中文摘要：

商南县松树沟超镁铁质岩体位于秦岭造山带商州-丹凤断裂以北，出露面积超过20km^2，是中国境内出露最大的阿尔卑斯型橄榄岩体，并以侵位方式与秦岭杂岩接触。该岩体主要由细粒纯橄榄岩、中粗粒纯橄榄岩和方辉橄榄岩等组成。地球化学特征显示明显亏损特征，同时不相容元素（从Rb到Nb）和LREE等元素相对HREE富集；纯橄榄岩的PGE含量明显低于方辉橄榄岩。与典型蛇绿岩的地幔橄榄岩对比研究，认为该岩体是经过熔体渗滤过程形成的纯橄榄岩体。

英文摘要：

Ultramafites in the Songshugou area, Shangnan county, Shaanxi Province, to the north of the Shangzhou-Danfeng fault is the largest Alpine-type ultramafic massif in China. Covering an area of about 20 km^2,and it is contact with the Qinling Group as intrusions. The rockbody is composed mainly of fine-grained dunite, medium dunite and harzburgite. Geochemical characteristics show ultramafites are depleted, while rocks from the Songshugou dunite body display clear enrichment of highly incompatible elements （Rb to Nb） and LREE compared HREE. The PGE concentrations of dunite are lower than harzburgite obviously. Compared with ophoplitic mantle peridotite, we propose that the Songshugou body is the product of peridotite with melt through melt percolation.