【摘要】 广东雷州半岛英峰岭火山岩中的巨晶包括石榴子石、单斜辉石、斜长石和钛铁矿。石榴子石和单斜辉石以富铁低镁为特征 ,Mg#分别为 0 .2 8～ 0 .46和 0 .47～ 0 .5 8。同时 ,石榴子石富含CaO (7.0 2 %～ 8.16 % ) ,而辉石巨晶富含Na2 O (2 .35 %～ 2 .71% )和Al2 O3(6 .97%～ 11.2 9% )。斜长石巨晶以富Na、K和低Ca为特征 ,属三元长石类的含钾更长石 (An30 .3～ 15.2 Ab64 .7～ 74 .8Or5.0～ 10 .0 ) 。石榴子石、单斜辉石、斜长石和钛铁矿巨晶各自具有明显的成分变化 ,而且相互间具有相关性 ,它们是由同一个富铁铝、贫镁钙的基性母岩浆结晶分异的结果。它们结晶于t >110 0℃和 p >1.5GPa的上地幔更多还原

【Abstract】 Megacrysts from the Yingfengling basaltic volcanic rocks in Leizhou Peninsula include garnet, clinopyroxene, plagioclase and ilmenite. Some garnets and clinopyroxenes are euhedral in form. Garnet and clinopyroxene are characterized by high FeO and low MgO, Mg\+#=0.28-0.46 and 0.47-0.58 respectively. Garnet is also rich in CaO (7.02%-8.16%), and clinopyroxene rich in Na\-2O (2.35%-2.71%) and Al\-2O\-3 (6.97%-11.29%). Plagioclase megacrysts which were found infrequently over the world are oligoclase (An\-\{30.3-15.2\}Ab\-\{64.7-74.8\}Or\-\{5.0-10.0\}) in the Yingfengling basalt. Great compositional changes are noticed in garnet, clinopyroxene, plagioclase and ilmenite, and these changes are coherent and probably result from crystallization\|differentiation. They crystallized in the upper mantle under the conditions of T>1100℃ and P>1.5 GPa. Their parental magma is the same as basaltic liquid with high FeO, Al\-2O\-3 and low MgO, K\-2O.更多还原