The environmental index of the rare earth elements in conodonts:Evidence from the Ordovician conodonts of the Huanghuachang Section,Yichang area  

作　　者：CHEN XiaoHong ZHOU Lian WEI Kai WANG Jin LI ZhiHong 

机构地区：[1]Wuhan Institute of Geology and Mineral Resources,Wuhan 430223,China [2]Geological Processes and Mineral Resources,State Key Laboratory of China University of Geosciences,Wuhan 430074,China

出　　处：《Chinese Science Bulletin》2012年第4期349-359,共11页

基　　金：supported by China Geological Survey(1212011121103 and 1212010710715);the National Natural Science Foundation of China(40972003 and 40673020)

摘　　要：High-resolution microanalysis was performed on conodonts collected from the Huanghuachang section in the Yichang area using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). This region is regarded as a standard section for the division and correlation of the Ordovician system in southern China. The results show that the values of (La/Yb)N and (La/Sm)N decrease, while the values of δCe increase as seawater deepens and energy decreases. As the sedimentary environment changes from shallow-water carbonate platform to platform margin to open continental shelf to shelf basin, rare earth element distribution curves gradually transform from a right inclined pattern to a flat pattern to a left inclined pattern and a hat-shaped pattern. The present work proves that the values and distributive patterns of rare earth elements in conodonts correspond with the sedimentary environment, and therefore provide reliable evidence for the application of rare earth element concentrations of biogenic phosphates such as conodonts for palaeoenvironmental reconstructions.High-resolution microanalysis was performed on conodonts collected from the Huanghuachang section in the Yichang area using laser ablation inductively coupled plasma mass spectrometry （LA-ICP-MS）. This region is regarded as a standard section for the division and correlation of the Ordovician system in southern China. The results show that the values of （La/Yb）N and （La/Sm）N decrease, while the values of 8Ce increase as seawater deepens and energy decreases. As the sedimentary environment changes from shallow-water carbonate platform to platform margin to open continental shelf to shelf basin, rare earth element distribution curves gradually transform from a right inclined pattern to a flat pattern to a left inclined pattern and a hat-shaped pattern. The present work proves that the values and distributive patterns of rare earth elements in conodonts correspond with the sedimentary environment, and therefore provide reliable evidence for the application of rare earth element concentrations of biogenic phosphates such as conodonts for palaeoenvironmental reconstructions.

关 键 词：稀土元素 宜昌地区 牙形石 奥陶系 环境指标 LA-ICP-MS 证据 黄花 

分 类 号：P618.130.2[天文地球—矿床学] O614.33[天文地球—地质学]