摘要
Age and geochemical studies on gabbro at Kayakedengtage, East Kunlun Mountains, Qinghai Province show that the gabbro was emplaced during Early Devonian belonging Ca-alklic series with evolution trend to Mg enrichment. The ∑REE are in range 28.9×10-6 to 154×10-6 with the obvious enrichment of LREE[(La/Yh)=4.1~5.1(>1)(LREE/HREE 3.52~5.60), Sm/Nd of rocks 0.23~0.25, showing derivation of the gabbro from the depleted mantle. However, δ(Ce)= 0.87~1.0, the negative Ce anomaly indicates derivation of the gabbro from contact zone of mantle and crust or the enriched mantle. Combined with the basalt tectonic discrimination diagrams, the gabbro may be the product of the post Caledonian Qimantage orogen extensional environment.