摘要
高密度浊流和砂质碎屑流作为深水环境重要的地质营力,但如何区分两种流体及其沉积,一直存在着争议。通过探讨两种流体的关系,有助于澄清深水沉积过程的相关认识,有助于正确区分两种流体的沉积,也有利于开展相关砂岩储层的预测。在分别回顾高密度浊流和砂质碎屑流的概念、特征及具体实例的基础上,对比了两者的流体性质和沉积特征,结合触发机制、形成过程及影响因素,从理论运用和实际运用两方面探讨了两者的关系。高密度浊流沉积可划分为底部、中部和上部三部分,垂向上具逆——正粒序。砂质碎屑流沉积富砂质,具块状层理,垂向上可由块状砂岩叠置形成。碎屑流形成的触发机制多样,且相对于中等至弱粘性碎屑流,强粘性碎屑流不易向浊流转换。与砂质碎屑流相比,高密度浊流在术语使用上更合理。如果碎屑流发生了流体转换,形成高密度浊流沉积;如果未发生,且物源富砂质,可以形成砂质碎屑流沉积。块状砂岩与上覆泥质沉积物呈突变接触时,可能为砂质碎屑流成因;与上覆沉积物为渐变接触时,构成正粒序,为高密度浊流成因。
While high-density turbidity current and sandy debris flow are two significant geological agents in deep-water environment,a dispute always exists in how to distinguish between the two kinds of fluids and their deposits. By discussing the relationship between the fluids,it is of help to clarifying deep-water sedimentary process,to properly distinguishing between their deposits and to predicting reservoir. On the basis of reviewing concept,characteristics and concrete examples,fluid properties and sedimentary characteristics are compared.Combined with triggering mechanism,forming process and influencing factors,the relationship between highdensity turbidity and sandy debris flow is discussed from the two aspects of basic theory and practical application.High-density turbidity current deposits can be divided into bottom part,middle part and upper part vertically,in coarsing upwards then fining. Abundant in sand,sandy debris flow deposits are characterized by massive bedding and can be formed by vertically superimposed massive sandstones. Triggering mechanisms of debris flow are various. Besides,in comparison with moderate to weak viscous ones,strong viscous debris flow is not likely to convert in turbidity. In the use of terms,high-density turbity is more suitable. If fluid conversion occurs in debries flow,so does high-density turbidity current deposits. If it does not happen and source is rich in sand,sandy debris flow deposits can be formed. Sandy debris flow can be used to explain abrupt contact between massive sandstone and overlying muddy sediments,while high-density turbidity current can explain gradual contact.
出处
《地质论评》
CAS
CSCD
北大核心
2015年第6期1281-1292,共12页
Geological Review
基金
国家自然科学基金资助项目(批准号41472096)的成果
关键词
浊流
高密度浊流
砂质碎屑流
重力流
turbidity current
high-density turbidity current
sandy debris flow
gravity flow
