Alakit and Daldyn kimberlite fields,Siberia,Russia:Two types of mantle sub-terranes beneath central Yakutia?   总被引：1，自引：1，他引：0  

I.V. Ashchepkov  A.M. Logvinova  T. Ntaflos  N.V. Vladykin  S.I. Kostrovitsky  Z. Spetsius  S.I. Mityukhin  S.A. Prokopyev  N.S. Medvedev  H. Downes 《地学前缘(英文版)》2017,8(4):671-692

Mineral data from Yakutian kimberlites allow reconstruction of the history of lithospheric mantle.Differences occur in compositions of mantle pyropes and clinopyroxenes from large kimberlite pipes in the Alakit and Daldyn fields.In the Alakit field.Cr-diopsides are alkaline,and Stykanskaya and some other pipes contain more sub-calcic pyropes and dunitic-type diamond inclusions,while in the Daldyn field harzburgitic pyropes are frequent.The eclogitic diamond inclusions in the Alakit field are sharply divided in types and conditions,while in the Daldyn field they show varying compositions and often continuous Pressure-Temperature(P-T) ranges with increasing Fe~# with decreasing pressures.In Alakit,Crpargasites to richterites were found in all pipes,while in Daldyn,pargasites are rare Dalnyaya and Zarnitsa pipes.Cr-diopsides from the Alakit region show higher levels of light Rare Earth Elements(LREE)and stronger REE-slopes,and enrichment in light Rare Earth Elements(LREE),sometimes Th-U,and small troughs in Nb-Ta-Zr.In the Daldyn field,the High Field Strength Elements HFSE troughs are more common in clinopyroxenes with low REE abundances,while those from sheared and refertilized peridotites have smooth patterns.Garnets from Alakit show HREE minima,but those from Daldyn often have a trough at Yand high U and Pb.PTX/O2 diagrams from both regions show similarities,suggesting similar layering and structures.The degree of metasomatism is often higher for pipes which show dispersion in P-Fe~# trends for garnets.In the mantle beneath Udachnaya and Aykhal,pipes show 6-7 linear arrays of P-Fe~# in the lower part of the mantle section at 7.5-3.0 GPa,probably reflecting primary subduction horizons.Beneath the Sytykanskaya pipe,there are several horizons with opposite inclinations which reflect metasomatic processes.The high dispersion of the P—Fe~# trend indicating widespread metasomatism is associated with decreased diamond grades.Possible explanation of the differences in mineralogy and geochemistry of the mantle sections may relate to their tectonic positions during growth of the lithospheric keel.Enrichment in volatiles and alkalis possibly corresponds to interaction with subduction-related fluids and melts in the craton margins.Incorporation of island arc peridotites from an eroded arc is a possible scenario.  相似文献   

Origin of REE-rich ferrocarbonatites in southern Siberia (Russia): implications based on melt and fluid inclusions     

Ilya R. Prokopyev  Alexander S. Borisenko  Andrey A. Borovikov  Galina G. Pavlova 《Mineralogy and Petrology》2016,110(6):845-859

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Geochronology and Ore Mineralization of the Dzheltula Alkaline Massif (Aldan Shield,South Yakutia)     

I. R. Prokopyev  A. A. Kravchenko  A. I. Ivanov  A. S. Borisenko  A. V. Ponomarchuk  A. I. Zaitsev  E. A. Kardash  A. A. Rozhkov 《Russian Journal of Pacific Geology》2018,12(1):34-45

The Dzheltula alkaline massif is located in the Tyrkanda ore region of the Chara–Aldan metallogenic zone of the Aldan–Stanovy Shield (South Yakutia). The region contains separate placer gold objects, which are being explored at the present time, and ore-bearing Mesozoic alkaline intrusions, which are weakly studied due to their poor accessibility. The Dzheltula massif (DM) is the largest exposed multiple-ring intrusion within the Tyrkanda ore region; therefore, it is considered as a typical object for geological, petrological, geochronological, and metallogenic studies. The DM consists of five magmatic phases of syenite composition. ⁴⁰Ar–³⁹Ar dating has established that the crystallization age of the oldest phase, the leucocratic syenite porphyry (pulaskite), is 121.1 ± 1.3 Ma. The crystallization age of the cross-cutting phases represented by syenite–porphyry dikes (laurvikites and pulaskites) ranges from 120.1 ± 2 to 118.3 ± 2.1 Ma. The youngest phase of the massif, trachyte, crystallized at 115.5 ± 1.6 Ma. According to the mineralogical and geochemical studies, two types of ore mineralization, namely gold and uranium–thorium–rare-earth (U–Th–REE), are established within the DM. The gold mineralization was found in the quartz–chlorite–pyritized metasomatites. It is confined to the NNE- and NNW-trending fault zones and coincides with the strike of the syenite porphyry dike belt. Uranium–thorium–rare-earth mineralization has been established in the quartz–feldspathic metasomatites localized in the outer contact of the massif. The juxtaposition of mineralization of different types in some zones of the Dzheltula syenite massif significantly increases the ore potential of the studied object within the Tyrkanda ore region.  相似文献   

Magnetite-apatite-dolomitic rocks of Ust-Chulman (Aldan shield,Russia): Seligdar-type carbonatites?     

Prokopyev  Ilya R.  Doroshkevich  Anna G.  Redina  Anna A.  Obukhov  Andrey V. 《Mineralogy and Petrology》2018,112(2):257-266

Mineralogy and Petrology - The Ust-Chulman apatite ore body is situated within the Nimnyrskaya apatite zone at the Aldan shield in Russia. The latest data confirm the carbonatitic origin of the...  相似文献   

Assessment of the Role of Carbonate–Bicarbonate Fluids in the Transport and Deposition of REEs in the Process of Ore Formation (Thermodynamic Modeling)     

Shironosova  G. P.  Prokopyev  I. R. 《Doklady Earth Sciences》2022,501(1):S13-S17

Doklady Earth Sciences - Thermodynamic calculations on the impact of carbonate–bicarbonate fluids cooling from 500 to 100°C on a monazite + calcite association with a simultaneous...  相似文献