豫西登封地区寒武系第二统朱砂洞组生物扰动构造及其地球化学特征  

Bioturbated Structures and Their Geochemical Features from the Zhushadong Formation of the Cambrian Series 2 in Dengfeng Area of West Henan

作　　者：庆国帅 齐永安[1] 杨文涛[1] 代明月[1] 白万备[1] 樊钰超 刘炳辰 Qing Guoshuai;Qi Yong’an;Yang Wentao;Dai Mingyue;Bai Wanbei;Fan Yuchao;Liu Bingchen(School of Resources and Environment,Henan Polytechnic University,Jiaozuo 454000,China)

机构地区：[1]河南理工大学资源环境学院,河南焦作454000

出　　处：《地球科学》2020年第4期1103-1114,共12页Earth Science

基　　金：国家自然科学基金项目(No.41872111)

摘　　要：生物扰动在现代海洋沉积物地球化学循环中起着重要作用,它影响着底栖生物群落特性、有机物分解速率、海水化学性质、沉积物氧化还原性以及营养物循环.豫西登封地区寒武系第二统朱砂洞组碳酸盐岩发育了大量以Thalassinoides主导的扰动构造,对其进行碳和氮同位素测定,可以了解扰动生物对沉积物生物地球化学循环影响.测试结果表明,潜穴充填物和围岩中δ13Ccarb值区别显著,不同扰动程度也差异明显,而δ13Corg和δ15N值差异不大,反映出生物对沉积物的扰动改造可以改变沉积物的氧化还原性及孔渗性,这一变化可能与生物扰动引起沉积物孔隙水含氧量增高导致的自生碳酸盐岩比例降低和成岩期白云岩化的增强有关.Thalassinoides造迹生物对沉积物的扰动改造不仅改变了沉积物的原始物理化学信息,促进了海水与沉积物的生物地球化学循环,而且诱导了沉积底质革命,扮演了显生宙早期生态系统工程建造者的角色.The bioturbation plays a critical role in modern marine biogeochemical cycling. It influences the character of benthic communities, decomposition rate of organic matter, chemical properties of seawater, redox properties of sediment and nutrient recycling. Abundant bioturbated structures dominated by Thalassinoides occur in carbonate rocks of the Cambrian Series 2 Zhushadong Formation in Dengfeng area of west Henan. The determination of carbon and nitrogen isotopes can help us to understand the influence of bioturbators reworking to sediment biogeochemical cycling. The determination results show that there is a great difference of δ13Ccarb value between the Thalassinoides burrow fillings and matrix, and it also displays a dramatic difference in different bioturbated intensity. But there exists a weak difference of δ13Corg and δ15N values between the Thalassinoides burrow fillings and matrix. The results mean that the sediment reworking of bioturbation can greatly change the redox property,porosity and permeability of sediments. The changes may be related to the decrease of the proportion of authigenic carbonates caused by the increase of oxygen content in sediment pore water and enhancement of dolomitization during diagenesis. The sediment mixing and reworking formed by Thalassinoides bioturbators not only have significantly changed the primary physical and chemical information and promoted the biogeochemical cycle between seawater and sediments, but also may have efficiently triggered the substrate revolution, acting as ecosystem engineers as well.

关 键 词：Thalassinoides 生物扰动构造 生物地球化学循环 碳同位素 朱砂洞组 沉积物 

分 类 号：P52[天文地球—古生物学与地层学]