Unique PGE–Cu–Ni Noril’sk Deposits, Siberian Trap Province: Magmatic and Tectonic Factors in Their Origin

Abstract

The unique and very large PGE–Cu–Ni Noril’sk deposits are located within the Siberian trap province, posing a number of questions about the relationship between the ore-forming process and the magmatism that produced the traps. A successful answer to these questions could greatly increase the possibility of discovering new deposits in flood basalt provinces elsewhere. In this contribution, we present new data on volcanic stratigraphy and geochemistry of the magmatic rocks in the key regions of the Siberian trap province (Noril’sk, Taimyr, Maymecha-Kotuy, Kulyumber, Lower Tunguska and Angara) and analyze the structure of the north part of the province. The magmatic rocks of the Arctic zone are characterized by variable MgO (3.6–37.2 wt %) and TiO2 (0.8–3.9 wt %) contents, Gd/Yb (1.4–6.3) and La/Sm (2.0–10.4) ratios, and a large range of isotopic compositions. The intrusions in the center of the Tunguska syneclise and Angara syncline have much less variable compositions and correspond to a “typical trap” with MgO of 5.6–7.2 wt %, TiO2 of 1.0–1.6 wt %, Gd/Yb ratio of 1.4–1.6 and La/Sm ratio of 2.0–3.5. This compositional diversity of magmas in the Arctic zone is consistent with their emplacement within the paleo-rift zones. Ore-bearing intrusions (the Noril’sk 1, Talnakh, Kharaelakh) are deep-situated in the Igarka-Noril’sk rift zone, which has three branches, namely the Bolsheavamsky, Dyupkunsky, and Lower Tunguska, that are prospected for discovering new deposits. One possible explanation for the specific position of the PGE–Cu–Ni deposits is accumulation of sulfides in these long-lived zones from the Neoproterozoic to the Mesozoic era during magmatic and metamorphic processes. Thus, trap magmatism, itself, does not produce large deposits, but mobilizes earlier formed sulfide segregations in addition carrying metals in the original magmas. These deposits are the results of several successive magmatic events, in which emplacement of the traps was the final event.

Latest Permian–Triassic magmatism of the Taimyr Peninsula: New evidence for a connection to the Siberian Traps large igneous province

“…Compressional forces and tectonic activity ceased within the Taimyr-Severnaya Zemlya fold-and-thrust belt during the Early Permian, and it has subsequently formed the northern margin of the Siberian Craton (Kurapov et al, 2020;Vernikovsky, 1996). Various researchers (Khain et al, 1991;Saunders et al, 2005;Dobretsov et al, 2013a;Afanasenkov et al, 2016;Krivolutskaya et al, 2019) propose an extensional environment close to Siberian margins and within the West Siberian basin in the Late Permian-Early Triassic. Particularly, the development of the Yenisei-Khatanga paleo-rift (Krivolutskaya et al, 2019) suggests that synchronous extension could appear within the Taimyr-Severnaya Zemlya foldand-thrust belt.…”

“…Various researchers (Khain et al, 1991;Saunders et al, 2005;Dobretsov et al, 2013a;Afanasenkov et al, 2016;Krivolutskaya et al, 2019) propose an extensional environment close to Siberian margins and within the West Siberian basin in the Late Permian-Early Triassic. Particularly, the development of the Yenisei-Khatanga paleo-rift (Krivolutskaya et al, 2019) suggests that synchronous extension could appear within the Taimyr-Severnaya Zemlya foldand-thrust belt. Vernikovsky et al (2003) reported U-Pb zircon ages of several syenite-granite intrusions from northwestern Taimyr (Fig.…”

“…Silicic cumulates are known to be found in extensional environments (Bachl et al, 2001). In the Late Permian-Triassic, extension caused by the Siberian Traps LIP activity (Krivolutskaya et al, 2019;Saunders et al, 2005) affected the Taimyr-Severnaya Zemlya fold-and-thrust belt. Thereby, we propose emplacement of the Late Permian-Middle Triassic Taimyr syenite-granite intrusions to be the result of Siberian Traps LIP magmatic activity as was suggested by Augland et al (2019) and Vernikovsky et al (2003).…”

Multiple Magma Conduits Model of the Jinchuan Ni-Cu-(PGE) Deposit, Northwestern China: Constraints from the Geochemistry of Platinum-Group Elements

“…The Ni/Pd versus Cu/Ir diagram shows most samples are in the range of high Mg basalt (Figure 10b). The genetic relationships are also suggested by the Ni/Cu ratios, which are lower than that segregated from komatiitic magmas (>7, [2]), but comparable with basalt magmas such as those from the Nadezhdinsky Formation at the Noril'sk region (~1, [61][62][63]) and Sudbury in Canada (1.2, [12]). The MgO content of parental magma of the Jinchuan intrusion was estimated to be 11.5-12.6 wt.% [17,30,64].…”

Petrographical and Mineralogical Characteristics of Magmatic Rocks in the Northwestern Siberian Traps Province, Kulyumber River Valley. Part I: Rocks of the Khalil and Kaya Sites

“…This study is focused on the Kulyumber area located in the middle part of the Kulyumber river valley which represents one of the least studied areas of the province (Figure 1). It is located between the Tunguska syncline and Norilsk-Igarka zone [48][49][50] and thus it provides information on the magmatic events within both structures at the Permian-Triassic boundary (250 ± 0.3 Ma; [51]). Within this territory effusive rocks and numerous intrusive bodies were found during the geological mapping.…”