DOI: 10.1016/j.palaeo.2013.04.005
论文题名: Population dynamics and taphonomy of the late triassic (Carnian) freshwater bivalves from krasiejów (Poland)
作者: Skawina A.
刊名: Palaeogeography, Palaeoclimatology, Palaeoecology
ISSN: 0031-0182
出版年: 2013
卷: 379-380 起始页码: 68
结束页码: 80
语种: 英语
英文关键词: Non-marine bivalves
; Palaeoecology
; Population
; Taphonomy
; Triassic
; Unionida
英文摘要: The Krasiejów clay pit (SW Poland) has so far been known for yielding mass accumulations of Late Triassic (Carnian) vertebrate fossils. However, unionoid bivalves occur abundantly within the 1 metre-thick shell-rich lacustrine interval at Krasiejów. They are most commonly preserved as shell imprints in the claystone or mudstone. A layer-by-layer quantitative sampling for shell external moulds was conducted directly in the bedding planes at two sites. The most numerous findings come from red and variegated layers in the upper part of this interval, which correspond to a well-aerated sediment. Single valves dominate at both sites and in all layers; valves in butterfly position are rare. The abundance of single valves throughout the sedimentation of the whole interval, both juveniles and adults, indicates that this interval represents the graveyard of a stable, reproducing population. The only exception is a bedding plane in the upper part of the lacustrine interval with numerous concretionary infills of closed valve interiors. They were presumably killed by a sudden load of sediment and, after the early diagenetic cementation was completed, they were winnowed from the mud. The mortality pattern is characterised by a high juvenile mortality (peak at about 13 mm), and a slight increase in subadult mortality (peak at about 30 mm; adult specimens reach 55 mm). Complete lack of early juvenile shells representing the stage with prominent ornamentation may have resulted from predation rather than from size-selective post-mortem preservation. The course of ontogeny shows virtually isometric growth. The range of variability of shell proportions within and between layers suggests the succession of monospecific populations. The Krasiejów lacustrine interval represents the oldest insight into the dynamics and taphonomy of unionoid palaeocommunity. © 2013 Elsevier B.V. All rights reserved. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/69735
Appears in Collections: 过去全球变化的重建
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作者单位: Department of Palaeobiology and Evolution, University of Warsaw, Banacha 2, 02-089 Warszawa, Poland
Recommended Citation:
Skawina A.. Population dynamics and taphonomy of the late triassic (Carnian) freshwater bivalves from krasiejów (Poland)[J]. Palaeogeography, Palaeoclimatology, Palaeoecology,2013-01-01,379-380