摘要
和林格尔玄武岩位于鄂尔多斯盆地东北缘,为华北克拉通西部新生代玄武岩的重要组成部分。通过对和林格尔玄武岩地球化学特征进行研究,可以解释其成因及岩浆起源问题。主量元素分析表明,和林格尔玄武岩为拉斑玄武岩,经历了橄榄石、辉石的分离结晶作用。稀土元素含量在98.7×10^(-6)~117.82×10^(-6),轻重稀土元素存在一定分异,轻稀土富集、重稀土亏损,具洋岛玄武岩(OIB)类似微量元素特征。和林格尔玄武岩主要起源于上涌软流圈地幔的部分熔融,并存在亏损软流圈与富集岩石圈地幔相互作用,没有或很少受到地壳物质混染,形成时对应的岩石圈厚度小于72 km。研究表明,在裂谷拉张环境下岩石圈地幔发生减薄,软流圈开始部分熔融形成研究区广泛分布的新生代玄武岩。
The Helinger basalts,located in the northeastern margin of Ordos Basin,are an important part of Cenozoic basalts in the western part of the North China Craton.By studying the geochemical characteristics of Helinger basalts,we can explain its genesis and origin of parent magma.The analysis of major elements indicates that the Hellinger basalts are tholeiitic basalts,which have undergone the separation and crystallization of olivine and pyroxene.The content of rare earth elements is 98.7×10^(-6)~117.82^(-6),and the light rare earth elements are enriched,while the heavy rare earth elements are depleted,which has similar characteristics of trace elements of ocean island basalt(OIB).Helinger basalts are mainly derived from the partial melting of the upwelling asthenosphere mantle,and there is interaction between the depleted asthenosphere and the enriched lithospheric mantle.There is no or little contamination by crustal materials,and the corresponding lithospheric thickness is less than 73 km when the basalts are formed.The results show that the lithospheric mantle thinned and the asthenosphere partially melted under the rift extension environment,forming Cenozoic basalts widely distributed in the study area.
作者
刘静静
崔军平
祁凯
陶华
成科璋
刘昊
Liu Jingjing;Cui Junping;Qi Kai;Tao Hua;Cheng Kezhang;Liu Hao(Department of Geology,Northwest University,Xi′an,Shaanxi,710069,China;State Key Laboratory of Continental Dynamics,Northwest University,Xi′an,Shaanxi,710069,China)
出处
《新疆地质》
CAS
CSCD
2023年第3期321-330,共10页
Xinjiang Geology
