云南梅树村前寒武系-寒武系界线剖面硅同位素研究  

SILICON ISOTOPE STUDY ON THE MEISHUCUN PRECAMBRIAN-CAMBRIAN BOUNDARY SECTION, YUNNAN

作　　者：李延河[1] 万德芳[1] 蒋少涌[1] 钟华[2] 

机构地区：[1]中国地质科学院矿床地质研究所 [2]中国科学院地质研究所

出　　处：《地质论评》1995年第2期179-187,共9页Geological Review

摘　　要：云南梅树村前寒武系-寒武系界线剖面是研究前寒武系-寒武系界线层型最重要的国际候选剖面之一。本文首次系统地研究了硅同位素在剖面中的变化规律,指出“C”点附近“界线粘土层”为火山成因,“B”点至“C”点之间有海底喷气活动;“C”点附近的δ^(13)C,δ^(18)O负异常与生物大量活动有关,而非“灾变”所致。The Meishucun section is considered as one of the best candidate for the international strato-type of the Precambrian-Cambrian boundary. Silicon isotope Variation in the section was first systematically studied, and two positive and one negative anomalies of δ30 Si were found. The 'boundary elay band' near Marker C appers to be volcauogflnic. The bulk of the 'boundary clay band' is represented by ordinary pelitic sitstone, which is beleived to be introduced by small amount of materials derived from submarine exhalation between Markers C and B. The negative δ13C and δ18O anomalies near Marker C were caused by substantial biological activity rather than by catastrophes.

关 键 词：前寒武纪 寒武纪 界线 硅同位素 地层 

分 类 号：P534.41[天文地球—古生物学与地层学] P595[天文地球—地质学]