KARAKTERISTIK ENDAPAN EMAS EPITERMAL SULFIDASI TINGGI DAN HUBUNGANNYA DENGAN MINERAL LEMPUNG HASIL ANALISA SPEKTRAL, DAERAH CIJULANG, KABUPATEN GARUT, PROVINSI JAWA BARAT

VERDIANSYAH, OKKI (2014) KARAKTERISTIK ENDAPAN EMAS EPITERMAL SULFIDASI TINGGI DAN HUBUNGANNYA DENGAN MINERAL LEMPUNG HASIL ANALISA SPEKTRAL, DAERAH CIJULANG, KABUPATEN GARUT, PROVINSI JAWA BARAT. Masters thesis, UPN ''VETERAN'' YOGYAKARTA.

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Abstract

Eksplorasi mineral bijih terutama emas saat ini memiliki target eksplorasi pada berbagai
tipe endapan.
Mineralisasi regional daerah Jawa Barat terdiri dari berbagai tipe endapan seperti endapan
emas epitermal sulfidasi rendah (Cikotok, Cikidang, Pongkor), endapan porfiri (Cihurip,
Jampang), vein epitermal Au–Zn,Pb,Cu (Arinem), tipe sulfidasi tinggi (Cibeureum,
Cijulang).
Geologi daerah Cijulang terdiri dari satuan andesit, crystalline tuff, phreatomagmatic
breccia, juvenile rich phreatomagmatic breccia, dan microdiorite yang merupakan anggota
Formasi Koleberes dan Formasi Jampang berumur Miosen akhir yang tertutup oleh satuan
vulkaniklastik muda berumur Pleiosen.
Endapan sulfidasi tinggi daerah Cijulang memiliki alterasi advanced argillic, argillic,
propilitic, dan silisifikasi (massive quartz – vuggy quartz) dan mineralisasi terbentuk pada
3 fase yaitu pembentukan silika-pirit, enargit-kalkopirit, dan enargit-tenantit-kalkopiritsfalerit-
galena-stibnit.
Analisa Terraspectral geology yang dilakukan pada conto permukaan dan pemboran,
ditemukan adanya kumpulan mineral: (1)acid clay: kaolinite WX, alunite, dickite,
pyrophillite: (2)Fe-Mg silicate: chlorite, biotite :(3)neutral clay: kaolinite PX,
montmorillonite, Mg – clay, palygorskite : (4)mica : illite, muscovitic illite, paragonitic
illite : (5)carbonate - sulfate : siderite, gypsum, dengan mineral penciri argilik lanjut
dominan yang dijumpai adalah kaolinit, dikit, pirofilit, sedangkan alunit hanya setempat
dijumpai.
Pola geokimia endapan emas high sulfidation epithermal daerah Cijulang berasosisasi
dengan alterasi silifikasi (massvie quartz), dengan hubungan positif terhadap keberadaan
mineral kaolinite-dickite yang berasosiasi oleh kehadiran pyrrophillite sebagai mineral
penciri pathway mineralisasi emas. Pada alterasi advanced argillic terlihat terdapat juga
anomali kehadiran emas (<0.2 ppm Au), yang berasosiasi dengan kehadiran pyrrophillitekaolinite-
dickite.
Model lithocap Cijulang merupakan tipe cebakan sulfidasi tinggi yang berhubungan
dengan tipe porfiri, yang berkembang pada tubuh diatrem.

Exploration of mineral deposits, especially gold deposits have an numerous target.
Regional mineralisation in West Java, consist of various deposit type as low sulfidation
vein epithermal (Cikotok, Cikidang, Pongkor), porphyry (Cihurip, Jampang), vein
epitermal Au–Zn,Pb,Cu (Arinem), and high sulfidation (Cibeureum, Cijulang).
Geology of Cijulang area consist of andesite, crystalline tuff, phreatomagmatic breccia,
juvenile rich phreatomagmatic breccia, and microdiorite, that’s member of Koleberes
Formation and Jampang Formaion in Late Miosen, is covered by Pliosen volcaniclastic
units.
Alteration of High Sulfidation Epithermal deposits in Cijulang consist of advanced argillic,
argillic, propilitic, and silisification (massive quartz – vuggy quartz) with 3 phase of
mineralisation: silica-pyrite, enargite-chalcopyrite, and enargite-tenantite-chalcopyritesphalerite-
galena-stibnite.
Terraspectral geology analysis performed on surface samples and drilling, discovered the
existence of mineral assemblages: (1)acid clay: kaolinite WX, alunite, dickite, pyrophillite:
(2)Fe-Mg silicate: chlorite, biotite :(3)neutral clay: kaolinite PX, montmorillonite, Mg –
clay, palygorskite : (4)mica : illite, muscovitic illite, paragonitic illite : (5)carbonate -
sulfate: siderite, gypsum, with a dominant advanced argillic mineral identifier is
encountered kaolinite , dickite , pirofilit , while alunit locally encountered.
Geochemical patterns of high sulfidation epithermal in Cijulang associated with area of
silisification alteration (massvie quartz), with a positive relationship to the presence of the
mineral kaolinite-dickite associated by the presence of a mineral pyrrophillite as gold
mineralization pathway identifier. In the advanced argillic alteration are also visible
presence of anomalous gold, which is associated with the presence of kaolinite - dickite -
pyrrophillite.
Lithocap models of Cijulang high sulfidation deposits associated with porphyry-type,
which develops in the body diatrem

Item Type: Thesis (Masters)
Subjek: T Technology > TA Engineering (General). Civil engineering (General)
Divisions: x. Faculty of Engineering, Science and Mathematics > School of Engineering Sciences
Depositing User: Erny Azyanti
Date Deposited: 18 May 2016 08:07
Last Modified: 18 May 2016 08:07
URI: http://eprints.upnyk.ac.id/id/eprint/1554

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