胶州大西庄晚中生代玄武岩中单斜辉石巨晶  

Clinopyroxene Megacrysts in the Late Mesozoic Basalts from Daxizhuang,Jiaozhou

作　　者：闫峻[1] 陈江峰[2] 

机构地区：[1]安徽理工大学资源与环境工程系,安徽淮南232001 [2]中国科学技术大学地球与空间科学学院,安徽合肥230026

出　　处：《安徽理工大学学报（自然科学版）》2005年第3期9-13,20,共6页Journal of Anhui University of Science and Technology:Natural Science

基　　金：安徽理工大学博士基金资助项目(2003YB02)

摘　　要：胶州大西庄晚白垩世碱性玄武岩中发现有单斜辉石巨晶,其矿物化学成分较为均一,S iO2含量在46.2%~47.6%之间,A l2O3为8.4%~9.0%,M gO为12.8%~14.6%,CaO为16.9%~17.5%,M g#值在72~76之间。除了S iO2含量稍低以外,和中国东部新生代玄武岩中单斜辉石巨晶化学成分的变化范围内一致。W o值【45%,属于为铝普通辉石。辉石巨晶的KD(Fe-M g)值为0.2~0.4,和碱性玄武岩浆平衡,平衡温压分别为1 396~1 422℃和2.4~2.6 GPa,表明其是寄主岩浆在高压下结晶的产物。大西庄单斜辉石巨晶和中国东部中新生代玄武岩中单斜辉石巨晶成分及成因上的相似性,揭示了该地区晚白垩世至新生代处于一致的动力学背景。The clinopyroxene megacrysts are discovered in the Late Mesozoic basalts from Daxizhuang in Jiaozhou.The clinopyroxene megacrysts show uniform chemical components,with SiO_2 contents from 46.2% to 47.6%,Al_2O_3 from 8.4% to 9.0%,MgO from 12.8% to 14.6%,CaO from 16.9% to 17.5% and Mg~# values from 72 to 76.The chemical components of clinopyroxene megacrysts from Daxizhuang varies in the range of that of clinopyroxene megacrysts hosted in Cenozoic basalts from the Eastern China,apart from little lower SiO_2 contents.Its Wo values are less than 45% and belong to Al-augite.The K_D(Fe-Mg) values(0.2～0.4) and equilibrium temperatures and pressures(T=1 396～1 422 ℃,P=2.4～2.6 GPa) of clinopyroxene megacrysts from Daxizhuang indicate that they were crystallized from hosted basaltic magma under high pressure.The compositional and original comparability between the clinopyroxene metacrysts host in Late Cretaceous basalts from Daxizhuang and Cenozoic basalts from Eastern China respectively suggest that Jiaozhou area were under the uniform dynamic setting from Late Cretaceous to Cenozoic.

关 键 词：单斜辉石 巨晶 玄武岩 晚白垩世 胶州 

分 类 号：P578[天文地球—矿物学]