摘要
贵州独山中泥盆统大河口组中含有丰富的遗迹化石Teichichnus Seilacher(包括5个遗迹种:潜穴及蹼状构造直立排列的Teichichnus rectus Seilacher,潜穴管具有二分枝现象的T.palmatus Seilacher,潜穴管近口孔部位膨大呈葫芦状的T.majiatunensis Wang,潜穴管近口孔部向上折曲的T.sinuosatus Wang和蹼状板构造呈S状扭曲的T.aff.sigmoi-dalis(Seilacher)。本文主要讨论其生态环境意义及地质意义。 通过野外观察及研究分析认为:与层面斜交的Teichichnus潜穴管为造迹生物居住和觅食的活动场所,为Seilacher(1967)的Cruaiana遗迹相的典型分子;蹼状构造的形成系造迹生物在保持一定生态位下与沉积或侵蚀作用相关,并可确定地层的顶底面;潜穴管口孔的弯曲程度和膨胀程度是区分遗迹种的重要特征,可利用Teichichnus的遗迹种和其潜穴管与层面之间的交角分析其沉积环境的微相变化;Teichichnus潜穴管口孔多迎着主水流方向发育,可指示古水流的方向。
There occur abundant ichnogenus Teichichnus, including five ichnospecies: T. rectus Seila-cher that the burrow and spreites are erectly arranged (P1. I, fig. 3; text - fig. 1-1), T. palmatus Seilacher that possesses two burrows (P1. I, fig. 3; text-fig. 1-2), T. majiatunensis Wang that the burrow near the mouth expand as cucurbit shape (P1. I, fig. 4; text-fig. 1-4), T. sinuosatus Wang that the part close to the mouth of burrow flex upwards (P1. I, fig. 5; text -fig. 1-4), T. aff. sig-moidalis that the burrow and spreites are as S - shaped (P1. I, fig. 6; text - fig. 1-5), from the Lower Devonian Dahekou Fm. in Dushan region, south Guizhou.
The burrows of the ichnogenus Teichichnus act as a sort of ' blindage' that are adapted for the changeable environments and forfended their enemies, and their U - spreites and board - type trace formed from what the organisms were living in constant deep under the seabed so that the burrows moved upward or down in sedimentation or erosion (text - fig. 3) . Teichichnus are the mains of the Cruziana ichnofa-cies (Seilacher, 1967) in shallow sublittoral setting where owned quieter water, enough illumination, natural salinity and plentiful organic matters and, slower sedimentation.
The bend and dilatants nearby to the mouth of burrow may be relation with the energy of water, so might represent the evolutional microenvironment of their ichnospecies and the angles of their burrows and spreites to layer. On the section of Dahekou Fm in Dushan, this is almost a regularity in a transgressive series, the Teichichnus that appeared in turn are T. sinuosatus, T. aff. sigmoidalis, T. palmatus, T. rectus, and T. majiatunensis.
The mouths of Teichichnus were mostly developed against in water - flow direction (text - fig. 2), and may be propitious to the organisms in obtaining more food and oxygen and removing excreta. It can help to determine the paleoflow direction. And the burrows and spreites of Teichichnus can help to determine the top and underside of stratum.
出处
《贵州地质》
2003年第3期145-149,F004,共6页
Guizhou Geology
基金
现代地层学和古生物学国家重点实验室基金(编号:023116)
贵州省科技基金
关键词
贵州
泥盆系
大河口组
化石
地质意义
生态环境
ichnogenus Teichichnus
bioenvironment
geological significance
Devonian
Dushan of Guizhou
