DISCOVER OF THE OPHIOLITE IN TAIPINGGOU AREA ON THE WESTERN MARGIN OF JIAMUSI MASSIF: Tectonic implication

Ophiolite was firstly found in Taipinggou area during the 1:250 000 regional geological survey of Jiayin and Taipinggou sheets. It occurs in the west of Jiamusi massif in Eastern of Heilongjiang Province, on the east of MudanjiangJiayin fault. The rock belt, extending in northeast direction, is distributed in and structurally bounded by the Mesoproterozoic Heilongjiang rock group. The ophiolite series is composed of ultramafic serpentinite, serpentinized peridotite-pyroxenite and metamorphosed basic rocks. The Taipinggou ophiolite belt was formed by the splitting of Jiamusi-Songnen massif. The ophiolite might be derived from the secondary oceanic crust formed in the minor spreading center near the subduction zone. Its character of P-MORB of slight LREE enrichment, with negative abnormity of Nd and Ta, suggests that the ophiolite be related to the subduction. The discovery of Taipinggou ophiolite provides new tectonic evidences for the study on the forming and evolving of the Proterozoic plate and Jiamusi massif. It is a significant guide to search mantle-related metal minerals in the region.