| dc.description.abstract | The paper presents data about the geology, geochemistry, structure, genesis and specific features
of the Bučim porphyry Cu deposit which is actively mined in Macedonia. The porphyry
mineralization (0.3 % Cu, 0.3-0.5 ppm Au) is spatially and temporarily associated with Tertiary
subvolcanic intrusions of latitic and latitic-andesitic composition. The intrusions occurred
during Oligo-Miocene time (24 to 27 Ma), a period of intensive tectono-magmatic
and ore-forming processes..
The latest results of this study identify an array of major ore (hypogen) minerals such
chalcopyrite, pyrite, magnetite, haematite, cubanite, valleriite, native Au and bornite and
secondary
enrichment zone minerals (within Čukar ore body) including chalcocite, covellite,
tenorite, native Cu, malachite, azurite etc. Added minerals such as calaverite, krennerite,
electrum, petzite and bismuth±selenium minerals (bismuthinite, galenobismutite, krupkaite,
friedrichite, emplectite, cosalite, laitakarite and native bismuth) are also present. Variations
of the δ34S values for the whole Bučim ore deposit ranged from +0.2 ‰ to +2.5 ‰ while
δ13C‰ and δ18O‰ isotope values ranged from -10.8 to -3.8‰ and from +14.0 to +22.7 ‰,
respectively. With regard to fluid inclusions, it was confirmed that beside the pre-dominant
gas-liquid, two-phase inclusions, there are also three-phase fluid inclusions (gas + liquid +
solid phase). Also, recent Sr and Nd isotope ratios (87Sr/86Sr 0.70666-0.70741 and 143Nd/144Nd
0.512487–0.512489) indicate slight contamination of the magmatic products by continental
crust material, due to partial melting of the deep parts of continental crust underthrust by collision
of continental blocks. The REE data show results that are comparable with high contents
of large ion lithophile elements (LILE), high Ba/Nb ratio (116.72-190.72) and depletion
in high field strength elements (HFSE) and Europium negative anomaly (0.68893-0.91251). | en_US |
English
norsk