ALTERASI DAN MINERALISASI CEBAKAN BIG GOSSAN KABUPATEN MIMIKA, PROVINSI PAPUA

  • Akhmad Fauzan Universitas Padjadjaran
  • Mega Fatimah Rosana Fakultas Teknik Geologi, Universitas Padjadjaran
  • Euis Tintin Yuningsih Fakultas Teknik Geologi, Universitas Padjadjaran
  • Dwie H. Saputra PT. Freeport Indonesia
  • Fernandy Meiriyanto PT. Freeport Indonesia

Abstract

Aktifitas magmatik dan tektonik yang diikuti oleh proses hidrotermal di Pulau Papua dimulai pada zaman Tersier yang menghasilkan batuan intrusi dan mineralisasi Cu-Au di wilayah Ertsberg – Grasberg dan berpengaruh terhadap proses pembentukan Cebakan Big Gossan. Dalam penelitian ini, dilakukan pemetaan alterasi, analisis petrografi dan mineragrafi untuk mengetahui karakteristik dan penyebaran alterasi  dan mineralisasi di Cebakan Big Gossan pada kedalaman 2.600 mdpl dan 2.640 mdpl. Berdasarkan himpunan mineral ubahannya dibedakan menjadi delapan zona, yaitu: Zona Diopsid – K-feldspar, Zona Kuarsa – Diopsid – Garnet, Zona Garnet – Diopsid + Epidot, Zona Biotit – K-feldspar + Epidot, Zona Garnet – Diopsid, Zona Aktinolit – Tremolit, Zona Kuarsa – Dolomit dan Zona Epidot – Klorit. Berdasarkan asosiasi mineral logamnya, dapat dikelompokan menjadi lima zona, yaitu: Zona Pirit, Zona Kalkopirit – Pirit – Magnetit – Sfalerit, Zona Kalkopirit – Pirit – Magnetit – Hematit – Sfalerit – Galena, Zona Kalkopirit – Pirit – Magnetit – Hematit serta Zona Magnetit – Hematit. Penyebaran zona alterasi dan mineralisasi di daerah penelitian menunjukan arah baratlaut – tenggara yang dikontrol oleh Sesar Big Gossan yang memiliki kesamaan arah.

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Published
2019-08-19
Section
Buletin Sumber Daya Geologi