CAJ | 학술논문

老河沟岩体和筛子岩岩体位于碧口地块西南部.岩体的SiO2(69.89%～71.69%)和Al2O3(15.01%～16.25%)含量均很高,A/CNK在1.04～1.12之间,为硅和铝过饱和类型,属典型的强过铝质花岗岩.稀土元素总量(∑REE)为33.13×10~(-6)～150.42×10~(-6),稀土元素配分曲线呈右倾型,具有弱的负铕异常.高场强元素(Ta、Nb、Ti等)具有明显的负异常,大离子亲石元素(Rb、Ba、Sr等)具有明显的正异常.岩体可能是以杂砂岩成分为主的沉积岩部分熔融形成的花岗质岩浆上升侵位过程中形成的,是一种典型的壳源成因类型.老河沟岩体和筛子岩岩体具有后碰撞岩浆活动的特征,是印支期华北和扬子地块碰撞导致地壳加厚环境下下地壳部分熔融的产物,形成于同碰撞(挤压环境)向碰撞后(伸展环境)转化阶段,为后造山花岗岩类.
로하구암체화사자암암체위우벽구지괴서남부.암체적SiO2(69.89%～71.69%)화Al2O3(15.01%～16.25%)함량균흔고,A/CNK재1.04～1.12지간,위규화려과포화류형,속전형적강과려질화강암.희토원소총량(∑REE)위33.13×10~(-6)～150.42×10~(-6),희토원소배분곡선정우경형,구유약적부유이상.고장강원소(Ta、Nb、Ti등)구유명현적부이상,대리자친석원소(Rb、Ba、Sr등)구유명현적정이상.암체가능시이잡사암성분위주적침적암부분용융형성적화강질암장상승침위과정중형성적,시일충전형적각원성인류형.로하구암체화사자암암체구유후팽당암장활동적특정,시인지기화북화양자지괴팽당도치지각가후배경하하지각부분용융적산물,형성우동팽당(제압배경)향팽당후(신전배경)전화계단,위후조산화강암류.
The Louhegou granite and the Shaiziyan granite,located in southern margin of Bikou block. The data of occurrence,petrography and geochemical are reported,the source and tectonic setting of the granite are discussed in this paper. The results show that the Louhegou granite and the Shaiziyan granite have high SiO_2(69.89%～71.69%),and Al2O3 composition, A/CNK=1.04～1.12. It is a type with supersaturation of Al and Si,a typical strongly peraluminous granites. The ∑REE has the range of 33.13×10~(-6)～150.42×10~(-6), REE diagram shows rightward incline and obvious Eu negative abnormity. The trace elements geochemistry was characterized by evidently negative anomaly of Ta,Nb,Ti,etc positive anomaly of Rb, Ba,Sr. The Louhegou granite and the Shaiziyan granite show post-collisional granitic characteristics. These rocks are post-orogenic granite,and are typical crust source petrogenesis. These granites mass are interpreted as a kind of syn-collisional granites resulted from the crustal thickening caused by the collision between the North China massif and Yangtze massif during the Indosinian. These rocks were transitional environment of compressional orogeny and extensional structure.