陕南镇巴东部地区基性岩墙群的构造意义  

Fectonic Meaning of Mafic Dyke Swarms in Zhenba Eastern Area in Shannan

作　　者：李夫杰[1] 杨骏[2] 

机构地区：[1]中铁一局集团有限公司,西安710054 [2]长安大学,西安710054

出　　处：《四川理工学院学报（自然科学版）》2011年第2期238-243,共6页Journal of Sichuan University of Science & Engineering(Natural Science Edition)

基　　金：国家自然科学基金项目(40572121;40234041);教育部科学技术研究重点项目(104175)

摘　　要：应用现代岩石地球化学分析方法,对镇巴东部地区基性岩墙群岩石地球化学特征进行系统分析,分析表明,Ta/Hf值在0.27~0.90之间,Th/Ta值在0.68~1.59之间,这与地幔柱成因的玄武岩系特征（Ta/Hf〉0.3,Th/Ta〈1.6）相符。根据分析提出早古生代期间扬子板块北缘南秦岭区发生一次重要的地幔热柱岩浆活动,也正是因为这次深部地幔热柱岩浆活动的存在才引发了该区大范围的拉张裂解。此次地幔热柱活动应该是早古生代期间整个南秦岭地区构造演化的主要深部驱动力来源,可能对晚古生代时期勉略洋盆的打开产生着重要的影响,同时对秦岭造山带古生代构造演化过程的研究也具有重要意义。Using the modern geochemistry analysis way,the article analyzes the geochemistry characteristics of Mafic Dyke Swarms,which is in Zhenba eastern area.The result shows that the numerical value of Ta/Hf is between 0.27and 0.90 and Th/Ta is between 0.68 and 1.59.This conclusion accords with the basalt characteristics,which comes into being for mantle plume.According to the conclusion,the article deduces that there is an important mantle plume magma action at the north of Yangtze plate,the south Qin Mountain during the early Paleozoic age and arouses the pull and rift valley action in big range.The article thinks that this mantle plume action should be the main deep driving power source for the whole south Qin Mountain conformation and evolvement in early Paleozoic age and may have very important effects on opening the Mianlue ocean basin in the late Paleozoic age and have important meaning on researching on Qin Mountain conformation and evolvement.

关 键 词：基性岩墙群 地慢柱 裂谷作用 北大巴山 

分 类 号：P534.46[天文地球—古生物学与地层学]