| 羌塘中部各拉丹冬一带鄂尔陇巴组火山岩特征及其构造环境 |
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| 关键词:central Qiangtang Late Triassic island arc tectonic setting |
| 基金项目:国土资源部地质调查项目(编号:2000130000135) |
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| Characteristics and Tectonic Setting of Eerlongba Formation Volcanic Rocks in Geladandong Area of Central Qiangtang |
| The Eerlongba Formation volcanic rocks in Geladandong area of central Qiangtang, consisting of the assemblage of basalt, andesite, rhyolite and tuff, are of basic-intermediate-intermediate-acid-acid series. The zircon U-Pb isotopic value is 212 Ma, suggesting Late Triassic. The main elements are characterized by low TiO 2 and high alkali (K 2O+N 2O), belonging to calc-alkalic-alkalic series. The chondrite-normalized REE patterns indicate that they are enriched in LREE. In addition, the MORB-normalized trace element patterns are characterized by the enrichment of LILE such as K, Rb, Ba and High Field Strength element of Th as well as the depletion of Ti. The average Ba/La ratio is 32.46, suggesting that the magma was formed in the island arc setting. The isotope geochemistry of Sr and Nd also supports this conclusion. Comprehensive geological, geochemical and chronological studies indicate that the volcanic rocks were formed in the Late Triassic island arc setting. |
| BAI Yun-shan,LI Li,NIU Zhi-jun,CUI Jiang-li.2005.Characteristics and Tectonic Setting of Eerlongba Formation Volcanic Rocks in Geladandong Area of Central Qiangtang[J].Acta Geoscientica Sinica,26(2):113-120. |
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