| 湖南中生代陆内构造变形的深部过程：煌斑岩地球化学示踪 |
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| 关键词:extension lamprophyre geochemical characteristics Hunan province |
| 基金项目:中国科学院知识创新工程项目(KZCX2102)，国家自然科学基金(40272092)，湖南省重点项目(2001) |
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| The Deep Process of the Mesozoic Intracontinental Tectonic Deformation in Hunan: Geochemical Tracer from the Lamprophyres |
| The Anhua-Xupu lamprophyre studied here was formed about 207 Ma or 172 Ma ago. It is characterized by high K 2O/Na 2O ratio (0.84～1.72), high K 2O+Na 2O content (>4.33%～6.41%),low TiO 2 content (0.54%～1.21%), high and variable Al 2O 3 content,strong enrichment of LILE and LREE, and distinct depletion of such HFSE as Nb, Ta and Ti. The isotopic components of the rock are of high 87Sr/ 86Sr and low 143Nd/ 144Nd ratio.The Sr-Nd isotope variation implies that the lamprophyre magma is derived mainly from an EMII metasomatic mantle source with low Nb/Th, La/Yb and Rb/Ba and high Ba/Nb ratios. The source is related to metasomatism of the lithosphere mantle with fluid released from the ancient subducted oceanic crust. The data of chemical elements and isotope geochemistry and an analysis of geological history indicate that the lamprophyre resulted from asthenosphere upwelling and the tectonic deformation in Hunan went into the crust extension-thinning stage in Triassic. |
| LIANG Xin-quan,FAN Wei-ming,WANG Yue-jun.2003.The Deep Process of the Mesozoic Intracontinental Tectonic Deformation in Hunan: Geochemical Tracer from the Lamprophyres[J].Acta Geoscientica Sinica,24(6):603-610. |
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