Naslov
Evolution of ore-bearing fluids in the Cu-Au porphyry ore body Vrshnik, the Buchim deposit, Republic of North Macedonia

Autori
Jurković, Iva ; Strmić Palinkaš, Sabina ; Čobić, Andrea ; Tasev, Goran ; Serafimovski, Todor

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, ostalo

Izvornik
Knjiga sažetaka, Abstracts Book / / Horvat, Marija ; Matoš, Bojan ; Wacha, Laura - Zagreb : Hrvatski geološki institut, 2019, 94-94

Skup
6. hrvatski geološki kongres s međunarodnim sudjelovanjem

Mjesto i datum
Zagreb, Hrvatska, 09.10.2019. - 12.10.2019

Vrsta sudjelovanja
Poster

Vrsta recenzije
Domaća recenzija

Ključne riječi
fluid inclusions, quartz, Buchim, ore deposit, porphyry

Sažetak
The Buchim porphyry Cu deposit (41.7° N, 22.3° E) is located in the contact zone between the Serbo-Macedonian Massif and the Vardar Zone approximately 90 km south-east from Skopje, Republic of North Macedonia. The total ore reserves have been estimated at 120 million metric tons with 0.3 % Cu and 0.3-0.5 g/t Au (SERAFIMOVSKI et al., 2016). The mineralization is spatially and temporary related to subvolcanic intrusions of the latitic and latitic-andesitic composition that intruded Precambrian gneisses, mica-schists and amphibolites. The U–Pb zircon dating yielded the intrusion age between 24.19 ± 0.62 Ma and 24.51 ± 0.89 Ma.(LEHMANN et al., 2013). The Buchim Cu deposit hosts 4 ore bodies: 1. Vrshnik ; 2. Bunardzik ; 3. Central ore body and 4. Chukar. Field data show a clear relationship that the Vrsnik intrusion is younger than the Central ore body and Bunardzik. The mineralization occurs as disseminations and forms of stockworks predominantly hosted by the gneisses along their contacts with the Oligocene intrusions. The Vrshnik ore body represents an exception, with ore mineralization predominantly hosted by the intrusion. The main ore mineral is chalcopyrite accompanied with variable amounts of pyrite, magnetite hematite, cubanite, bornite, native gold and quartz. The ongoing fluid inclusion study revealed that syn-ore quartz may host several generations of fluid inclusions indicating a complex evolution of hydrothermal fluids in the Buchim Cu-Au porphyry deposit. According to their petrographic characteristics at room temperature (Fig. 1) , the following types of fluid inclusions have been recognized: Type 1) Two phase, L-rich inclusions (L+V) with the degree of fill around 0.8, ; Type 2) Two phase, V-rich inclusions (V+L) with the degree of fill around 0.2 ; Type 3) Three phase inclusions that consist of liquid, vapor and a transparent isotropic solid phase (L+V+S) ; Type4) Four phase inclusions that consist of liquid, vapor and two transparent isotropic solid phases (L+V+S1+S2) ; Type 5) Four phase inclusions that contain liquid, vapor, a transparent isotropic solid phase and an opaque solid phase (L+V+S+O) ; Type 6) Polyphase inclusions with liquid, vapor, two transparent isotropic solids and an opaque solid phase (L+V+S1+S2+O) ; and Type 7) Polyphase inclusions with liquid, vapor, two transparent isotropic solids, a transparent anisotropic solid spase and an opaque solid phase (L+V+S1+S2+ S3+O), where L stands for liquid, V for vapor, S for transparent solid and O for opaque phase. Those inclusions that contain opaque minerals represent remains of ore-bearing fluids (Types 5-7). They are characterized by high homogenization temperatures (380-680ºC) and high salinities (26.9-74 wt.% NaCl equiv.). A broad range of homogenization temperatures and salinities indicate that mixing with colder and diluted fluids affected deposition of the Cu-Au mineralization. The main ore-forming phase was followed with several barren hydrothermal overprints (Types 1-4). Comparing to ore- bearing inclusions, the homogenization temperatures of the L+V+S inclusion types are somewhat lower (260-600 ºC) as well as their salinities (30.8-54.5 wt.% NaCl equiv.). The L+V inclusions are characterized by the lowest recorded temperatures of homogenization (218- 420 ºC) and salinities (6.5-29 wt.% NaCl equiv.).

Izvorni jezik
Engleski

Znanstvena područja
Geologija

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