Original paper

Recent geochemical data from Noril'sk, USSR - The relative roles of the mantle and crust in the genesis of Siberian traps and mineralized and unmineralized intrusions

Lightfoot, P. C.; Doherty, W.; Naldrett, A. J.; Gorbachev, N. S.; Fedorenko, V. A.

Global Tectonics and Metallogeny Volume 4 Number 1-2 (1991), p. 65 - 68

published: Jan 1, 1991

DOI: 10.1127/gtm/4/1991/65

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ArtNo. ESP136000401006, Price: 19.00 €

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Abstract

The investigated sequence of the Siberian Trap at Noril'sk, USSR, consists of at least 45 flows which have been divided into six suites. The lowermost suite, the Ivakinsky (Iv), consists of trachybasalts and basalts characterised by high TiO2 (2.07-3.28 wt%), Ce (73-132 ppm), Ce/Yb (>22), and K2O, accompanied by low Mg-numbers (0.32-0.42). The Ivakinsky is transitional into the overlying Syverminsky (Sv). Picritic basalts of the Gudchichinsky (Gd) overlie the Syverminsky and the more picritic members have low TiO2 (1.21-1.86 wt), Ce (13-22), Ce/Yb (< 22) and high sm/nd (> 0.23), together with high Mg-numbers in excess of 0.57. The geochemistry of the Gudchichinsky suite is distinctive and perhaps unrelated to the other suites. The succeeding Nadezhdinsky tholeiitic basalts have low TiO2 (< 1.14 wt%), ce (< 41), sm/nd (< 0.27), and mg-number (0.53-0.59), but high th/yb (0.75) and sio2 (49.5-55.2). The uppermost groups of tholeiitic flows belong to the Morongovsky (Mr) and Mokulaevsky (Mk).

Keywords

Noril'sk • USSR • Siberian trap • trachybasalt • tholeiitic