KARAKTERISITIK ENDAPAN POLIMETALIK EMAS DAN LOGAM DASAR DAERAH DOLOK PANGKURUHAN, KECAMATAN PEGAGAN HILIR, KABUPATEN DAIRI, PROVINSI SUMATERA UTARA

CHARACTERISTICS OF POLYMETALLIC GOLD AND BASE METAL DEPOSITS DOLOK PANGKURUHAN AREA, PEGAGAN HILIR DISTRICT, DAIRI REGENCY, NORTH SUMATRA PROVINCE

  • Iwan Nursahan Pusat Sumber Daya Mineral Batubara dan Panas Bumi
  • Juan Aprilio Rafael L P Universitas Padjadjaran
  • Prima M Hilman Pusat Sumber Daya Mineral Batubara dan Panas Bumi
  • Aton Patonah Universitas Padjadjaran
Kata Kunci: Mineralisasi, polimetalik, tipe urat, epithermal, sulfida menengah-tinggi

Abstrak

Beberapa kegiatan penyelidikan terdahulu di daerah Dolok Pangkuruhan, Kabupaten Dairi, Provinsi Sumatera Utara telah menemukan beberapa lokasi mineralisasi emas dan logam dasar. Tulisan ini membahas terkait karakteristik alterasi dan mineralisasi emas dan logam dasar berdasarkan hasil penyelidikan tahun 2023 dengan tujuan untuk menentukan karakteristik alterasi dan mineralisasi serta model tipe endapannya. Metoda penelitian yang digunakan meliputi pemetaan geologi semi rinci, alterasi dan mineralisasi, analisis XRD, spektral, mineragrafi, serta analisis inklusi fluida. Alterasi yang berkembang terdiri dari : argilik, argilik lanjut, filik-pirit dan filik-silisifikasi. Mineralisasi terdapat empat tipe: a. Urat Au-galena (Dolok Pangkuruhan) yang dicirikan adanya native gold dan tekstur urat bentuk kristalin dan colloform; b. Mineralisasi galena, sfalerit (Aek Sulfi), dengan ciri tekstur masif dan banded; c. urat kuarsa-silisifikasi-sfalerit-galena (Sungai Sembilin);  d. urat kuarsa-bornit-kalkopirit (Sungai Sikiring-kiring). Hasil analisis inklusi fluida diinterpretasikan sebagai endapan epitermal dengan temperatur  pembentukan mineralisasi berkisar 240oC s.d. 346oC. Berdasarkan analisis sekwen paragenesa  dapat diinterpretasikan karakteristik mineralisasi sebagai model endapan polimetalik (Au-Pb dan Zn-Pb-Cu) tipe urat epitermal sulfida  menengah – tinggi.

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Diterbitkan
2024-07-02
Bagian
Buletin Sumber Daya Geologi