河北涿鹿县口前燕山期中酸性和酸性岩浆岩的岩石学特征及其成因

PETROLOGICAL CHARACTERISTICS AND PETROGENESIS OFINTERMEDIATE - ACIDIC ROCKS OF YANSHAN PERIODIN KOUQIAN, ZHUOLU COUNTY, HEBEI PROVINCE

涿鹿县口前一带燕山期中酸性、酸性岩浆侵入作用和喷出作用发育.在1:5万区域地质调查的基础上,对口前一带的侵入岩、喷出岩进行了较为详细的岩相学、岩石化学、地球化学和矿物化学研究,认为口前酸性侵入岩、喷出岩与中酸性侵入岩具有不同的岩石学特征.据协变图谱法判别岩石成因,中粒二长花岗岩、似斑状二长花岗岩和火山岩分别由源岩经过约73%、31%、9%的批式熔融作用形成,而中酸性侵入岩岩浆由分离结晶作用形成,该作用受控于岩浆中斜长石、角闪石的结晶分离.

Invasion and volcanism of intermediate-acidic magma were common in Yanshan Period in the region of Kouqian of Zhuolu County. The characteristics of petrography, petrochemistry and mineral chemistry of the magmatic rocks in this region have been discussed on the basis of regional geological survey. It is suggested that characteristics of petrology of acidic intruded rocks and volcanic rocks are different from that of intermediate intruded ones. It is indicated that the former rocks were formed by partial melting and the medium-grained monzonitic granite, porphyritic monzonitic granite and the volcanic rocks in kouqian were respectively formed by about 73%, 31% and 9% melting of the source rocks. It is also shown that the neutral intruded rocks were formed by the fractional crystallization, controlled by the crystallization and fraction of plagioclase and hornblende.