摘要
大庙斜长岩杂岩体是中国唯一的岩体型斜长岩杂岩体。稀土元素(REE)地球化学研究表明,控杂岩体中斜长岩、苏长岩、铁磷矿属同源斜长—苏(辉)长质岩浆不同演化阶段的产物。成岩(矿)作用具液态分异和结晶分异双重性。REE和Sc的丰度、Eu/Eu比值等参量能为铁磷矿勘查提供示踪判据。
Damiao anorthosite complex is the only massif anorthosite complex dilcovered(continued on p.84) in China.The Rb-Sr age of the anorthosite is 1686±193 Ma,Sm-Nd age 1735±239 Ma(Xie Guanghun et al.1988), and the Rb-Sr age of the metamorphie rock series of Dantaz Group intrudea by anorthosite is 2453±113.3 Ma,aad of the norite is 1004 ±105.2 Ma.The formation of the complex occurres in two main stages. The early aaorthosite, which lically passes into leueonorite, occurres on a large scale. Mediumgrained norite and norite rich in iron and phosphorus were formed in a later stage,and minor mangerite, quarts monzonite occur in the western margin of the complex.The simulation of REE compatibility and parental magma indicates that the Complex and the associated iron-phosphorus ores were derived from an anorthosi-tic-noritic and gabbroic magma. The quantitative simulation of REE taking La as the representive and REE abundance patterns of varous rock (ores), and typical REE retions and correlated diagrames suggest that the lithogenesis(mineralization) was characterised by a dual-feature of a liquious differentiation anda fractional crystallization, and the liquious differentiation predominated in the evolution from anothosit to norite and from iron-phosphorus ore to vanadic-titanic magnetite.
关键词
斜长岩
铁磷矿
稀土元素
地球化学
anorthosite, iron-phosphorus, magma, liquious differentiation,crys-tallization
