Geochemistry of Dominant Low-Ti Basalts

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Geochemistry of Dominant Low-Ti Basalts of the
Siberian Traps and Subduction-Related Model of
Their Origin
Ivanov A.V. Institute of the Earths Crust,
Siberian Branch, Russian Academy of Sciences

• Flood basalt geochemistry
• 1.1. Columbia River 1.2. Siberian Traps

2. Subduction-related model for flood basalts
(Siberian Traps)
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Columbia river
Os-isotope data are after Chesley and Ruiz (1998)
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Columbia river
Data are plotted after Hooper and Hawkesworth
(1993)
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Columbia river
Data are plotted after Hooper and Hawkesworth
(1993)
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Columbia river
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Columbia river
High-Mg basalts of Klyuchevskoi volcano
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Siberian Traps
Pangea
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Siberian Traps
Ages are for basalts only !
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Siberian Traps
Approximate size of the Columbia River flood
basalts
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Siberian Traps
Norilsk
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Siberian Traps
Upper Morongovsky subsuite to Samoedsky suite
basalts are not contaminated
Saddle Mountains
Imnaha
Data are plotted after Wooden et al. (1993)
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Siberian Traps
Data are plotted after Wooden et al. (1993)
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Siberian Traps
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Siberian Traps
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Siberian Traps
Subduction signatures are more prominent
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Model
After Ohtani (2005)
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Model
Based on Bina et al. (2001), Litasov and Ohtani
(2003), Hirschmann et al. (2005)
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Siberian Traps
2300 km
Transbaikalian belt (Andean-type orogen)
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Model
Transbaikalian belt
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Model
Siberian Traps, Norilsk event
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Model
Siberian Traps, Tunguska event
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Conclusions
1. Primitive mantle-derived flood basalts (with
Siberian Traps and Columbia River as examples)
show similarities with typical island-arc
basalts. They are remarkably different with ocean
island basalts. 2. Flood basalt origin can be
explained by water-recycling through transition
zone of mantle via stagnated (by depth)
subduction.
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Thanks!