Depositional chemistry of chert during late Paleozoic from western Guangxi and its implication for t

来源 :Science China(Earth Sciences) | 被引量 : 0次 | 上传用户:t_bear
下载到本地 , 更方便阅读
声明 : 本文档内容版权归属内容提供方 , 如果您对本文有版权争议 , 可与客服联系进行内容授权或下架
论文部分内容阅读
Continual deep-water sediments from the late Early Devonian to the Late Permian extended in wide areas of western Guangxi.We analyzed the major,trace,and rare earth elements of the Upper Paleozoic cherts in Badu,western Guangxi.High non-terrigenous SiO2 contents(Sinon-ter/Sibulk(%)> 80%) and pure chert components(> 70%) indicate a large extent of silicification in the Upper Paleozoic cherts,except for the Upper Devonian-Lower Carboniferous Luzhai Formation cherts,which have lower non-terrigenous SiO2 contents(avg.71.8%) and pure chert components(40%-70%).The Al/(Al+Fe+Mn) ratios and Feter/Febulk(%) values of samples from the lowest horizon of the Pingen Formation are 0.05-0.26,13.1%-14.5%,respectively,indicating hydrothermal origins.All other samples show high Al/(Al+Fe+Mn) ratios(0.39-0.81) and high Feter/Febulk(%) values(23.1%-186.8%),indicating non-hydrothermal origins.The Pingen Formation and Liujiang Formation cherts show slightly-moderately negative Ce anomalies(0.71±0.07,0.81±0.08,respectively) and higher Y/Ho ratios(33.49±1.27,36.10±2.05,respectively) than PAAS.This suggests that these cherts were deposited in the open marine basin,rather than in the intracontinental rift basin as previously assumed.The Luzhai Formation cherts may be deposited near the seamount or seafloor plateaus with no negative Ce anomalies(1.09±0.07) and no significant Y-Ho fractionation(Y/Ho=28.60±1.25).The Nandan Formation and Sidazhai Formation cherts were deposited in the open-ocean basin with moderately negative Ce anomalies(0.67±0.08,0.73±0.11,respectively) and high Y/Ho ratios(36.01±1.00,32.00±2.25,respectively).On the basis of our studies about cherts,we conclude that the Youjiang Basin originated as part of the Paleo-Tethys that controlled the depositional environments of cherts during late Paleozoic.The rift of the Youjiang Basin had occurred at least since the Early-Middle Devonian.The basin had a trend of evolving into an open-ocean basin during the Early-Middle Permian. Continual deep-water sediments from the late Early Devonian to the Late Permian extended in wide areas of western Guangxi.We analyzed the major, trace, and rare earth elements of the Upper Paleozoic cherts in Badu, western Guangxi. High non-terrigenous SiO2 contents (> 80% of Sinon-ter / Sibulk (%)) and pure chert components (> 70%) indicate a large extent of silicification in the Upper Paleozoic cherts, except for the Upper Devonian-Lower Carboniferous Luzhai Formation cherts, which has lower non-non The Al / (Al + Fe + Mn) ratios and Feter / Febulk (%) values ​​of samples from the lowest horizon of the Pingen Formation of 0.05-0.26, 13.1% -14.5%, respectively, indicated hydrothermal origins. All other samples show high Al / (Al + Fe + Mn) ratios (0.39-0.81) and high Feter / Febulk -186.8%), indicating non-hydrothermal origins. Pingen Formation and Liujiang Formation cherts show slightly-moderately negative Ce anomalies (0.71 ± 0.07, 0.81 ± 0.08, respectively) and higher Y / Ho ratios (33.49 ± 1.27,36.10 ± 2.05, respectively) than PAAS. This suggests that these cherts were deposited in the open marine basin, rather than in the intracontinental rift basin as previously assumed. The Luzhai Formation cherts may be deposited near the seamount or seafloor plateaus with no negative Ce anomalies (1.09 ± 0.07) and no significant Y-Ho fractionation (Y / Ho = 28.60 ± 1.25). The Nandan Formation and Sidazhai Formation cherts were deposited in the open -ocean basin with moderately negative Ce anomalies (0.67 ± 0.08, 0.73 ± 0.11, respectively) and high Y / Ho ratios (36.01 ± 1.00, 32.00 ± 2.25, respectively). On the basis of our studies on cherts, we conclude that the Youjiang Basin originated as part of the Paleo-Tethys that controlled the depositional environments of cherts during late Paleozoic.The rift of the Youjiang Basin occurred occurred at least since the Early-Middle Devonian.The basin had a trend of evolving into an open-ocean basin during the Early-Middle Pe rmian.
其他文献
省委书记王珉在今年全省经济工作会议上明确指出:“要强化执行力建设。成事之要在于行。落实不好、执行不力,再好的政策和思路都是一纸空文。”所谓执行力,就是把握规律、创
一、前言控制写作教学法早已广泛应用于英语写作教学当中,同时该教学法具备有效性及快速性的特点,是一种相对成功的教学方法。在初中英语写作的具体教学过程中,积极采用控制
学了N多年的英语,深知了解文化对学好语言的重要性,于是本刊顾问刘雪梅与众多整天在英语教学及英语学习中摸爬滚打的前战友共同开辟一个新的战场,深挖广探英语文化,以期帮助
通过亲身经历,讲述化学课堂上在传授化学知识的同时,渗透一些与化学有关的哲学思想,帮助学生找到正确的学习方法、增强学习动力,形成健康的人生观。 Through his personal e
Today is New Year’s Eve.It is a traditional Chinese festival.Mum is cooking in the kitchen.My Dad and I are putting the Spring Festival couplets on the wall.My
The Keap1–Nrf2–ARE pathway is an important antioxidant defense mechanism that protects cells from oxidative stress and the Keap1–Nrf2 protein–protein intera
2007年上海客车展上,世界上三大传动技术生产商伏依特、艾里逊和采埃孚,前两者缺席,惟有采埃孚亮相。在采埃孚展区,记者碰到了采埃孚集团客车传动系统业务部总裁、采埃孚传动
背景与目的:有研究显示结直肠癌主要表达的雌激素受体β(estrogen receptorβ,ERβ)与肿瘤转移相关。基质金属蛋白酶7(matrix metalloproteinase-7,MMP-7)在结直肠癌组织中高
瑜伽是一种特别的健身运动,在运动过程中存在着明显的生理和心理的交互影响作用。文章通过综述国内外有关瑜伽健心方面的研究,从古代瑜伽的起源、瑜伽的生理基础和瑜伽的特点
如何维护光驱$宁波大学职教学院@谢良辰$宁波大学职教学院@张頲请下载后查看,本文暂不支持在线获取查看简介。 How to maintain the optical drive $ Vocational College of
期刊