The layered intrusions in the Panzhihua-Xiehang area may be grouped into two types:basicrock masses represented by the Panzhihua roekbody and basic-uhrabasic rock masses represented bythe Hongge rockbody.Their major difference lies in that the former has poorly developed ultramaficfacies,while the latter is characterized by well developed mafic facies and ultramafic facies.Thereexists apparent rhythmic stratification in the rock masses,which can be basically divided into fourgrades in terms of superimposition relationship and multicycle characters.Both direct and indirect evidence suggest that the magma responsible for the layered intrusions inhis area should be a transition-type alkaline ohvine basalt magma derived directly from partialmelting of the upper mantle.In rhythmic cycles of various grades,the magmatic evolution ischaracterized obviously by periodicity and early enrichment of Fe and Ti,which is evidently differentfrom the evolution of the Skaergaard magma in which Fe and Ti are enriched at the late stage.The FCAdiagram can be used to describe the unique evolutionary trend of magma in this area.It isdemonstrated in this diagram that the enrichment of Fe and Ti is consistent with the increase ofbasicity.In the upper magmatic chamber,the evolutionary trend of magma is conditioned by thedifference in pressure,and this enables magma to form different types of rock assemblage.In the Fo-Di An system,when the pressure exceeds 5×18~8 Pa,forsterite is incompatible with anorthite,andthe rock facies sequence of Hongge type might form;when the pressure is lower than 5×10~8 Pa,forsterite can coexist with anorthite,and the rock facies sequence of Panzhihua type is likely to form ifthe magma is relatively rich in Mg and Fe components. The layered intrusions in the Panzhihua-Xiehang area may be grouped into two types: basicrock mass represented by the Panzhihua roekbody and basic-uhrabasic rock mass represented by the Hongge rockbody. Their major difference lies in that the former has poorly developed ultramaficfacies, while_ latter is characterized well well developed microfic facies and ultramafic facies. Thereexists apparent rhythmic stratification in the rock masses, which can be basically divided into fourgrades in terms of superimposition relationship and multicycle characters.Both direct and indirect evidence suggest that the magma responsible for the layered intrusions inhis area should be a transition-type alkaline ohvine basalt magma derived directly from partialmelting of the upper mantle. rhythmic cycles of various grades, the magmatic evolution is characterized obviously by periodicity and early enrichment of Fe and Ti, which is evidently differentfrom the evolution of the Skaergaard magma in which Fe and Ti are enriched at the late stage. The FCAdiagram can be used to describe the unique evolutionary trend of magma in this area. If is demonstrated in this diagram that the enrichment of Fe and Ti is consistent with the increase of basicity. in the upper magmatic chamber, the evolutionary trend of magma is conditioned by thedifference in pressure, and this enables magma to form different types of rock assemblage. the fo-di An system, when the pressure exceeds 5 × 18 ~ 8 Pa, forsterite is incompatible with anorthite, andthe rock facies sequence of Hongge type might form; when the pressure is lower than 5 × 10 ~ 8 Pa, forsterite can coexist with anorthite, and the rock facies sequence of Panzhihua type is likely to form if the magma is relatively rich in Mg and Fe components.