辽宁中西部中新生代火山岩的稀土元素测定、分布模式及其构造意义

REE DETERMINATION AND REE DISTRIBUTION PATTERNS OF MESO-CENOZO1C VOLCANIC ROCKS IN CENTRAL-WESTERN LIAONING PROVINCE AND THEIR GEOTECTON1C IMPLICATIONS

随着新全球构造学说的不断深入研究，稀土元素(REE)的分布模式对确定消减带或板内火山岩的成因模式有着重要作用。特别是在造岩元素由于造山作用时期或后期变化而带来不确定性时，REE的分布模式、特点对恢复和研究火山岩的起源及岩浆的演化过程是十分有意义的。对辽宁中西部中新生代火山岩系按喷发旋回的顺序进行系统的同位素年龄和REE分量的测定，对了解火山岩带的大地构造性质也是很有意义的。

The BEE distribution patterns of Meso-Cenozoic volcanic rocks in the central-wes-tern Liaoning Province are characterized by high LREE/HREE ratio. The REE distri-bution patterns in volcanic rocks ranging from early Jurassic to early Tertiary in this area are essentially the same.A comparison of (La/Yb)N and (Ce/Yb)N ratios in the studied rocks with those in ocean-crustal basalts shows that the former rocks possess the characteristic values for rift-type rocks.The REE distribution patterns in these volcanic rocks provide further evidence of the rift-type geotectonic environment in this area.