Field evidence, petrography and mineral chemistry of the Titanium rich intrusions in NW Urmia Lake

The layered intrusions with Fe-Ti oxides mineralization are exposed in several parts of northwest of Urmia Lake. These intrusions are present at the extremity of NW side of the Sanandaj-Sirjan zone with Permian age. These layered mafic – ultramafic rocks are intruded into the Precambrian metamorphic rocks. Field, petrography and mineral chemistry investigations of two important and large intrusions at the GKMUC and GhMUC are discussed and compared together. Ultramafic part in both intrusions is surrounded by the mafic part and their marginal is surrounded by non-layered gabbros. The mafic parts are mostly noritic in GKMUC and gabbroic in GhMUC. In the GKMUC, there are pure cumulates of ilmenite and titanomagnetite that are not found in the GhMUC. The Fe-Ti±Ap oxide-rich phases in GhMUC are present only within the ultramafic parts (consisting of dunite, verlite, and slightly clinopyroxenite), while the Fe-Ti oxide rich phases without apatite in GKMUC are present in cumulative, ultramafic (including verlite, pyroxenite and slightly dunite) and slightly in the mafic and even anorthosite parts. The GKMUC spinels are more hercynite in composition  rather than GhMUC. These differences indicate different crystallization paths and possibly different origin .