TIERING OF TRACE FOSSIL ASSEMBLAGES IN PLIOPLEISTOCENE BATHYAL DEPOSITS OF BOSO PENINSULA, JAPAN
TIERING OF TRACE FOSSIL ASSEMBLAGES IN PLIOPLEISTOCENE BATHYAL DEPOSITS OF BOSO PENINSULA, JAPAN
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DOI：
10.2307/3515031
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发表时间：
1993-12-01
期刊：
影响因子：
1.6
通讯作者：
KOTAKE, N
中科院分区：
文献类型：
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作者：
KOTAKE, N
根据日本中部博索半岛上新世-更新世深海泥岩火山灰层下的例子，重建了由地表沉积物供给体反向输送活动产生的微量化石组合的层序。这些痕迹化石包括球粒陨石（分为五种形态）、植藻化石和辐射隧道结构，这里将其命名为“星形洞穴”。“所有这些结构都代表了追踪器粪便材料的储存箱。发现上新世层序为6层，更新世层序为4层。洞穴的穿透深度与洞穴大小（总体和隧道直径）之间没有明确的关系。此外，相关的软体动物化石和岩性特征表明了这些沉积盆地的含氧底水条件。因此，分层可能与沉积物中溶解氧、孔隙水、食物来源的划分等环境因素没有密切关系，但它代表了沉积物中排泄空间的空间分离。沉积物中排泄空间的分层可能表明了同时居住在基质上并利用同一海底作为觅食地的穴居生物避免排泄和生存空间的种间竞争的策略。
Tiering of assemblages of trace fossils produced by the inverted conveyor activity of surface deposit-feeders was reconstructed on the basis of the examples occurring just below volcanic ash layers in the Plio-Pleistocene deep-sea mudstone of Boso Peninsula, central Japan. The trace fossils include Chondrites (subdivided into five morphotypes), Zoophycos, and radiating tunnel structures named herein ''star-shaped burrows. '' All of these structures represent storage bins for fecal material of the tracemakers.Six tiers for the Pliocene sequence and four tiers for the Pleistocene sequence were recognized. No clear-cut relationship between penetration depth of burrows and burrow size (overall and tunnel diameter) was evident. In addition, associated molluscan fossils and lithologic features are indicative of oxygenated bottom water conditions for these sedimentary basins. Consequently, tiering may not be closely related to such environmental factors as dissolved oxygen of the bottom and pore waters or partitioning of the food source in the sediments, but it represents the spatial segregation of the excretory space in the sediment. Stratification of excretory space in the sediment may indicate strategy to avoid interspecific competition of egestion and living space by the burrow-producers that inhabited the substrate simultaneously and utilized the same sea floor as their feeding place.