PETROGENESIS OF CENOZOIC VOLCANIC-ROCKS IN TENGCHONG REGION OF WESTERN YUNNAN PROVINCE, CHINA

The Tengchong Cenozoic volcanic racks belong to the high-K calc-alkaline rock series. They are strongly depleted in high field strength (HFS) elements and enriched in large-ion lithophile (LIL) elements and LREE. The generation of Tengchong volcanic rocks has been considered to be related to the evolution of the Neo-Tethys. The Indian Plate was subducted beneath the southeastern Asia continent, which resulted in the formation of Indo-Burman Arc in the Late Cretaceous-Palaeocene time. The collision between the Indian continent and Indo-Burman Arc started in Eocene and lasted to the present. The Andaman Sea and the Inner Burman Tertiary Basin are a back-arc basin that has been extended since the Late Miocene. A distinct characteristic of Tengchong volcanics is that they show a chemical affinity related to island arc but their generation postdated the subduction of the ocean plate.