scholarly journals Liquid immiscibility and problems of ore genesis (according to experimental data)

2019 ◽  
Vol 27 (5) ◽  
pp. 577-597
Author(s):  
Yu. B. Shapovalov ◽  
A. R. Kotelnikov ◽  
I. N. Suk ◽  
V. S. Korzhinskaya ◽  
Z. A. Kotelnikova
Keyword(s):  
Partition Coefficients ◽  
Liquid Immiscibility ◽  
Ore Deposits ◽  
Silicate Melt ◽  
Distribution Of Elements ◽  
Ore Minerals ◽  
Silicate Liquids ◽  
L1 And L2 ◽  
Salt Systems ◽  
Alkaline Fluid

The results of an experimental study of phase relations and distribution of elements in silicate melt–salt systems (carbonate, phosphate, fluoride, chloride) melt, silicate melt I–silicate melt II, and also in fluid – magmatic systems in the presence of alkali metal fluorides are presented. Salt extraction of a number of ore elements (Y, REE, Sr, Ba, Ti, Nb, Zr, Ta, W, Mo, Pb) was studied in liquid immiscibility processes in a wide temperature range of 800–1250°С and pressure of 1–5.5 kbar. It is shown that the partition coefficients are sufficient for the concentration of ore elements in the quantity necessary for the genesis of ore deposits. In the fluid-saturated melt of trachyrhyolite, the separation into two silicate liquids has been determined. The partition coefficients of a number of elements (Sr, La, Nb, Fe, Cr, Mo, K, Rb, Cs) between phases L1 and L2 has been obtained. The interaction processes of a heterophase fluid in the granite (quartz)–ore mineral–heterophase fluid (Li, Na, K-fluoride) system were studied at 650–850°C and P = 1 kbar. The formation of the phase of a highly alkaline fluid–saturated silicate melt – Ta and Nb concentrator is shown as a result of the reaction of the fluid with the rock and ore minerals.

scholarly journals Interphase distribution of rare and rare earth elements in silicate-fluorine systems at T = 800–1200˚C AND P = 1–2 kbar (experimental investigation)

2019 ◽  
Vol 484 (5) ◽  
pp. 595-599
Author(s):  
A. R. Kotelnikov ◽  
N. I. Suk ◽  
V. S. Korzhinskaya ◽  
Z. A. Kotelnikova ◽  
Yu. B. Shapovalov
Keyword(s):  
Experimental Investigation ◽  
Rare Earth ◽  
Phase Composition ◽  
Rare Earth Elements ◽  
Partition Coefficients ◽  
Silicate Melt ◽  
Fluoride Salt ◽  
Interphase Distribution ◽  
Salt Melt ◽  
Salt Systems

The melting in the system of aluminosilicate (granite) melt — fluoride salt melt at T = 800–1200˚C and P = 1–2 kbar was experimentally investigated. The data on the phase composition of silicate-salt systems and the character of the interphase distribution of ore components are presented. The partition coefficients of rare-earth elements between the granite melt and fluoride phase at 900–1200˚C, P = 1–2 kbar were obtained. It is shown that REE enrich the fluoride phase with respect to the silicate melt. Elements of the (V, Nb, Ta), (Ti, Zr, Hf) groups almost always prefer a silicate melt relative to fluoride.

Noble metal nanonugget insolubility in geological sulfide liquids

Geology ◽  
2020 ◽  
Vol 48 (9) ◽  
pp. 939-943 ◽  
Author(s):  
Michael Anenburg ◽  
John A. Mavrogenes
Keyword(s):  
Noble Metal ◽  
Partition Coefficients ◽  
Noble Metals ◽  
Analytical Techniques ◽  
Liquid Immiscibility ◽  
Experimental Methods ◽  
Ore Deposits ◽  
Nanometer Scale ◽  
Clear Liquid ◽  
Planetary Differentiation

