塔里木盆地志留系遗迹化石组合及其沉积环境

Silurian ichnoassemblages of Talimu Basin and their sedimentary environments

依据化石生态和沉积学特征 ,系统地研究了塔里木盆地志留系遗迹化石的组成、分类及其沉积环境 ,认为存在 4种遗迹化石组合 :①Palaeophycus Planolites遗迹组合 ,由进食潜穴、滤食居住潜穴和觅食迹组成 ,包括Planolites,Palaeophycus,Macaronichnus,Skolithos,Ophiomorpha和Taenidium等遗迹属 ,反映了潮间带混合坪沉积环境 ;②Skolithos遗迹组合 ,由居住潜穴组成 ,常见遗迹属有Skolithos,Ophiomorpha ,Arenicolites,Thalassinoides和Cylindrichnus,代表了前滨或潮下带砂坪沉积环境 ;③Planolites Taenidium遗迹组合 ,以进食潜穴和居住潜穴为特征 ,主要组成分子有Taenidium ,Planolites,Palaeophycus,Skolithos,Arenicolites和Thalassinoides等遗迹属 ,指示了具有周期性风暴影响的过渡带沉积环境 ;④Helminthopsis遗迹组合 ,主要由觅食迹组成 ,其中以Helminthopsis和Zoophycos遗迹属最为常见 。

Based on the systematic research of the compositions, sorts and sedimentary environments of ichnofossils from Silurian of Talimu Basin, it is held that there are four kinds of ichnoassemblages: (1) Palaeophycus-Planolites ichnoassemblage, which is composed of fodinichnia, domichnia and pascichnia including Planolites, Palaeophycus, Macaronichnus, Skolithos, Ophiomorpha, Taenidium and so on, and may display mixed flat sedimentary environment; (2) Skolithos ichnoassemblage, which consists of Skolithos, Ophiomorpha, Arenicolites, Thalassinoides and Cylindrichnus, and may represent such sedimentary environments as foreshore and sand flat; (3) Planolites-Taenidium ichnoassemblage, which is characterized by such fodinichnia and domichnia as Taenidium, Planolites, Palaeophycus, Skolithos, Arenicolites and Thalassinoides, generally indicates transition zone sedimentary environment periodically influenced by storm; (4) Helminthopsis ichnoassemblage, which is mainly composed of pascichnia, occurs in offshore sedimentary environment with low hydrodynamic condition.