Geochemistry, petrography and rock magnetic properties of the high- and low-Ti alkaline basalts from intra-plate riftogenic setting

The goal of proposed study is to establish the petrogenetic evolution of the intraplate nephelinite to tephrite series (37-30 Ma), characteristic in high- and low-Ti contents and located in the riftogenic setting. The high-Ti rock types are characterized not only by distinctive high TiO2 contents (2.6-5.0 wt%), but also by Ti/Y ratios >500, similarly to basaltic (or tholeiitic) rocks in the LIPs. The low-Ti types exhibit <2.6 wt% TiO2 and Ti/Y ratio<500. Petrological and geochemical studies (electron microprobe, determination of trace elements using ICP-MS, INAA, PIGE and PIXE methods, Sr-Nd-Pb, oxygen stable isotopes, and K-Ar age determination) will be accomplished to constrain the comagmatic relations to one or several magmatic sources (degree of decompression melting, magmatic mixing/mingling and of lithospheric contamination). Rock magnetic properties and opaque mineralogy will contribute to interpretation of lava flows with both normal and reversal magnetic polarity.