| 辽西义县组早期火山事件层地球化学特征及意义 |
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| 引用本文： | 王铁晖,巩恩普,陈晓红,许江,黄文韬.辽西义县组早期火山事件层地球化学特征及意义[J].世界地质,2018,37(2):466-477. |
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| 作者姓名： | 王铁晖 巩恩普 陈晓红 许江 黄文韬 |
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| 作者单位： | 1. 东北大学 资源与土木工程学院, 沈阳 110819;2. 东北大学 秦皇岛分校, 河北 秦皇岛 066004 |
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| 基金项目： | 国家自然科学基金资助项目（41172003）；国家重点基础研究发展规划（973计划）项目（2012CB821905）；中央高校基本科研业务费专项资金资助项目（N120601001）联合资助. |
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| 摘 要： | 义县盆地早白垩世义县组为一套火山-沉积岩系,沉积层中多含凝灰质成分。为了解沉积期火山活动对沉积层产生的影响,对砖城子层火山碎屑泥灰岩(火山事件层)和纹层状泥灰岩夹层、大康堡层纹层状泥灰岩进行岩石学和地球化学的研究。研究表明:火山事件层中含大量的火山碎屑(20%±),其他各层均含凝灰质成份。样品中主量元素Ca O、Mg O和Si O_2含量较高,Si O_2含量变化较大,Al_2O_3含量较低;微量元素与上地壳(UCC)元素比值多小于1,大多数微量元素(Rb、Th、Nb、REE等)处于亏损状态,火山事件层富集Li、Sc、As、Sr和Ag元素。沉积期火山活动对沉积层中Si O_2和K_2O含量影响较大,并可能导致As元素富集。火山事件层样品化学风化指数(CIW)在82~91之间,呈逐渐增加的趋势,指示风化作用强烈。
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| 关 键 词： | 义县组 火山事件层 地球化学 化学风化指数(CIW) 早白垩 辽西 |
| 收稿时间： | 2017-09-19 |
| 修稿时间： | 2018-03-12 |
Geochemical characteristics and significance of volcanic event strata of early Yixian Formation,western Liaoning |
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| WANG Tie-hui,GONG En-pu,CHEN Xiao-hong,XU Jiang,HUANG Wen-tao.Geochemical characteristics and significance of volcanic event strata of early Yixian Formation,western Liaoning[J].World Geology,2018,37(2):466-477. |
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| Authors: | WANG Tie-hui GONG En-pu CHEN Xiao-hong XU Jiang HUANG Wen-tao |
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| Institution: | 1. College of Resources and Civil Engineering, Northeastern University, Shenyang 110819, China;2. Northeastern University at Qinhuangdao, Qinhuangdao 066004, Hebei China |
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| Abstract: | A series of volcanic-sedimentary rocks occurred in the Early Cretaceous Yixian Formation of Yixian Basin, of which the sedimentary rocks contain tuffaceous components. The petrology and geochemistry of the volcaniclastic marl rock (volcanic event strata), laminated marl interlayers in Zhuanchengzi layer, and laminated marl in Dakangpu layer have been studied, in order to understand the effect of volcanic activity on the sedimentary successions. The results show that large number of volcaniclastics exit in the sample of volcanic event strata (20% ±), and other layers contain tuffaceous components. The content of the major elements (e. g. CaO+MgO) is high, with great variations of SiO2. The Al2O3 values is low. The ratio of the trace elements to the upper continental crust (UCC) elements is mostly less than 1, indicating the depletion of most trace elements (e.g. Rb, Th, Nb and REE). Li,Sc,As,Sr and Ag are enriched in volcanic event strata. The volcanic activity can influence the contents of SiO2 and K2O in the sedimentary layers, and it may lead to the enrichment of As element. The chemical index of weathering (CIW) range from 82 to 91 with gradually increasing trend in volcanic event strata, indicating strong weathering. |
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| Keywords: | Yixian Formation volcanic event strata geochemistry chemical index of weathering(CIW) Early Cretaceous western Liaoning |
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