摘要
内蒙古桌子山地区中奥陶统公乌素组遗迹化石十分丰富.本文共鉴定、描述14个遗迹属、17个遗迹种,其中1新遗迹属——Biscopulatichnus、4新遗种和6未定种.并根据不同遗迹属在不同层位中的相对丰度,建立了4个遗迹组合,自下而上的顺序是:1. Taenidium-Phycodes 组合;2. Volkichnium 组合;3. Helminthopsis 组合;4. Granularia-Circulichnus 组合,大致相当于 Seilacher (1967) 的 Zoophycos 遗迹相,反映出公乌素组沉积期,水体较深且宁静、缺氧、有机质含量高,推测应为大陆斜坡环境.
Abundant trace fossils are discovered from the Middle Ordovician Gongwusu Formation in Zhuozishan, Inner Mongolia, with 14 ichnogenera (including 1 new ichnogenus) described in this paper, namely, Arthrophycus, Biscopulatichnus ichnogen. nov., Chondrites, Circulichnus, Granularia, Helminthopsis. Nereites, Paleodictyon. Phycodes. Scolicia. Sublorenzinia. Taenidium. Volkichnium and Zoophycos. Based on the characteristics of the trace fossils, four trace fossil assemblages have been established, which are briefly described in ascending order as follows: 1. Taenidium-Phycodes assemblage, ranging from Beds 2-4, dominated by Taenidium and Phycodes, also including the ichnogenera Granularia, Arthrophycus. Biscopulatichnus, Chondrites, and Volkichnium. 2. Volkichnium assemblage, occurring in Bed 5 of the formation, in which the radiate trace fossil Volkichnium is most abundant, co-existing with the ichnogenera Arthrophycus, Granularia, Phycodes and Sublorenzinia. 3. Helminthopsis assemblage, ranging from Beds 6 to 8, characterised by the occurrence of abundant winding trace fossil Helminthopsis, together with a small number of the netlike Paleodic tyon. 4. Granularia-Circulichnus assemblage, restr ted to Bed 9, mainly composed of pellet-walled Granularia, together with Circulichnus, Helminthopsis, Nereites, Phycodes, Volkichnium, and Zoophycos. It is believed that the above-mentioned four assemblages correspond broadly to Seilacher's (1967) Zoophycos ichnofacies, which indicates the circalittoral to bathyal, anoxic quiet water environment. This is also supported by the occurrence of abundant graptolites and some small, thin-shelled brachiopods as well as their good preservation in the formation. Description of new ichnotaxa Biscopulatichnus ichnogen. nov. Type ichnospecies: Biscopulatichnus wuhaiensis ichnosp. nov. Etymology: Combination of Latin 'Bi' with 'scopilas'. Diagnosis: Traces with unequal ribs radiating in two opposite directions and resembling two brooms with their axes longitudinally connected; without areola
出处
《古生物学报》
CAS
CSCD
北大核心
1993年第1期88-104,145-148,共17页
Acta Palaeontologica Sinica
关键词
遗迹相
公乌素组
痕迹化石
trace fossils, Zoophycos, iclnofacies, Middle Ordovician Gongwusu Formation, Inner Mongolia
