Ladinian radiolarian fauna, siliceous rock from the Xianshuihe Belt, West Sichuan and their tectonic significance

Ladinian radiolarian fauna, including Muelleritortis, Baumgartneria, Oertlispongus,Paroertlispongus, Pseudoertlispongus, etc., was discovered from the siliceous rock of the Runiange Formation in the Xianshuihe belt, West Sichuan Province. Geochemical test on five samples from the siliceous rock indicates that SiO2 content varies in 71.16%-90.06% and Si/Al ratio, in 49-71, which shows that the siliceous rock contains more terrigenous mud sediments.The siliceous rock is characterized by the large ratios of Al203/(Al203+Fe203) (0.63-0.81) and TiN (>26), the low ratio of V/Y (<2.8), and low vanadium content (<23 μg/g), which are similar to the geochemical characteristics of continental margin siliceous rock. The Ce/Ce* ratios of the four samples vary in 1.02-1.47 and the LaN/CeN ratio, in 0.75-1.07, which imply that the siliceous rock was deposited in the continental margin basin. But only one sample is similar to the oceanic siliceous rock in REE. Turbidite-siliceous rock bearing radiolarian-basalt assemblage and the geochemical characteristics of the siliceous rock indicate that the Xianshuihe belt is in the strong rift stage in the Ladinian age.

作 者： LIANG Bin FENG Qinglai WANG Quanwei GUO Jianqiu ZHONG Changhong Li Zhenjiang   作者單位： LIANG Bin,FENG Qinglai,GUO Jianqiu(Faculty of Earth Science, China University of Geosciences, Wuhan 430074, Chinaa)

WANG Quanwei,ZHONG Changhong,Li Zhenjiang(Sichuan Geological Survey, Chengdu 610000, China) 

刊 名： 中國科學(xué)D輯（英文版）  SCI 英文刊名： SCIENCE IN CHINA (EARTH SCIENCES)  年，卷(期)： 2005 48(1)  分類號： P5  關(guān)鍵詞： siliceous rock   radiolarians   Triassic   the Xianshuihe belt   West Sichuan  

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