Abstract Noble metals (NMs) in Earth’s magmatic systems are thought to be controlled entirely by their strong partitioning to sulfide liquids. This chemical equilibrium is at the root of various models, ranging from NM deposit formation to planetary differentiation. Noble metals commonly occur as sub-micrometer phases known as nanonuggets. However, the assumptions that nanometer-scale thermodynamic equilibrium partitioning is attained and that NM nanonuggets are soluble in sulfide liquids have never been validated. Using novel experimental methods and analytical techniques we show nanometer-scale NM ± Bi phases attached to exterior surfaces of sulfide liquids. Larger phases (≤1 µm) show clear liquid immiscibility textures, in which Fe, Cu, and Ni partition into sulfide liquids whereas NMs partition into bismuthide liquids. Noble metal compositions of sulfides and their associated NM phases vary between adjacent droplets, indicating NM disequilibrium in the system as a whole. We interpret most nanometer-scale NMs contained within sulfides to be insoluble as well, suggesting that previously reported sulfide–silicate partition coefficients are overestimated. Consequently, sulfide liquids likely play a secondary role in the formation of some NM ore deposits.

The partition coefficients of Nd and Sm for the sulphides: first data from Palaeoproterozoic layered Cu-Ni-PGE complexes of Fennoscandian Shield

2021 ◽  
Author(s):  
Pavel Serov ◽  
Tamara Bayanova
Keyword(s):  
Partition Coefficients ◽  
Sulfide Minerals ◽  
Spectrometric Method ◽  
New Mineral ◽  
Mass Spectrometric Method ◽  
Time Data ◽  
Mean Values ◽  
Geological Processes ◽  
Ore Minerals ◽  
Monchegorsk Pluton

<p>The Sm-Nd systematics is one of the most demanded isotope-geochronological tools to study ancient geological complexes. With the accumulation of knowledge about the REE in various geological processes, the question arises of extending the capabilities of the Sm-Nd method by using new mineral geochronometers. The research focused on defining the time of the ore process and its position in the general geochronological scale of formation of the geological site become particularly important. There is a pressing need for defining possible forms of REE occurrence in a lattice of geochronometer minerals in the Sm-Nd study of accessory minerals (e.g. fluorite, burbankite, eudialite, ruthile, etc.) and ore minerals (ilmenite, chrome-spinellid, sulfide minerals). The Sm-Nd method of dating ore processes using sulphide minerals, successfully used on several geological objects, made it possible to determine the main stages of ore formation and confirm geochronologically the conclusions about the syngenetic or epigenetic nature of the ore process.</p><p>Pyrite, pentlandite, chalcopyrite and pyrrhotite from the main industrial fields of the Fennoscandinavian shield were studied: Monchegorsk pluton, Fedorovo-Pansky intrusion, Pechenga, Penicat intrusion and Ahmavaara (Finland). Using a mass-spectrometric method 35 sulphide monofractions were analyzed. The partition coefficients for Nd and Sm were established: for pyrite - 0.229 (Nd) and 0.169 (Sm); for pyrrhotite - 0.265 (Nd) and 0.160 (Sm); for chalcopyrite - 0.229 (Nd) and 0.161 (Sm); for pentlandite – 0.158 (Nd) and 0.082 (Sm). The mean values for D<sub>Nd</sub> are 0.201, for D<sub>Sm</sub>=0.145 and resulting D<sub>Nd</sub>/D<sub>Sm</sub> about 1.4.</p><p>Probably, the distribution of REE in sulfide minerals is inherited from fluids during sulfide formation. REE concentrations in sulphide may reflect the composition of the fluid.</p><p>Thus, for the first time data on Sm and Nd concentrations have been obtained by mass spectrometry. Coefficients of neodymium and samarium distribution in sulfides have been calculated for major Cu-Ni-PGE complexes of Fennoscandia.</p><p> </p><p>This study performed under the theme of scientific research 0226-2019-0053 and were supported by the RFBR  18-05-70082.</p>

scholarly journals Compositional boundary layers trigger liquid unmixing in a basaltic crystal mush

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Victoria C. Honour ◽  
Marian B. Holness ◽  
Bernard Charlier ◽  
Sandra C. Piazolo ◽  
Olivier Namur ◽  
...  
Keyword(s):  
Boundary Layers ◽  
Liquid Immiscibility ◽  
Atom Probe ◽  
Immiscible Liquid ◽  
Ore Deposits ◽  
Crystal Mush ◽  
Compositional Zoning ◽  
Resolution Imaging ◽  
River Plain ◽  
Crystal Interfaces

