Three iron-, titanium-rieh layered basie-ultrabasie intrusives have been described.They occur in an approximately south-north striking belt of tectonie-magmatic complex within an anteklise. Iron and titanium were concentrated in the lower or middle lower parts of these intrusives in the early and middle stages of differentiation, during which 《FeO》 may have played an important role. Intimate spatial and temporal association as well as common petroehemical features (i.e., high iron and titanium contents) have been found between these layered intrusives and the syenite and alkalisyenite plutons. All of these rocks are considered as hypogene produets of the differentiation of the. Omeishan basaltic magma. In other words, the hypogene differentiation of the iron (titanium)-rieh, sub-alkali Omeishan basaltic magma under the same tectonic-geological conditions resulted in the formation of the rock series of layered intrusives (peridotite→iron, titanium-rich ultramafic rocks→iron, titanium-rich gabbro, plagioclasite)→syenite, alkali-syenite.
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