西秦岭甘南地区二叠纪–三叠纪遗迹化石及其古环境意义  

Trace fossils and their paleoenvironmental significance of the Permian–Triassic succession in the Gannan region of West Qinling

作　　者：党志英 张立军[1] DANG Zhi-ying;ZHANG Li-jun(Institute of Resource and Environment,Henan Polytechnic University,Key Laboratory of Biogenic Trace and Sedimentary Minerals of Henan Province,Collaborative Innovation Center of Coalbed Methane and Shale Gas for Central Plains Economic Region,Jiaozuo 454003,Henan,China)

机构地区：[1]河南理工大学资源环境学院,河南省生物遗迹与成矿过程重点实验室,中原经济区煤层(页岩)气河南省协同创新中心,河南焦作454003

出　　处：《古生物学报》2020年第4期430-444,共15页Acta Palaeontologica Sinica

基　　金：河南省自然科学基金(212300410349);河南省高校基本科研业务费专项资金(NSFRF00340)资助。

摘　　要：西秦岭甘南地区晚二叠世–中三叠世半深海–深海相地层中赋存丰富的遗迹化石,出现了居住迹、觅食迹、停歇迹和牧食迹4大类,14属,包括:Arenicolites、Chondrites、Dictyodora、Diplichnites、Diplopodichnus、Helminthopsis、Laevicyclus、Lockeia、Nereites、Palaeophycus、?Phycodes、Planolites、Protovirgularia、Scolicia。二叠纪乐平统毛毛隆组主要包括Protovirgularia组合、 Dictyodora–Helminthopsis组合和Diplichnites–Palaeophycus组合,上述3个遗迹化石组合主要由牧食迹和觅食迹组成,结合沉积相标志,指示了斜坡相沉积环境。早三叠世山尕岭群识出现了Diplopodichnus–Planolites组合,结合相应岩性及沉积相标志,反映了斜坡–盆地的深海沉积环境。中三叠世古浪堤组出现了Laevicyclus组合和丰富多样的沉积构造,指示了浊积扇的内扇环境。Abundant trace fossils are found in the Permian Lopingian to Middle Triassic bathyal–abyssal strata of the Gannan region from West Qinling, China, which can be distinguished into domichnia, fodinichnia, cubichnia and pascichnia. Fourteen ichnogenera were identified, including Arenicolites, Chondrites, Dictyodora, Diplichnites, Diplopodichnus, Helminthopsis, Laevicyclus, Lockeia, Nereites, Palaeophycus, ?Phycodes, Planolites, Protovirgularia, and Scolicia. The Lopingian Maomaolong Formation mainly consists of Protovirgularia, Dictyodora–Helminthopsipsis, and Diplichnites–Palaeophycus assemblages. These three trace fossil assemblages are mainly composed of fodinichnia and pascichnia, indicating a continental slope environment. The Diplopodichnus–Planolites assemblage was identified in the Early Triassic Shan-ga-ling Group, which combining with associated lithology and sedimentary structures, suggest a base-of-slope apron environment. The Middle Triassic Gulangdi Formation is composed of Laevicyclus assemblage and diverse sedimentary structures, representing a proximal-mid fan of turbidite fan environment.

关 键 词：二叠纪–三叠纪 深海相 遗迹化石 遗迹组合 古环境 

分 类 号：Q915.2[天文地球—古生物学与地层学]