Abstract The separation of immiscible liquids has significant implications for magma evolution and the formation of magmatic ore deposits. We combine high-resolution imaging and electron probe microanalysis with the first use of atom probe tomography on tholeiitic basaltic glass from Hawaii, the Snake River Plain, and Iceland, to investigate the onset of unmixing of basaltic liquids into Fe-rich and Si-rich conjugates. We examine the relationships between unmixing and crystal growth, and the evolution of a nanoemulsion in a crystal mush. We identify the previously unrecognised role played by compositional boundary layers in promoting unmixing around growing crystals at melt-crystal interfaces. Our findings have important implications for the formation of immiscible liquid in a crystal mush, the interpretations of compositional zoning in crystals, and the role of liquid immiscibility in controlling magma physical properties.

Experimentally determined sulfide melt-silicate melt partition coefficients for iridium and palladium

1994 ◽  
Vol 117 (1-4) ◽  
pp. 361-377 ◽  
Author(s):  
C.L. Peach ◽  
Edmond A. Mathez ◽  
Reid R. Keays ◽  
S.J. Reeves
Keyword(s):  
Partition Coefficients ◽  
Silicate Melt ◽  
Sulfide Melt

Role of rheological heterogeneities in vein-ore localization

1993 ◽  
Vol 30 (1) ◽  
pp. 113-123 ◽  
Author(s):  
C. Castaing ◽  
D. Cassard ◽  
Y. Gros ◽  
M. Moisy ◽  
J. C. Chabod
Keyword(s):  
Lower Order ◽  
Shear Zones ◽  
Ore Deposits ◽  
Second Order ◽  
Massif Central ◽  
First Order ◽  
Ore Localization ◽  
Ore Minerals ◽  
Partial Destruction

Structural studies of the Saint-Salvy zinc deposit and other Hercynian, veinhosted ore deposits in the French Massif Central and Pyrénées reveal a fourstage evolution of mineralized structures under rheological control: (i) localization of potential mineralized areas, guided by the presence of first-order lithological or structural heterogeneities that caused stress and strain perturbations; (ii) creation of second-order heterogeneities, corresponding to indurated shear zones that acted as rheological discontinuities; (iii) tectonic activation of these second-order heterogeneities, opening voids that allowed circulation of hydrothermal fluids and periodic trapping of ore minerals; (iv) reworking and partial destruction of the mineralized structures, caused by the reactivation of anisotropic surfaces acting as zones of weakness. The interaction between preexisting, first-order heterogeneities and regional shear strain caused instability, which in turn produced second-order and then lower-order heterogeneities. Such progressively smaller heterogeneities induced an increasingly focused, centripetal localization of structural disturbances that enabled hydrothermal fluid channelling. This is the reason that lower-order and late structures preferentially bear economic mineralization.

Geochemical significance and Formation of Suçatı Pb-Zn Deposits – Eastern Taurides

2020 ◽  
Author(s):  
Ali Erdem Bakkalbasi ◽  
Hatice Nur Bayram ◽  
Mustafa Kumral ◽  
Ali Tugcan Unluer
Keyword(s):  
Carbonate Rocks ◽  
Field Studies ◽  
Hydrothermal Activity ◽  
Ore Deposits ◽  
Central Anatolia ◽  
Lower Permian ◽  
Ore Minerals ◽  
Geochemical Significance ◽  
Mvt Deposits ◽  
Marine Platform

