摘要
扬子地区下寒武统广泛发育了1套黑色岩系,被认为是中国南方4套海相烃源岩之一。但由于该套烃源岩时代老、有机质成熟度高,故对其有机岩石学特征探讨还没有定论。通过光片、薄片的对比观察,结合扫描电镜和能谱等分析,详细研究了研究区下寒武统黑色岩系的有机岩石学特征,并尝试性地探讨了其油气地质意义。结果表明湘西三岔地区下寒武统黑色岩系中的有机质可划分为有形态组分、无形态组分。其中有形态组分又可分为植物藻类组(层状藻类体、结构藻类体Ⅰ、结构藻类体Ⅱ)、动物有机组、细菌型的菌类体及混合型海相镜质体;无形态组分主要为微粒体和沥青质体。从观察到的有机质组分反映了该套黑色岩系的生源母质具有多重属性,但从统计的各组分含量上来讲主要为浮游菌藻类、底栖宏观藻类、浮游动物和底栖海绵等,其有机质类型主要为Ⅰ型和Ⅱ型。系统的有机岩石学研究表明有机质差异主要是由母质类型的差异所造成,宏观底栖藻类和大型低等水生植物(如浅海底栖叶状体植物)的发育是形成Ⅱ型有机质的主要因素。对牛蹄塘组有机岩石学特征的分析为该套黑色岩系的油气生成潜力的研究提供了重要基础。
The lower Cambrian black rock series,which is one of the four suits of regional marine source rocks in southern China,distributes widely in Yangtze area.However,the organic petrological features especially organic maceral determination for the succession has not been studied in detail due to the old age and high maturity.In this study,we conducted comprehensive organic petrological research on the black rock succession based on observation of the rock slice and polished section under microscopy and SEM-EDS-analysis（scanning electron microscopy-energy dispersive X-ray spectroscopy analysis）;and then the petroleum geological implication was tentatively discussed.The results show that the macerals are grouped into structural and amorphous macerals.Furthermore the structural maceral can be divided into plant algae（lamellar algae,structural algae Ⅰ,structural algae Ⅱ）,animal organic matters,sclerotinite,and vitrinite-like maceral.The main components of amorphous maceral are fine grained maceral and bituminite.Therefore,there are multiple attributes of organic sources for this black rock succession.However,planktonic algae and fungi,benthic macro alga,actitarchs,animal plankton and benthic spongia are the main organic sources on the basis of statistic research,thus the main organic matter types are Ⅰ and Ⅱ.In addition,comprehensive organic petrological study allows to draw a conclusion that the multiple organic resources cause the divergence of organic matter types Ⅰ and Ⅱ,and the benthic macro alga and low large aquatic plants（such as benthic leafy body plants in the shallow sea） is the main components for the type Ⅱ organic matter.The organic petrological study on the Niutitang Formation provides important data for petroleum geological implication research.
出处
《天然气地球科学》
EI
CAS
CSCD
北大核心
2012年第6期1077-1089,共13页
Natural Gas Geoscience
基金
国家自然科学基金(编号:40973051
40638042)联合资助
关键词
牛蹄塘组
有机岩石学
显微组分
有机质类型
Niutitang Formation
Organic petrology
Maceral
Organic matter types
