Two ree distributed pattern , lree - depleted and flat , which display a specific character of typical mid - ocean ridge tholeiite , indicate that primary magma may be derived from near primary or a typical large ion lithophile element ( lile ) - depleted mantle 岩石稀土元素配分模式可分为lree平坦型和lree亏损型两类，指示了其原始岩浆起源于近原始或典型的大离子元素亏损型的地幔，为典型的大洋中脊拉斑玄武岩的特征。
2.
2 both the hanging wall and the footwail rock of ore bodies are garnet biotite schist , protoliths are alkaline volcanic rocks ( tracyh andesite ) . according to characteristics of trace elements assemblages and the setting of tectonics , these alkaline volcanic rocks were derived from the lower degree melting of metasomatic and enriched mantle ( eml ) in the initial stage of middle proterozoic epoch . they strongly enriched in large ion lithophile elements ( lile ) , such as ba 2 、矿体顶、底板围岩(石榴石黑云母片岩、钠长黑云母片岩等)的原岩为碱性火山岩(粗面安山岩) ，相对富集大离子亲石元素ba 、 cs 、 rb 、 k 、 lree及贫zr 、 sr 、 ti 、 hf 、 hree ，为早元古代末期-中元古代早期交代富集地幔低程度部分熔融所形成的碱性火山岩。