<p><strong>Geochemical significance and Formation of  Suçatı Pb-Zn Deposits – Eastern Taurides</strong></p><p>Hatice Nur Bayram<sup>(1)*</sup>, Ali Erdem Bakkalbaşı <sup>(1)*</sup>, Mustafa Kumral<sup>(1)</sup>, Ali Tuğcan Ünlüer<sup>(1)</sup></p><p><sup>(1)</sup>Istanbul Technical University, Department of Geological Engineering, Istanbul/Turkey</p><p>(*E-mail: [email protected])</p><p> </p><p>The Middle Tauride Orogenic Belt is a productive enviroment in terms of Pb-Zn ore deposits, mostly associated with Permian aged dolomitized, shallow marine platform type carbonate rocks. There have been many studies on the origin of the ore deposits in the region, there are two important approaches that stand out for the formation of the ore deposits: the first theory is hydrothermal deposits with magmatic origin, and the other theory is Missisippi Valley-type (MVT) deposits related with the carbonate rocks commonly found in the region. Field studies at the Suçatı (Kayseri – Yahyalı, Central Anatolia, Turkey, East of Aladağlar extension of the Taurides) ore district in the Aladağ geologic unit indicate that the deposits in the region are associated with Paleo-Tethys limestones, fossiliferous limestones and dolomitic limestones. Mineralization is related to Lower Permian aged carbonate rocks include primary mineralization ore minerals as galena, sphalerite, smithsonite and goethite and as a product of hydrothermal activity, calcite mineral filled within fractures and cracks represents gangue minerals. As a result of geochemical analysis of the samples collected from the ore zones, PbO values range between 25.93% - 0.012%, ZnO values range between 51.01% - 0.042%, Fe<sub>2</sub>O<sub>3</sub> values range between 42.81% - 10.21%. In conclusion hydrothermal activities closely related with compressional and extentional tectonic regimes took place in multiphase mineralization.</p><p> </p><p><strong>Keywords:</strong> Pb-Zn Deposits, MVT, Taurides, Yahyalı</p>

On genesis of massive sulfide polymetallic ore deposits of Rudny Altai

2021 ◽  
pp. 3-16
Author(s):  
B. DIYACHKOV ◽  
M. MIZERNAYA ◽  
A. PYATKOVA ◽  
A. BISATOVA ◽  
A. MIROSHNIKOVA ◽  
...  
Keyword(s):  
Precious Metals ◽  
Massive Sulfide ◽  
Ore Deposits ◽  
Vertical Range ◽  
Long Duration ◽  
Ore Minerals ◽  
Ore Mineralization ◽  
High Concentrations ◽  
Individual Grains ◽  
Polymetallic Ore

Many geologists assign most of large- and medium-sized massive sulfide polymetallic ore deposits of Eastern Kazakhstan to the VMS type. These ore deposits formed in the Devonian, under conditions of rifting and active basalt-andesite-rhyolite volcanism. Ore bodies of these deposits are noted to be clearly confined to formations of several geochronologic levels (D1e to D3fm). Hydrothermal-sedimentary syngenetic and hydrothermal-metasomatic ores are distinguished. High concentrations of base metals in the ores (above 10 % sum metals) and their rather simple mineral composition (chalcopyrite, pyrite, galena, and sphalerite) are a characteristic feature of all the massive sulfide polymetallic ore deposits of Rudny Altai. The ores are noted to be multicomponental, with elevated contents of the admixtures of precious metals and rare elements (Cd, Se, Bi, Te, Ta, W, etc.). Mineralogical investigations of the ores have demonstrated an intricate relationships of the major ore minerals (chalcopyrite, pyrite, sphalerite, galena) that exhibit several generations and different geochemical specialization. Minerals of Au, Ag, Te, Bi, and other elements are encountered as individual grains or microscopic inclusions and stringers in minerals of Cu, Pb, and Zn. A significant vertical range of the ore mineralization (more than 100 m), the complexity and long duration of the ore-forming processes, the clearly defined confinement of the ore mineralization to certain geochronologic levels, – all these allow us to suppose a possibility of discovery of new ore lodes or individual ore deposits within the already known ore fields of the Kazakhstan segment of Rudny Altai

Liquid Immiscibility in a Silicate Melt

Nature ◽  
1955 ◽  
Vol 176 (4476) ◽  
pp. 305-305 ◽  
Author(s):  
W. A. CASSIDY ◽  
E. R. SEGNIT
Keyword(s):  
Liquid Immiscibility ◽  
Silicate Melt
Sign in / Sign up

Export Citation Format

Share Document