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28 samples of Cenozoic volcanic rocks collected from Shandong Province have been datedby K-Ar method. They are mainly Neogene with an age range of 4-19 m. y. The basalts fromLinqu and Yishui in west Shandong Province are Miocene and those from Penglai and Qixiain east Shandong Province are Miocene and Pliocene in age. The basalts from Wudi in northShandong Province are Middle-Early Pleistocene in age. In each area the duration of volcaniceruption was estimated at about 2-3 m. y. Pb and Sr isotopic compositions and U, Th, Pb, Rb, Sr, and major elements in most ofthe samples were determined. The isotopic compositions are: ~(206)Pb/~(204)Pb——16.92-18.48.~(207)Pb/~(204)Pb——15.30-15.59,~(208)Pb/~(204)Pb——37.83-38.54, and (~(87)Sr/~(86)Sr)_i——0.70327-0.70632.There are some positive or negative linear correlations between ~(206)Pb/~(204)Pb and ~(207)Pb/~(204)Pb,Ph isotopes and Pb content, Pb isotopes and Sr isotopes, and Sr isotopes and other elements.The basaltic rocks from east and west Shandong Province have somewhat differences inisotopic composition and element content. The basalts probably are products of multi-stageevolution of the mantle. They have preserved the primary features of the source, althoughthey were influenced, to some extent, by the contamination of crustal materials.
They are mainly Neogene with an age range of 4-19 my The basalts from Linqu and Yishui in west Shandong Province are Miocene and those from Penglai and Qixiain east Shandong Province are Miocene and Pliocene in age. The basalts from Wudi in northShandong Province are Middle-Early Pleistocene in age. In each area the duration of volcaniceruption was estimated at about 2-3 my Pb and Sr isotopic compositions and U, Th, Pb, Rb, Sr, and major elements in most of the samples were determined. The isotopic compositions are: (206) Pb / ~ (204) Pb - 16.92-18.48 ~ 207 Pb / 204 Pb - 15.30 -15.59, ~ (208) Pb / ~ (204) Pb-37.83-38.54, and ~ (87) Sr / ~ (86) Sr) _i ~ 0.70327-0.70632.There are some positive or negative linear correlations between ~ (206) Pb / ~ (204) Pb and ~ (207) Pb / ~ (204) Pb, Ph isotopes and Pb content, Pb isotopes and Sr isotopes, and Sr isotopes and other elements. ast and west Shandong Province have somewhat differences inisotopic composition and element content. The basalts probably are products the multi-stage evolution of the mantle. They have preserved the primary features of the source, althoughthey were influenced, to some extent, by the contamination of crustal materials.