Low-Ti melts from the southeastern Siberian Traps Large Igneous Province: Evidence for a water-rich mantle source?

Journal of Earth system science

Elena I Demonterova1¹  Sergei V Rasskazov1¹  Tatyana A Yasnygina1¹  Alexei V Ivanov1¹ 

[1] Institute of the Earth’s Crust, Siberian Branch of Russian Academy of Sciences, Lermontov St. 128, Irkutsk 664 033, Russia.$$

关键词: Large igneous provinces;    basalts;    trace elements;    Geochemistry;    Geodynamics;    Mineralogy and Petrology.;   

DOI  :  

学科分类：天文学(综合)

来源: Indian Academy of Sciences

【 摘 要 】

Siberian Traps Large Igneous Province (STLIP) is one of the most voluminous volcanic provinces on Earth. The dominant erupted rocks are low-Ti basalts, which make up 80% by volume of the classical Noril’sk lava sequence. In the west Siberian basin and Maymecha-Kotuy area, the low- Ti basalts make up about 99% and 50% by volume, respectively. Dolerite sills in the Angara– Taseevskaya Syncline at the southeastern STLIP exhibit trace element patterns and Sr isotope ratios typical of the low-Ti basalts of the Noril’sk sequence. The most Mg-rich (MgO 9.5–11 wt%) and hence least differentiated dolerites are characterized by trace element patterns with Ta-Nb depletion, low Ce/Pb and high Sr/Pr. These trace element features are similar to water-saturated, mantle wedge-derived island arc basalts. These imply an important role of subduction fluid-derived trace elements in the source of melting beneath the Angara–Taseevskaya Syncline and other regions of the STLIP. Less magnesium rocks (MgO 3.8–6.1 wt%) with less prominent Ta-Nb depletion, higher Ce/Pb and lower Sr/Pr could be produced via olivine-plagioclase fractionation of primary high-magnesium melts.

【 授权许可】

Unknown