College of Geography and Planning��Ludong University��Yantai 264025��Shandong��China

Being influenced by the faults��Penglai basalts were mainly centralized at the north of Penglai are- a��distributing as NE to NNE trend�� Volcanic activities are divided into four stages: the nearly EW basement tec- tonic formation of Precambrian; the development of NE-NNE fault structure in Mesozoic; the mantle plume intense upwelling at Late Mesozoic��and the end phase of volcanic activity in Cenozoic�� The basalt eruption was mainly fo- cused on the Cenozoic��and the lithologics were primarily as vesicular basalt��picrite-porphyrite and augite perido- tite�� The analysis of constant elements indicated that the elements of Penglai basalt were different from the average elements of basalt of world in lower contents of Al2O3��CaO and MnO and higher contents of K2O��MgO and Na2O; while compared with Chinese basalt��in lower contents of Al2O3��K2O and Na2O and higher content of CaO��P2O5 and MgO�� The analysis of microelement indicated that Penglai basalt had the typical rightward rare earth element distribution patterns of the continental basalt with moderately abnormal negative europium�� There were two mantle metasomatism processes in Penglai area in the Cambrian and in the Late Mesozoic to Cenozoic��