TY - JOUR

T1 - Micro- to nanoscale textures of gold in arsenopyrite and scorodite from the As-Au-Bi assemblage of Drenjak locality (Serbia)

AU - Jelić, Ivana

AU - Zavašnik, Janez

AU - Lazarov, Marina

AU - Zdravković, Alena

AU - Kovač, Sabina

AU - Stojanović, Jovica

AU - Pacevski, Aleksandar

N1 - Funding Information: We are grateful to two anonymous referees for their helpful comments that improved and clarified the manuscript, as well as to the Associate Editor for careful and constructive handling of the manuscript. We acknowledge the support from ARRS, P1-0417, BI-RS/18-19-035 and 451-03-47/2023-01/200126.

PY - 2023/12

Y1 - 2023/12

N2 - Arsenopyrite and pyrite are important carriers of Au that is present in the form of microscopic and “invisible” gold. Such gold can be expected to be released upon the process of oxidation of these sulfides. In studied gold mineralization at Drenjak, related to the granitoids of the Oligocene-Miocene Kopaonik Ore District, the main arsenopyrite-pyrite-(bismuthinite) sulfide assemblage was formed in the quartz bodies and partly replaced by scorodite (FeAsO4·2H2O) and Bi-arsenate. With only up to 5 ppm of gold recorded by LA-ICP-MS, aforementioned sulfide minerals are here practically free from lattice-bound gold. Native gold is present in the mineralization, generally ranging in grain size from 20 µm down to the nanoparticles, as revealed by TEM. It is mainly hosted by arsenopyrite and scorodite. In arsenopyrite, gold is polycrystalline and consists of nanocrystallites 20–30 nm in size. It was deposited after arsenopyrite, healing its cavities and microcracks, often associated with native bismuth and bismuthinite. The abundance of gold and Bi minerals correlates with the presence of scorodite. Two types of gold are present in scorodite and Bi arsenate: i) prevailing relict Au grains retained after arsenopyrite oxidation, ii) colloidal-like gold co-precipitated with the arsenates.

AB - Arsenopyrite and pyrite are important carriers of Au that is present in the form of microscopic and “invisible” gold. Such gold can be expected to be released upon the process of oxidation of these sulfides. In studied gold mineralization at Drenjak, related to the granitoids of the Oligocene-Miocene Kopaonik Ore District, the main arsenopyrite-pyrite-(bismuthinite) sulfide assemblage was formed in the quartz bodies and partly replaced by scorodite (FeAsO4·2H2O) and Bi-arsenate. With only up to 5 ppm of gold recorded by LA-ICP-MS, aforementioned sulfide minerals are here practically free from lattice-bound gold. Native gold is present in the mineralization, generally ranging in grain size from 20 µm down to the nanoparticles, as revealed by TEM. It is mainly hosted by arsenopyrite and scorodite. In arsenopyrite, gold is polycrystalline and consists of nanocrystallites 20–30 nm in size. It was deposited after arsenopyrite, healing its cavities and microcracks, often associated with native bismuth and bismuthinite. The abundance of gold and Bi minerals correlates with the presence of scorodite. Two types of gold are present in scorodite and Bi arsenate: i) prevailing relict Au grains retained after arsenopyrite oxidation, ii) colloidal-like gold co-precipitated with the arsenates.

KW - Arsenopyrite

KW - Bi-arsenate

KW - Gold

KW - Gold nanocrystallites

KW - Native bismuth

KW - Scorodite

UR - http://www.scopus.com/inward/record.url?scp=85176375549&partnerID=8YFLogxK

U2 - 10.1016/j.oregeorev.2023.105711

DO - 10.1016/j.oregeorev.2023.105711

M3 - Article

AN - SCOPUS:85176375549

VL - 163

JO - Ore geology reviews

JF - Ore geology reviews

SN - 0169-1368

M1 - 105711

ER -