Partial melting of mantle source of the peridotite from Ni Nưa area, Thanh Ha Province and lts implications for tectonic setting

Ng Xun Thnh, Phạm Trung Hiếu, Phạm Ngọc Dũng

The Ni Nưa peridotites, parts of ophiolitic complex of the Sng M suture zone, represent collision site between the Indochina and South China blocks. The peridotites are mainly composed of dunite, harzburgite and some intruded gabbro-diabases. Study of rock textures, mineral and geochemical composition indicated that they are typical those of mantle rocks, which were experienced partial melting in the mantle source. Mineral and geochemical composition of the harzburgites are used to calculate partial melting degrees of mantle. The results show that the mantle sources experienced partial melting degrees of around 20% to over 40% to form Ni Nưa peridotites. In comparison with data from different modem tectonic settings, the Ni Nưa peridotites were formed in a fore-arc tectonic setting.

Người bin tập: GS. TS Trần Văn Trị.