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Three iron,titanium-rich layered basic-ultrabasic intrusives have been described.Theyoccur in an approximately south-north striking belt of tectonic-magmatic complex within ananteklise.Iron and titanium were concentrated in the lower or middle-lower parts of theseintrusives at the early and the middle stages of differentiation,during which FeO may haveplayed an important role.Intimate special and temporal association as well as commonpetrochemical features(i.e.,high iron and titanium contents)have been found between theselayered intrusives and the syenite and alkali-syenite plutons.All of these rocks are consideredas hypogene products of the differentiation of the Omeishan basaltic magma.In other words,the hypogene differentiation of the iron(titanium)-rich,sub-alkali Omeishan basltic magmaunder the same structural-geological conditions resulted in the formation of the rock seriesof layered intrusives(peridotite→iron,titanium-rich ultramafic rocks→iron,titanium-rich gabbro,plagioclasite)→syenite,alkali-syenite.
Three iron, titanium-rich layered basic-ultrabasic intrusives have been described. Theoccur in an approximately south-north striking belt of tectonic-magmatic complex within ananteklise. Iron and titanium were concentrated in the lower or middle-lower parts of these intrusives at the early and the middle stages of differentiation, during which FeO may have played an important role. Intemate special and temporal association as well as common petrochemical features (ie, high iron and titanium contents) have been found between these layered intrusives and the syenite and alkali-syenite plutons. All of these rocks are considered as hypogene products of the differentiation of the Omeishan basaltic magma. Other words, the hypogene differentiation of the iron (titanium) -rich, sub-alkali Omeishan basltic magmaunder the same structural-geological conditions resulted in the formation of the rock seriesof layered intrusives (peridotite → iron, titanium-rich ultramafic rocks → iron, titanium-rich gabbro, plagiocl asite → syenite, alkali-syenite.