摘要
This paper presents the major-and trace elements and Sr-Nd-Pb isotopes of the meta-basalts from the Ganlongtang-Nongba ophiolitic mélange which is situated at the middle part of the Changning-Menglian Paleo-Tethys suture zone. The Nongba basalts are mainly composed of alkaline and tholeiitic basalts. The Ganlongtang tholeiitic basalts show typical characteristics of N-MORB in terms of TiO2, Mg, K2O and LILEs, but have variable Sr-Nd-Pb isotopic compositions probably resulted from crustal contamination. It is proposed that the Changning-Menglian ancient ocean basin experienced a complete growth process from an embryonic to a mature ocean basin.