华北地台北缘几个超基性岩带的侵位年代及其演化  

EMPLACEMENT AGES AND EVOLUTION OF SEVERAL ULT- RABASIC ROCK BELTS ON THE NORTHERN MARGIN OF THE NORTH CHINA PLATFORM

作　　者：陈森煌 刘道荣[1] 包志伟[1] 朱乃娟 毛存孝[2] 朱炳泉[2] 

机构地区：[1]冶金部天津地质研究院,天津300061 [2]中国科学院地球化学研究所广州分部,510640

出　　处：《地球化学》1991年第2期128-133,共6页Geochimica

基　　金：国家自然科学基金(4870186)

摘　　要：通过华北地台北缘两侧超基性岩带Sm-Nd同位素等时线测定,首次获得位于燕山南岩带的放马峪岩体为2010±155Ma,属于燕山中岩带的罗匠沟岩体为881±29Ma,属于西拉木伦岩带的柯单山岩体为665±46Ma。华北地台北缘内外两侧超基性岩带(体)侵位由老到新的演化关系,与该区构造演化关系是一致的。Three EW-extending ultrabasic rock belts occur along the northern margin of the North China Platform, i.e., the Yanshan South Belt, the Yanshan Middle Belt and the Xilamulun Ophiolite Belt in going from south to north, respectively.The emplacement ages of the ultrabasic massives have been determined by the Sm-Nd method and the whole-rock Sm-Nd isotopic isochron ages are 2010 + 155 Ma (Fangmayu massif, Yanshan South Belt), 881±29Ma (Luojianggou massif, Yanshan Middle Belt) and 665±46 Ma(Kedanshan massif, Xilamulun Ophiolite Belt). Chronology data for the ultrabasic massives indicate that the emplacement evolution of the three ultrabasic rock belts shows a trend of becoming younger from south to north, in consistence with the evolution of geotectonics there.Samples from the three ultrabasic massives were dated at (143Nd/144Nd)0 = 0.510004, 0.511506 and 0.511726, with εNdt=-0.25, 0 and -0.95, respectively, demonstrating that the magma was derived from the upper mantle.

关 键 词：地台 超基性岩 华北 侵位年代 演化 

分 类 号：P588.125[天文地球—岩石学]