The Transangara alkaline Pluton, Yenisei Range: Rb-Sr and Sm-Nd isotope ages and sources of feldspathoid magmas in Late Precambrian

Neoproterozoic Alkaline Igneous Rocks, Carbonatites and Gold Deposits of the Yenisei Ridge, Central Siberia: Evidence of Mantle Plume Activity and Late Collision Shear Tectonics Associated with Orogenic Gold Mineralization

“…This interpretation is supported by recent data of Ar–Ar isotopic dating of magnesio‐arfvedsonite (725.9 ± 6.3 Ma) and phlogopite (637.6 ± 5.7 Ma) from the Penchenga carbonatite complex (Vrublevskii et al ., 2011), which suggest a significant period of carbonatite magmatism and mantle plume activity. The foregoing interpretations are supported further by Sm–Nd and Rb–Sr isotopic data from the Transangara ijolite–nepheline–syenite massif, which indicate a period of basic‐alkaline magmatism during 680–610 Ma (Sazonov et al ., 2007). However, the interpretations are not yet efficiently constrained because, for example, there is evidence of polychronous occurrence of intraplate magmatism for a period of 100–150 Ma in the NE part of the Kuznetsky Alatau Ridge and Gorny Altai (Vrublevskii et al ., 2004a, b).…”

“…Thus, according to our recent isotopic data, the rocks of the foidolite (or ijolite) intrusive phase are younger than the foyaites. Accordingly, the foyaites can be regarded as products of the earliest intrusive phase of the Transangara Massif relative to the ijolites (Sazonov et al ., 2007). However, there are some difficulties with isotope researches of muscovite‐bearing syenites, the nature of which is not clear yet.…”

“…The existence of basic‐alkaline and carbonatite‐bearing magmatic rocks in the Yenisei Ridge indicate post‐orogenic rifting and break‐up of the Siberian paleocontinent and plausible plume activity in deep‐seated mantle horizons within the 730–610 Ma period (Vrublevskii et al ., 2003; Sazonov et al ., 2007; Vernikovsky et al ., 2008). This interpretation is supported by recent data of Ar–Ar isotopic dating of magnesio‐arfvedsonite (725.9 ± 6.3 Ma) and phlogopite (637.6 ± 5.7 Ma) from the Penchenga carbonatite complex (Vrublevskii et al ., 2011), which suggest a significant period of carbonatite magmatism and mantle plume activity.…”

“…The late or post‐collisional magmatism in the Central Angarian Terrane was controlled by continental rifting with the development of the Early Vendian alkaline basic, ultrabasic, and carbonatite‐bearing small intrusions. Typical of these intrusions are bodies of the Penchenga fenite‐carbonatite complex and the Transangara foidic syenite massif (Vrublevskii et al ., 2003; Sazonov et al ., 2007) (Fig. 1).…”

“…However, a possible synchronization of Au‐sulfide mineralization, which represents the most common type of Au deposits in the ridge, with Neoproterozoic riftogenic alkaline and carbonatite magmatism can be proposed because several centers of similar alkaline and carbonatite magmatism have been documented in the Transangarian where the Yenisei Ridge is situated. The products of these alkaline and carbonatite magmatism have mantle plume natures and approximately correspond temporally to one of the epochs (during 725–670 Ma) of the Late Precambrian riftogenic destruction of the Rodinia super‐continent fragments (Vrublevskii et al ., 2003; Sazonov et al ., 2007; Li et al ., 2008; Nozhkin et al ., 2008; Vernikovsky et al ., 2008).…”