山东青岛和日照滨岸潮间带现代生物遗迹组成与分布特征*

在山东青岛和日照滨岸潮间带可见到现代生物营造的各种遗迹。通过分析这些生物遗迹与其沉积背景的关系,取得以下成果: (1)研究区生物遗迹中,层面遗迹以腹足类动物的拖迹为主,层内遗迹以居住迹丰度最高,且类型多样。(2)建立了2个生物遗迹组合: 一是高潮区组合,主要遗迹类型包括珠带拟蟹守螺拖迹、沙蚕的拖迹、摄食迹和居住迹、四角蛤的居住迹、弹涂鱼的爬行迹和居住迹、鸭嘴海豆芽的居住迹以及螃蟹的居住迹和摄食迹;该组合产生的沉积物底层具有含泥量较高,水、氧、有机质含量均较丰富及基底较稳固等特点。二是中低潮区组合,主要由斑玉螺的拖迹和停息迹、扁玉螺的爬行迹和停息迹、寄居蟹的爬行迹、长竹蛏的居住迹、虾蛄的爬行迹和居住迹、鸭嘴海豆芽的居住迹以及螃蟹的居住迹和摄食迹组成;该组合产生的沉积物底层具有含泥量较低、粒度较粗、间隙水不易保存、有机质含量低等特点;研究区潮间带为急剧多变的海洋环境,该遗迹组合可指示温带季风气候条件下的海洋潮间带沉积环境。(3)通过分析各种造迹生物及其遗迹的组成和空间分布特征以及其与底层沉积物和沉积环境的关系,建立了研究区潮间带沉积中的生物遗迹组合及其沉积环境分布模式。

Composition and distribution characteristics of modern biogenic traces in intertidal flat in Qingdao and Rizhao area,Shandong Province

Many traces of modern animals are found in the intertidal flat in Qingdao and Rizhao area,Shandong Province. By analyzing the relationship between the traces and the sedimentary environment,the results indicate that: (1)The major surface traces observed in the study area are the repichnia of gastropods,and the major interior traces are the domichnia. The type of the traces is multitudinous. (2)Two biogenic traces assembles are established. One is the biogenic traces assemble in the upper intertidal flat,which are mainly repichnia made by Cerithidea cingulata,repichnia,fodinichnia and domichnia made by Nereis succinea, domichnia made by Mactra veneriformis Reeve,repichnia and domichnia made by Periophthalmua cantonensis,domichnia made by Lingula anatina, domichnia and fodinichnia made by Brachyura. The characteristics of the sediment where this traces assembles produced include the high clay content,the abundance of water,oxygen and organic matter,the stable sediment. The other is the biogenic traces assemble produced in the middle and lower intertidal flat,which are mainly repichnia and cubichnia made by Natica maculosa,repichnia and cubichnia made by Glossaulax didyma,repichnia made by Solen gouldi,repichnia and domichnia made by Oratosquilla oratoria,domichnia made by Lingula anatina,domichnia and fodinichnia made by Brachyura. The characteristics of the sediment where this traces assembles produced include the lower clay content,the rough granularity,the interstitial water hold hard,the lower content of the organic matter,etc. For the intertidal flat of the study area belongs to changeable marine environment,this biogenic traces assembles can indicate the marine intertidal flat sediment environment of monsoon climate of medium latitudes. (3)By analyzing the modern animals and the traces' distribution characteristics,the relationship between the traces and the substrate,and summarizing the relationship of the traces' distribution characteristics and the sedimentary environment,the biogenic traces assemble and the distribution model of ichnoassemblages in the study area was established.