摘要
首次发现于蓟县高于庄组(约1 450 Ma)的遗迹化石Spirelluchnum(ichnogen.nov.)是垂直层面的螺旋型潜穴,穴深3～3.5 cm,最大宽度为3 cm.化石产于岩层内,呈规则的顺时针螺旋体,颜色比围岩深,随着围岩新鲜程度的增加,二者反差变小.这些特征表明该化石为后生动物的遗迹.距今约14.5亿年前动物遗迹化石的发现,有可能使后生动物出现的时间推前8～9亿年,同时为后生动物的起源和进化提供可靠的化石证据.
The trace fossils, Spirelluchnum (ichnogen.nov.), newly discovered in Gaoyuzhuang Formation (about 1 450 Ma) in the Jixian section are the spiral burrows, and perpendicular to the bed surface with depth of 3 ~ 3.5 cm. The fossils occur in the bed with three-dimensional space. The colour of the fossils is slightly darker than that in the surrounding rock and in the fresh rock. The fossil bodies show regular spiral shape with clockwise direction. The maximum length of the burrows is about 3 cm. The facts above-mentioned suggest that they are the trace metazoan fossils. And the metazoan was of simple structure without branches, symmetrical in both sides, and has front end and rare end. And it may existed before 1 450 Ma. The newly discovered trace fossils in Gaoyuzhuang Formation provide the Precambrian biologic contents to the study of creatural origination, and it can put the occurrence time of the metazoan forward about 800 ～ 900 Ma earlier than before. Fossils Description Spirelluchnum(ichnogen.nov.) Genus shape: Spirelluchnum sunae ichnosp. nov.(Fig.3). Character: It is the spirell Gyrolithes, they may be left spirell or right spirell with equal length and parallel each other. The trace fossil shows pipe shape or pressed-to-boma pipe shape, simple and no branched structure, the pipe fossil has 1 ~ 10 mm in diameter, and they are paralleled, no cross each other. Comparison: The new trace species are similar to Gyrolithes DeSappporta, 1884 [26 ~ 28], but the latter are thicker, and they can reach several millimeter in diameter. They are widely considered to be the Gyrolithes fossils formed when the crustacea of decapoda left burrows. Distribution: in Medium Proterozoic , Jixian, China. Spirelluchnum sunae Sun.(ichnosp.nov.) ( Fig.3). Holotype Fig.3-c,d,e,f; No. Jcg 25 Description: The fossils are the spiral Gurolithes perpendicular to the bed surface. The spirals are paralleled and normal clockwise with approximately equal width. The maximum width of the Gyrolithes coiled burrows is about 3 ~ 4 cm with three-di
出处
《地质调查与研究》
2005年第2期65-70,共6页
Geological Survey and Research
基金
国家自然科学基金(40372003)
中国地质调查局资助项目(200313000052)
关键词
后生动物
遗迹化石
高于庄组
蓟县剖面
metazoan
trace fossil
Gaoyuzhuang Formation
Jixian Section
