Petrographical and Geochemical Characteristics of Magmatic Rocks in the Northwestern Siberian Traps Province, Kulyumber River Valley. Part II: Rocks of the Kulyumber Site

Minerals

Boris Belyatsky¹  Alexander Dolgal²  Andrey Lapkovsky³  Bronislav Gongalsky⁴  TamaraB. Bayanova⁵  Nadezhda Krivolutskaya⁶ 

[1] A.P. Karpinsky Russian Geological Research Institute, Sredny Prospect, 74, 199106 St. Petersburg, Russia;Geological Department, Perm State University, 15 Bukireva, 614990 Perm, Russia;Geological Institute of Kola Scientific Center, Russian Academy of Sciences, Fersman st., 14, 184209 Apatity, Russia;Institute Geology of Ore Deposits, Petrography, Mineralogy and Geochemistry, Russian Academy of Sciences, Staromonetny per., 35, 119109 Moscow, Russia;Norilskgeology Ltd., Grazhdansky pr., 11, 195220 St. Petersburg, Russia;Vernadsky Institute of Geochemistry and Analytical Chemistry, Russian Academy of Sciences, Kosygin st. 19, 119991 Moscow, Russia;

关键词: Siberian traps;    Norilsk-Igarka paleorift;    Kulyumber river valley;    magmatism;    geochemistry;   

DOI  :  10.3390/min10050415

来源: DOAJ

【 摘 要 】

The origin of the Siberian trap province is under discussion even though numerous models of its formation have been created over the last three decades. This situation is mainly due to lack of modern geochemical data on magmatic rocks around the province. These data are a very important tool to reconstruct of magmatic evolution within the province in time and space and to understand a mechanism of province formation. Geochemical study has only been carried out so far for the Norilsk and Meimecha–Kotuy areas. For the first time, we have studied the geochemical and mineralogical characteristics of magmatic rocks at the Kulyumber river valley located 150 km to south from the Norilsk ore district, in the junction of the Tunguska syneclise and Norilsk–Igarka zone. It comprises three sites, i.e., Khalil, Kaya, and Kulyumber. The geochemical data on the magmatic rocks of the Khalil and Kaya sites were published earlier (Part I). This article (Part II) regards geochemical and mineralogical data on igneous rocks at the Kulyumber site. Seventeen intrusive bodies (41 samples) and six samples of sedimentary rocks were studied by X-ray fluorescence (XRF) and inductively coupled plasma mass spectrometry (ICP-MS). Isotopes analyses (Sr, Nd, Pb) were conducted for 12 samples. These data were compared with data for intrusions of the Norilsk area, the Dzhaltulsky massif, Kureyka river, and intrusions in Angara river valley published earlier. The whole list of analyses includes 102 items. Three groups of intrusive rocks were recognized: (1) Mafic rocks with elevated K₂O without negative Ta-Nb and Pb-positive anomalies, with (Gd/Yb)n = 2.0 and εNd = −1.0; attributed to a new Kulyumbinsky complex; (2) subalkaline rocks with elevated SiO₂,TiO₂, P₂O_5, and K₂O with small negative Ta-Nb and positive Pb anomalies and (Gd/Yb)n = 1.8, εNd = −3.8; Ergalakhsky complex; and (3) mafic rocks with strong Ta-Nb and Pb anomalies and (Gd/Yb)n = 1.2–1.4, εNd = +0.4–+2.2. The third group is rather nonhomogeneous and includes intrusions of the Norilsk, Kuryesky, Katangsky, Ogonersky, and Daldykansky complexes differing in MgO content and trace element distribution (values of Ta-Nb, Pb, and Sr anomalies). Three groups of intrusive bodies had different magma sources and different condition of crystallization reflecting their origin in rift and platform regimes.

【 授权许可】

Unknown