A mantle plume origin for the Siberian traps: uplift and extension in the West Siberian Basin, Russia

被引:123
作者
Saunders, AD [1 ]
England, RW [1 ]
Relchow, MK [1 ]
White, RV [1 ]
机构
[1] Univ Leicester, Dept Geol, Leicester LE1 7RH, Leics, England
关键词
mantle plume; Siberian Traps; large igneous provinces; flood basalts; West Siberian Basin; FLOOD BASALTS; CRUSTAL CONTRIBUTIONS; VOLCANIC-ROCKS; RAPID ERUPTION; TRACE-ELEMENT; NORILSK AREA; EVOLUTION; GEOCHEMISTRY; MAGMATISM; PETROCHEMISTRY;
D O I
10.1016/j.lithos.2004.09.010
中图分类号
P3 [地球物理学]; P59 [地球化学];
学科分类号
0708 ; 070902 ;
摘要
The West Siberian Basin (WSB) records a detailed history of Permo-Triassic rifting, extension and volcanism, followed by Mesozoic and Cenozoic sedimentation in a thermally subsiding basin. Sedimentary deposits of Permian age are absent from much of the basin, suggesting that large areas of the nascent basin were elevated and exposed at that time. Industrial seismic and well log data from the basin have enabled extension and subsidence modelling of parts of the basin. Crustal extension (beta) factors are calculated to be in excess of 1.6 in the northern part of the basin across the deep Urengoy graben. 1-D backstripping of the Triassic to Cenozoic sedimentary sequences in this region indicates a period of delayed subsidence during the early Mesozoic. The combination of elevation, rifting and volcanism is consistent with sublithospheric support, such as a hot mantle plume. This interpretation accords with the geochemical data for basalts from the Siberian Traps and the West Siberian Basin, which are considered to be part of the same large igneous province. Whilst early suites from Noril'sk indicate moderate pressures of melting (mostly within the garnet stability field), later suites (and those from the West Siberian Basin) indicate shallow average depths of melting. The main region of magma production was therefore beneath the relatively thin (ca. 50-100 km) lithosphere of the basin, and not the craton on which the present-day exposure of the Traps occurs. The indicated uplift, widespread occurrence of basalts, and short duration of the volcanic province as a whole are entirely consistent with published models involving a mantle plume. The main argument against the plume model, namely lack of any associated uplift, appears to be untenable. (C) 2004 Elsevier B.V. All rights reserved.
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页码:407 / 424
页数:18
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