During diagenetic process , there may exist the fractional crystallization of clino - pyroxene , plagioclase , olivine and ti - fe oxide , and the accumulation of olivine . the alkalic - ultramafic dikes formed by low degree partial melting ( 3 . 4 % ) of enriched mantle , consist of single olivine pyroxenolite , the dominating olivine fractionation is evident 成因上為富集地幔部分熔融作用的結(jié)果,但在成巖過程中也可能存在單斜輝石、斜長石、橄欖石和ti - fe氧化物等礦物的分離結(jié)晶作用。