承德三岔口基性岩墙地球化学特征及地质意义
Geochemistry and Petrogenesis of the Sanchakou Maifc Dyke in Chengde,Hebei Province, China

杨毓红 ¹ 刘燊 ² ^* 胡瑞忠 ¹ 冯彩霞 ² 冯光英 ¹ 杨朝贵 ¹ 齐有强 ¹

文摘	对承德三岔口基性岩墙进行了锆石LA-ICP-MS U-Pb年代学和岩石地球化学研究。定年结果表明岩墙属晚印支期(222.1±1.6) Ma岩浆活动的产物;地球化学特征显示岩墙具有拉斑玄武岩特征,轻稀土(LREE)和大离子亲石元素(LILE)相对富集岩墙,亏损Nb、Ta和Ti等。同位素组成特征显示,岩墙具有正的初始Sr比值和负的ε_(Nd) (t)值。以上特征都暗示三岔口基性岩墙可能来源于富集的岩石圈地幔。根据年代学、地球化学和前期研究成果认为,与三岔口基性岩墙同期位于华北北缘的东西向侵入岩带,可能是华北克拉通减薄的最初表现。
其他语种文摘	Zircon LA-ICP-MS U-Pb dating and geochemical analysis have been carried on the mafic dyke from Sanchakou area,Hebei Province. The isotopic dating results indicate mafic dykes, with the age of (222.1 ± 1.6) Ma, were resulted from the Late Indosinian magmatism. Geochemical characteristics indicate they belong to tholeiite basalt, rich in LREE and LILE, as well as obviously depleted in Nb, Ta and Ti. Moreover, Sr-Nd isotopic composition means that the mafic dyke has high initial ~(87)Sr/~(86)Sr ratios and negative ε_(Nd) (t) (from-9.3 to -6.1). As it mentioned above, it’s implied that the studied mafic dyke was derived from enriched lithospheric mantle. The Chronology, geochemisty and previous studies suggest that the Early Mesozoic intrusion zone coexistent with mafic dykes in Sanchakou area, in northern North China block, might be formed in the early period of lithospheric thinning.
来源	吉林大学学报. 地球科学版 ,2012,42(6):1796-1806 【核心库】
关键词	锆石U-Pb年龄 ; 地球化学 ; Sr-Nd同位素 ; 基性岩墙 ; 岩石成因 ; 承德
地址	1. 中国科学院地球化学研究所, 矿床地球化学国家重点实验室, 贵阳, 550002 2. 西北大学地质学系, 大陆动力学国家重点实验室, 西安, 710069
语种	中文
ISSN	1671-5888
学科	地质学
基金	国家自然科学基金项目 ; 西北大学大陆动力学国家重点实验室基金
文献收藏号	CSCD:4731770