TY - JOUR

T1 - Platinum-group minerals of Pt-placer deposits associated with the svetloborsky Ural-Alaskan type massif, middle urals, Russia

AU - Stepanov, Sergey Yu

AU - Palamarchuk, Roman S.

AU - Kozlov, Aleksandr V.

AU - Khanin, Dmitry A.

AU - Varlamov, Dmitry A.

AU - Kiseleva, Daria V.

PY - 2019/1/20

Y1 - 2019/1/20

N2 - The alteration of platinum group minerals (PGM) of eluval, proximal, and distal placers associated with the Ural-Alaskan type clinopyroxenite-dunite massifs were studied. The Isovsko-Turinskaya placer system is unique regarding its size, and was chosen as research object as it is PGM-bearing for more than 70 km from its lode source, the Ural-Alaskan type Svetloborsky massif, Middle Urals. Lode chromite-platinum ore zones located in the Southern part of the dunite “core” of the Svetloborsky massif are considered as the PGM lode source. For the studies, PGM concentrates were prepared from the heavy concentrates which were sampled at different distances from the lode source. Eluvial placers are situated directly above the ore zones, and the PGM transport distance does not exceed 10 m. Travyanistyi proximal placer is considered as an example of alluvial ravine placer with the PGM transport distance from 0.5 to 2.5 km. The Glubokinskoe distal placer located in the vicinity of the Is settlement are chosen as the object with the longest PGM transport distance (30–35 km from the lode source). Pt-Fe alloys, and in particular, isoferroplatinum prevail in the lode ores and placers with different PGM transport distance. In some cases, isoferroplatinum is substituted by tetraferroplatinum and tulameenite in the grain marginal parts. Os-Ir-(Ru) alloys, erlichmanite, laurite, kashinite, bowieite, and Ir-Rh thiospinels are found as inclusions in Pt-Fe minerals. As a result of the study, it was found that the greatest contribution to the formation of the placer objects is made by the erosion of chromite-platinum mineralized zones in dunites. At a distance of more than 10 km, the degree of PGM mechanical attrition becomes significant, and the morphological features, characteristic of lode platinum, are practically not preserved. One of the signs of the significant PGM transport distance in the placers is the absence of rims composed of the tetraferroplatinum group minerals around primary Pt-Fez alloys. The sie of the nuggets decreases with the increasing transport distance. The composition of isoferroplatinum from the placers and lode chromite-platinum ore zones are geochemically similar.

AB - The alteration of platinum group minerals (PGM) of eluval, proximal, and distal placers associated with the Ural-Alaskan type clinopyroxenite-dunite massifs were studied. The Isovsko-Turinskaya placer system is unique regarding its size, and was chosen as research object as it is PGM-bearing for more than 70 km from its lode source, the Ural-Alaskan type Svetloborsky massif, Middle Urals. Lode chromite-platinum ore zones located in the Southern part of the dunite “core” of the Svetloborsky massif are considered as the PGM lode source. For the studies, PGM concentrates were prepared from the heavy concentrates which were sampled at different distances from the lode source. Eluvial placers are situated directly above the ore zones, and the PGM transport distance does not exceed 10 m. Travyanistyi proximal placer is considered as an example of alluvial ravine placer with the PGM transport distance from 0.5 to 2.5 km. The Glubokinskoe distal placer located in the vicinity of the Is settlement are chosen as the object with the longest PGM transport distance (30–35 km from the lode source). Pt-Fe alloys, and in particular, isoferroplatinum prevail in the lode ores and placers with different PGM transport distance. In some cases, isoferroplatinum is substituted by tetraferroplatinum and tulameenite in the grain marginal parts. Os-Ir-(Ru) alloys, erlichmanite, laurite, kashinite, bowieite, and Ir-Rh thiospinels are found as inclusions in Pt-Fe minerals. As a result of the study, it was found that the greatest contribution to the formation of the placer objects is made by the erosion of chromite-platinum mineralized zones in dunites. At a distance of more than 10 km, the degree of PGM mechanical attrition becomes significant, and the morphological features, characteristic of lode platinum, are practically not preserved. One of the signs of the significant PGM transport distance in the placers is the absence of rims composed of the tetraferroplatinum group minerals around primary Pt-Fez alloys. The sie of the nuggets decreases with the increasing transport distance. The composition of isoferroplatinum from the placers and lode chromite-platinum ore zones are geochemically similar.

KW - Placer system

KW - Platinum group elements

KW - Platinum group minerals

KW - Svetloborsky massif

KW - Ural platinum belt

KW - Ural-Alaskan massif

KW - COMPLEX

KW - platinum group minerals

KW - NUGGETS

KW - KAMCHATKA

KW - RIVER

KW - NORTHERN

KW - SVETLY BOR

KW - GROUP-ELEMENT MINERALIZATION

KW - CLINOPYROXENITE-DUNITE MASSIFS

KW - CHROMITITES

KW - NIZHNY-TAGIL

KW - Ural Platinum belt

KW - placer system

KW - platinum group elements

UR - http://www.scopus.com/inward/record.url?scp=85061752361&partnerID=8YFLogxK

UR - http://www.mendeley.com/research/platinumgroup-minerals-ptplacer-deposits-associated-svetloborsky-uralalaskan-type-massif-middle-ural

U2 - 10.3390/min9020077

DO - 10.3390/min9020077

M3 - Article

AN - SCOPUS:85061752361

VL - 9

JO - Minerals

JF - Minerals

SN - 2075-163X

IS - 2

M1 - 77

ER -