta] : Universitas Gadjah Mada 2013
• Subjects: ETD
• Online Access: https://repository.ugm.ac.id/118789/; http://etd.ugm.ac.id/index.php?mod=penelitian_detail&sub=PenelitianDetail&act=view&typ=html&buku_id=58765
• Institution: Universitas Gadjah Mada

This study is dealing with geology and characteristics of mineralogy of the skarn Big Gossan, Ertsberg district, Tembagapura, Papua. Lithologies that make up the Big Gossan consists of Quartz Sandstone, Hornfels KKel, Hornfels Kkeh, Eksoskarn Tw, Diorite Intrusion Big Gossan. Dominant geological aspects that control the formation of the Big Gossan skarn precipitation is in the form of Eksoskarn Tw lithology and geological structure in the form of a sinistral slip fault called bedding plane fault with the direction N280 ° -290 ° E. Bedding plane fault is also a lithological contact between the rock of Waripi Formation, Ekmai Formation and diorite intrusion. Mapping, altered mineral identification (using petrographic and X-Ray Diffraction analyses), and also metallic mineral identification (using mineragraphy analyses), the Big Gossan skarn is mineralogically characterized by prograde alteration comprising garnet (andradite) and clino-pyroxene (diopside), and retrograde alteration composed of epidote, chlorite, calcite, anhydrite and sericite. Ore mineralization is typified by chalcopyrite, pyrite, sphalerite, galena, magnetite, hematite, marcasite, covelite and chalcosite, formed at retrograde stage. Base on metallic mineral dominated mineralization in Big Gossan grouped into Calcic-Cooper Skarn. Ore textures observed in mineragraphy observation is the replacement texture, infilling texture and exsolution texture. Based on observations of ore textures and mineral formation temperature approaches according to Morrison (1997) the deposition of mineral paragenesis Big Gossan skarn grouped into two stages, the stages of prograde and retrograde. Big Gossan skarn Paragenesis deposition begins with the formation of prograde minerals such as garnet, clinopyroxen, quartz, pyrite and chalcopyrite at high temperatures then deposited succesive retrograde minerals such as epidote, chlorite, calcite, anhydrite, chalcopyrite, pyrite, galena, sphalerite, marcasite, hematite, covelite and chalcosite at lower temperatures.