北秦岭松树沟超镁铁岩的成因类型

THE GENETIC CLASSIFICATION OF SONGSHUGOU ULTRAMAFIC ROCKS IN NORTH QINLING MOUNTAINS

The genetic classification of ultramafic rocks is the long-disputed subject. After integrated studies and analyses in field geology, petrology and geochemistry, the writer think that Songshugou ultramafic rocks in North Qinling can be divided into three genetic types, that is the magma crystallization (MA) type, the mantle residue (R) type and the metasomatism (ME) type. The MA type is further divided into two subtypes of basaltic magma crystallization (BMA) and ultramafic magma crystallization (UMA). The ME type also into two subtypes of mantle metasomatism (MME) and crustal metasomatism (CME). Therefore the Songshugou body is a typical example of Alpine-type multigenetic ultramafic body. The author think that achievements of this paper will push studies of genetic classification of Alpine-type ultramafic rocks forward.