摘要
采集了皖北新元古代沟后组和寒武纪猴家山组石灰岩,进行系统的岩石学和稀土地球化学分析,研究了灰岩中稀土的来源及其特征,并据此对灰岩形成的海水稀土配分模式进行反演,探讨了皖北新元古代-寒武纪大地构造背景。结果表明:沟后组石灰岩稀土元素总量较高(10.66～30.68 ppm),轻重稀土分异明显,轻稀土富集,NdSN/YbSN在1.12～1.46之间,受陆源碎屑混染影响严重;猴家山组石灰岩稀土总量偏低(1.63～7.79 ppm),轻重稀土分异微弱,轻稀土略亏损,LaSN/NdSN在0.35～1.28,受陆源影响较小;石灰岩样品均具有程度不同的La正异常、Ce负异常和Y正异常;猴家山组灰岩反演海水稀土特征与新元古代海水略有差异,与现代海水稀土组成特征一致;沟后组和猴家山组石灰岩分别形成于大陆岛弧和大洋岛弧环境。
The analysis of petrological and rare earth elemental（REE） had been carried out for the limestone collected from the Neoproterozoic（Gouhou Formation） and Cambrian（Houjiashan Formation） in northern Anhui province,and the origin of REE and its characteristics in limestone had been studied.The rare earth elemental distribution patterns of seawater which precipitated limestone and tectonic background in Neoproterozoic-Cambrian also discussed respectively.The results showed that the REE in limestone from Gouhou Formation were characterized by the more high total REE（10.66~30.68 ppm）,the LREE（light REE） enrichment with the NdSN/YbSN ranging from 1.12 to 1.46,intensive fractionation between LREE and HREE（high REE） and serious effect with terrestrial materials;the characteristics of REE in limestone from Houjiashan Formation included the lower total REE（1.63~7.79 ppm）,light LREE depletion（NdSN/YbSN=1.12~1.46）,light fractionation between LREE and HREE and the slight contamination of clastic.All limestone samples showed various degrees in negative Ce anomaly,positive La and Y anomaly.The REE characteristics of inversed seawater from Houjiashan limestone conformed to the modern seawater,with slight difference from the seawater in Neoproterozoic.The limestone from Gouhou Formation and Houjiashan Formation were deposited in the continental and oceanic island arc,respectively.
出处
《中国稀土学报》
CAS
CSCD
北大核心
2013年第1期108-118,共11页
Journal of the Chinese Society of Rare Earths
基金
国家自然科学基金(41173106)
安徽省教育厅自然科学项目(KJ2011B177)
宿州学院科研平台开放课题(2011YKF22)资助
关键词
新元古代
寒武纪
石灰岩
稀土元素
皖北
neoproterozoic
cambrian
limestone
rare earth element
northern Anhui Province
