ALKALI-RICH INTRUSIVE ROCKS IN THE QINGHAI-XIZANG PLATEAU AND ITS VICINITIES AS EXEMPLIFIED BY KUGANZI AND TAIHE PLUTONS

The alkali-rich intrusive rocks in the Qinghai-Xizang Plateau can be d ivided into two series in terms of dark-colored rock-forming minerals, petrochemical composition and trace elements: i) sodic alkaline serie s rocks consisting of alkaline rocks and alkali granite which contain dark-colored minerals, such as aeginine augite, aegirine and riebeckit e, and being petrochemically enriched in alkali and sodium but low in Ca, Sr and Ba; ii) potassic alkaline series rocks consisting of alkali ne rocks and alkali granite which contain non-alkaline dark-colored mi nerals (diopside, edenite), and being petrochemically enriched in alka li, K and Ca with high abundances of Sr and Ba.