TY  - JOUR
A1  - Barkov, Andrei Yu
A1  - Tamura, Nobumichi
A1  - Shvedov, Gennadiy I.
A1  - Stan, Camelia V.
A1  - Ma, Chi
A1  - Winkler, Björn
A1  - Martin, Robert F.
T1  - Platiniferous tetra-auricupride: a case study from the Bolshoy Khailyk Placer Deposit, Western Sayans, Russia
T2  - Minerals
N2  - Tetra-auricupride, ideally AuCu, represents the only species showing the coexistence of Au with an elevated level of Pt, as in the case of a detrital grain studied structurally for the first time, from an ophiolite-associated placer at Bolshoy Khailyk, western Sayans, Russia. We infer that tetra-auricupride can incorporate as much as ~30 mol. % of a “PtCu” component, apparently without significant modification of the unit cell. The unit-cell parameters of platiniferous tetra-auricupride are: a 2.790(1) Å, c 3.641(4) Å, with c/a = 1.305, which are close to those reported for ordered AuCu(I) in the system Au–Cu, and close also to the cell parameters of tetraferroplatinum (PtFe), which both appear to crystallize in the same space group, P4/mmm. These intermetallic compounds and natural alloys are thus isostructural. The closeness of their structures presumably allows Pt to replace Au atoms so readily. The high extent of Cu + Au enrichment is considered to be a reflection of geochemical evolution and buildup in levels of the incompatible Cu and Au with subordinate Pt in a remaining volume of melt at low levels of fO2 and fS2 in the system.
KW  - platiniferous tetra-auricupride
KW  - Pt-for-Au substitution
KW  - platinum
KW  - gold
KW  - ophiolite
KW  - Bolshoy Khailyk placer
KW  - western Sayans
KW  - Russia
Y1  - 2019
UR  - http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/57161
UR  - https://nbn-resolving.org/urn:nbn:de:hebis:30:3-571610
SN  - 2075-163X
VL  - 9
IS  - Article 160
PB  - MDPI
CY  - Basel
ER  -