Trace Elements in Sulfides and Gold of the Olimpiada Deposit (Yenisei Ridge): Ore Substance Sources and Fluid Parameters

2021 ◽  
Vol 62 (03) ◽  
pp. 306-323
Author(s):  
S.A. Silyanov ◽  
A.M. Sazonov ◽  
P.A. Tishin ◽  
B.M. Lobastov ◽  
N.A. Nekrasova ◽  
...  

Abstract —We consider the distribution of trace elements and precious metals in sulfides and native gold of the Olimpiada deposit. Analysis of the obtained data provided conclusions about the source of ore substance and the parameters of the ore-forming fluid. We think that the deposit was formed by a medium- to high-temperature fluid with variable salinity and acidity/alkalinity, with chloride complexes dominating. The redox potential changed in the course of ore formation, but the ore mineralization formed under reducing conditions. The early Au–As mineralization might have formed with the major participation of crustal substance, but the supply of substance from another, probably deep-seated, source was also possible. The Au–Sb paragenesis differs significantly in REE and precious-metal (primarily PGE) distribution, which might indicate a different source of substance (with a higher portion of a deep-seated component) during the formation of such parageneses. The Au/Ag ratios in sulfides, gold, and ores of the Olimpiada deposit point to the presence of Au and Ag sulfide minerals.

Minerals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 354
Author(s):  
Anatoly M. Sazonov ◽  
Aleksei E. Romanovsky ◽  
Igor F. Gertner ◽  
Elena A. Zvyagina ◽  
Tatyana S. Krasnova ◽  
...  

The gold and platinum-group elements (PGE) mineralization of the Guli and Kresty intrusions was formed in the process of polyphase magmatism of the central type during the Permian and Triassic age. It is suggested that native osmium and iridium crystal nuclei were formed in the mantle at earlier high-temperature events of magma generation of the mantle substratum in the interval of 765–545 Ma and were brought by meimechite melts to the area of development of magmatic bodies. The pulsating magmatism of the later phases assisted in particle enlargement. Native gold was crystallized at a temperature of 415–200 °C at the hydrothermal-metasomatic stages of the meimechite, melilite, foidolite and carbonatite magmatism. The association of minerals of precious metals with oily, resinous and asphaltene bitumen testifies to the genetic relation of the mineralization to carbonaceous metasomatism. Identifying the carbonaceous gold and platinoid ore formation associated genetically with the parental formation of ultramafic, alkaline rocks and carbonatites is suggested.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yanlu Xing ◽  
Joël Brugger ◽  
Barbara Etschmann ◽  
Andrew G. Tomkins ◽  
Andrew J. Frierdich ◽  
...  

AbstractReaction-induced porosity is a key factor enabling protracted fluid-rock interactions in the Earth’s crust, promoting large-scale mineralogical changes during diagenesis, metamorphism, and ore formation. Here, we show experimentally that the presence of trace amounts of dissolved cerium increases the porosity of hematite (Fe2O3) formed via fluid-induced, redox-independent replacement of magnetite (Fe3O4), thereby increasing the efficiency of coupled magnetite replacement, fluid flow, and element mass transfer. Cerium acts as a catalyst affecting the nucleation and growth of hematite by modifying the Fe2+(aq)/Fe3+(aq) ratio at the reaction interface. Our results demonstrate that trace elements can enhance fluid-mediated mineral replacement reactions, ultimately controlling the kinetics, texture, and composition of fluid-mineral systems. Applied to some of the world’s most valuable orebodies, these results provide new insights into how early formation of extensive magnetite alteration may have preconditioned these ore systems for later enhanced metal accumulation, contributing to their sizes and metal endowment.


Author(s):  
Aneta Olszewska ◽  
Anetta Hanć

Abstract Purpose Tooth enamel might provide past chronological metabolic, nutritional status and trace metal exposure during development. Thus, the trace elements distribution embedded in tooth tissues represents an archive of the environmental conditions. The choice of biomarker is estimated as critical to the measurement of metal exposure. Natal teeth are defined as teeth being present at birth. Methods LA-ICP-MS provides a quantitative assessment of spatial distribution of trace elements in a natal tooth. The objective of the current study was to compare concentrations of building and other elements in a rare but reliable and valid biomarker - natal tooth. Results It have been reported presence of potentially toxic elements: Pb, Cu, Mn, Cd, Ni distributed in prenatally and perinatally formed enamel and dentine. Conclusions Analyses of deciduous enamel can provide answers into individuals’ earliest development, including critical pre- and perinatal period.


1977 ◽  
Vol 34 (1) ◽  
pp. 39-50 ◽  
Author(s):  
P.P. Parekh ◽  
P. Möller ◽  
P. Dulski ◽  
W.M. Bausch

2007 ◽  
Vol 71 (1) ◽  
pp. 81-91 ◽  
Author(s):  
J. V. Owen ◽  
J. Dostal ◽  
M. Fisera

AbstractSmall (m-scale) peridotite enclaves at Planany (central Czech Republic) are separated from their gneissic host rocks by a narrow (cm-scale) reaction rim comprising an inner, tremolite + phlogopite zone and an outer, essentially monomineralic phlogopite zone. Both retain an Mg# very similar to that of the peridotite (Mg# = 81), but relative to this reference frame, show large increases in LILE (K, Rb, Ba) and radionuclides (U, Th). On a smaller scale, however, there has been a mineralogically-controlled decoupling of various components, particularly among the HFSE and REE, the former favouring the phlogopite-rich outer layer of the reaction rim, the latter the amphibole-rich inner zone. Taken together, however, the reaction zones preserve key compositional features of their inferred protolith.


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