摘要
塔里木盆地西北缘柯坪断隆中奥陶统其浪组中上段L M灰泥互层沉积地层中发育远源钙质风暴岩 ,其中发育属Zoophycos遗迹相的Phycodes Megagrapton遗迹组合 ,包括Belorhape,Circulichnus ,Dendrichnites ,Gordia ,Granularia ,Megagrapton ,Phycodes,Planolites,Protopaleodictyon ,Rhabdoglyphas等遗迹属。该组合遗迹形态主要为分枝迹 ,习性以觅食迹为主 ,显著特点是包含多种深水遗迹分子。这些特征与以往报道的风暴岩中遗迹组合特征有明显的差别。该组合反映其浪组风暴岩形成于滨外风暴浪基面以下水体较深且水动力较弱的静水地带。
The Qilang Formation of Middle Ordovician in northwest Tarim basin is composed of laminae marl and laminae limestone with abundance graptolites and trilobites.This kind of marl and limestone thin alternation is typical L M (limestone marl) cycle.There are about thirty beds of distal calcareous tempestites in Middle Upper Qilang Formation.In the plane and bottom of the tempestites ten trace fossils were found and they are: Belorhape, Circulichnus, Dendrichnus,Gordia, Granularia,Megagrapton,Phycodes,Planolites,Protopaleodictyon and Rhabdoglyphas . Because of abundance of Phycodes and Magagrapton ,these trace fossils can be named Phycodes Magagrapton assemblage which are predominant in fodinichnia and shape of ramification,and belong to Zoophycos ichnofacies proposed by Seilacher.This assemblage represent quiet lower energy sedimentary environments under main storm wave level.Based on the fact that event deposition has close relation to the trace fossils,it is believed that Phycodes\|Megagrapton assemblage can be a fine auxiliary marker to judge distal tempestite and to differentiate the e vent and normal limestone.
出处
《沉积学报》
CAS
CSCD
北大核心
2000年第1期68-72,共5页
Acta Sedimentologica Sinica
