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Abstrak (Bhs. Indonesia)

Daerah penelitian terletak di daerah Mapun dan sekitarnya, Kecamatan Lubuk Sikaping, Kabupaten Pasaman, Provinsi Sumatera Barat. Daerah penelitian termasuk dalam wilayah yang dikaji oleh Pusat Sumber Daya Geologi (PSDG) Bandung. Metode yang digunakan untuk mengkaji kondisi geologi dan karakteristik endapan mineral logam pada daerah penelitian berupa metode survey (kerja lapangan) dan metode eksperimental (analisis studio/laboratorium). Data-data yang didapatkan berdasarkan metode penelitian diolah menjadi peta lintasan, peta geologi, peta geomorfologi, peta pola aliran sungai, dan peta zonasi alterasi. Beberapa sampel batuan digunakan sebagai conto analisis laboratorium dengan menggunakan metode analisis Petrografi, PIMA, FA-AAS, Mineragrafi, dan Kandungan Kimia Unsur.  Lokasi penelitian terdiri dari tiga satuan geomorfologi yaitu satuan dataran aluvial-fluvial, satuan perbukitan struktural sesar, dan satuan lembah struktural sesar. Daerah penelitian tersusun atas 6 satuan litologi, dari tua ke muda yakni satuan batuan metamorf, satuan batugamping, satuan intrusi granit, satuan batuan vulkanik tak terbedakan, satuan breksi, dan satuam endapan aluvial. Batuan induk dari alterasi dan mineralisasi pada daerah penelitian merupakan intrusi  granit yang termasuk dalam formasi Batolit Tandungkumbang, batuan metamorf  berupa marble, slate, dan filit yang termasuk dalam formasi Kuantan, dan batugamping yang termasuk dalam formasi Kuantan, anggota Batugamping. Struktur geologi yang mengontrol terjadinya mineralisasi adalah kekar. Mineral bijih yang dijumpai berupa pirit, kalkopirit, galena, sfalerit, bornit, kovelit, hematit, dan pirolusit. Berdasarkan mineral alterasi dan mineral bijih yang dijumpai pada daerah ini, diperkirakan bahwa endapan ini terbentuk pada suhu antara 120-340oC dengan pH mendekati netral. Berdasarkan data penelitian dan pembandingan dengan model endapan skarn sebelumnya, tipe endapan mineral logam pada daerah penelitian merupakan endapan skarn tipe eksoskarn.

Abtrak (Bhs. Inggris)

The research area is located at Mapun and surrounding area , Lubuk Sikaping District, Pasaman Regency, West Sumatera. This reasearch area is  Pusat Sumber Daya Geologi (PSDG) Bandung research area. The method which used to assess geological conditions and characteristics of ore mineral deposits at research area are survey method (fieldwork) and experimental methods (studio analysis / laboratory). The datas which obtained by the research methods are lithostratigraphic data, position of the rock data, rock units, alteration process, mineralization process, and the characteristics of ore mineral deposits, which are processed into track map, geological map, geomorphology map, flow pattern map, and zoning alteration map. Some selected samples are analyzed in laboratory by some methods which are petrographic mehods, PIMA, FA-AAS, mineragraphy method, and the content of Chemical Elements. There are three morphological units in this area, which are alluvial-fluvial plain unit, structural hilly fault unit, and structural valley fault unit. There are six lithological units in this area, which are metamorphic rock unit, limestone unit, granit intrusion unit, undifferentiated volcanic rock  unit, breccia unit, and alluvial  unit. Host rock of mineralization reasearch area are granite intrusion (which is included to Tandungkumbang Batholite Formation), metamorphic rock, marmer (which is included to Kuantan Formation, and limestone (which is included to Kuantan formation -  limestone member). The geology structure which control alteration and mineralization are extension fracture which is controlled by Granite intrusion. Ore minerals which can identified in research area are pyrite, chalcopyrite, galena, sphalerite,bornite, covelite, hematite, and pyrolusite. There are three stage of alteration and mineralization, which are Contact Metamorphism stage, Prograde Anhydrous Skarn stage, and Retrograde Hydrous Skarn stage. Based on alteration and ore minerals which found in research area, that are interpreted that deposits were formed at temperature by 120 - 340oC  with netral pH. Based on the datas and former model, the ore mineral deposits of the research area are skarn deposits which include to exsoskarn type.

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