中文摘要：

对辽西北票地区的大比例尺（1∶1000）地质填图工作表明,该地出露的＂兴隆沟组＂不是单斜地层,而是经历了强烈变形的地质体,有小岩株侵入其中。因此,根据地质产状,结合岩性、成岩年龄和岩石地球化学元素特征,北票地区兴隆沟火成岩可以分为两大套：第一套为144Ma的高镁英安质岩株,第二套为变形的中侏罗世火山岩。第一套火成岩具有低钾（K2O〈2%）、高镁（Mg#〉60）、高钙（CaO〉5%）、低Rb、高Sr/Y值（〉60）的特点,其中相当部分的岩石具高Cs低Li特征。第二套火山岩已强烈变形,具有高钾（K2O〉2%）、低镁（Mg#〈60）、低钙（多数CaO〈4%）、相对高Rb、相对低Sr/Y值（多数〈60）和低Cs高Li的特征。第一套高镁英安岩是典型的埃达克岩①,是基性下地壳部分熔融物与地幔反应的结果,其形成可能与兴蒙造山带陆壳俯冲或拆沉有关。第二套高钾钙碱性火山岩的形成则与下地壳拆沉作用无关,可能属于来自兴蒙造山带南部的远距离推覆岩片。

英文摘要：

The large scale（1∶1000）field mapping in the Beipiao area,western Liaoning Province shows that,the ＂Xinglonggou Formation＂ exposed in here is not a monoclinic stratum,but a suit of strongly deformed volcanic rocks,and intruded by some small stocks.Consequently,two kinds of igneous rocks are identified in the ＂Xinglonggou Formation＂ exposed in the Beipiao area,based on the field occurrence,lithology,crystallization age and geochemical characteristics of these rocks.The 144 Ma high-magnesium dacitic plugs belong to the first group,and they intrude into the deformed Mid-Jurassic volcanic rocks.The first group igneous rocks exhibit characteristics of low potassium（K2O 2%）,high magnesium（Mg# 60）and calcium（CaO 5%）content,low Rb content,but high Sr/Y ratio（ 60）.Among these rocks,most of them have high Cs but low Li content.The second group igneous rocks are volcanic rock and have been strongly deformed.Compared with the rocks of first group,they have high potassium（K2O 2%）and Rb content,but low magnesium（Mg# 60）and calcium（most samples CaO 4%）content;meanwhile,they have lower Sr/Y ratios（in general 60）,and low Cs and high Li contents.The first group high-Mg dacites are typical adakite.They might result from partial melting of the mafic lower crust of Xing＇an-Mongolian orogenic belt,and assimilated with mantle peridotite during ascending.The partial melting might be related to the subduction of Xing＇an-Mongolian orogenic belt beneath North China Craton,or to the delamination of thickened lower crust of Xing＇an-Mongolian orogenic belt,but not to the delamination of thickened lower crust of North China Craton.The second group belongs to high-potassium calc-alkaline volcanic rocks,and may not be related to the delamination of lower continental crust,and this suit may belong to a long-traveled south-vergent thrusting sheet from the southern segment of Xing＇an-Mongolian orogenic belt.