摘要
在对扬子地台贵州瓮安陡山沱组剖面干酪根碳同位素组成进行分析后发现其变化显示了一定的规律性。碳同位素规律变化反映了最初的沉积信息,特别是有机质埋藏量的变化。获得的陡山沱期沉积岩中碳同位素组成研究结果初步反映了震旦-寒武交变期沉积环境的面貌;碳同位素组成变化规律可以用于反映扬子地台沉积层序和世界同期地层全球碳循环的对比和参考。为扬子区陡山沱期环境变化和生物演化提供了证据。δ13Cker值在-32.3‰和-24.5‰(PDB)间漂移与δ13Ccarb值在-4.9‰和3.6‰(PDB)间的变化,反映了当时海水的碳同位素组成。无机和有机碳同位素组成之差的Δδorg-carb值沿剖面不断变化,是由于沉积有机质中有促进发酵功能的细菌数量比例变化所致。
Secular variations of carbon isotopic composition of organic and carbonate carbon in Doushantuo Formation,which is exposed on the Yangtze Platform at Weng′an,Guizhou Province,south China,were recognized.δ^(13)C values for organic matter varied from -33.4‰ to -26.5‰.The carbon isotopic composition for carbonate carbon displayed variations between -4.9‰ and 3.6‰.A change in the isotopic difference (Δδ_(org-carb)) between both isotope records reflected a difference in the proportional contribution of bacterial biomass to the total sedimentary organic matter.In general,the observed changes were considered to be the primary depositional values,notably variations in the burial of organic matter.The study provided new carbonate carbon and organic carbon isotope data and curves during the Doushantuo interval of terminal Neoproterozoic and early Paleozoic age,and reflected variations of sedimentary environment and also offered important correlation and reference for sedimentary sequence and global stratum of the same period.Furthermore,it presented crucial information for completely understanding for territorial and global events.
出处
《矿物岩石》
CAS
CSCD
北大核心
2005年第2期75-80,共6页
Mineralogy and Petrology
基金
国家自然科学基金(批准号:40303001)
关键词
瓮安
震旦-寒武交变期
陡山沱组
瓮安生物群
成磷事件
碳酸盐岩和干酪根碳同位素组成
Weng′an
Neoproterozoic-Paleozoic interval
Doushantuo Formation
Weng′an biota
phosphogenic event
carbonate and organic carbon isotope excursion
