关键词: 基性-超基性岩, 洋脊玄武岩, 稀土元素, 大陆边缘, 新生代火山岩

Abstract: The preliminary exploratory results about the basic-ultrabasic rocks of the Karakoram and western Kunlun Mts. are reported in this paper. The Kudi ultramafic rock bodies belong to the Alpine-type associations in general, but there are some differences between the Kudi bodies and the typical ophiolitic metamorphic peridotites in petrochemistry. At present, there is insufficient evidence to make a full interpretation of the formation of these bodies. The Middle Proterozoic metamorphic volcanics in Akazi section may have originated in a strongly attenuated continental lithosphere. According to the discriminations of the rare element and REE geochemistry the Upper Proterozoic metamorphic mafic lavas in Yixikgou section probably are formed at a Mid-ocean ridge and present truce oceanic lithosphere. Late Paleozoic volcanics may have erupted in a continental margin area. Relative strong continental volcanic activity existed in Cenozoicera, in which especially the Quaternary continental floor volcanics may be related to the rapid uplifting of the Qinghai-X izang plateau. The occurrences, petrological and geochemical characteristics and erupting stages of the volcanics found in southern Kunlun Mts. have been discussed in detail in the paper.

Key words: basic-ultrabasic rock, mid-ocean ridge basalt, continental margin, Ceno-zoic volcanic rock, Rare Earth Element (REE)