西秦岭北带泥盆纪Nereites遗迹相及其环境分析  

Nereites Trace facies(Devonian) in the Northern Belt of West Qingling Mountains and its Environment Analysis

作　　者：晋慧娟[1] 李育慈[1] 

机构地区：[1]中国科学院兰州地质研究所,兰州730000

出　　处：《沉积学报》1998年第1期15-22,共8页Acta Sedimentologica Sinica

基　　金：国家自然科学基金!49672127

摘　　要：西秦岭北带泥盆系舒家坝组下一中上部的巨厚陆源碎屑岩系中含有极丰富的遗迹化石，它们可为解释该组沉积环境提供重要信息：（1）由大量典型深水遗迹化石组成的Nereites遗迹相，可与世界各地浊积岩系和复理石相中的Nereites遗迹相进行对比，该遗迹相主要发育在浊流沉积区直至深海平原，其沉积水深最大可超过2000m；（2）舒家坝组的遗迹群落中，除大量属深水型分子外，还见有典型的浅水分子，两种水深性质不同的遗迹组合共生在一个沉积剖面，正是浊积岩系和复理石相才具有的独特分布特征；（3）根据沉积层序和遗迹组合的对比确认舒家坝组不存在风暴岩。Widely exposed in the northern belt of West Qingling Mountains,the Shujiaba Formation (Devonian) is a set of extremely thick terrigenous elastic rock measures. Two sharply different viewpoints on the paleogeography environment of the formation still exist,i. e. shallow sea and deep sea factes. This paper placed emphasis on the 43 ichnogenera discovered by the authors to discuss the paleoenvironment information provided by them.The description and plates of the 43 trace fossils of the Shujiaba Fm. have been reported openly,and they are:Acanthorhaphe, Arthrophus, Belorhaphe, Bostricophyton, Buthotrephis, Chondrites, CoChilichnus, Cosmorhaphe, Dictyodora, Fucusopsis, Glockeria, Gordia, Granularia, Helicolithus, Helminthofda, Helminthopsis, Lennea, Lophoctenium, Megagrapton, Neonereites, Nereites, Paleohelminthoida, Paleodictyon, Planolites, Protopaleodictyon, Protovirgularia, Rhabdoglyphus, Rhabdoichnus, Rusophycus (?), Saerichnites, Sagittichnus, Scolicia, Skolithos, Spirophycus, Spirorhaphe, Squamodictyon, Subphyllochorda, Sublorenzinia, Subularia, Taphrhelminthoida, Taphrhelminthopsis, Tuberculichnus, Urohelminthoida.Some cognition was reached according to the study on the trace fossil groups mentioned above,that is, 1)Classified in terms of trace factes,only a few ichnogenera existing in the near source turbidite of trace group in the Shujiaba Fm. belonged to the Skolithos trace factes,but a majority of trace fossil ichnogenera belonged to the Nereites factes. They were preserved on the interface between Section To and Te in the thin-bedded turbidite formed in the distal area of turbidity current. According to the researches at home and abroad, it could be seen that it is the unique feature of th trace fossil assemblage in vertical distribution in turbidite measures or flysch factes that the trace factes of deep and shallow water co-exist in a single depositional profile, just like the Shujiaba Fm.2)Classified according to the morphology,the already discovered trace fossils were predominated by the curved, spira

关 键 词：环境分析 遗迹相 西秦岭 泥盆纪 古环境 

分 类 号：P534.44[天文地球—古生物学与地层学] P531[天文地球—地质学]