中酸性侵入岩氧化钾平面分布规律及其与地壳厚度的关系

K_2O SPATIAL DISTRIBUTION OF MESOZOIC INTRUSIVE MAGMATIC ROCKS AND ITS CORRELATION WITH THE CRUST DEPTH

燕山地区中生代陆内造山作用强烈，形成数百个中生代中酸性侵入体。本区侵入岩（ｗｓｉｏ２为６０％～７６％）的氧化钾分布具有南北分区、东西分带的特征。燕山北区中酸性侵入岩Ｋ２Ｏ含量普遍较高，平均为５．０％，而燕山南区中酸性侵入岩Ｋ２Ｏ含量平均为４．０％。统计分析表明，燕山陆内造山带中生代中酸性侵入岩氧化钾与地壳厚度呈线性相关，相关直线方程为ｗｋ２０＝０．３７４十０．１０１Ｈ；地壳厚度是决定燕山地区中生代侵入岩氧化钾空间分布的主要因素，与板块边缘岛弧带火山岩氧化钾空间分布的主要制约因素明显不同。

Widely distributed Mesozoic innercontinental orogeny has caused the intrusion of several hundreds of magmatic bodies in Yanshan Area where the K2O content of Mesozoic in trusive magmatic rocks decreases gradually from the north to the south and from the west to the east.K2O content of Mesozoic intrusive magmatic rocks in Yanshan innercontinental orogeny is correlated statistically with crust depth( H), with a statistic linear equation wk2o=0. 374+0.101 H, which is different from that of island irc volcanoes in plate margines. This equation provides quantitative information for sttldying palaeostructures of mantle-crust border surface in continental Yenshan Area.