Nickel-(Bi,Ag) sulphide mineralization from NYF Vepice pegmatite, Milevsko pluton, southern Bohemia (Czech Republic) - a reflection of the parental granite chemistry

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216224%3A14310%2F20%3A00117253" target="_blank" >RIV/00216224:14310/20:00117253 - isvavai.cz</a>

Nalezeny alternativní kódy

RIV/00023272:_____/20:10134882

Výsledek na webu

<a href="http://dx.doi.org/10.3190/jgeosci.310" target="_blank" >http://dx.doi.org/10.3190/jgeosci.310</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.3190/jgeosci.310" target="_blank" >10.3190/jgeosci.310</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Nickel-(Bi,Ag) sulphide mineralization from NYF Vepice pegmatite, Milevsko pluton, southern Bohemia (Czech Republic) - a reflection of the parental granite chemistry

Popis výsledku v původním jazyce

Unusual high- to low-T sulphide mineralization with Ni-(Bi, Ag) phases was examined at the NYF intragranitic pegmatite No. III from Vepice near Kovainv enclosed in the Milevsko Pluton, Moldanubian Zone, Southern Bohemia. Zoned pegmatite dike, up to 30 cm thick, has transitional contact with host durbachite and its internal structure includes transitional unit, border granitic unit, graphic unit, blocky unit (Kfs+Qz), quart, core and small miarolitic pocket. Sulphide mineralization locally associated with calcite and fluorite is represented by common pyrite with minor galena, accessory chalcopyrite, sphalerite, marcasite, native Bi and Ni-(Bi, Ag) minerals - argentopentlandite, parkerite and pentlandite. It is developed in small miarolitic pockets and on pegmatite fractures cutting all pegmatite units. Irregular anhedral grains and aggregates of argentopentlandite, &lt;200 mu m in size, associated with chalcopyrite, have empirical formula Ag-0.97 (Fe4.88Ni3.10Cu0.04Co0.01)(Sigma 8.03) (S7.96As0.03)(Sigma 7.99). Zoned irregular aggregates of parkerite, 20-30 mu m in size, are typically associated with pentlandite, or overgrow galena and yield empirical formula (Ni3.02Fe0.02Co0.01)(Sigma 3.06)(Bi(1.73)Sb(0.05)AS(0.04))(Sigma 1.92)S-2.02. Pentlandite is present in two morphological forms: rare lenticular to isometric anhedral grains, -200 pm in size, and numerous small tabular crystals, &lt;= 20 mu m in length, in subparallel arrangement rimming aggregates of other sulphides. Empirical formula is (Ni4.57Fe4.14Co0.25)(Sigma 8.96)(S8.01As0.02)(Sigma 8.03). Evaluation of relative chronology of the sulphide minerals is complicated mainly due to complex textural relations. Pyrite + marcasite are likely pseudomorphs after pyrrhotite as the earliest phase whereas pentlandite and native Bi are among the latest. Early sulphides (pyrrhotite, chalcopyrite, sphalerite, argentopentlandite) crystallized at T &lt; similar to 550-400 degrees C, whereas pyrite, marcasite, galena, parkerite, and native Bi at T &lt;240 degrees C. Cooling of the system below T similar to 200 degrees C appeared soon after transformation of pyrrhotite to pyrite+marcasite aggregates. Sulphides manifest that concentrations of Ni in residual pegmatite melt and exsolved fluids were high enough to facilitate saturation of Ni-sulphides. Very high Ni/Co ratio in sulphides reflects a much lower concentration of cobalt in durbachite. The examined Ni-(Bi, Ag) sulphides manifest that high concentrations of highly compatible Ni in parental granite may be reflected in accessory minerals from its pegmatite.

Název v anglickém jazyce

Nickel-(Bi,Ag) sulphide mineralization from NYF Vepice pegmatite, Milevsko pluton, southern Bohemia (Czech Republic) - a reflection of the parental granite chemistry

Popis výsledku anglicky

Unusual high- to low-T sulphide mineralization with Ni-(Bi, Ag) phases was examined at the NYF intragranitic pegmatite No. III from Vepice near Kovainv enclosed in the Milevsko Pluton, Moldanubian Zone, Southern Bohemia. Zoned pegmatite dike, up to 30 cm thick, has transitional contact with host durbachite and its internal structure includes transitional unit, border granitic unit, graphic unit, blocky unit (Kfs+Qz), quart, core and small miarolitic pocket. Sulphide mineralization locally associated with calcite and fluorite is represented by common pyrite with minor galena, accessory chalcopyrite, sphalerite, marcasite, native Bi and Ni-(Bi, Ag) minerals - argentopentlandite, parkerite and pentlandite. It is developed in small miarolitic pockets and on pegmatite fractures cutting all pegmatite units. Irregular anhedral grains and aggregates of argentopentlandite, &lt;200 mu m in size, associated with chalcopyrite, have empirical formula Ag-0.97 (Fe4.88Ni3.10Cu0.04Co0.01)(Sigma 8.03) (S7.96As0.03)(Sigma 7.99). Zoned irregular aggregates of parkerite, 20-30 mu m in size, are typically associated with pentlandite, or overgrow galena and yield empirical formula (Ni3.02Fe0.02Co0.01)(Sigma 3.06)(Bi(1.73)Sb(0.05)AS(0.04))(Sigma 1.92)S-2.02. Pentlandite is present in two morphological forms: rare lenticular to isometric anhedral grains, -200 pm in size, and numerous small tabular crystals, &lt;= 20 mu m in length, in subparallel arrangement rimming aggregates of other sulphides. Empirical formula is (Ni4.57Fe4.14Co0.25)(Sigma 8.96)(S8.01As0.02)(Sigma 8.03). Evaluation of relative chronology of the sulphide minerals is complicated mainly due to complex textural relations. Pyrite + marcasite are likely pseudomorphs after pyrrhotite as the earliest phase whereas pentlandite and native Bi are among the latest. Early sulphides (pyrrhotite, chalcopyrite, sphalerite, argentopentlandite) crystallized at T &lt; similar to 550-400 degrees C, whereas pyrite, marcasite, galena, parkerite, and native Bi at T &lt;240 degrees C. Cooling of the system below T similar to 200 degrees C appeared soon after transformation of pyrrhotite to pyrite+marcasite aggregates. Sulphides manifest that concentrations of Ni in residual pegmatite melt and exsolved fluids were high enough to facilitate saturation of Ni-sulphides. Very high Ni/Co ratio in sulphides reflects a much lower concentration of cobalt in durbachite. The examined Ni-(Bi, Ag) sulphides manifest that high concentrations of highly compatible Ni in parental granite may be reflected in accessory minerals from its pegmatite.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10504 - Mineralogy

Projekt

—

Návaznosti

S - Specificky vyzkum na vysokych skolach

Rok uplatnění

2020

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Journal of Geosciences

ISSN

1802-6222

e-ISSN

1803-1943

Svazek periodika

65

Číslo periodika v rámci svazku

3

Stát vydavatele periodika

CZ - Česká republika

Počet stran výsledku

13

Strana od-do

187-199

Kód UT WoS článku

000580587700005

EID výsledku v databázi Scopus

2-s2.0-85092526037