黄河三角洲潮坪环境中现代生物遗迹组成与分布特征

沉积物中的生物遗迹记录是生物与环境相互作用的结果，是沉积环境及生态环境的良好指示标志。通过野外观察和实验室研究方法（取样，粒度分析，CT扫描及三维重构等技术），研究了黄河三角洲潮坪环境现代生物遗迹的组成与分布特征。取得了以下几点认识:1）潮坪各个微环境中现代生物遗迹的分布有很大的差异性。现代生物遗迹主要分布在潮间带中，并且，从泥坪到混合坪到砂坪依次减少。潮上带主要有日本大眼蟹的层面进食迹和层内U形、Y形、多分叉形的居住潜穴。潮间带的泥坪中有大量日本大眼蟹的层面进食迹和层内U形、Y形、多分叉的居住潜穴，少量双齿围沙蚕的层面爬行迹，觅食迹，和层内的垂直、Y形居住潜穴，跳跳鱼的层面爬行迹，泥螺的层面拖迹，红带织纹螺的层面觅食迹；混合坪中有大量双齿围沙蚕的层面爬行迹，觅食迹和层内的垂直、Y形居住潜穴，少量日本大眼蟹的层面进食迹和层内U形、Y形、多分叉的居住潜穴，托氏昌螺的层面觅食迹，四角蛤的垂直潜穴，少量豆形拳蟹的层面爬行迹和层内Y形居住潜穴，泥螺的层面拖迹；砂坪中有竹蛏的垂直进食和居住潜穴，棒锥螺的觅食迹，以及秀丽织纹螺的觅食迹。2）对日本大眼蟹、双齿围沙蚕和四角蛤所造的层内潜穴，进行了三维重构，为精细研究这些潜穴的建构特征提供了图像基础。

The Composition and Distribution Characteristics of Biogenic Sedimentary Structures in Tidal Flat of Yellow River Delta

Ichnology in sediments is the result of interaction of organisms and environment,and it is a good indicator of both sedimentary and ecological environment. In this study,the results of fieldwork and experimental methods (box corer,grain analysis,X-ray computed tomography,three-dimensional reconstruction) revealed the composition and distribution of biogenic sedimentary structures in the tidal flat of the Yellow River delta. The two main results were:(1) The distribution of biogenic sedimentary structures varies at the micro-environment scale of the tidal flat. The biogenic sedimentary structures are mainly distributed in the intertidal flat. The abundance declines from mudflat to mixed-flat to sandflat. Specifically,there are feeding trails on the surface and Y-shaped and U-shaped burrows produced by Macrophthalmus japonicus in the supratidal zone. There are a number of feeding trail on the surface and Yshaped,U-shaped burrows produced by Macrophthalmus japonicus,crawling trails produced by Periophthalmus cantonensis,trails produced by Bullacta exarata on the surface,grazing trails produced by Nassarius succinctus,and a small number of crawling trails,grazing trails and vertical Y-shaped burrows in the mudflat. A large number of these occur in the sediment:grazing trails produced by Umbonium thomasi,vertical burrow produced by Mactra veneriformis Reeve,Bullacta exarata trails on the surface,and a small number of feeding trails and Yand U-shaped burrows in the sediment,grazing trails on the surface and Y-shaped burrow produced by Philyra pisum de Haan in the mixed flat,and vertical feeding and dwelling burrows of Solen gouldi,grazing trails of Turritella bacillum Kiener,and grazing trail produced by Nassaurius festiva.(2) We reconstructed the burrows of Macrophthalmus japonicus,Perinereis aibuhitensis and Mactra veneriformis Reeve to obtain three-dimensional images,providing an image basis for reconstructing the nature of burrows.