The early tertiary alkali basalts from yangyuan which contain abundant mantle xenoliths exhibit very homogeneous sr - nd isotopes with snd = 5 . 5 . their pb isotopes are similar to those of the depleted mantle ( dm ) and their trace element characteristics resemble those of oceanic island basalts ( oib ) 含幔源包体的阳原早第三纪碱性玄武岩具有均一的sr - nd同位素组成( nd 5 . 5 ) ，其pb同位素组成与亏损地幔( dm )相似。
